Patent Publication Number: US-10774667-B2

Title: Steam turbine and methods of assembling the same

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional application and claims priority to U.S. patent application Ser. No. 14/098,997, filed Dec. 6, 2013, for “STEAM TURBINE AND METHODS OF ASSEMBLING THE SAME,” now issued as U.S. Pat. No. 9,702,261, which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     The embodiments described herein relate generally to steam turbines, and more particularly, to methods and systems for cooling turbine components of the steam turbine. 
     As steam turbines rely on higher steam temperatures to increase efficiency, steam turbines should be able to withstand the higher steam temperatures so as not to compromise the useful life of the turbine. During a typical turbine operation, steam flows from a steam source through an inlet in a housing to flow parallel to an axis of rotation along an annular hot steam path. Typically, turbine stages are disposed along the steam path such that the steam flows through vanes and blades of subsequent turbine stages. The turbine blades may be secured to a plurality of turbine wheels, with each turbine wheel being mounted to or integral to the rotor shaft for rotation therewith. Alternatively, the turbine blades may be secured into a drum type turbine rotor rather than individual wheels, with the drum integral with the shaft. 
     Conventionally, turbine blades may include an airfoil extending radially outwardly from a substantially planar platform and a root portion extending radially inwardly from the platform. The root portion may include a dovetail or other means to secure the blade to the turbine wheel of the turbine rotor. In general, during operation of the steam turbine, steam flows over and around the airfoil of the turbine blade, which is subject to high thermal stresses. These high thermal stresses may limit the service life of the turbine blades. Moreover, the blade root and adjacent rotor may experience high thermal temperatures and stresses from the steam flow. Conventional steam turbines may use blade and rotor body materials that are more temperature resistant. These temperature resistant materials, however, may increase the cost of the turbine blades. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In one aspect, a steam turbine is provided. The steam turbine includes a housing and a first steam inlet coupled in flow communication to the housing which is configured to discharge a first steam flow within the housing. A second steam inlet is configured to provide a second steam flow. A stator is coupled to the housing and includes plurality of vanes. A rotor is coupled to the housing and located within the stator, wherein the rotor and the stator are configured to form a first flow path there between and in flow communication with the first steam flow. The rotor includes a plurality of blades coupled to the rotor, wherein at least one root of the plurality of blades has a first side, a second side and a passageway coupled in flow communication to the first side and the second side. The passageway is configured to receive the second steam flow within the at least one root. The at least one root of the plurality of blades includes an angel wing configured to seal the second steam flow from the first flow path. 
     In another aspect, a rotor assembly is provided. The rotor assembly is coupled to a housing and located within a stator of a steam turbine. The rotor assembly includes a rotor coupled to the housing and has a first flow path configured to receive a first steam flow. A plurality of blades is coupled to the rotor, wherein at least one root of the plurality of blades has a first side, a second side and a passageway coupled in flow communication to the first side and the second side. The passageway is configured to receive a second steam flow. The at least one root of the plurality of blades includes an angel wing configured to seal the second steam flow from the first flow path. 
     In yet another aspect, a method of assembling a steam turbine is provided. The method includes coupling a stator to a housing and coupling a first steam inlet in flow communication to the housing. The method further includes forming a first flow path within the housing and in flow communication with the first steam inlet, and configuring a second steam inlet to provide a second steam flow. A rotor is coupled to the housing and within the stator. The rotor includes a plurality of blades coupled to the rotor. At least one root of the plurality of blades has a first side, a second side and a passageway coupled in flow communication to the first side and the second side. The passageway is configured to receive the second steam flow within the at least one root. The at least one root of the plurality of blades includes an angel wing configured to seal the second steam flow from the first flow path. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side elevational view of an exemplary steam turbine and an exemplary flow assembly coupled to the steam turbine. 
         FIG. 2  is a partial view of the flow assembly shown in  FIG. 1 . 
         FIG. 3  is a side elevational view of another exemplary steam turbine and another exemplary flow assembly coupled to the steam turbine. 
         FIG. 4  is a side elevational view of another exemplary steam turbine and another exemplary flow assembly coupled to the steam turbine. 
         FIG. 5  is a side elevational view of another exemplary steam turbine and another exemplary flow assembly coupled to the steam turbine. 
         FIG. 6  is a side elevational view of another exemplary steam turbine and another exemplary flow assembly coupled to the steam turbine. 
         FIG. 7  is a side elevational view of another exemplary steam turbine and another exemplary flow assembly coupled to the steam turbine. 
         FIG. 8  is a side elevational view of another exemplary steam turbine and another exemplary flow assembly coupled to the steam turbine. 
         FIG. 9  is a side elevational view of another exemplary steam turbine and another exemplary flow assembly coupled to the steam turbine. 
         FIG. 10  is a side elevational view of another exemplary steam turbine and another exemplary flow assembly coupled to the steam turbine. 
         FIG. 11  is an exemplary flowchart illustrating a method of manufacturing a steam turbine. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The embodiments described herein relate generally to steam turbines. More particularly, the embodiments relate to methods and systems for facilitating fluid flow within turbine components of the steam turbine. It should be understood that the embodiments described herein for component cooling are not limited to turbine blades, and further understood that the description and figures that utilize a steam turbine and blades are exemplary only. Moreover, while the embodiments illustrate the steam turbine and blades, the embodiments described herein may be included in other suitable turbine components. Additionally, it should be understood that the embodiments described herein relating to flow paths need not be limited to turbine components. Specifically, the embodiments may generally be used in any suitable article through which a medium (e.g., water, steam, air, fuel and/or any other suitable fluid) is directed for cooling a surface of the article and/or for maintaining the temperature of the article. 
       FIG. 1  illustrates a side elevational view of a steam turbine  100  and a flow assembly  102  coupled to steam turbine  100 .  FIG. 2  is a partial view of flow assembly  102  shown in  FIG. 1 . In the exemplary embodiment, steam turbine  100  includes a high pressure, single flow turbine with a negative root reaction cooling configuration  104 . Alternatively, steam turbine  100  may include any pressure and flow configuration to enable steam turbine  100  to function as described herein. Steam turbine  100  includes a plurality of pressurized sections  106 . More particularly, steam turbine  100  includes a high pressure section  108  and an intermediate pressure section  110 . High pressure section  108  includes a plurality of stages  112  in a facing and spaced relationship with respect to each other. Each stage  12  includes a rotating assembly  114  and a stationary assembly  116 . In each stage  112 , rotating assembly  114  includes a rotor  118  disposed axially about an axis of rotation  120  of steam turbine  100 . 
