A method for measuring the loss of a turbovane counter-rotating blast

Abstract

The present application aims at providing a turbine blade reverse rotation air blowing loss measuring method, two turbine test pieces are designed, one turbine test piece is provided with a complete set of double-layer turbine blades, and a partition structure is used to block air from passing through the reverse rotation channel, and the other turbine test piece is provided with only forward rotation blades without reverse rotation blades. During the test, under the same air source inlet parameters, compressed air is used to drive the two turbine test pieces to rotate respectively, and the output power is measured, the output power of the reverse rotation turbine before modeling is obtained through a turbine modeling conversion relationship, the difference between the two output powers is the air blowing loss generated by the reverse rotation of the reverse rotation blades, and the influence of the structural size, gas temperature, gas pressure, working speed and other parameters on the reverse rotation air blowing loss of the turbine blade is obtained through finite element simulation calculation. The present application can solve the problem of measuring the reverse rotation air blowing loss of the double-layer turbine blade, and is an air blowing loss measuring method with simple operation and high measuring accuracy.

Description

Technical Field

[0001] The present invention relates to a method for testing a reversing turbine, specifically a method for measuring blower loss. Background Technology

[0002] Reversible gas turbines have become one of the main propulsion systems for ships due to their high reverse power density, steering flexibility, and ease of maintenance. Reversible gas turbines employ a dual-gas passage + double-layer turbine blade design, with the outer passage serving as the reverse passage and the inner passage as the forward passage. A gas switching mechanism at the front end distributes the gas flow path. When gas flows only through the lower forward blades, the turbine rotor rotates forward; when gas flows only through the upper reverse blades, the turbine rotor rotates in the reverse direction. Under most operating conditions, the reversible gas turbine only uses the forward function. In this case, when gas flows through the forward passage and drives the forward blades, no gas flows through the reverse blades, causing them to rotate in the reverse direction. In this state, the reverse blades continuously agitate the surrounding gas, generating a large amount of disordered and chaotic gas flow on their surface, resulting in power loss. This power loss is the blower loss caused by the reverse blades rotating in reverse. The presence of blower loss reduces the power output of the forward turbine, affecting the overall efficiency of the gas turbine.

[0003] Accurate measurement of the airflow loss of reversing turbine blades is a prerequisite for studying low-airflow-loss reversing turbines. Currently, research on airflow loss mainly focuses on theoretical calculations, obtaining airflow loss through fluid dynamics software. There are few reports on methods for measuring the airflow loss of reversing turbine blades. Therefore, a method for measuring the airflow loss of double-layer turbine blades in reverse rotation has become an urgent problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a method for measuring the reverse blowing loss of turbine blades, which can solve the problem of measuring the reverse blowing loss of double-layer turbine blades.

[0005] The objective of this invention is achieved as follows:

[0006] The present invention provides a method for measuring the reverse airflow loss of turbine blades, characterized in that: a molded turbine test piece A and a turbine test piece B are set up, wherein the turbine test piece A has double-layer turbine blades and uses a baffle structure to block airflow through the reversing channel, and the turbine test piece B, based on the turbine test piece A, includes forward turbine blades and removes the reversing turbine blades;

[0007] (1) The operating parameters under rated conditions are modeled to obtain the inlet parameters of turbine test pieces A and B, including inlet total temperature, total pressure, flow rate and turbine rotor speed;

[0008] (2) On the turbine test bench, connect the air source to the inlet of the turbine test piece A, connect the dynamometer to the output end of the turbine rotor of the turbine test piece A, increase the air source flow rate, so that the compressed air only flows through the forward blades, drive the turbine test piece A to rotate in the forward direction until the rated operating parameters of the turbine test piece A are reached, stabilize for 10 minutes, and complete the measurement of the output power Pa.

[0009] (3) On the turbine test bench, connect the air source to the inlet of the turbine test piece B, connect the dynamometer to the output end of the turbine rotor of the turbine test piece B, increase the air source flow rate, so that the compressed air only flows through the forward blades, drive the turbine test piece B to rotate in the forward direction until the rated operating parameters of the turbine test piece B are reached, stabilize for 10 minutes, and complete the measurement of the output power Pb.

[0010] (4) Based on the modeling formula, the power values ​​of turbine test pieces A and B are converted to the output power before modeling, which are PA and PB respectively;

[0011] (5) Calculate the reverse turbine blade reverse blowing loss PB-PA before modeling;

[0012] (6) Considering the differences in parameters such as structural size, gas temperature, gas pressure, and operating speed of turbine blades before and after modeling, the corresponding relationship between structural size, gas temperature, gas pressure, operating speed and turbine blade reverse blowing loss is obtained through finite element simulation calculation, and the correction coefficient C of reverse turbine blade reverse blowing loss is obtained.

