A high-speed small-power turbine performance test method
By improving the turbine performance testing process and data processing methods, the problem of the impact of mechanical power consumption on high-speed, low-power turbines was solved, enabling accurate measurement of turbine efficiency and torque, and improving the precision and consistency of turbine performance testing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XIAN AEROSPACE PROPULSION INST
- Filing Date
- 2025-06-10
- Publication Date
- 2026-07-10
AI Technical Summary
In traditional turbine performance testing methods, the mechanical power consumption of high-speed, low-power turbines accounts for a large proportion, resulting in poor accuracy in turbine efficiency measurement and failing to meet the testing accuracy requirements of engine systems. In particular, the power consumption characteristics of components such as bearings and seals change nonlinearly with test speed and operating time, making them difficult to estimate accurately.
A high-speed, low-power turbine performance testing method is adopted. By conducting turbine output characteristic tests and power consumption characteristic tests in a preset sequence, the dynamometer is set to drive or load mode. Combined with the fixed flow rate and pressure supply of the cooling flow path, the turbine torque and efficiency are measured and corrected. The quadratic curve is used to simulate the power consumption and torque variation law, thereby reducing the random error in the test process.
It significantly improves the accuracy of turbine performance testing, accurately measures the combined power consumption of bearings and seals, corrects turbine output characteristics, and improves the accuracy and consistency of turbine efficiency measurement.
Smart Images
Figure CN120889682B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a test method for the performance of a high-speed, low-power turbine, belonging to the field of engine testing technology. Background Technology
[0002] In liquid rocket upper stages or space engines, high-pressure staged combustion cycle systems are becoming increasingly popular to improve engine performance. The turbopump, a crucial component of liquid rocket engines, supplies propellant at a specific pressure to the thrust chamber at a defined flow rate. The turbine uses high-temperature combustion gases generated by the gas generator as its working fluid, providing power to the pump. For low-thrust high-pressure staged combustion cycle engines, the turbine experiences high pressure, high speed, low flow rate, and low power. To balance the turbine's axial force, it is typically designed as a low-reaction transonic turbine. Although three-dimensional flow field simulation can predict turbine performance parameters, significant performance variations exist between multiple turbines due to differences in manufacturing precision, particularly in blade machining. Turbine efficiency and flow area are critical parameters for engine system tuning calculations, and accurate experimental results are essential to obtain the actual performance parameters for each turbine.
[0003] Traditional turbine performance testing uses a hydraulic or electric dynamometer as the load and hot air (40–150°C) as the turbine working fluid, simulating actual turbine operating conditions according to similarity conversion principles. By adjusting the dynamometer load, the turbine power output characteristics at different speeds are measured, and the turbine back pressure is adjusted through the turbine outlet orifice plate or regulating valve, thereby obtaining the turbine performance parameters as a function of speed ratio under different pressure ratios.
[0004] In actual testing, both the test piece and the test bench shaft system require bearing support. Bearings are typically cooled and lubricated using lubricating oil or water, necessitating dynamic seals at both ends of the cooling circuit to prevent leakage of the cooling medium. High-speed bearing operation and cooling medium flow both generate power consumption. Additionally, frictional power consumption occurs between the dynamic seals and the shaft system. This mechanical power consumption leads to a decrease in the measured turbine output torque, affecting the accuracy of turbine efficiency measurements. For engines with higher thrust, the turbine power is greater, resulting in a larger turbine output torque under test conditions. The mechanical power consumption of the test piece and test bench shaft system is relatively small, generally not exceeding 1% of the turbine output torque. A fixed correction factor can be used to correct the measured torque, or even, when the mechanical power consumption is very small, it can be ignored.