     A plurality of blades  122  is coupled to rotating assembly  114  at platforms, wherein blades  122  extend radially outward from platforms  123  and toward stationary assembly  116 . Blades  122  include a pair of opposing angel wings  196  radially extending from opposing blade sides. Angel wings  196  include seals  121  such as, but not limited to brush seals, which extend toward stationary assembly  116 . Moreover, adjacent angel wings  196 , such as but not limited to, angel wing  193  and angel wing  195 , are configured in a sealable configuration to facilitate providing a seal between angel wing  193  and angel wing  195  while providing rotational movement of angel wing  193  and angel wing  195  with respective blade roots  125 . More particularly, angel wing  193  includes a first overlapping portion  197  and angel wing  195  includes a second overlapping portion  199  which is removably coupled to first overlapping portion  197 . Portions  197  and  199  are configured to reduce and/or eliminate flow communication of first flow path  130  with blade roots  125 . A plurality of blade roots  125  is coupled to rotor  118 . Blade roots  125  include a dovetail configuration such as, but not limited to, a tangential dovetail and/or an axial dovetail configuration. Blade root  125  can include any dovetail configuration to enable steam turbine  100  to function as described herein. Roots  125  are configured to couple blades  122  to a turbine wheel or a rotor body  127  of rotor  118 . Angel wings  196 , blade roots  125 , and rotor body  127  are configured to define a cooling passage  134  between blade roots  125 . 
     Stationary assembly  116  includes a housing  124 , a stator  126  and a plurality of stationary vanes  128 . Stationary vanes  128  include an end cover  180  facing rotor body  127 . Housing  124  is configured to enclose at least one of rotor  118 , blades  122 , stator  126  and vanes  128 . In the exemplary embodiment, rotor  118  and stator  126  are configured in a spaced relationship to define a first flow path  130  there between and within housing  124 . Vanes  128  are coupled in a plurality of slots  132  of stator  126  and arranged in circumferential stages that are located between stages of blades  122 . 
     Stationary assembly  116  further includes a steam inlet  136  coupled in flow communication to first flow path  130 . Steam inlet  136  is configured to channel or route a first steam flow  138  at high pressures and high temperatures toward first flow path  130  and in flow communication with the plurality of blades  122 . In the exemplary embodiment, steam inlet  136  is located within housing  124  and is in flow communication with a steam source  140  such as, for example, a boiler or heat recovery steam generator. Steam inlet  136  further includes a bowl area  142  having a bowl insert  144  and a leakage flow path  146 . Bowl insert  144  is coupled in flow communication to first flow path  130  and rotor  118 . 
     In the exemplary embodiment, at least one root  125  of the plurality of roots  125  includes a first side  152 , a second side  154  and a body  156  located there between. First side  152  is located upstream from second side  154  with respect to first steam flow  138 . Moreover, first side  152  and second side  154  are configured in flow communication to respective cooling passages  134 . Root  125  further includes a passageway  158  defined within body  156  and coupled in flow communication to first side  152  and second side  154 . Moreover, passageway  158  is configured in flow communication to cooling passages  134 . In the exemplary embodiment, passageway  158  defines a second flow path  160  within root  125  and in flow communication to cooling passages  134 . Cooling passage  134  and second flow path  160  define a cooling circuit of rotor  118 . Second flow path  160  is configured to facilitate discharging a second steam flow  162  within root  125  and into cooling passages. Angel wings  196  and/or end cover  180  are configured to facilitate minimizing and/or eliminating flow communication between cooling passages  134  and first flow path  138 . More particularly, adjacent angel wings  196  are configured to facilitate directing second steam flow  162  from root  125 , through cooling passage  134 , and into adjacent blade roots  125  to facilitate enhancing cooling of blade roots  125  and/or rotor body  127 . In the exemplary embodiment, first flow path  130  and second flow path  160  are configured in negative root reaction configuration  104  as described herein. 
     Rotating assembly  114  further includes a seal assembly  164  coupled to rotor  118 . Seal assembly  164  includes a first seal member  166  and a second seal member  168 . In the exemplary embodiment, first seal member  166  includes a packing head  170 , which is coupled to rotor  118  at an upstream position from steam inlet  136 . Moreover, packing head  170  includes a third flow path  172  having a first end  174  coupled in flow communication to second flow path  160  and a second end  176  coupled in flow communication to intermediate pressure section  110 . A plurality of packing rings  178  is located within third flow path  172 . Second seal member  168  includes cover  180  coupled to at least one vane  128  and located between vane  128  and rotor  118 . Cover  180  includes a first end  182  extending into cooling passage  134  and a second end  184  extending into bowl area  142 . More particularly, second end  184  is coupled and arranged in flow communication to bowl insert  144 . In the exemplary embodiment, a seal  186  is coupled to cover  180  and extends toward angel wings  196  and located between second flow path  160  and third flow path  172 . 
     Steam flow that does not perform work by flowing through the plurality of blades  122  and rotating rotor  118  is considered leakage fluid. Leakage fluid that does not perform work in a steam turbine  100  results in a loss output. First seal member  166  and second seal member  168  are configured to reduce steam flow between rotor  118  and packing head  170  to facilitate reducing output loss. More particularly, first seal member  166  and second seal member  168  are configured to reduce the volume of leakage fluids, so more fluid performs work by rotating rotor  118  in steam turbine  100 . 
     During an exemplary operation, first steam flow  138 , at high pressures and high temperatures, is directed from steam source  140 , through steam inlet  136  and toward first flow path  130 . More particularly, first steam flow  138  is directed toward the plurality of blades  122  and the plurality of vanes  128 . As first steam flow  138  contacts the plurality of blades  122 , first steam flow  138  rotates the plurality of blades  122  and rotor  118 . First steam flow  138  passes through stages  112  in a downstream direction and continues through successive plurality of stages (not shown) in a similar manner. 
