A turbine device for improving the sealing performance of the wheel rim and the aerodynamic performance of the turbine

Abstract

The present invention discloses a turbine device for improving the rim sealing performance and turbine aerodynamic performance, comprising: a stator-rotor disc cavity and a rotor hub end wall, the rotor hub end wall being arranged above the stator-rotor disc cavity; the stator-rotor disc cavity includes a stator disc wall surface, a jet groove is arranged at the stator disc wall surface near the rim, and the rotor hub end wall is an asymmetric end wall. In this application, the vortex structure in the rim clearance is broken by the jet groove, so that the rim sealing performance of the stator-rotor disc cavity is improved, and the inlet vortex intensity of the downstream rotor is reduced, providing good inlet conditions for the control of secondary flow by the asymmetric end wall of the downstream rotor; by setting the rotor hub end wall as an asymmetric end wall, the development of the hub secondary flow along the flow direction is delayed, and the overall turbine aerodynamic performance is enhanced. This combined structure can improve the rim sealing performance of the stator-rotor disc cavity while enhancing the turbine aerodynamic performance.

Description

Technical Field

[0001] The present invention relates to the technical field of gas turbine devices, and in particular to a turbine device capable of improving wheel rim sealing performance and turbine aerodynamic performance. Background Art

[0002] Increasing the gas temperature before the turbine is the most direct and effective means to improve the thrust-to-weight ratio. For every 100°C increase in the gas temperature before the turbine, the engine thrust increases by about 8%. The gas temperature before the turbine is still increasing at a rate of about 20-30°C / year, which has long exceeded the high temperature resistance limit of the turbine material, making the turbine working environment even worse, especially the high-speed rotating turbine wheel and rotor blade roots. Therefore, effective cooling and thermal protection measures are the key ways to increase the gas temperature before the turbine and ensure that the components are durable and resistant to high temperatures.

[0003] At present, the cooling gas is mainly drawn out from the compressor and transported to the turbine disc cavity, passing through the wheel disc, blades, sealing devices, etc. to cool the turbine disc cavity and blades. At the same time, the cooling gas entering the disc cavity can also prevent the mainstream high-temperature combustion gas from invading the inside of the turbine disc cavity through the sealing structure, causing the turbine disc temperature to be too high, which seriously affects the working safety and service life of the engine. In addition, the sealing gas will eventually enter the mainstream channel and interfere with the mainstream. Studies have shown that a 1% increase in gas intrusion may cause the life of the turbine disc to decrease by 50%. On the other hand, when the sealing cooling gas volume is reduced by 50%, the turbine efficiency can be increased by 0.5% and the fuel consumption rate can be reduced by 0.9%. Therefore, the rim flow will affect both the rim sealing performance and the mainstream aerodynamic performance of the turbine at the same time, and this effect is opposite.

[0004] However, the control strategy based on a single performance in the prior art cannot simultaneously improve the mainstream gas performance and sealing performance of the turbine. For example, the mainstream aerodynamic performance of the turbine can be improved through end wall design or shaping, but the effect on suppressing gas intrusion and improving the sealing performance is minimal. Structural designs that improve the sealing performance generally cause increased interference between the outflowing cold air and the mainstream, thereby reducing the mainstream aerodynamic performance of the turbine. Summary of the invention

[0005] The present invention provides a turbine device for improving the sealing performance of a wheel rim and the aerodynamic performance of a turbine, so as to solve the problem that the sealing performance and the aerodynamic performance of a turbine cannot be improved simultaneously in the prior art.

[0006] The present invention provides a turbine device for improving the rim sealing performance and turbine aerodynamic performance, comprising: a stationary-rotating disk cavity and a rotor hub end wall, wherein the rotor hub end wall is arranged above the stationary-rotating disk cavity; the stationary-rotating disk cavity comprises a stationary disk wall surface, wherein the stationary disk wall surface is provided with a jet groove near the rim, and the rotor hub end wall is a non-axisymmetric end wall.

[0007] Optionally, the turbine device further includes a first-stage stator vane, a first-stage rotor vane, and a second-stage stator vane. Among them, the first-stage stator vane is located on one side of the end wall of the rotor hub, the first-stage rotor vane is located on the other side of the end wall of the rotor hub, and the second-stage stator vane is located on the side of the first-stage rotor vane away from the first-stage stator vane.

[0008] Optionally, the stator-rotor disc cavity further includes a disc wall surface, which is located on one side below the end wall of the rotor hub.

[0009] Optionally, the stator disc wall surface and the rotor disc wall surface form an internal air flow channel and an air flow channel in the disc cavity gap of the disc cavity.

[0010] Optionally, the disc cavity formed by the stator disc wall surface and the rotor disc wall surface is further provided with a disc cavity outlet and a cooling gas inlet.