[0005] However, for low-thrust upper stages or space engines, under test conditions, the turbine output power is low, the speed is high, and the torque is low, with mechanical power consumption accounting for more than 10%. Accurate correction of the output torque is necessary to obtain accurate turbine efficiency. The power consumption of bearings, seals, etc., changes non-linearly with speed, and the power consumption also changes with the extension of test operation time as the seals wear. These factors mean that a fixed correction factor cannot characterize the actual power consumption characteristics. Summary of the Invention
[0006] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a high-speed, low-power turbine performance test method. This solves the problem that traditional turbine test methods are limited by the fact that the power consumption characteristics of bearings, seals, etc. in the test product assembly change nonlinearly and complexly with the test speed and operating time, and there are differences between test units. The actual power consumption is difficult to estimate accurately, resulting in poor turbine efficiency measurement accuracy and failing to meet the turbine performance test accuracy requirements of engine systems.
[0007] The technical solution of this invention is: a method for testing the performance of a high-speed, low-power turbine, comprising:
[0008] The test procedure includes turbine output characteristic tests and two power consumption characteristic tests of the turbine product conducted in a preset sequence. The turbine output characteristic tests include turbine output characteristic tests at various pressure ratios and repeated turbine output characteristic tests at the rated pressure ratio. The preset sequence is: first power consumption characteristic test of the turbine product, turbine output characteristic test at various pressure ratios, second power consumption characteristic test of the turbine product, and repeated turbine output characteristic test at the rated pressure ratio. The test speeds of the power consumption characteristic tests and the turbine output characteristic tests are consistent to ensure a one-to-one correspondence. During the power consumption characteristic tests, the dynamometer is set to drive mode, and the cooling flow path of the turbine product and the test fixture assembly is supplied with cooling water or lubricating oil at a fixed flow rate and pressure. The turbine product inlet valve is closed, and the turbine product blades are not driven by airflow.
[0009] The data processing flow uses the sequence number of the two turbine output characteristic tests as the independent variable and the torque of the two turbine product power consumption characteristic tests as the boundary condition to simulate the change of turbine power consumption torque with the test sequence. Based on the power consumption torque at different speed points under each pressure ratio of the turbine output characteristic test corresponding to each sequence number, the torque and turbine efficiency of the turbine output characteristic test are corrected.
[0010] Furthermore, the power consumption characteristic test and each turbine output characteristic test both involve steady-state data measurement at 11 uniformly distributed speeds. The 11 uniformly distributed speeds are 11 points between 0.2N0 and 1.2N0, where N0 is the test speed corresponding to the rated speed ratio under the rated pressure ratio. The steady-state time is 5 to 10 seconds at each speed, excluding the acceleration process.
[0011] Furthermore, during the turbine output characteristic test, the dynamometer is in load mode, the assembly cooling flow path supplies cooling water or lubricating oil at a fixed flow rate and pressure, the turbine product inlet valve is opened, and hot air is supplied to drive the turbine blades to do work.
[0012] Furthermore, during the turbine output characteristic test, the rotational speed, torque, turbine inlet and outlet gas pressure, turbine inlet gas temperature, and turbine inlet gas flow rate are measured to calculate the turbine efficiency and flow area before power consumption correction; during the turbine output characteristic test, the pressure between the turbine moving and stationary blades and the axial thrust are measured to calculate the turbine reaction force and axial force.
[0013] Furthermore, the power consumption characteristic test process only measures two parameters: rotational speed and torque, in order to calculate the power loss of the bearings, seals and cooling flow paths in the test assembly.
[0014] Furthermore, the sequence number i of the turbine output characteristic test at each pressure ratio is 1, 2, 3...K, where K is the number of test pressure ratios. The test sequence is to first perform the turbine output characteristic test at the rated pressure ratio, and then perform the turbine output characteristic test alternately at higher and lower pressure ratios.