     As first steam flow  138  flows from steam inlet  136  and through first flow path  130 , first steam flow  138  is configured to flow past the plurality of blades  122  and the plurality of vanes  128 . Due to a negative root reaction, a temperature of first steam flow  138  at second side  154  of root  125  is different than a temperature of first steam flow  138  at first side  152 . In the exemplary embodiment, the temperature at second side  154  is cooler than first side  152  of root  125  but a pressure of first steam flow  138  at second side  154  of root  125  is higher than a pressure of first steam flow  138  at first side  152  of root  125 . First steam flow  138  at second side  154  of root  125  at a higher pressure than first side  152  of root  125  is used to force cooler steam as second steam flow  162  into second flow path  160 . More particularly, first steam flow  138 , based at least on pressure and temperature differentials on upstream and downstream sides of blades  122 , is configured to back feed second steam flow  162  through second flow path  160 . Second flow path  160  is configured to receive second steam flow  162  and direct second steam flow  162  within root  125  and out of first side  152 . As cooler steam of second steam flow  162  moves through second flow path  160 , heat of root  125  and/or rotor body  127  is transferred to second steam flow  162  to facilitate cooling root  125  and/or rotor body  127 . 
     Angel wings  196  and seal  186  of cover  180  are configured to reduce and/or eliminate leakage of a first portion  188  of second steam flow  162  that exits second side  154 , flows into cooling passage  134  and to reduce and/or eliminate mixing with first steam flow  138  in first flow path  130 . A second portion  190  of second steam flow  162  moves between cover  180  and rotor  118  and either through packing rings  186  or to flow and mix with bowl insert steam flow  187 . Second portion  190  is configured to flow through third flow path  172  and within packing head  170  for further use by at least one of reheat section (not shown) and/or low pressure section (not shown). In the exemplary embodiment, second portion  190  moves within intermediate pressure section  110  to facilitate controlling the pressure of steam flow across sealing members  178  to control the amount of steam leakage flowing through packing head  170 . 
       FIG. 3  is a cross sectional view of another flow assembly  192  coupled to steam turbine  100 . In  FIG. 3 , similar components include similar element numbers as shown in  FIGS. 1-2 . Steam turbine  100  includes a high pressure, single flow turbine having an external cooling configuration  194 . Alternatively, steam turbine  100  may include any pressure and flow configuration to enable steam turbine  100  to function as described herein. Steam turbine  100  includes high pressure section  108  and section  110 . Moreover, angel wings  196  extend into opposing cooling passages  134 . 
     In the exemplary embodiment, steam inlet  136  is coupled in flow communication to first flow path  130 . Moreover, another steam inlet  198  is coupled to housing  124  and located external to housing  124 . More particularly, steam inlet  198  is coupled to an external steam source  200  such as, for example, a boiler or a heat recovery steam generator, typically with steam temperatures below that of first steam flow  138 . Steam inlet  198  is coupled in flow communication to at least one vane  128 . In the exemplary embodiment, vane  128  includes a radial flow path  202  having a first end  204 , a second end  206  and a passageway  208  coupled to and extending there between. First end  204  is coupled in flow communication to steam inlet  198  and second end  206  is coupled in flow communication to cooling passages  134 . Steam inlet  198  is configured to direct second steam flow  162  from external steam source  200  and into housing  124 . More particularly, first end  204  is configured to receive second steam flow  162  from steam inlet  198  and direct second steam flow  162  through radial flow path  202 . Second end  206  is configured to direct second steam flow  162  into cooling passages  134 . 
     During an exemplary operation, first steam flow  138 , at high pressures and high temperatures, is directed from steam source  140 , through steam inlet  136  and toward first flow path  130 . More particularly, first steam flow  138  is directed toward the plurality of blades  122  and the plurality of vanes  128 . As first steam flow  138  contacts the plurality of blades  122 , first steam flow  138  rotates the plurality of blades  122  and rotor  118 . First steam flow  138  passes through stages  112  in a downstream direction and continues through successive plurality of stages (not shown) in a similar manner. 
     Moreover, second steam flow  162 , at lower temperatures and pressures than first steam flow  138 , moves from first end  204 , through radial flow path  202  and out of second end  206 . As second steam flow  162  moves through passageway  208 , heat of vanes  128  is transferred to second steam flow  162  to facilitate cooling vanes  128 . Second steam flow  162  exits second end  206  and flows into cooling passage  134  at a temperature that is less than first steam flow  138 . More particularly, a first portion  210  of second steam flow  162  moves between angel wings  196  and vanes  128  to facilitate cooling roots  125  and rotor body  127 . Angel wings  196  and/or seal  186  of cover  180  are configured to reduce and/or eliminate leakage of first portion  210  of second steam flow  162  that exits second end  206 , flows into cooling passage  134  and mixes with first steam flow  138  in first flow path  130 . Alternatively, angel wings  196  and/or seal  186  can be configured to facilitate second steam flow  162  within cooling passage  134  mixing with first steam flow  138  in first flow path  130 . A second portion  212  of second steam flow  162  is configured to flow into second flow path  160 . As the cooler steam of second steam flow  162  moves through second flow path  160 , heat is transferred from root  125  and/or root body  127  to second steam flow  162  to facilitate cooling root  125  and/or rotor body  127 . 
     Second portion  212  of second steam flow  162  moves between cover  180  and rotor  118  and either through seal  186  or to flow and mix with bowl insert steam flow  187  depending on cooling intent. Second portion  212  is configured to flow through third flow path  172  and within packing head  170  for further use by at least one of reheat section (not shown) and/or low pressure section (not shown). In the exemplary embodiment, second portion  212  moves within intermediate pressure section  110  to facilitate controlling the pressure of steam flow across sealing members  178  to control the amount of steam leakage flowing through packing head  170 . 
       FIG. 4  is a cross sectional view another flow assembly  214  coupled to steam turbine  100 . In  FIG. 4 , similar components include the same element numbers as  FIGS. 1-3 . Steam turbine  100  includes a high pressure, single flow turbine having an external cooling configuration  216 . Alternatively, steam turbine  100  may include any pressure and flow configuration to enable steam turbine  100  to function as described herein. In the exemplary embodiment, steam inlet  136  is coupled in flow communication to first flow path  130 . Moreover, another steam inlet  218  is coupled to packing head  170  and located external to housing  124 . More particularly, steam inlet  218  is coupled to an external steam source  220 . In the exemplary embodiment, steam inlet  218  is further coupled in flow communication to section  110 . More particularly, steam inlet  218  is coupled in flow communication to packing head  170 . Packing head  170  includes a packing flow path  222  coupled in flow communication to steam inlet  218  and third flow path  172 . 
