Patent Publication Number: US-2012031600-A1

Title: Turbine intercooler

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present disclosure relates generally to intercoolers and, more particularly, intercoolers with a set of conducting members disposed in a flow path of compressed gaseous fluid. 
     2. Discussion of the Prior Art 
     Intercoolers in turbines are provided to cool air that is compressed in the low pressure compressor before it is channeled to the high pressure compressor. In their conventional structures, intercoolers experience degradation in internal areas that are difficult to access for maintenance or replacement. Thus, intercoolers with an alternative structure that is easier to maintain or fix, and is more efficient, would be desirable. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The following summary presents a simplified summary in order to provide a basic understanding of some aspects of the systems and/or methods discussed herein. This summary is not an extensive overview of the systems and/or methods discussed herein. It is not intended to identify key/critical elements or to delineate the scope of such systems and/or methods. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later. 
     In accordance with one aspect, the present invention provides an intercooler including a shell with an inlet and an outlet. The shell defines a first chamber. The intercooler further includes a plurality of elongate conducting members. Each of the conducting members includes a first end section and a second end section and is disposed such that each of the first end sections is inside the first chamber of the shell and such that each of the second end sections is disposed exteriorly of the shell. Each of the second end sections is disposed in a flow path of at least one cooling medium so as to undergo evaporative cooling. 
     In accordance with another aspect, the present invention provides an intercooler including a shell defining a first chamber and a plurality of elongate conducting members. Each of the conducting members includes a first end section and a second end section and is disposed such that each of the first end sections is inside the first chamber of the shell and such that each of the second end sections converges toward one another. Each of the second end sections is disposed in a flow path of at least one cooling medium so as to undergo evaporative cooling. 
     In accordance with yet another aspect, the present invention provides a method of cooling compressed gaseous fluid including the steps of disposing each of first end sections of a plurality of elongate conducting members in a flow path of compressed gaseous fluid such that heat from the compressed gaseous fluid is transferred toward second end sections of the conducting members by way of conduction, disposing each of second end sections of the conducting members in a flow path of at least one cooling medium, and generating a flow of the at least one cooling medium moving toward the second end sections such that heat from the second end sections is transferred to the cooling medium. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The foregoing and other aspects of the present invention will become apparent to those skilled in the art to which the present invention relates upon reading the following description with reference to the accompanying drawings, in which: 
         FIG. 1  shows a schematic view of a part of a turbo machine; 
         FIG. 2  shows a first example embodiment of an intercooler; 
         FIG. 3  shows a variation of the first example embodiment of the intercooler; 
         FIG. 4  shows a second example embodiment of the intercooler; 
         FIG. 5  shows a first example of fins formed on conducting members; 
         FIG. 6  shows a second example of fins formed on the conducting members; and 
         FIG. 7  shows an example of an arrangement pattern of the conducting members. 
         FIG. 8  shows an example of an alternative embodiment of the conducting members. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Examples of embodiments that incorporate one or more aspects of the present invention are described and illustrated in the drawings. These illustrated examples are not intended to be a limitation on the present invention. For example, one or more aspects of the present invention can be utilized in other embodiments and even other types of devices. 
     Turning to the shown example of  FIG. 1 , a schematic of a turbo machine, such as a gas turbine engine, is illustrated partially and shows an intercooler  10 , a low-pressure compressor  12  (LPC), and a high-pressure compressor  14  (HPC). Fluid  11  that is compressed at the LPC  12  is channeled to the intercooler  10  where the temperature of the compressed gaseous fluid  11  is lowered prior to being channeled downstream to the HPC  14 . 
       FIGS. 2 and 3  show variations of a first example embodiment of the intercooler  10  in a schematic fashion. The intercooler  10  includes a shell  16  and a cooler  18 . The shell  16  includes an inlet  16   a  in fluid communication with the LPC  12  and an outlet  16   b  in fluid communication with the HPC  14 . The shell  16  forms a first chamber  20  in fluid communication with the LPC  12  and the HPC  14  such that compressed gaseous fluid  11  is channeled through the first chamber  20 . The cooler  18  may include a casing  22  forming a peripheral wall defining a second chamber  24  in which various features for providing cooling are located as will be described below. 