[0015] Furthermore, the calculation of power consumption torque at different speed points under each pressure ratio includes:
[0016] Based on the variation of power consumption torque with test sequence number using a quadratic curve simulation, the power consumption torque at different speed points under each pressure ratio is calculated, and the corresponding curve equations and boundary conditions are as follows:
[0017] M'(i,n t )=A(n t [i-(K+2)] 2 +B(n t )
[0018] M'(0,n t )=M'1(n t )
[0019] M'(K+1,n t )=M'2(n t )
[0020] In the formula, M'(i,n) t This refers to the first turbine product's i-th turbine output characteristic test at an speed of n. t The power consumption torque correction at the operating point, M'1(n t ) and M'2(n t These represent the power consumption characteristic tests for the first and second turbine products, respectively, at a speed of n. tPower consumption torque value at the operating point; A(n) t ) and B(n t (n) represents the rotational speed. t The coefficients of the quadratic equation at the operating point are obtained by substituting the above boundary conditions into the quadratic equation; the subscript t indicates the turbine.
[0021] Furthermore, the correction of the torque and turbine efficiency in the turbine output characteristic test includes:
[0022] M e (i,n t )=M(i,n t )+M'(i,n t )
[0023]
[0024] In the formula, M(i,n) t ) and M e (i,n t (i) represents the first turbine product's i-th turbine output characteristic test, with a speed of n. t The measured and corrected torque values at the operating point, η(i,n) t ) and η e (i,n t (i) represents the first turbine product's i-th turbine output characteristic test, with a speed of n. t Turbine efficiency before and after correction at the operating point; the subscript t indicates the turbine.
[0025] Furthermore, the turbine product is subjected to repeated turbine output characteristic tests at the rated pressure ratio to obtain 11 data points. These data points are then combined with the 11 data points from the first turbine output characteristic test at the same rated pressure ratio to perform quadratic curve fitting, thereby obtaining the final test result of the turbine output characteristic test at the rated pressure ratio, in order to reduce random errors in the test process; the subscript t indicates the turbine.
[0026] Furthermore, the relationship curves between turbine efficiency, flow area, reaction force, axial force and turbine speed ratio under various pressure ratio conditions in the turbine output characteristic test of the turbine product are obtained by least squares fitting, and the fitted curves are quadratic curves.
[0027] The advantages of this invention compared to the prior art are:
[0028] (1) By improving the test process, this invention utilizes the power consumption characteristic test under the speed conditions that correspond one-to-one with the turbine output characteristic test to accurately measure the relationship between the comprehensive power consumption of the bearing, seal and its cooling flow path and the test speed, and corrects the turbine output torque and power accordingly. This achieves the technical effect of considering the influence of speed change and test batch difference to correct the output characteristics and significantly improve the test accuracy.
[0029] (2) This invention sets up a power consumption characteristic test before and after the turbine output characteristic test, and uses a quadratic curve to simulate the change law of the comprehensive power consumption of the test product with the operating time (wear), and obtains the actual power consumption of each output characteristic test. It realizes the technical effect of correcting the output characteristics by considering the influence of operating time (wear) and accurately obtaining the turbine efficiency under different pressure ratio conditions.
[0030] (3) The present invention uses repeated turbine output characteristic tests at rated pressure ratio and the results of the first turbine output characteristic test at the same pressure ratio as effective data points for fitting, thereby reducing random errors in the test process and further improving the accuracy of turbine performance testing under rated conditions. Attached Figure Description
[0031] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:
[0032] Figure 1 This is a schematic diagram of the turbine performance testing method of the present invention;
[0033] Figure 2 This is a schematic diagram of a typical acceleration process curve of the present invention;
[0034] Figure 3 This is a schematic diagram showing the relationship between power and torque as a function of rotational speed, as measured by the power consumption characteristic test of this invention.
[0035] Figure 4 This is a schematic diagram showing the relationship between turbine efficiency and turbine speed ratio before and after correction at the rated pressure ratio of this invention. Detailed Implementation
[0036] To better understand the above technical solutions, the technical solutions of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solutions of the present invention, rather than limitations on the technical solutions of the present invention. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.