     During an exemplary operation, first steam flow  138 , at high pressures and high temperatures, is directed through steam inlet  136  and toward first flow path  130 . More particularly, first steam flow  138  is directed toward the plurality of blades  122  and the plurality of vanes  128 . As first steam flow  138  contacts the plurality of blades  122 , first steam flow  138  rotates the plurality of blades  122  and rotor  118 . First steam flow  138  passes through stages  112  in a downstream direction and continues through successive plurality of stages (not shown) in a similar manner. 
     Moreover, second steam flow  162 , at lower temperatures and pressures than first steam flow  138 , moves from steam inlet  218  and into packing flow path  222 . Second steam flow  162  moves through packing flow path  222  and a first portion  224  of second steam flow  162  moves into third flow path  172  and through packing rings  178  that are located within third flow path  172 . First portion  224  moves through packing head  170  for further use by at least one reheat section (not shown) and/or a low pressure section (not shown). First portion  224  moves within intermediate pressure section  110  to facilitate controlling the pressure of steam flow across sealing members  178  to control the amount of steam leakage flowing through packing head  170 . 
     A second portion  226  of second steam flow  162  moves through third flow path  172  and toward rotor  118 . Second portion  226  flows and mixes with bowl insert steam flow  187 . Second portion  226  flows between cover  180  and rotor  118  and through packing rings  186 . Second portion  226  exits packing rings  186  and flows into cooling passage  134  at a pressure that is less than first steam flow  138 . More particularly, second portion  226  flows between angel wings  196  and vanes  128 . Angel wings  196  and/or cover  180  are configured to reduce and/or eliminate leakage of second steam flow  162  that flows into cooling passage  134  and mixes with first steam flow  138  in first flow path  130 . Alternatively, angel wings  196  and/or cover  180  can be configured to facilitate second steam flow  162  within cooling passage  134  mixing with first steam flow  138  in first flow path  130 . Second portion  226  of second steam flow  162  is also configured to flow into second flow path  160 . As the cooler steam of second portion  226  moves through second flow path  160 , heat of root  125  and/or rotor body  127  is transferred to second portion  226  to facilitate cooling root  125  and/or rotor body  127 . 
       FIG. 5  is a cross sectional view another flow assembly  228  coupled to steam turbine  100 . In  FIG. 5 , similar components include the same element numbers as  FIGS. 1-4 . Steam turbine  100  includes a reheat, single flow turbine having a negative root reaction configuration  230 . Alternatively, steam turbine  100  may include any heat, pressure and flow configuration to enable steam turbine  100  to function as described herein. In the exemplary embodiment, steam turbine  100  includes a reheat section  232 . 
     Stationary assembly  116  includes a steam inlet  234  coupled in flow communication to a first flow path  236 . Steam inlet  234  is configured to channel or route a first steam flow  238  at high pressures and high temperatures toward first flow path  236  and in flow communication with the plurality of blades  122 . In the exemplary embodiment, steam inlet  234  is located within housing  124  and is in flow communication with a steam source  239  such as, for example, a boiler or heat recovery steam generator. Steam inlet  234  further includes bowl area  142  having bowl insert  144  and leakage flow path  146 . 
     At least one root  125  of the plurality of roots  125  includes first side  152 , second side  154  and body  156  located there between. First side  152  is located upstream from second side  154  with respect to first steam flow  238 . First side  152  and second side  154  are configured in flow communication to respective cooling passages  134 . Root  125  further includes passageway  158  defined within body  156  and coupled in flow communication to first side  152  and second side  154 . Moreover, passageway  158  is configured in flow communication to cooling passages  134 . In the exemplary embodiment, passageway  158  defines a second flow path  240  within root  125 . Second flow path  240  is coupled to root  125  and cooling passages  134 . Moreover, second flow path  240  is configured to facilitate discharging a second steam flow  242  within root  125 , through cooling passages  134  and in flow communication with angel wings  196 . In the exemplary embodiment, first flow path  236  and second flow path  240  are configured in negative root reaction configuration  230 . 
     During an exemplary operation, first steam flow  238 , at high pressures and high temperatures, is directed from steam source  239 , through steam inlet  234  and toward first flow path  236 . More particularly, first steam flow  238  is directed toward the plurality of blades  122  and the plurality of vanes  128 . As first steam flow  238  contacts the plurality of blades  122 , first steam flow  238  rotates the plurality of blades  122  and rotor  118 . First steam flow  238  passes through stages  112  in a downstream direction and continues through successive plurality of stages (not shown) in a similar manner. 
     As first steam flow  238  flows from steam inlet  234  and through first flow path  236 , first steam flow  238  is configured to flow past the plurality of blades  122  and the plurality of vanes  128 . Due to a negative root reaction, a temperature of first steam flow  238  at second side  154  of root  125  is different than a temperature of first steam flow  238  at first side  152 . In the exemplary embodiment, the temperature at second side  154  is cooler than first side  152  of root  125  but a pressure of first steam flow  238  at second side  154  of root  125  is higher than a pressure of first steam flow  238  at first side  152  of root  125 . First steam flow  238  at second side  154  of root  125  at a higher pressure than first side  152  of root  125  is used to force cooler steam as second steam flow  242  into second flow path  240 . More particularly, first steam flow  238 , based at least on pressure and temperature differentials on upstream and downstream sides of blades  122 , is configured to back feed second steam flow  242  through second flow path  240 . Second flow path  240  is configured to receive second steam flow  242  and direct second steam flow  242  within root  125  and out of first side  152  of root  125 . As cooler steam of second steam flow  242  moves through second flow path  240 , heat of root  125  and/or rotor body  127  is transferred to second steam flow  242  to facilitate cooling root  125  and/or rotor body  127 . 