     As shown in  FIGS. 2 and 3 , the shell  16  and the cooler  18  are connected by a plurality of elongate conducting members  26  each of which include a first end section  26   a  and a second end section  26   b . The conducting members  26  may be cylindrical, pipe-like structures and are sufficiently elongate to connect the shell  16  and the cooler  18  such that the first end section  26   a  is disposed in the first chamber  20  of the shell  16  and a second end section  26   b  is disposed in the second chamber  24  of the cooler  18 . The elongate conducting members  26  may be formed of metals that are sufficiently conductive so that the first end section  26   a  can draw heat from gas in the shell  16  and transmit such heat to the second end section  26   b  that can be cooled inside the cooler  18 . For example, the conducting members  26  may be made of copper, stainless steel, carbon steel, or other metals or alloys. In yet another example, the conducting members  26  may be superconductive and examples of such superconducting members may be found in U.S. Pat. Nos. 6,132,823, 6,811,720, 6,911,231, and 6,916,430. 
     The arrangement of the conducting members  26  inside the first chamber  20  is such that highly efficient heat transfer can occur longitudinally about the conducting members  26  and such that pressure drop in the first chamber  20  is small thereby improving turbine efficiency. 
     In the embodiments of  FIGS. 2 and 3 , the second end sections  26   b  may be disposed in a path of a cooling medium to accomplish cooling. As such, the second chamber  24  of the cooler  18  may include a discharger  28  which releases as one cooling medium a cooling liquid  35  (e.g., water) toward the second end sections  26   b  although the released cooling liquid  35  may or may not contact the second end sections after discharge. In one example, the discharger  28  may be embodied as a spray that releases a cooling liquid  35  from an elevated area within the cooler  18  as shown in  FIGS. 2-3 . Additionally, the second end sections  26   b  may be embedded inside a wick element  30  which is disposed underneath the discharger  28  so as to absorb and retain some of the cooling liquid  35  by capillary action. The wick element  30  may be formed of various materials that are durable, non-dissolving material capable of wicking action via surface tension, retaining water, and capable of allowing evaporation of water retained in the wick when exposed to flowing gas. For example, the wick element  30  may be embodied as a sponge or a bundle of woven fibers or plastics that is capable of retaining the cooling fluid by capillary action and that is sufficiently dimensioned such that a bulk of the second end sections  26   b  can be embedded therein. The cooling liquid  35  retained by the wick element  30  is kept in proximity with the second end sections  26   b  for a longer period of time rather than simply passing by the conducting members  26  such that the time during which heat transfer can occur is prolonged. 
     Additionally, the cooler  18  may include a blower  32 , such as an axial fan, a centrifugal fan, or an air suction device, that generates a movement of air  33  across the conducting members  26  or the wick element  30  thereby placing the conducting members  26  in a flow path of another cooling medium. In the embodiment shown in  FIGS. 2-3 , movement of air  33  is in an upward direction within the cooler  18  although the flow path of the air  33  may vary. In these embodiments, the casing  22  of the cooler  18  is configured with openings  34  formed by louvers near the base to allow ambient air to refill the gap left by the air that has moved out of the second chamber  24  of the cooler  18 . The openings  34  may include a filter to guard against contaminants in ambient air from entering the cooler  18 . The blower  32  may be located at a top of the cooler  18  which may also include a vent  36  which may be covered by a grille or filter near the blower  32 . 
     Moreover, a container  38  may be disposed at a base of the cooler  18  to recover cooling liquid  35  that falls from the discharger  28  and is not retained by the wick element  30 . Furthermore, the recovered cooling liquid  35  may be rerouted to the discharger  28  via a recirculation system  40 , which may include a pump  45 , to be thereafter released again from the discharger  28 . The recirculation system  40  may include a control system  42  for controlling the circulation of cooling fluid  35  back to the discharger  28  or adapting the supply of cooling fluid  35  depending on atmospheric conditions. The control system  42  may adjust the recirculation system  40  in response to operating conditions, such as modifying the degree of cooling or the volume flow of the re-circulated cooling liquid  35  depending on a number of conditions such as ambient temperature of the environment in which the intercooler  10  is located. The cooling liquid  35  which has absorbed heat from the conducting members  26  while falling from the discharger  28  may be cooled by counter flow of air  33  generated by the blower  32 . Moreover, the blower  32  can generate evaporation of the cooling liquid  35  (e.g., water) captured in the wick element  30  such that the conducting members  26  are cooled by the latent heat property of the cooling liquid  35 . The recirculation system  40  may include a filter to guard against contaminants in the cooling liquid  35  from moving through the recirculation system  40 . Without the recirculation system  40 , the discharger  28  may simply be connected to a source of the cooling liquid  35  and the container  38  may simply lead to a drainage system. 