[0037] The following description, in conjunction with the accompanying drawings, provides a more detailed explanation of a high-speed, low-power turbine performance testing method provided by an embodiment of the present invention. Specific implementation methods may include:
[0038] The test procedure includes turbine output characteristic tests and two power consumption characteristic tests of the turbine product conducted in a preset sequence. The turbine output characteristic tests include turbine output characteristic tests at various pressure ratios and repeated turbine output characteristic tests at the rated pressure ratio. The preset sequence is: first power consumption characteristic test of the turbine product, turbine output characteristic test at various pressure ratios, second power consumption characteristic test of the turbine product, and repeated turbine output characteristic test at the rated pressure ratio. The test speeds of the power consumption characteristic tests and the turbine output characteristic tests are consistent to ensure a one-to-one correspondence. During the power consumption characteristic tests, the dynamometer is set to drive mode, and the cooling flow path of the turbine product and the test fixture assembly is supplied with cooling water or lubricating oil at a fixed flow rate and pressure. The turbine product inlet valve is closed, and the turbine product blades are not driven by airflow.
[0039] The data processing flow uses the sequence number of the two turbine output characteristic tests as the independent variable and the torque of the two turbine product power consumption characteristic tests as the boundary condition to simulate the change of turbine power consumption torque with the test sequence. Based on the power consumption torque at different speed points under each pressure ratio of the turbine output characteristic test corresponding to each sequence number, the torque and turbine efficiency of the turbine output characteristic test are corrected.
[0040] Furthermore, the power consumption characteristics and turbine output characteristics of the product were tested by measuring steady-state data at 11 speeds evenly distributed from 0.2N0 to 1.2N0, where N0 is the test speed corresponding to the rated speed ratio under the rated pressure ratio, and the steady-state data was measured for 5 to 10 seconds at each speed (excluding the acceleration process).
[0041] In one possible implementation, the dynamometer in the product power consumption characteristic test process is in drive mode, the cooling flow path of the turbine product assembly supplies cooling water or lubricating oil at a fixed flow rate and pressure, the turbine product inlet valve is closed, and the turbine blades are driven without airflow.
[0042] In one possible implementation, the product power consumption characteristic test process measures only two parameters: rotational speed and torque, in order to calculate the power loss of the bearings, seals and cooling flow paths in the turbine product assembly under test.
[0043] Furthermore, in one possible implementation, the dynamometer in the turbine output characteristic test process is in load mode, the turbine product assembly cooling flow path supplies cooling water or lubricating oil at a fixed flow rate and pressure, the turbine product inlet valve is opened, and hot air is supplied to drive the turbine blades to do work.
[0044] Optionally, in one possible implementation, the turbine output characteristic test process measures parameters such as rotational speed, torque, turbine inlet and outlet gas pressure, turbine inlet gas temperature, and turbine inlet gas flow rate to calculate turbine efficiency (before power consumption correction) and equivalent flow area.
[0045] In one possible implementation, the turbine output characteristic test process measures the pressure between the turbine blades and the axial thrust to calculate the turbine reaction force and axial force.
[0046] Furthermore, the test sequence number i for the turbine output characteristics at each pressure ratio is 1, 2, 3...K, where K is the number of test pressure ratios. The preferred test sequence is to first test at the rated pressure ratio, and then alternate between higher and lower pressure ratios.
[0047] In one possible implementation, the power consumption torque varies with the test sequence number according to a quadratic curve, and the corresponding curve equation and boundary conditions are as follows:
[0048] M'(i,n t )=A(n t [i-(K+2)] 2 +B(n t )
[0049] M'(0,n t )=M'1(n t )
[0050] M'(K+1,n t )=M'2(n t )
[0051] In the formula, M'(i,n) t (i) represents the i-th turbine output characteristic test at a speed of n. t The power consumption torque correction at the operating point, M'1(n t ) and M'2(n t These represent the first and second product power consumption characteristic tests, with a rotational speed of n. t The power consumption and torque value at the operating point. A(n) t ) and B(n t (n) represents the rotational speed. t The coefficients of the quadratic equation at the operating point are obtained by substituting the above boundary conditions into the quadratic equation.