     A first portion  244  of second steam flow  242  exits first end  152 , flows into cooling passage  134  and flow communication with angel wings  196 . Angel wings  196  and/or cover  180  are configured to reduce and/or eliminate leakage of first portion  244  of second steam flow  242  that exits first end  152 , flows into cooling passage  134  and mixes with first steam flow  238  in first flow path  236 . Alternatively, angel wings  196  and/or cover  180  can be configured to facilitate second steam flow  242  within cooling passage  134  mixing with first steam flow  238  in first flow path  236 . A second portion  246  of second steam flow  242  is configured to flow and mix with bowl insert steam flow  187  and continues to flow into third flow path  172 . Second portion  246  is configured to flow through third flow path  172  and within packing head  170  for further use by a low pressure section (not shown). In the exemplary embodiment, second portion  246  moves within section  110  to facilitate controlling the pressure of steam flow across sealing members  178  to control the amount of steam leakage flowing through packing head  170 . 
       FIG. 6  is a cross sectional view another flow assembly  248  coupled to steam turbine  100 . In  FIG. 6 , similar components include the same element numbers as  FIGS. 1-5 . Steam turbine  100  includes a reheat, single flow turbine having a positive cooling configuration  250 . Alternatively, steam turbine  100  may include any heat, pressure and flow configuration to enable steam turbine  100  to function as described herein. 
     In the exemplary embodiment, steam inlet  234  is coupled in flow communication to first flow path  236 . Moreover, another steam inlet  252  is coupled to housing  124  and located external to housing  124 . Steam inlet  252  is coupled to another turbine component such as, for example, an external steam source  254 . In the exemplary embodiment, steam inlet  252  is further coupled in flow communication to intermediate pressure section  110 . More particularly, steam inlet  252  is coupled in flow communication to packing head  170 . Packing head  170  includes a packing flow path  256  coupled in flow communication to steam inlet  252  and third flow path  172 . Moreover, packing head  170  includes a packing bleed path  258  coupled in flow communication to third flow path  172 . 
     During an exemplary operation, first steam flow  238 , at high pressures and high temperatures, is directed from steam source, through steam inlet  234  and toward first flow path  236 . More particularly, first steam flow  238  is directed toward the plurality of blades  122  and the plurality of vanes  128 . As first steam flow  238  contacts the plurality of blades  122 , first steam flow  238  rotates the plurality of blades  122  and rotor  118 . First steam flow  238  passes through stages  112  in a downstream direction and continues through successive plurality of stages (not shown) in a similar manner. 
     Moreover, second steam flow  242 , at lower temperatures and pressures than first steam flow  238 , moves from steam inlet  252  and into packing flow path  256 . Second steam flow  242  moves through packing flow path  256  and a first portion  260  moves into third flow path  172  and through packing rings  178  that are located in third flow path  172 . First portion  260  moves toward intermediate pressure section  110  to facilitate controlling the pressure of steam flow across sealing members  178  to control the amount of steam leakage flowing through packing head  170 . First portion  260  continues to move from third flow path  172  and into packing bleed path  258  for further use by at least one of high pressure section (not shown) and low pressure section (not shown). 
     A second portion  262  of second steam flow  242  moves through third flow path  172  and toward rotor  118 . Second portion  262  continues to flow and mix with bowl insert steam flow  189 . Second portion  262  flows between cover  180  and rotor  118  and through packing rings  186 . Second steam flow  242  exits packing rings  186  and flows into cooling passage  134 . Second portion  262  flows into cooling passage  134  at a pressure that is less than first steam flow  238 . More particularly, second portion  262  flows between angel wings  196  and vanes  128 . Angel wings  196  and/or seal  186  of cover  180  are configured to reduce and/or eliminate leakage of second steam flow  242  that flows into cooling passage  134  and mixes with first steam flow  238  in first flow path  236 . Alternatively, angel wings  196  and/or seal  186  can be configured to facilitate second steam flow  242  within cooling passage  134  mixing with first steam flow  238  in first flow path  236 . Second portion  262  of second steam flow  242  is also configured to flow into second flow path  240 . As the cooler steam of second portion  262  moves through second flow path  240 , heat of root  125  and/or rotor body  127  is transferred to second portion  262  to facilitate cooling root  125  and/or rotor body  127 . 
       FIG. 7  is a cross sectional view another flow assembly  264  coupled to steam turbine  100 . In  FIG. 7 , similar components include the same element numbers as  FIGS. 1-6 . Steam turbine  100  includes a high pressure, reheat turbine with a negative root reaction configuration  266 . Alternatively, steam turbine  100  may include any heat, pressure and flow configuration to enable steam turbine  100  to function as described herein. In the exemplary embodiment, packing head  170  is coupled to high pressure section  108  and reheat section  232 . More particularly, third flow path  172  is coupled in flow communication to second flow path  160  of high pressure section  108  and second flow path  240  of reheat section  232 . 
     During an exemplary operation, first steam flow  138 , at high pressures and high temperatures, is directed from steam source  140 , through steam inlet  136  and toward first flow path  130 . More particularly, first steam flow  138  is directed toward the plurality of blades  122  and the plurality of vanes  128 . As first steam flow  138  contacts the plurality of blades  122 , first steam flow  138  rotates the plurality of blades  122  and rotor  118 . First steam flow  138  passes through stages  112  in a downstream direction and continues through successive plurality of stages (not shown) in a similar manner. 
     As first steam flow  138  flows from steam inlet  136  and through first flow path  130 , first steam flow  138  is configured to flow past the plurality of blades  122  and the plurality of vanes  128 . Due to a negative root reaction, a temperature of first steam flow  138  at second side  154  of root  125  is different than a temperature of first steam flow  138  at first side  152 . In the exemplary embodiment, the temperature of first steam flow  138  at second side  154  is cooler than first side  152  of root  125  but pressure of first steam flow  138  at second side  154  of root  125  is higher than pressure of first steam flow  138  at first side  152  of root  125 . First steam flow  138  at second side  154  of root  125  at a higher pressure than first side  152  of root  125  is used to force cooler steam as second steam flow  162  into second flow path  160 . More particularly, first steam flow  138 , based at least on pressure and temperature differentials on upstream and downstream sides of blades  122 , is configured to back feed second steam flow  162  through second flow path  160 . Second flow path  160  is configured to receive second steam flow  162  and direct second steam flow  162  within root  125 . As cooler steam of second steam flow  162  moves through second flow path  160 , heat of root  125  and/or rotor body  127  is transferred to second steam flow  162  to facilitate cooling root  125  and/or rotor body  127 . 