     Some of the second end sections  26   b  or some parts of the second end sections  26   b  may be disposed outside the wick element  30  and may experience only forced convective cooling through air flow generated by the blower  32  but not evaporative cooling. 
     The casing  22  of the cooler  18  may be embodied in a variety of shapes and arrangements. For example, the casing  22  may be oriented upright and be shaped like a box, a cylinder, frustocone, etc. If the cooler  18  is a substantially upright and cylindrical structure, the cooler  18  may be described as a tower cooler  18   a . The shell  16  may also be embodied in a variety of shapes and arrangements. For example, the shell  16  may be oriented in a substantially upright ( FIG. 2 ) or horizontal ( FIGS. 3 and 4 ) manner and may be shaped like a box, a cylinder ( FIGS. 2 and 3 ), a ring ( FIG. 4 ), etc. It may be possible to reduce an area occupied by a footing of the intercooler  10  with a vertical arrangement of the shell  16  and the cooler  18  as shown in  FIG. 2 . Moreover, the arrangement of the shell  16  relative to the cooler  18  may affect the number of conducting members  26  that connect the two. Specifically, if the conducting members  26  are straight, the conducting members  26  may only be disposed in a limited area where parts of the shell  16  and the cooler  18  are immediately and laterally adjacent. However, it may be possible to modify the shape of the conducting members  26  and provide conducting members  26  connecting the shell  16  and the cooler  18  even if an area where parts of the shell  16  and the cooler  18  are immediately and laterally adjacent is small. 
     In an alternative embodiment of  FIG. 4 , the shell  16  is arranged to surround or substantially encircle the tower cooler  18   a  with the inlet and the outlet disposed in one radial direction about the tower cooler  18   a . The conducting members  26  that extend from the first chamber  20  of the shell  16  to the interior of the cooler are disposed in a plurality of radial directions with respect to the tower cooler  18   a  such that the first end sections  26   a  are in the flow path of the compressed gaseous fluid  11  and the second end sections  26   b  are in the path of at least one cooling medium. Several features shown in the cooler of  FIGS. 2-3  are omitted from  FIG. 4  in order to illustrate the arrangement of the conducting members  26 . Thus, the tower cooler of  FIG. 4  may include the blower, the filter, the wick element, the container, the recirculation system, the heat exchanger or other features similarly as shown in  FIGS. 2-3 . 
       FIGS. 5 and 6  show example embodiments of the conducting members  26 . A cross-section of the conducting members  26  may be circular such that a fluid passing by the conducting members  26  can undergo a more streamlined flow and be evenly distributed in the spaces between the conducting members  26 . In order to enhance heat exchange, the first end sections  26   a  or the second end sections  26   b  may be configured with fins  44 , as shown in  FIGS. 5 and 6 , which may be provided at regular intervals along a longitudinal axis of the conducting members  26 . The fins  44  may be provided longitudinally throughout the conducting members  26  or may be provided within a longitudinal portion of the conducting members  26 . For example, the fins  44  may be provided only on the first end sections  26   a . The fins  44  are provided to increase surface areas on which heat exchange can occur between the conducting members  26  and the cooling medium as the air  33  moves in between the fins  44 . The longitudinal spacing between the fins  44  is not drawn to scale and the fins  44  may be located closer to or apart from one another than the embodiments shown in  FIG. 5  or  6  in order to alter a heat transfer coefficient at the end sections  26   a ,  26   b  of the conducting members  26 . For example, the fins  44  may be located so close to one another as to provide a gap that is smaller than the thickness of the fins  44 . As shown in the embodiments of  FIGS. 5-6 , the fins  44  may be embodied as circular flanges  44   a , rectangular flanges  44   b  or other polygonal or irregular shapes but may also be embodied in a variety of geometries affecting heat transfer efficiency. For example, the rectangular flanges  44   b  may be slightly bent at the corners toward the two longitudinal ends of the conducting members  26  and the directions in which the corners are bent may alternate as shown in  FIG. 6 . 