[0052] In one possible implementation, the torque and turbine efficiency correction formulas for the turbine output characteristic test are as follows:
[0053] M e (i,n t )=M(i,n t )+M'(i,n t )
[0054]
[0055] In the formula, M(i,n) t ) and M e (i,nt (i) represents the i-th turbine output characteristic test, with a speed of n. t The measured and corrected torque values at the operating point, η(i,n) t ) and η e (i,n t (i) represents the i-th turbine output characteristic test, with a speed of n. t Turbine efficiency before and after the correction at the operating point.
[0056] In one possible implementation, the relationship curves between turbine efficiency, flow area, reaction force, axial force and turbine speed ratio under each pressure ratio condition are obtained by least squares fitting, and the better fitting curve is a quadratic curve.
[0057] In one possible implementation, the repeated turbine output characteristic test at the rated pressure ratio uses the same method to correct the turbine efficiency, with the corresponding test number i being K+2, and the power consumption correction amount M'(i,n) t ) is B(n t ).
[0058] Optionally, in one possible implementation, the repeated turbine output characteristic test at the rated pressure ratio yields 11 data points, which are then combined with the 11 data points from the first test at the same pressure ratio to perform quadratic curve fitting, thereby obtaining the final test result at the rated pressure ratio, in order to reduce random errors in the test process.
[0059] In the solution provided in the embodiments of the present invention, reference is made to... Figure 1 This invention provides a high-speed, low-power turbine performance testing method. The test flow diagram is as follows: Test start > First product power consumption characteristic test (sequence number 0) > Turbine output characteristic test at various pressure ratios (sequence numbers 1 to K) > Second product power consumption characteristic test (sequence number K+1) > Rated pressure ratio repeated turbine output characteristic test (sequence number K+2) > Test end;
[0060] The experimental data processing flowchart is as follows: Data processing start > Calculate power consumption equation coefficients A and B > Calculate power consumption torque correction for each sequence number > Repeat the test at each pressure ratio / rated pressure ratio to correct turbine output torque and efficiency > Obtain turbine performance curve by quadratic curve fitting > Data processing end;
[0061] The experimental data processing is carried out after the experimental process is completed, and the final turbine performance is obtained after data processing.
[0062] The following example, using a turbine performance test of a liquid rocket engine, illustrates the specific implementation method.
[0063] The test system mainly includes the turbine product assembly under test, a hot air supply system, and a dynamometer system. The dynamometer system includes an electric dynamometer, a torque meter, and a coupling. The electric dynamometer can be used as a load for dynamometer testing or as a drive motor, and it has a constant speed regulation function. The torque meter is installed between the product under test and the dynamometer; the measured torque is the torque output or consumed by the turbine product, eliminating the influence of the dynamometer's own mechanical efficiency.
[0064] First, the turbine assembly under test is connected to the test bench and, after normal debugging, the test begins. The test procedure is as follows: first product power consumption characteristic test, turbine output characteristic test at various pressure ratios, second product power consumption characteristic test, and repeated turbine output characteristic test at rated pressure ratio. The purpose of the two product power consumption characteristic tests is to obtain the power consumption characteristics generated by the bearings, seals, and their cooling flow paths, as a basis for correcting the turbine output torque and efficiency. The purpose of the repeated turbine output characteristic test at rated pressure ratio is to reduce random errors in the test process.