[0011] Optionally, the circumferential position of the jet slot is located downstream of the trailing edge of the guide vane.

[0012] Optionally, the tangential direction of the jet slot is arc-shaped, and the circumferential range is 1 / 5 of a single channel of the guide vane.

[0013] Optionally, the radial height of the jet slot is 1 / 3 of the radial height of the air flow channel in the disc cavity gap.

[0014] Optionally, the jet slot is arranged at a position on the stator disc wall surface close to the high radius of the rim.

[0015] Optionally, the end wall of the rotor hub is an asymmetric end wall with a concave suction surface side and a convex pressure surface side.

[0016] A turbine device for improving the rim sealing performance and turbine aerodynamic performance in the present invention has the following advantages:

[0017] By arranging a jet slot on the stator disc wall surface close to the rim, the vortex structure in the rim gap can be broken, and by setting the end wall of the rotor hub as an asymmetric end wall, a combined structure near the rim is formed, so that the rim sealing efficiency of the stator-rotor disc cavity is improved, that is, the sealing performance is enhanced. At the same time, since the vortex structure in the rim gap is broken, the vortex intensity at the inlet of the downstream rotor is reduced, providing good inlet conditions for the downstream rotor asymmetric end wall to control the secondary flow; by setting the end wall of the rotor hub as an asymmetric end wall, the development of the hub secondary flow along the flow direction is delayed, and the overall turbine aerodynamic performance is improved. This combined structure can improve the rim sealing performance of the stator-rotor disc cavity while enhancing the turbine aerodynamic performance. Description of the Drawings

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0019] Figure 1 It is a schematic diagram of the overall structure of a turbine device for improving the rim sealing performance and turbine aerodynamic performance provided by an embodiment of the present invention;

[0020] Figure 2 For Figure 1 It is a schematic diagram of the structure of the middle stator-rotor disc cavity;

[0021] Figure 3 It is a schematic diagram of the three-dimensional structure of the first-stage stator domain including a jet groove of a turbine device for improving the rim sealing performance and turbine aerodynamic performance provided by an embodiment of the present invention;

[0022] Figure 4 For Figure 2 It is a schematic diagram of the relative position of the middle stator disc wall surface and the jet groove;

[0023] Figure 5 It is a schematic diagram of the non-axisymmetric end wall structure of a turbine device for improving the rim sealing performance and turbine aerodynamic performance provided by an embodiment of the present invention;

[0024] Figure 6 It is a schematic diagram of the circumferential distribution of the radius of the hub non-axisymmetric end wall (hub) provided by an embodiment of the present invention;

[0025] Figure 7 It is a schematic diagram of the sealing efficiency in the radial direction of the disc cavity (used to characterize the sealing performance) provided by an embodiment of the present invention;

[0026] Figure 8 It is a curve diagram of the change of entropy generation along the flow direction provided by an embodiment of the present invention (used to characterize the main flow aerodynamic performance of the turbine).

[0027] Explanation of reference numerals:

[0028] 1. First-stage stator vane; 2. First-stage rotor vane; 3. Second-stage stator vane; 4. Stator-rotor disc cavity; 5. Rotor hub end wall; 6. Stator disc wall surface; 7. Rotor disc wall surface; 8. Internal air flow channel in the disc cavity; 9. Gap air flow channel in the disc cavity; 10. Outlet of the disc cavity; 11. Inlet of cooling gas; 12. Jet groove. Detailed implementation manners

[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] As Figures 1-8 shown, the embodiment of the present invention provides a turbine device for improving the rim sealing performance and turbine aerodynamic performance. The present invention provides a turbine device for improving the rim sealing performance and turbine aerodynamic performance, including: a stator-rotor cavity 4 and a rotor hub end wall 5, and the rotor hub end wall 5 is arranged above the stator-rotor cavity 4; the stator-rotor cavity 4 includes a stator disk wall surface 6, a jet groove 12 is arranged near the rim on the stator disk wall surface 6, and the rotor hub end wall 5 is an axisymmetric end wall.

[0031] In the turbine device for improving the rim sealing performance and turbine aerodynamic performance proposed in the present invention, by arranging the jet groove 12 near the rim on the stator disk wall surface 6, the vortex structure in the rim gap can be broken, and by setting the rotor hub end wall 5 as an axisymmetric end wall, a combined structure near the rim is formed, so that the sealing efficiency of the stator-rotor cavity 4 is improved, that is, the sealing performance is improved. At the same time, since the vortex structure in the rim gap is broken, the vortex intensity at the inlet of the downstream rotor is reduced, providing good inlet conditions for the control of the secondary flow by the axisymmetric end wall of the downstream rotor; by setting the rotor hub end wall 5 as an axisymmetric end wall, the development of the hub secondary flow along the flow direction is delayed, and the overall turbine aerodynamic performance is improved. This combined structure can improve the sealing efficiency of the stator-rotor cavity 4 while improving the turbine aerodynamic performance.

