Abstract:
An inlet transition section and an inlet bowl entry can be designed to reduce a number of turbomachine casing designs. Using relationships between flow properties, distances between elements, crossover/supply pipe diameter, ideal cross sectional area, aspect ratio, and inlet bowl entry size, a transition from circular cross section to substantially polygonal cross section can be made while enabling adoption of a single size of substantially polygonal inlet bowl entry for a plurality of turbine sizes and/or crossover/supply pipe sizes with minimal losses.

Description:
BACKGROUND OF THE INVENTION 
     The disclosure relates generally to turbomachinery, such as steam turbines, and more particularly, to inlet assemblies for turbomachinery. 
     A turbomachine can receive a supply of fluid from a supply conduit via an inlet assembly. The inlet assembly can guide the flow from the supply conduit to a rotor of the turbomachine, and can reshape and redirect the flow. An inlet transition section of the inlet assembly can guide the flow to an inlet bowl of the assembly. The inlet bowl can redirect the flow, such as by turning it through an angle to be received by the rotor. Typically, the inlet bowl will be connected to the inlet transition section along an edge of the inlet bowl, which results in a polygonal or substantially polygonal connection. The inlet transition section can reshape and direct the flow from the circular cross section pipe to the polygonal or substantially polygonal opening to minimize aerodynamic and/or other losses through the transition. However, typically the inlet assembly is specific to a given supply conduit, or at least to a specific turbomachine model, resulting in a large number of inlet assembly designs. 
     BRIEF DESCRIPTION OF THE INVENTION 
     Embodiments of the invention disclosed herein may take the form of a turbomachine inlet transition section that can include a substantially circular entry and a reshaping portion beginning at the substantially circular entry. The reshaping portion can end in an intermediate region of the inlet transition section having a first substantially polygonal cross section. A cross section of the reshaping portion can change from substantially circular at the entry to the first substantially polygonal cross section at the intermediate region while maintaining substantially constant cross sectional area throughout the reshaping portion. The inlet transition section can also include a prismoidal portion beginning at the intermediate region and ending at an inlet transition section exit having a second substantially polygonal cross section that is of the same type of polygon as the first substantially polygonal cross section while being of substantially different dimension. 
     Another embodiment can include a modular turbomachine inlet assembly system including a first plurality of inlet transition sections having substantially identical exits of a first size. Each inlet transition section can include an entry, and the entries of the first plurality of inlet transition sections can include at least two different sizes. Each inlet transition section can additionally include a reshaping portion that is a geometric scale of each other reshaping portion of the first plurality of inlet transition sections. The inlet assembly system can also include at least one inlet bowl having an entry of the first size configured for connection to an exit of an inlet transition section of the first plurality of inlet transition sections. 
     A further embodiment can include a modular turbomachine inlet assembly system having at least two inlet transition sections. Each inlet transition section can include a respective substantially circular entry and a respective substantially polygonal exit. The at least two inlet transition sections can include entries of at least two different diameters, while the substantially polygonal exits can have substantially identical dimensions, a first angle between each respective entry and a respective wall of each respective inlet transition section being substantially equal in all of the at least two inlet transition sections. The system can also include at least one inlet bowl having a substantially polygonal entry of substantially identical dimension to the substantially polygonal exits of the at least two inlet transition sections. Each inlet bowl substantially polygonal entry can correspond to and be configured for attachment to an exit of one of the at least two inlet transition sections. 
     Other aspects of the invention provide methods of making embodiments of the invention disclosed herein, as well as variants of the apparatus, which include and/or implement some or all of the actions and/or features described herein. The illustrative aspects of the invention are designed to solve one or more of the problems herein described and/or one or more other problems not discussed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       These and other features of the disclosure will be more readily understood from the following detailed description of the various aspects of the invention taken in conjunction with the accompanying drawings that depict various aspects of the invention. 
         FIG. 1  shows a schematic elevation diagram of a turbomachine including an inlet assembly according to embodiments of the invention disclosed herein. 
         FIG. 2  shows a schematic elevation diagram of an example of an inlet assembly according to embodiments of the invention disclosed herein. 