[0065] To facilitate the correction of turbine output torque at various speeds, the product's power consumption characteristics and turbine output characteristics tests were conducted under completely consistent speed conditions. Steady-state data measurements were performed at 11 speeds evenly distributed between 0.2N0 and 1.2N0, where N0 is the test speed corresponding to the rated speed ratio at the rated pressure ratio. The test speeds correspond to the turbine speed ratio range. Based on the efficiency characteristics of typical transonic turbines and the requirements of variable operating conditions in the engine system, the speed range was selected as 0.2 to 1.2 times the rated speed. Stabilization at each speed was maintained for 5–10 seconds (excluding the acceleration process), which meets the requirement for stable data acquisition. A typical acceleration process is shown below. Figure 2 As shown. During a single power consumption characteristic or turbine output characteristic test, the speed increases in a step-like manner, with each speed step stabilizing for approximately 5–10 seconds. After reaching the maximum speed and stabilizing for 5–10 seconds, the test bench cuts off the air supply (dynamometer load mode) or shuts down the dynamometer motor control (dynamometer drive mode), and the speed rapidly drops to 0.
[0066] During the product power consumption characteristic test, the dynamometer is in drive mode, and the cooling flow path of the turbine product assembly is supplied with cooling water or lubricating oil at a fixed flow rate and pressure. The turbine product inlet valve is closed, and the turbine blades are not driven by airflow. The test process only measures two parameters: speed and torque, to calculate the power loss of the bearings, seals, and cooling flow path in the tested turbine product assembly.
[0067] During turbine output characteristic testing, the dynamometer is in load mode. The turbine assembly's cooling flow path supplies cooling water or lubricating oil at a fixed flow rate and pressure. The turbine inlet valve is open, supplying hot air to drive the turbine blades. During the test, parameters such as rotational speed, torque, turbine inlet and outlet gas pressure, turbine inlet gas temperature, and turbine inlet gas flow rate are measured to calculate turbine efficiency (before power consumption correction) and equivalent flow area. Simultaneously, the pressure between the turbine's moving and stationary blades and the axial thrust are measured to calculate turbine reaction force and axial force.
[0068] When conducting turbine output characteristic tests at various pressure ratios, the test sequence number i is sequentially assigned the value 1, 2, 3...K, where K is the number of test pressure ratios. The optimal test sequence is to first test at the rated pressure ratio, then alternate between higher and lower pressure ratios. During the test, as the operating time increases, the sealing lip gradually wears, and the power consumption torque gradually decreases. According to the wear law of dynamic seals, the change in power consumption torque can be simplified as a quadratic curve variation following the test sequence number. The corresponding curve equation and boundary conditions are as follows:
[0069] M'(i,n t )=A(n t [i-(K+2)] 2 +B(n t )
[0070] M'(0,n t )=M'1(n t )
[0071] M'(K+1,n t )=M'2(n t )
[0072] In the formula, M'(i,n) t (i) represents the i-th turbine output characteristic test at a speed of n. t The power consumption torque correction at the operating point, M'1(n t ) and M'2(n t These represent the first and second product power consumption characteristic tests, with a rotational speed of n. t The power consumption and torque value at the operating point. A(n) t ) and B(n t (n) represents the rotational speed. t The coefficients of the quadratic equation at the operating point are obtained by substituting the above boundary conditions into the quadratic equation.
[0073] Based on the calculated power consumption torque correction, the torque and turbine efficiency of the turbine output characteristic test are corrected using the following formula:
[0074] M e (i,n t )=M(i,nt )+M'(i,n t )
[0075]
[0076] In the formula, M(i,n) t ) and M e (i,n t (i) represents the i-th turbine output characteristic test, with a speed of n. t The measured and corrected torque values at the operating point, η(i,n) t ) and η e (i,n t (i) represents the i-th turbine output characteristic test, with a speed of n. t Turbine efficiency before and after the correction at the operating point.
[0077] After obtaining the turbine efficiency under various pressure ratios using the above correction method, the relationship curves between turbine efficiency, flow area, reaction force, axial force, and turbine speed ratio are fitted according to the quadratic curve law under each pressure ratio condition. The least squares method can be used for fitting. The final set of fitted curves characterizes the turbine's full operating range characteristics.