[0013] (7) Obtain the final reversing turbine blade blowout loss P = C * (PB - PA).

[0014] The present invention may also include:

[0015] 1. The calculation process for PA and PB in step (4) is as follows:

[0016]

[0017] PA represents the turbine output power before modeling; Pa represents the turbine output power after modeling; m represents the turbine flow rate before modeling; m* represents the turbine flow rate after modeling; T0 represents the turbine inlet temperature before modeling; T0* represents the turbine inlet temperature after modeling.

[0018]

[0019] PB represents the turbine output power before modeling; Pb represents the turbine output power after modeling.

[0020] 2. The aerodynamic parameters of the guide vanes and moving vanes of turbine test pieces A and B are the same.

[0021] 3. When turbine test pieces A and B are tested separately, the test parameters should be kept consistent, that is, the inlet total temperature, total pressure and speed should be the same.

[0022] The advantages of this invention are: it can solve the problem of measuring the blower loss of double-layer turbine blades in reverse rotation, and is a blower loss measurement method that is simple to operate and has high measurement accuracy. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the turbine test piece A.

[0024] Figure 2 This is a schematic diagram of the turbine test piece B.

[0025] Figure 3 Layout diagram of the measurement system for turbine blade reverse-blowing loss;

[0026] Figure 4 This is a flowchart of the present invention. Detailed Implementation

[0027] The invention will now be described in more detail with reference to the accompanying drawings:

[0028] Combination Figure 1-4 Considering the large structural dimensions of marine reversible turbines, it is difficult to achieve full-scale blowout loss tests on double-layer turbine blades. Therefore, turbine modeling tests are conducted. The modeling ratio is rationally selected based on the actual dimensions of the reversible turbine, and the turbine is modeled. The modeled turbine is referred to as the turbine test piece. To measure the blowout loss caused by the reverse rotation of the turbine blades, two turbine test pieces with different structures are designed. Turbine Test Piece A: Equipped with a complete set of double-layer turbine blades and using a baffle structure to block airflow through the reversing passage. Turbine Test Piece B: Equipped only with forward-moving turbine blades. Apart from these differences, the other structures of the two turbine test pieces are identical.

[0029] Turbine test specimen A structure as follows Figure 1 As shown, turbine test piece A mainly consists of a casing 9, forward guide vanes 10, reverse guide vanes 11, reverse moving vanes 12, forward moving vanes 13, a diaphragm 14, a wheel 15, a support 16, a shaft 17, a coupling 18, and an exhaust pipe 19. The diaphragm 14 is an annular structure, located between the two casings. The inner ring of the diaphragm 14 cooperates with the reverse guide vanes 11 to seal the reversing passage, ensuring that the compressed air entering from the front can only drive the turbine rotor to rotate forward through the forward guide vanes 10 and the forward moving vanes 13. The rotor of turbine test piece A has a double-support cantilever structure, and a coupling 18 is equipped at the rear end of the shaft 17 for connection to the dynamometer.

[0030] Turbine test specimen B structure as follows Figure 2As shown, turbine test piece B mainly consists of a casing 1, a forward guide vane 2, a forward moving vane 3, a wheel disc 4, a support 5, a shaft 6, a coupling 7, and an exhaust pipe 8. Compressed air entering from the front drives the turbine rotor to rotate forward by passing through the forward guide vane 2 and the forward moving vane 3. The rotor of turbine test piece B has a double-support cantilever structure, and a coupling 18 is equipped at the rear end of shaft 17 for connection to a dynamometer.

[0031] The forward guide vane 10 has the same aerodynamic parameters as the forward guide vane 2, and the forward moving vane 13 has the same airfoil parameters as the forward moving vane 3. The two turbine test pieces have identical structures, including the wheel disc, support, shaft, coupling, and exhaust pipe.

[0032] The turbine test bench layout is as follows: Figure 3 As shown, the turbine test bench mainly consists of an air source 20, a regulating device 21, a diffuser section 22, a transition section 23, a turbine test piece 24, a coupling 25, and a dynamometer 26. Compressed air is used as the power source to rotate turbine test pieces A and B, and the output power is measured by the dynamometer 26. This test system is equipped with a flow regulating device 21, a diffuser section 22, and a transition section 23 to provide stable, adjustable-flow compressed air.

[0033] The operating parameters of the reversing turbine under rated operating conditions are modeled to obtain the inlet parameters of the turbine test piece. The main parameters include the total inlet temperature, total pressure, flow rate, and turbine rotor speed of the test piece.

[0034] Install turbine test piece A on the test bench, connect the inlet flange of turbine test piece A to the outlet flange of transition section 23, connect coupling 18 to dynamometer 26, and adjust the air source flow rate until the rated operating parameters of turbine test piece A are reached. After stabilizing for 10 minutes, complete the power measurement in Pa.