         FIG. 3  shows a schematic elevation diagram of the example shown in  FIG. 2  with portions of the inlet assembly separated according to embodiments of the invention disclosed herein are used. 
         FIG. 4  shows a schematic cross sectional diagram of two examples of portions of inlet assemblies taken along line  4 - 4  in  FIG. 2  according to embodiments of the invention disclosed herein. 
         FIG. 5  shows a schematic cross sectional diagram of two examples of portions of inlet assemblies taken along line  5 - 5  in  FIG. 2  according to embodiments of the invention disclosed herein. 
         FIG. 6  is a schematic top view of an example of an inlet assembly highlighting cross sections at an entry, intermediate region or boundary, and exit of an inlet transition section according to embodiments of the invention disclosed herein. 
     
    
    
     It is noted that the drawings may not be to scale. The drawings are intended to depict only typical aspects of the invention, and therefore should not be considered as limiting the scope of the invention. In the drawings, like numbering represents like elements between the drawings. 
     The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to  FIG. 1 , a turbomachine can include one or more casings  10  with which an inlet assembly  100  according to embodiments may be used. Inlet assembly  100  can take fluid from a supply conduit  12 , reshape and/or scale the flow, and redirect the flow into one or more turbomachine casings  10 . Turning to  FIG. 2 , inlet assembly  100  can include an entry  102  configured to be connected to supply conduit  12  and at least one exit  104  configured to transfer fluid to a respective turbomachine casing  10 . Entry  102  can be part of and/or included in an inlet transition section  110 , and exit(s)  104  can be part of and/or included in an inlet bowl  130 . Flow can be redirected, for example, along a centerline CL of turbomachine casing  10  in embodiments, which can also be a longitudinal axis of inlet bowl  130  and/or turbomachine casing  10 . 
     Turning now to  FIG. 2 , inlet transition section  110  can reshape and scale a flow passing from entry  102  to inlet bowl  130 , such as with a reshaping portion  112  and a prismoidal portion  114 , respectively. Entry  102  can have a diameter D, and two sizes of entry  102  are shown in  FIG. 2  to illustrate aspects of the invention. It should be noted, however, that only one entry  102  would be used in practice, so that, in the example shown, entry  102  would have either smaller diameter D 1  or larger diameter D 2 , but not two at the same time. 
     Reshaping portion  112  can include end walls  116  and a plurality of side walls  118 , which can be planar and/or curved as may be suitable and/or desired. Reshaping portion  112  can thus gradually change the cross section of inlet transition section  110  from a circle at entry  102  to a polygon at an intermediate region  120  between reshaping portion  112  and prismoidal portion  114 , which can also be viewed as a boundary. In embodiments, a cross sectional area of reshaping portion  112  is substantially constant, which can reduce and/or substantially minimize losses through reshaping portion  112 . Prismoidal portion  114 , itself including end walls  122  and side walls  124 , can extend between intermediate region  120  and an exit  126  of inlet transition section  110 . In embodiments, the cross sections at intermediate region  120  and exit  126  can be of the same type of polygon, but of different dimension(s). In addition, changing dimensions of the polygonal cross section can be done gradually so as to minimize losses. 
     With particular reference to  FIG. 3 , inlet bowl  130  can include an entry  132  of substantially identical cross section and dimension as inlet transition section exit  126 . Inlet bowl entry can be connected to inlet transition section exit  126 , which, combined with inlet transition section  126 , can be construed as a polygonal interface  140 . In embodiments, the polygonal interface  140  can include additional elements, such as flanges, gaskets, adapters, or the like, to facilitate connection of inlet transition section exit  126  and inlet bowl entry  132 . In embodiments, inlet bowl entry  132  is formed in an annular portion  134  of inlet bowl  130 , while exit(s)  104  of inlet assembly  100  and inlet bowl  130  can be formed in a frustroconical portion  136  of inlet bowl  130 . In particular, entry  132  can be formed in a chordic plane parallel to a longitudinal axis of inlet bowl  130 . As used herein, “chordic plane” refers to a plane extending through parallel chords of substantially identical dimension and location on opposite ends  137  of annular portion  134 . Fluid thus can enter inlet bowl  130  perpendicular to the longitudinal axis of inlet bowl  130  and/or centerline CL (seen in  FIG. 1 ) and can be redirected by inlet bowl  130  to exit inlet bowl  130  in another direction, such as parallel to the longitudinal axis of inlet bowl  130  and/or centerline CL. 