[0078] Experimental measurements introduce some random errors. To improve performance accuracy under rated pressure ratio conditions, the turbine output characteristic test under rated pressure ratio is repeated once. After the repeated test, the turbine efficiency is corrected using the same method. The corresponding test number i is set to K+2, and the power consumption correction amount M'(i,n) t ) is B(n t Based on two turbine output characteristic tests at rated pressure ratio, a total of 22 valid data points were obtained. These data points were used to perform quadratic curve fitting to obtain the final test results at rated pressure ratio, thereby reducing random errors in the test process.
[0079] like Figure 3 In the graph, the horizontal axis represents turbine speed (divided by the rated test speed and then dimensionless), the left vertical axis represents shaft power consumption (divided by the turbine's rated output power and then dimensionless), and the right vertical axis represents power consumption torque (divided by the turbine's rated output torque and then dimensionless). As can be seen from the graph, power consumption torque and shaft power consumption exhibit a non-linear relationship with speed. At the rated test speed, power consumption torque accounts for approximately 9%. Without output torque correction, turbine efficiency would be significantly underestimated. Furthermore, since the proportion of shaft power consumption varies significantly with speed, using a fixed mechanical efficiency correction cannot accurately reflect the actual power consumption changes, leading to severe distortion of the turbine efficiency curve.
[0080] like Figure 4In the figure, the horizontal axis represents the turbine speed ratio, and the vertical axis represents the turbine efficiency. The circled data point fitting curve represents the efficiency obtained from the first turbine output characteristic test at rated pressure ratio (before correction), while the triangular data point fitting curve represents the efficiency obtained from the second (repeated) turbine output characteristic test at rated pressure ratio (before correction). The value of the triangular data point fitting curve is significantly higher than that of the circled data point fitting curve. This is because the shaft power consumption decreases significantly with increasing operating time, leading to an increase in the measured turbine output power over time. Therefore, turbine efficiency correction must consider the change in shaft power consumption with operating time. The square data point fitting curve represents the turbine efficiency correction curve after correction according to the method described in this invention. The result is consistent with the design simulation calculation result. Multiple engine test runs have verified that the turbine efficiency correction method proposed in this invention is accurate and reliable.
[0081] The method described in this invention was used to complete multiple turbine performance tests on a liquid rocket engine, obtaining accurate turbine performance parameters, which were verified through multiple hot-fire tests of the entire engine.
[0082] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
[0083] The contents not described in detail in this specification are common knowledge to those skilled in the art.
Claims
1. A method for testing the performance of a high-speed, low-power turbine, characterized in that, include: The test procedure includes turbine output characteristic tests and two power consumption characteristic tests of the turbine product conducted in a preset sequence. The turbine output characteristic tests include turbine output characteristic tests at various pressure ratios and repeated turbine output characteristic tests at the rated pressure ratio. The preset sequence is: first power consumption characteristic test of the turbine product, turbine output characteristic test at various pressure ratios, second power consumption characteristic test of the turbine product, and repeated turbine output characteristic test at the rated pressure ratio. The test speeds of the power consumption characteristic tests and the turbine output characteristic tests are consistent to ensure a one-to-one correspondence. During the power consumption characteristic tests, the dynamometer is set to drive mode, and the cooling flow path of the turbine product and the test fixture assembly is supplied with cooling water or lubricating oil at a fixed flow rate and pressure. The turbine product inlet valve is closed, and the turbine product blades are not driven by airflow. The data processing flow uses the sequence number of the two turbine output characteristic tests as the independent variable and the torque of the two turbine product power consumption characteristic tests as the boundary condition to simulate the change of turbine power consumption torque with the test sequence. Based on the power consumption torque at different speed points under each pressure ratio of the turbine output characteristic test corresponding to each sequence number, the torque and turbine efficiency of the turbine output characteristic test are corrected.