[0032] In an exemplary embodiment, the turbine device further includes a first-stage stator blade 1, a first-stage rotor blade 2, and a second-stage stator blade 3. Among them, the first-stage stator blade 1 is located on one side of the rotor hub end wall 5, the first-stage rotor blade 2 is located on the other side of the rotor hub end wall 5, and the second-stage stator blade 3 is located on the side of the first-stage rotor blade 2 away from the first-stage stator blade 1.

[0033] Specifically, the first-stage stator blade 1 and the first-stage rotor blade 2 form pressures that are alternately high and low in the circumferential direction in the mainstream through interaction.

[0034] In an exemplary embodiment, the stator-rotor cavity 4 further includes a rotor disk wall surface 7, and the rotor disk wall surface 7 is located on one side below the rotor hub end wall 5.

[0035] In an exemplary embodiment, the stator disk wall surface 6 and the rotor disk wall surface 7 form an internal air flow channel 8, a disk cavity gap air flow channel 9, a disk cavity outlet 10, and a cooling gas inlet 11 of the disk cavity.

[0036] Among them, the total cold air volume is 0.5% of the mainstream flow rate. Among them, 1 / 3 of the cooling air flow enters from the jet slot 12 at twice the tangential speed of the rotor hub, and 2 / 3 of the cooling air flow enters from the cooling gas inlet 11. Through CFD calculation, the jet slot 12 breaks the vortex structure existing in the air flow channel 9 of the disc cavity gap, improves the sealing performance. Before and after setting the jet slot 12, the sealing efficiency in the radial direction of the static-rotating disc cavity 4 is as Figure 7 shown.

[0037] Specifically, Computational Fluid Dynamics (CFD) is a discipline for predicting fluid flow, heat and mass transfer, chemical reactions and other physical phenomena. The calculation method of CFD is to discretize the continuous physical field by the finite volume method to simplify the partial differential equation group into an algebraic equation group, and then solve the algebraic equation group by numerical methods to obtain the flow field solution.

[0038] The numerical calculation and boundary conditions in the CFD calculation are as follows:

[0039] Take a 1 / 18 sector channel as the calculation domain and use commercial CFD software for numerical simulation. In the unsteady calculation, the SST turbulence model is adopted, and the interface is the transient rotor / stator interface. The movement of the rotor blade through a channel is divided into 42 steps, and the physical time step is 60 / (2700×54×42), that is, 9.8×10-6 s. The rotor blade row rotates around the Z axis at a speed of 2700 r / min. The distribution of the total pressure along the span is given at the inlet, the total pressure at the mid-diameter is 139.6 KPa, the total temperature is 328 K, and the inlet free-stream turbulence intensity is 6%. The distribution of the static pressure along the span is given at the outlet section of the calculation domain. All the walls (blades and upper and lower end walls) are adiabatic non-slip walls. The dynamic viscosity coefficient and thermal conductivity coefficient of the working medium gas are both given by the Sutherland formula. The sealing cold air enters the static-rotating disc cavity 4 from the cooling gas inlet 11 and the jet slot 12 respectively.

[0040] Furthermore, Figure 8 is the curve graph of the entropy increase changing along the flow direction. Refer to Figure 8 , it can be seen that the loss in the rotor flow direction is reduced and the efficiency is improved. It should be noted that the entropy increase represents loss.

[0041] In addition, when only the end wall 5 of the rotor hub is set as an axisymmetric end wall and the jet slot 12 is not set at the rim of the static disc wall 6, from Figure 8 it can be seen that the axisymmetric end wall slows down the development of the secondary flow in the rotor domain, but enhances the vortex intensity at the rotor inlet caused by the outflow of the sealing cold air. Therefore, the loss at the rotor inlet is amplified, and the turbine efficiency is not improved as a whole.

[0042] In summary, the main reason for the poor control effect of the rotor hub end wall 5 is that the non-axisymmetric end wall causes an increase in the intensity of the sealing gas vortex. At the same time, the jet groove 12 is provided, and the rotor hub end wall 5 is a non-axisymmetric end wall, which reduces the loss at the outlet of the stator-rotor cavity 4. The loss in the rotor passage is also reduced compared to the original turbine device as Figure 8 shown, thereby achieving an improvement in the aerodynamic performance of the turbine.

[0043] In this embodiment, in the region with a relatively high mainstream pressure, the mainstream high-temperature gas passes through the cavity gap air flow passage 9 from the cavity outlet 10 and enters the internal air flow passage 8 of the cavity, thereby causing gas intrusion. In addition, the cooling gas radially upward passes through the internal air flow passage 8 of the cavity and the cavity gap air flow passage 9 from the cooling gas inlet 11, and then enters the mainstream passage from the cavity outlet 10.