     Where inlet bowl  130  includes an annular portion  134 , entry  132  can have a substantially polygonal cross section. Inlet transition section exit  126 , therefore, can have a cross section matching that of entry  132 , so that both can be polygonal or substantially polygonal, as can a cross section of inlet transition section  110  at intermediate region  120 . While the cross sections of inlet transition section exit  126  and inlet bowl entry  132 , as well as elements of polygonal interface  140  as may be employed, will have substantially identical dimensions, the cross section of intermediate region  120  can have different dimensions, as will be explained in more detail below. 
     Embodiments contemplate the provision of multiple sizes of inlet transition sections  110  that can be used with a single size of inlet bowl  130  to accommodate supply conduits of various diameters, as suggested in  FIGS. 2-5 . In other words, in a plurality of inlet transition sections  110  having entries or inlets  102  of at least two diameters, any inlet transition section  110  with an inlet  102  of diameter D within a range of diameters can be used with a particular size of inlet bowl entry  132 . For example, if D 1  is a minimum inlet diameter and D 2  is a maximum inlet diameter, inlet transition regions of both diameters and for any diameter therebetween can be provided that will terminate in exits of substantially identical dimension. To simplify provision of such a range of sizes, embodiments contemplate direct or geometric scaling of reshaping portion  112 . Thus, dimensions of substantially all parts of reshaping portion  112  increase and/or decrease by a same proportion as between two sizes of inlet transition section  110 , but substantially all parts retain the same orientation(s) relative to each other for all inlet transition sections in the range of sizes. Each reshaping section  112  can therefore be viewed as a geometric scale of every other reshaping portion  112  in the plurality of inlet transition sections  110 . 
     Since a larger diameter inlet transition section  110  will have a reshaping portion  112  of greater height than a smaller diameter inlet transition section  110 , geometry of prismoidal portion  114  can be varied to provide a suitable conduit between a given reshaping portion  112  and inlet bowl  130 , as will be explained below. This allows a single reshaping portion  112  design or arrangement to be used in the range of sizes, which can reduce design time and cost. 
     With reference to  FIG. 4 , an inlet transition section  110  with an entry  102  of diameter D 1  can have a first angle θ 1  between entry  102  and reshaping portion end walls  116 , and a second angle θ 2  between end walls  116  and prismoidal portion end walls  122  at intermediate region  120 . According to embodiments, inlet transition section  110  with a different diameter D 2  can be used with the same inlet bowl by scaling reshaping portion  112 , in which first θ 1  is kept constant. As a result, end walls  116  have the same orientation for all diameters in a given range of inlet transition section sizes, as seen in  FIG. 4  where end walls  116  are substantially parallel. However, a height h reshape  of reshaping portion  112  can be unique to each diameter D of inlet  102 , so that if diameter D 2  is different from diameter D 1 , h reshape  will also be different, and second angle θ 2  must be changed to connect reshaping portion  112  to an inlet bowl  130  of the same size. By changing second angle θ 2 , an angle φ between each end wall  122  and outer wall  138  is also changed. In embodiments, end walls  122  of prismoidal portion  114  can meet an outer wall  138  of inlet bowl annular portion  134  substantially tangentially, as seen in  FIG. 4  so that angle φ can be substantially 180°. However, to accommodate and/or provide inlet transition sections  110  of various sizes for a given inlet bowl size, angle φ can be less than or greater than 180°. To minimize losses in a flow through inlet assembly  100 , embodiments can impose limits on angle φ for a given installation and/or inlet bowl size, which may affect a range of inlet transition section sizes that can be provided. Any such limits can be derived using thermodynamic and/or fluid dynamic and/or physical principles known to those skilled in the art and can take into account additional factors, such as height h transition section  of inlet transition section  110 , height h reshape  of reshaping portion  112 , height h prismoid  of prismoidal portion  114 , and/or dimensions of the polygonal cross section used for inlet bowl entry  132  and/or inlet transition section exit  126 , though other factors and/or dimensions of inlet assembly  100  may be determined and/or considered as desired and/or appropriate. 