[0035] Install turbine test piece B on the test bench, connect the inlet flange of turbine test piece B to the outlet flange of transition section 23, connect coupling 7 to dynamometer 26, and adjust the air source flow rate until it reaches the rated operating parameters of turbine test piece A. After stabilizing for 10 minutes, complete the power Pb measurement.

[0036] When testing turbine test piece A and turbine test piece B, the test parameters should be consistent, that is, the inlet total temperature, inlet total pressure, speed and outlet static pressure should be the same.

[0037] Based on the modeling formula (see below), the power values ​​of the two turbine test pieces are converted to the output power before modeling, which are PA and PB, respectively.

[0038]

[0039] PA: Turbine output power before molding;

[0040] Pa: Turbine output power after modeling;

[0041] m: Turbine flow rate before modeling;

[0042] m*: Turbine flow rate after modeling;

[0043] T0: Turbine inlet temperature before molding;

[0044] T0*: Turbine inlet temperature after modeling;

[0045]

[0046] PB: Turbine output power before modeling;

[0047] Pb: Turbine output power after modeling;

[0048] m: Turbine flow rate before modeling;

[0049] m*: Turbine flow rate after modeling;

[0050] T0: Turbine inlet temperature before molding;

[0051] T0*: Turbine inlet temperature after modeling;

[0052] The blower loss due to the reverse turbine blades before modeling is PB-PA.

[0053] Considering the differences in turbine blade dimensions, gas temperature, gas pressure, and operating speed before and after modeling, finite element simulation is used to obtain the corresponding relationships between structural dimensions, gas temperature, gas pressure, operating speed, and turbine blade reversing airflow loss. A correction coefficient C for the reversing turbine blade reversing airflow loss is then obtained. The final reversing turbine blade airflow loss is calculated as P = C * (PB - PA).

[0054] The present invention has the following beneficial effects: The present invention provides a method for measuring turbine reverse blower loss that is simple to operate and has high measurement accuracy.

Claims

1. A method for measuring the blower loss of turbine blades in reverse rotation, characterized in that: Set up a molded turbine test piece A and a turbine test piece B. Turbine test piece A has double-layer turbine blades and uses a baffle structure to block airflow through the reversing passage. Turbine test piece B is based on turbine test piece A, including forward turbine blades and removing the reversing turbine blades. (1) The operating parameters under rated conditions are modeled to obtain the inlet parameters of turbine test pieces A and B, including the total inlet temperature, total pressure, flow rate and turbine rotor speed; (2) On the turbine test bench, connect the air source to the inlet of the turbine test piece A, connect the dynamometer to the output end of the turbine rotor of the turbine test piece A, increase the air source flow rate, so that the compressed air only flows through the forward blades, drive the turbine test piece A to rotate in the forward direction until the rated operating parameters of the turbine test piece A are reached, stabilize for 10 minutes, and complete the measurement of the output power Pa. (3) On the turbine test bench, connect the air source to the inlet of the turbine test piece B, connect the dynamometer to the output end of the turbine rotor of the turbine test piece B, increase the air source flow rate, so that the compressed air only flows through the forward blades, drive the turbine test piece B to rotate in the forward direction until the rated operating parameters of the turbine test piece B are reached, stabilize for 10 minutes, and complete the measurement of the output power Pb. (4) Based on the modeling formula, convert the power values ​​of turbine test pieces A and B to the output power before modeling, which are PA and PB respectively; (5) Calculate the reverse turbine blade reverse blowing loss PB-PA before modeling; (6) Considering the differences in structural dimensions, gas temperature, gas pressure, and operating speed parameters of turbine blades before and after modeling, the corresponding relationship between structural dimensions, gas temperature, gas pressure, operating speed and turbine blade reverse blowing loss is obtained through finite element simulation calculation, and the correction coefficient C of reverse blowing loss of turbine blades is obtained. (7) Obtain the final reversing turbine blade blower loss P=C*(PB-PA).

2. The method for measuring the reverse-flow blower loss of turbine blades according to claim 1, characterized in that: The calculation process for PA and PB in step (4) is as follows: PA represents the turbine output power before modeling; Pa represents the turbine output power after modeling; m represents the turbine flow rate before modeling; m* represents the turbine flow rate after modeling; T0 represents the turbine inlet temperature before modeling; T0* represents the turbine inlet temperature after modeling. PB represents the turbine output power before modeling; Pb represents the turbine output power after modeling.

3. The method for measuring the reverse-flow blower loss of turbine blades according to claim 1, characterized in that: The aerodynamic parameters of the guide vanes and moving vanes of turbine test pieces A and B are the same.

4. The method for measuring the reverse-flow blower loss of turbine blades according to claim 1, characterized in that: When turbine test pieces A and B are tested separately, the test parameters are kept consistent, that is, the inlet total temperature, total pressure and speed are the same.

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