[0044] In an exemplary embodiment, the circumferential position of the jet groove 12 is located downstream of the trailing edge of the guide vane.

[0045] In an exemplary embodiment, the tangential direction of the jet groove 12 is arc-shaped, and the circumferential range is 1 / 5 of a single channel of the guide vane, and the radial height is 1 / 3 of the radial height of the cavity gap air flow passage 9.

[0046] Specifically, by changing the intake angle and flow rate of the air flow at the jet groove 12, the magnitude of the jet tangential velocity can be changed.

[0047] In an exemplary embodiment, the jet groove 12 is provided at a position on the stator disk wall surface 6 close to the high radius of the rim.

[0048] In an exemplary embodiment, the rotor hub end wall 5 is a non-axisymmetric end wall that is concave on the suction surface side and convex on the pressure surface side.

[0049] Specifically, the rotor hub end wall 5 is shaped by the "trigonometric function method". The shaping function along the circumferential direction selects a sine function with a period of two grid pitches, as described in the following formula:

[0050]

[0051] where: y PS is the circumferential position of the pressure surface, y ss is the circumferential position of the suction surface, y represents the circumferential position coordinate, and α is the circumferential angle.

[0052] Considering that the internal air flow pressure field in the cascade passage changes most violently, and it is also the main area for the generation and development of secondary flow and various vortices, the axial shaping function is applied between the leading edge and the trailing edge of the blade, thereby determining the shaping range of the non-axisymmetric end wall three-dimensional surface. According to the trigonometric function curve, the amplitude control function expression is determined, as described in the following formula:

[0053]

[0054] Where: z LE and z TE are the flow direction positions of the leading edge and the trailing edge respectively, H b is the blade height, C h is the amplitude coefficient, and z is the flow direction position coordinate.

[0055] Specifically, the specific value of C h is 0.05, which is used to determine the peak (valley) of the convex (concave) non-axisymmetric end wall surface. The local structural schematic diagram of the combined structure of the jet groove 12 and the non-axisymmetric end wall profile is as Figure 5 shown, Figure 6 is the schematic diagram of the circumferential distribution of the non-axisymmetric end wall (hub) radius, where the radius of the reference rim (hub) is 0.33 m.

[0056] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they learn the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0057] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A turbine device for improving wheel rim sealing performance and turbine aerodynamic performance, characterized in that: include: A stationary-rotating disc cavity (4) and a rotor hub end wall (5), wherein the rotor hub end wall (5) is arranged above the stationary-rotating disc cavity (4); the stationary-rotating disc cavity (4) comprises a stationary disc wall surface (6), a jet groove (12) is arranged on the stationary disc wall surface (6) near the wheel rim, and the rotor hub end wall (5) is a non-axisymmetric end wall with a concave suction surface side and a convex pressure surface side; The rotor hub end wall (5) is shaped using a "trigonometric function method", in which a sine function with a period of two pitches is selected as a circumferential shaping function, as described in the following formula: Where: y PS is the circumferential position of the pressure surface, y SS is the circumferential position of the suction surface, y represents the circumferential position coordinate, and α is the circumferential angle; The stationary-rotating disc cavity (4) further comprises a rotating disc wall surface (7), wherein the rotating disc wall surface (7) is located on one side below the rotor hub end wall (5); The stationary disk wall surface (6) and the rotating disk wall surface (7) form an internal air flow channel (8) of the disk cavity and an air flow channel (9) in the disk cavity gap; The jet groove (12) is in an arc shape in the tangential direction, and its circumferential range is 1 / 5 of a single channel of the guide vane; The radial height of the jet groove (12) is 1 / 3 of the radial height of the disc cavity gap airflow channel (9), and the jet groove (12) is arranged on the stationary disc wall surface (6) of the disc cavity gap airflow channel (9).

2. A turbine device for improving wheel rim sealing performance and turbine aerodynamic performance according to claim 1, characterized in that: The turbine device further comprises: A first-stage stator blade (1) located on one side of the rotor hub end wall (5); A first-stage rotor blade (2) located on the other side of the rotor hub end wall (5); The second-stage stator blades (3) are located on a side of the first-stage rotor blades (2) away from the first-stage stator blades (1).

3. A turbine device for improving wheel rim sealing performance and turbine aerodynamic performance according to claim 1, characterized in that: The disc cavity formed by the stationary disc wall surface (6) and the rotating disc wall surface (7) is also provided with a disc cavity outlet (10) and a cooling gas inlet (11).

4. A turbine device for improving wheel rim sealing performance and turbine aerodynamic performance according to claim 1, characterized in that: The circumferential position of the jet groove (12) is located downstream of the trailing edge of the guide vane.

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