     As seen in  FIG. 5 , scaling reshaping section  112  as described above can affect additional relationships between elements of inlet transition section  112 . For example, a third angle θ 3  between entry  102  and side walls  118  can be kept substantially the same for all diameters within a range of inlet transition section sizes. However, a fourth angle θ 4  will be varied accordingly to connect reshaping section  112  to an inlet bowl  130  of a given size. As a result, an additional angle ψ between prismoidal portion side walls  124  and inlet bowl annular portion end walls  137  will also vary. It should be noted that a given reshaping geometry scaling can be based on maintaining either first angle or third angle constant in a range of sizes. Similarly, it should also be noted that limits can be imposed on additional angle ψ in similar fashion to any that might be imposed on angle φ. 
     The examples described above can be representative of a system and method of standardizing turbomachine inlet assemblies. For example,  FIGS. 4 and 5  show two inlets simultaneously, one having a smaller entry  102  than the other, yet both meeting the same polygonal cross section at inlet transition section exits  126 . Thus, as described above, a single size and configuration of polygonal interface  140  can be used with a plurality of sizes of inlet transition sections  110 , or at least with inlet transition sections  110  having a plurality of entry diameters, thus enabling a single polygonal interface  140  to connect a single design of inlet bowl  130  with a plurality of sizes of inlet transition sections  110 . In addition, additional ranges or pluralities of sizes of inlet transition sections  110  could be provided for additional inlet bowl sizes, a respective range for each inlet bowl size or design. Further, a single interface size can be used on a range of inlet bowl sizes by maintaining a thickness of inlet bowl annular portion  134  substantially constant for a range of sizes of inlet bowl  130 , which can allow a single polygonal interface  140  to be applied by moving inlet bowl entry  132  toward or away from the longitudinal axis and/or centerline CL of inlet bowl  130 . Embodiments thus contemplate a plurality of polygonal interface sizes combined with a plurality of sizes of inlet transition section  110  and inlet bowl  130  that can accommodate a wide variety of turbomachine installations while reducing a design and inventory burden. 
     As described above, and with reference to  FIG. 6 , inlet transition section reshaping portion  112  can change in cross section from circular to polygonal or substantially polygonal, and prismoidal portion  114  can change dimension(s) of the cross section to fit interface  140 . For the sake of convenience in describing embodiments of the invention, the example of a polygonal cross section shown in the FIGS. is rectangular, but it should be understood that this is not limiting and that any polygon could be used as appropriate and/or desired. In addition to the change in cross section in reshaping portion  112 , a cross sectional area A transition section  can be substantially constant through reshaping portion  112 . Thus, an entry  102  of diameter D 2  can have an area of π/4D 2   2 , and a polygonal or substantially polygonal cross section at intermediate region  120 , which can also be viewed as a boundary, can be sized so that its area (W boundary ×L boundary  for the rectangular example shown) is equal to π/4D 2   2 , or at least as close as is feasible. As also seen in  FIG. 6 , the dimensions of the polygonal cross section at intermediate region or boundary  120  and those of interface  140  can be different, though the polygon used can be the same. Thus, W boundary ≠W interface  in the example shown, and L boundary ≠L interface , but the cross section in the example is rectangular at both locations. An aspect ratio of the cross section can be useful in embodiments, and typically the aspect ratio at intermediate region  120  will be closer to a value of 1 than the aspect ratio at interface  140  since the cross section at intermediate region  120  has substantially the same area as that of the circular cross section of entry  102 . In embodiments, constraints may be placed on the aspect ratio as a function of transition angles between inlet transition section  110  and entry  102 , transition angles between inlet transition section  110  and inlet bowl outer wall  138 , flow properties, and/or other factors as may be suitable and/or desired. 
     While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.