     A first portion  268  of second steam flow  162  exits first end  152 , flows into cooling passage  134 . Angel wings  196  and/or seal  186  of cover  180  are configured to reduce and/or eliminate leakage of first portion  268  of second steam flow  162  that exits first end  152 , flows into cooling passage  134  and mixes with first steam flow  138  in first flow path  130 . Alternatively, angel wings  196  and/or seal  186  can be configured to facilitate second steam flow  162  within cooling passage  134  mixing with first steam flow  138  in first flow path  130 . A second portion  270  of second steam flow  162  moves between cover  180  and rotor  118  and either through packing rings  186  or to flow and mix with bowl insert steam flow  187 . Second portion  270  is configured to flow through third flow path  172  and within packing head  170  for further use by reheat section  232 . In the exemplary embodiment, second portion  270  moves within intermediate pressure section  110  to facilitate controlling the pressure of steam flow across sealing members  178  to control the amount of steam leakage flowing through packing head  170 . 
     Second portion  270  continues to flow from packing head  170  and into reheat section  232 . More particularly, second portion  270  of second steam flow  162  moves through third flow path  172  and toward rotor  118 . Second portion  270  continues to flow and mix with bowl insert steam flow  189 . Second portion  270  flows between cover  180  and rotor  118  and through packing rings  186 . Second steam flow  162  exits packing rings  186  and flows into cooling passage  134 . Second portion  270  moves into cooling passage  134  at a pressure that is less than first steam flow  238 . More particularly, second portion  270  flows between angel wings  196  and vanes  128  and mixes with first steam flow  238 . Second portion  270  is also configured to flow into second flow path  240 . As the cooler steam of second portion  270  moves through second flow path  240 , heat of root  125  and/or rotor body  127  is transferred to second steam flow  162  to facilitate cooling root  125  and/or rotor body  127 . 
       FIG. 8  is a cross sectional view of another flow assembly  272  coupled to steam turbine  100 . In  FIG. 8 , similar components include similar element numbers as shown in  FIGS. 1-7 . Steam turbine  100  includes a high pressure, reheat turbine having an external cooling configuration  274 . Alternatively, steam turbine  100  may include any pressure, heat and flow configuration to enable steam turbine  100  to function as described herein. In the exemplary embodiment, packing head  170  is coupled to high pressure section  108  and reheat section  232 . More particularly, third flow path  172  is coupled in flow communication to second flow path  160  of high pressure section  108  and second flow path  240  of reheat section  232 . 
     Steam inlet  136  is coupled to housing  124  and located external to housing  124 . Moreover, steam inlet  136  is coupled to external steam source  140 . Steam inlet  136  is configured to direct steam flow  138  from external steam source  140  and into housing  124 . More particularly, steam inlet  136  is coupled in flow communication to at least one vane  128 . Another steam inlet  276  is coupled in flow communication to packing head  170 . In the exemplary embodiment, steam inlet  276  is further coupled to another turbine component (not shown), for example, a high pressure stage. Moreover, a bowl bleed path  278  is coupled in flow communication to third flow path  172 . 
     During an exemplary operation, first steam flow  138 , at high pressures and high temperatures, is directed from steam source  140 , through steam inlet  136  and toward first flow path  130 . More particularly, first steam flow  138  is directed toward the plurality of blades  122  and the plurality of vanes  128 . As first steam flow  138  contacts the plurality of blades  122 , first steam flow  138  rotates the plurality of blades  122  and rotor  118 . First steam flow  138  passes through stages  112  in a downstream direction and continues through successive plurality of stages (not shown) in a similar manner. 
     Moreover, second steam flow  162 , at lower temperatures and pressures than first steam flow  138 , moves through vane  128 . As second steam flow  162  moves through vane  128 , heat of vanes  128  is transferred to second steam flow  162  to facilitate cooling vanes  128 . Second steam flow  162  exits vane  128  and flows into cooling passage  134 . Second steam flow  162  moves into cooling passage  134  at a pressure that is less than first steam flow  138 . More particularly, a first portion  280  flows between angel wings  196  and vanes  128 . Angel wings  196  and/or cover  180  are configured to reduce and/or eliminate leakage of second steam flow  162  that flows into cooling passage  134  and mixes with first steam flow  138  in first flow path  130 . Alternatively, angel wings  196  and/or seal  186  can be configured to facilitate second steam flow  162  within cooling passage  134  mixing with first steam flow  138  in first flow path  130 . A second portion  282  of second steam flow  162  is configured to flow into second flow path  160 . As the cooler steam of second steam flow  162  moves through second flow path  160 , heat of root  125  and/or rotor body  127  is transferred to second steam flow  162  to facilitate cooling root  125  and/or rotor body  127 . 
     Second portion  282  of second steam flow  162  continues to move between cover  180  and rotor  118  and either through packing rings  186  or to flow and mix with bowl insert steam flow  187 . Second steam flow  162  path is configured to flow through third flow path  172  and within packing head  170  for further use by reheat section  232 . In the exemplary embodiment, second portion  282  moves to intermediate pressure section  110  to facilitate controlling the pressure of steam flow across sealing members  178  to control the amount of steam leakage flowing through packing head  170 . Bowl bleed path  278  is configured to direct second portion  282  of second steam flow  162  from third flow path  172  to bowl (not shown) for bleeding steam from packing head  170 . 
     Second portion  282  continues to flow from packing head  170  and into reheat section  232 . Second portion  282  of second steam flow  162  moves through third flow path  172  and toward rotor  118 . Second portion  282  continues to flow and mix with bowl insert steam flow  189 . Second portion  282  flows between cover  180  and rotor  118  and through packing rings  186 . Second steam flow  162  exits packing rings  186  and flows into cooling passage  134 . Second steam flow  162  moves into cooling passage  134  at a pressure that is less than first steam flow  138 . More particularly, second portion  282  flows between angel wings  196  and vanes  128 . Angel wings  196  and/or cover  180  are configured to reduce and/or eliminate leakage of second portion  282  of second steam flow  162  that flows into cooling passage  134  and mixes with first steam flow  238  in reheat section  232 . Alternatively, angel wings  196  and/or seal  186  can be configured to facilitate second portion  282  within cooling passage  134  mixing with first steam flow  238  in reheat section  232 . Second portion  282  of second steam flow  162  is also configured to flow into second flow path  240 . As the cooler steam of second portion  282  moves through second flow path  240 , heat of root  125  and/or rotor body  127  is transferred to second steam flow  162  to facilitate cooling root  125  and/or rotor body  127 . Steam inlet  276  is configured to inject cooler steam flow  284  into second portion  282  to facilitate decreasing the temperature of second steam flow  162  within reheat section  232 . 