     Because a plurality of conducting members  26  is disposed in the intercooler  10 , a pattern in which the conducting members  26  are arranged may also affect a heat transfer coefficient between the cooling medium and the conducting members  26 .  FIG. 7  partially shows a flow path of the compressed gaseous fluid  11  through an arrangement of the conducting members  26  in which the first end sections  26   a  are configured with fins  44   a . In a pattern where all of the conducting members  26  are parallel to one another, as shown in  FIG. 7 , the pattern may be divided into a plurality of subsets  46  of conducting members  26  that are parallel and vertically aligned. In the pattern of  FIG. 7 , although each subset  46  includes conducting members  26  that are parallel and vertically aligned, two neighboring subsets  46  are misaligned or staggered horizontally about one another such that the flow path of the cooling medium encounters a greater number of conducting members  26 , compared to a pattern in which neighboring subsets  46  are also horizontally aligned, thereby generating increased heat exchange between the compressed gaseous fluid  11  and the first end sections  26   a . Such horizontal misalignment between neighboring subsets  46  can also be implemented to the embodiment of  FIG. 4  even if all of the conducting members  26  are not parallel to one another due to the radial arrangement of the subsets  46 . Similarly, in such a configuration, the subsets  46  would include parallel and vertically aligned conducting members  26  but neighboring subsets  46  would be horizontally misaligned. 
     The intercooler  10  described herein provides an apparatus for removing heat from compressed gaseous fluid  11  traveling from the LPC to the HPC. The first end sections  26   a  of the conducting members  26  take away heat from the compressed gaseous fluid  11  and transmit the heat to the second end sections  26   b . The first end sections  26   a  may be configured with fins  44  to enhance heat exchange between the compressed gaseous fluid  11  and the first end sections  26   a . The second end sections  26   b  can be disposed in a flow path of one or more cooling medium (e.g., cooling liquid  35  and/or air  33 ) to enhance heat loss from the second end sections  26   b  to the atmosphere. By providing the second end sections  26   b  in the wick element  30 , the cooling liquid  35  can be cooled by convective cooling (i.e., the upward movement of air  33  generated by the blower  32  in counter flow with downwardly falling cooling liquid  35 ) or the evaporative cooling (i.e., gasification of the cooling liquid  35  taking away heat from neighboring cooling liquid  35  in the wick element  30 ). In case of the cooling liquid  35 , the cooling liquid  35  can be recovered after being released toward the second end sections  26   b  and re-circulated for cooling prior to being released again toward the second end sections  26   b.    
     In the embodiment of  FIG. 4 , the donut-shaped shell  16  substantially encircling the tower cooler  18   a  allows the compressed gaseous fluid  11  to move smoothly therethrough without facing obstructions such that the compressed gaseous fluid  11  experiences a low pressure drop and the overall efficiency of the gas turbine is improved. Other shell shapes, e.g. U-shape, providing smooth curving path for the air flow yield similar benefit of low pressure drop. 
       FIG. 8  shows an alternative embodiment of the conducting members  26 .  FIG. 8  only shows one of the first end section  26   a  or the second end section  26   b  of the conducting members  26  but the same configuration can be implemented on the other end section. In this embodiment, each end of the plurality of the conducting members  26  includes submembers  50  which are finned similarly to  FIGS. 5-6 . The submembers  50  transition to a header  52  which includes transition sections  54  at each end and a bundled section therebetween  56 . The transition sections  54  and the submembers  50  are located inside the shell  16  or the casing  22  while the bundled section  56  extends through the shell  16  or the casing  22  thus reducing the number of holes formed on the shell  16  or the casing  22  to one. 
     The invention has been described with reference to the example embodiments described above. Modifications and alterations will occur to others upon a reading and understanding of this specification. Example embodiments incorporating one or more aspects of the invention are intended to include all such modifications and alterations insofar as they come within the scope of the appended claims.