       FIG. 9  illustrates a side elevational view of a steam turbine  100  and a flow assembly  286  coupled to steam turbine  100 . In  FIG. 9 , similar components include similar element numbers as shown in  FIGS. 1-8 . In the exemplary embodiment, steam turbine  100  includes a high pressure, reheat turbine having a negative root reaction cooling configuration  288 . Alternatively, steam turbine  100  may include any pressure and flow configuration to enable steam turbine  100  to function as described herein. In the exemplary embodiment, packing head  170  is coupled to high pressure section  108  and reheat section  232 . More particularly, third flow path  172  is coupled in flow communication to second flow path  160  of high pressure section  108  and second flow path  240  of reheat section  232 . 
     In the exemplary embodiment, steam inlet  136  is coupled in flow communication to first flow path  130 . Another steam inlet  290  is coupled in flow communication to packing head  170 . In the exemplary embodiment, steam inlet  290  is further coupled to another turbine component (not shown), for example, a high pressure stage. Moreover, bowl bleed path  278  is coupled in flow communication to third flow path  172 . 
     During an exemplary operation, first steam flow  138 , at high pressures and high temperatures, is directed from steam source  140 , through steam inlet  136  and toward first flow path  130 . More particularly, first steam flow  138  is directed toward the plurality of blades  122  and the plurality of vanes  128 . As first steam flow  138  contacts the plurality of blades  122 , first steam flow  138  rotates the plurality of blades  122  and rotor  118 . First steam flow  138  passes through stages  112  in a downstream direction and continues through successive plurality of stages (not shown) in a similar manner. 
     As first steam flow  138  flows from steam inlet  136  and through first flow path  130 , first steam flow  138  is configured to flow past the plurality of blades  122  and the plurality of vanes  128 . Due to a negative root reaction, first steam flow  138 , based at least on pressure and temperature differentials on upstream and downstream sides of blades  122 , is configured to back feed second steam flow  162  through second flow path  160 . Second flow path  160  is configured to receive second steam flow  162  and direct second steam flow  162  within root  125  and out of first side  152  of root  125 . As cooler steam of second steam flow  162  moves through second flow path  160 , heat of root  125  and/or rotor body  127  is transferred to second steam flow  162  to facilitate cooling root  125  and/or rotor body  127 . 
     A first portion  292  of second steam flow  162  exits first end  152 , flows into cooling passage  134 . Angel wings  196  and/or seal  186  of cover  180  are configured to reduce and/or eliminate leakage of a first portion  292  of second steam flow  162  that exits first end  152 , flows into cooling passage  134  and mixes with first steam flow  138  in first flow path  130 . Alternatively, angel wings  196  and/or seal  186  can be configured to facilitate first portion  292  mixing with first steam flow  138  in first flow path  130 . A second portion  294  of second steam flow  162  moves between cover  180  and rotor  118  and either through packing rings  186  or to flow and mix with bowl insert steam flow  187 . Second portion  294  is configured to flow through third flow path  172  and within packing head  170  for further use by reheat section  232 . In the exemplary embodiment, second portion  294  moves to intermediate pressure section  110  to facilitate controlling the pressure of steam flow across sealing members  178  to control the amount of steam leakage flowing through packing head  170 . Bowl bleed path  278  is configured to direct second portion  294  from third flow path  172  to bowl (not shown) for bleeding steam from packing head  170 . 
     Second portion  294  continues to flow from packing head  170  and into reheat section  232 . Second portion  294  of second steam flow  162  moves through third flow path  172  and toward rotor  118 . Second portion  294  continues to flow and mix with bowl insert steam flow  189 . Second portion  294  flows between cover  180  and rotor  118  and through packing rings  186 . Second portion  294  exits packing rings  186  and flows into cooling passage  134 . Second portion  294  moves into cooling passage  134  at a pressure that is less than first steam flow  238 . More particularly, second portion  294  flows between angel wings  196  and vanes  128 . Angel wings  196  and/or cover  180  are configured to reduce and/or eliminate leakage of a second portion  294  of second steam flow  162  that flows into cooling passage  134  and mixes with first steam flow  238  in reheat section  232 . Alternatively, angel wings  196  and/or cover  180  can be configured to facilitate second steam flow  162  within cooling passage  134  mixing with reheat section  232 . Still further, second portion  294  of second steam flow  162  is configured to flow into second flow path  240 . As the cooler steam of second portion  294  moves through second flow path  240 , heat of root  125  and/or rotor body  127  is transferred to second portion  294  to facilitate cooling root  125  and/or rotor body  127 . Steam inlet  290  is configured to inject cooler steam  284  into second portion  294  of second steam flow  162  to facilitate decreasing the temperature of second portion  294  within reheat section  232 . 
       FIG. 10  illustrates a side elevational view of a steam turbine  100  and a flow assembly  296  coupled to steam turbine  100 . In  FIG. 10 , similar components include similar element numbers as shown in  FIGS. 1-9 . In the exemplary embodiment, steam turbine  100  includes a high pressure, reheat turbine with an external cooling configuration  298 . Alternatively, steam turbine  100  may include any pressure and flow configuration to enable steam turbine  100  to function as described herein. In the exemplary embodiment, packing head  170  is coupled to high pressure section  108  and reheat section  232 . More particularly, third flow path  172  is coupled in flow communication to second flow path  160  of high pressure section  108  and second flow path  240  of reheat section  232 . 
     In the exemplary embodiment, steam inlet  136  is coupled in flow communication to first flow path  130 . Moreover, another steam inlet  299  is coupled to housing  124  and located external to housing  124 . More particularly, steam inlet  299  is coupled to external steam source  140  and coupled in flow communication to intermediate pressure section  110 . In the exemplary embodiment, steam inlet  299  is further coupled in flow communication to packing head  170 . 
     During an exemplary operation, first steam flow  138 , at high pressures and high temperatures, is directed from steam source  140 , through steam inlet  136  and toward first flow path  130 . More particularly, first steam flow  138  is directed toward the plurality of blades  122  and the plurality of vanes  128 . As first steam flow  138  contacts the plurality of blades  122 , first steam flow  138  rotates the plurality of blades  122  and rotor  118 . First steam flow  138  passes through stages  112  in a downstream direction and continues through successive plurality of stages (not shown) in a similar manner. 
     Moreover, second steam flow  162 , at lower temperatures and pressures than first steam flow  138 , moves from steam inlet  299  and into third flow path  172 . Second steam flow  162  moves through third flow path  172  and a first portion  300  moves into third flow path  172  and through packing rings  178  that are located in third flow path  172 . First portion  300  continues to flow into high pressure section  108 . A second portion  302  moves toward intermediate pressure section  110  to facilitate controlling the pressure of steam flow across sealing members  178  to control the amount of steam leakage flowing through packing head  170 . 
     Second portion  302  continues to flow from packing head  170  and into reheat section  232 . Second portion  302  of second steam flow  162  moves through third flow path  172  and toward rotor  118 . Second portion  302  continues to flow and mix with bowl insert steam flow  189 . Second portion  302  flows between cover  180  and rotor  118  and through packing rings  186 . Second portion  302  exits packing rings  186  and flows into cooling passage  134 . Second portion  302  moves into cooling passage  134  at a pressure that is less than first steam flow  238 . More particularly, second portion  302  flows between angel wings  196  and vanes  128 . Angel wings  196  and/or cover  180  are configured to reduce and/or eliminate leakage of second portion  302  of second steam flow  162  that flows into cooling passage  134  and mixes with first steam flow  238  in reheat section  232 . Alternatively, angel wings  196  and/or seal  186  can be configured to facilitate second steam flow  162  within cooling passage  134  mixing with reheat section  232 . Second portion  302  of second steam flow  162  is configured to flow into second flow path  240 . As the cooler steam of second portion  302  of second steam flow  162  moves through second flow path  240 , heat of root  125  and/or rotor body  127  is transferred to second portion  302  to facilitate cooling root  125  and/or rotor body  127 . 
       FIG. 11  is an exemplary flowchart illustrating a method  1100  of manufacturing a steam turbine, for example steam turbine  100  (shown in  FIG. 1 ). Method includes coupling  1102  a stator, for example stator (shown in  FIG. 1 ), to a housing, for example housing  124  (shown in  FIG. 1 ). A steam inlet, such as steam inlet  136  (shown in  FIG. 1 ) is coupled  1104  in flow communication to the housing. Method  1100  includes coupling the steam inlet internal to the housing. Alternatively, method  1100  includes coupling the steam inlet external to the housing. 
     In the exemplary method  1100 , the stator includes a plurality of vanes, for example vanes  122  (shown in  FIG. 1 ). Method includes forming  1106  a first flow path, such as first flow path  130  (shown in  FIG. 3 ), within the housing and in flow communication with the steam inlet. A rotor, for example rotor  118  (shown in  FIG. 1 ), is coupled  1108  to the housing and within the stator. In the exemplary method, the rotor includes a plurality of blades, for example blades  122  (shown in  FIG. 1 ), wherein at least one root, such as root  125  (shown in  FIG. 1 ), of the plurality of blades includes a first side, for example first side  152  (shown in  FIG. 1 ), a second side, for example second side  154  (shown in  FIG. 1 ), and a passageway, for example passageway  158  (shown in  FIG. 1 ), coupled in flow communication to the first and second sides. The passageway is configured to define a second flow path, for example second flow path  160  (shown in  FIG. 1 ), in flow communication with the first flow path. In the exemplary method, the first and second flow paths are configured in a negative root reaction configuration, for example negative root reaction configuration  104  (shown in  FIG. 1 ). 
     Method  1100  further includes coupling a seal assembly, for example seal assembly  164  (shown in  FIG. 1 ), to the rotor and in flow communication with the second flow path. In the exemplary method  1100 , the seal assembly includes a third flow path, for example third flow path  172  (shown in  FIG. 1 ), coupled in flow communication to the second flow path. Moreover, the seal assembly includes an packing head, for example packing head  170  (shown in  FIG. 1 ), and a plurality of packing rings, such as packing rings  178  (shown in  FIG. 1 ). 
     A technical effect of the systems and methods described herein includes at least one of: directing steam flow within turbine components; cooling the turbine components; increasing the efficiency of the steam turbine; increasing the operating life of the steam turbine and decreasing at least the operating and maintenance cost of the steam turbine. 
     The exemplary embodiments described herein facilitate directing cooling medium along and or within a heated surface such as a turbine blade or turbine rotor of a steam turbine. The embodiments describe a cooling architecture for cooling steam turbine drum rotors. More particularly, the embodiments describe cooling the rotor and dovetail region as this region experiences heat effects such as, but not limited to, creep rupture. Within a bucket-rotor interface, the cooling effect of the exemplary embodiments is directed toward the rotor body portion of the dovetail joint as rotor materials can have less creep capability than bucket materials. The embodiments described herein use a first flow path and a second flow path within to enhance heat transfer effectiveness. Moreover, the embodiments described herein facilitate increasing turbine efficiency and/or output and/or temperature capabilities while reducing operational and maintenance costs associated with the turbine. Still further, the embodiments described herein enhance component life and facilitate refurbishment of parts. The first and second flow path improve steam flow cooling for a plurality of turbine sections such as, for example, high pressure sections, intermediate pressure sections, reheat sections and/or low pressure sections. 
     Exemplary embodiments of a turbine component and methods for assembling the turbine component are described above in detail. The methods and systems are not limited to the specific embodiments described herein, but rather, components of systems and/or steps of the methods may be utilized independently and separately from other components and/or steps described herein. For example, the methods may also be used in combination with other manufacturing systems and methods, and are not limited to practice with only the systems and methods as described herein. Rather, the exemplary embodiment can be implemented and utilized in connection with many other thermal applications. 
     Although specific features of various embodiments of the invention may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the invention, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.