2. The method for testing the performance of a high-speed, low-power turbine according to claim 1, characterized in that, The power consumption characteristic test and each turbine output characteristic test both involve steady-state data measurement at 11 uniformly distributed speeds. The 11 uniformly distributed speeds are 11 points between 0.2N0 and 1.2N0, where N0 is the test speed corresponding to the rated speed ratio under the rated pressure ratio. The steady-state time is 5 to 10 seconds at each speed, excluding the acceleration process.
3. The method for testing the performance of a high-speed, low-power turbine according to claim 1, characterized in that, During the turbine output characteristic test, the dynamometer is in load mode, the assembly cooling flow path supplies cooling water or lubricating oil at a fixed flow rate and pressure, the turbine product inlet valve is opened, and hot air is supplied to drive the turbine blades to do work.
4. The method for testing the performance of a high-speed, low-power turbine according to claim 1, characterized in that, During the turbine output characteristic test, the turbine speed, torque, turbine inlet and outlet gas pressure, turbine inlet gas temperature, and turbine inlet gas flow rate are measured to calculate the turbine efficiency and flow area before power consumption correction. During the turbine output characteristic test, the pressure between the turbine moving and stationary blades and the axial thrust are measured to calculate the turbine reaction force and axial force.
5. The method for testing the performance of a high-speed, low-power turbine according to claim 4, characterized in that, The power consumption characteristic test process only measures two parameters: rotational speed and torque, in order to calculate the power loss of the bearings, seals and cooling flow paths in the test assembly.
6. The method for testing the performance of a high-speed, low-power turbine according to claim 4, characterized in that, The sequence number i of the turbine output characteristic test at each pressure ratio is 1, 2, 3...K, where K is the number of test pressure ratios. The test order is to first perform the turbine output characteristic test at the rated pressure ratio, and then perform the turbine output characteristic test alternately at higher and lower pressure ratios.
7. The method for testing the performance of a high-speed, low-power turbine according to claim 4, characterized in that, The calculation of power consumption torque at different speed points under various pressure ratios includes: Based on the variation of power consumption torque with test sequence number using a quadratic curve simulation, the power consumption torque at different speed points under each pressure ratio is calculated, and the corresponding curve equations and boundary conditions are as follows: M'(i,n t )=A(n t )[i-(K+2)] 2 +B(n t ) M'(0,n t )=M'1(n t ) M'(K+1,n t )=M'2(n t ) In the formula, M'(i,n) t This refers to the first turbine product's i-th turbine output characteristic test at an speed of n. t The power consumption torque correction at the operating point, M'1(n t ) and M'2(n t These represent the power consumption characteristic tests for the first and second turbine products, respectively, at a speed of n. t Power consumption torque value at the operating point; A(n) t ) and B(n t (n) represents the rotational speed. t The coefficients of the quadratic equation at the operating point are obtained by substituting the above boundary conditions into the quadratic equation; the subscript t indicates the turbine.
8. The method for testing the performance of a high-speed, low-power turbine according to claim 7, characterized in that, The correction of torque and turbine efficiency in the turbine output characteristic test includes: M e (i,n t )=M(i,n t )+M'(i,n t ) In the formula, M(i,n) t ) and M e (i,n t (i) represents the first turbine product's i-th turbine output characteristic test, with a speed of n. t The measured and corrected torque values at the operating point, η(i,n) t ) and η e (i,n t (i) represents the first turbine product's i-th turbine output characteristic test, with a speed of n. t Turbine efficiency before and after correction at the operating point; the subscript t indicates the turbine.
9. The method for testing the performance of a high-speed, low-power turbine according to claim 8, characterized in that, The turbine product was subjected to repeated turbine output characteristic tests at the rated pressure ratio to obtain 11 data points. These data points were then combined with the 11 data points from the first turbine output characteristic test at the same rated pressure ratio to perform quadratic curve fitting, thereby obtaining the final test results of the turbine output characteristic test at the rated pressure ratio and reducing random errors in the test process. The subscript t indicates the turbine.
10. The method for testing the performance of a high-speed, low-power turbine according to claim 4, characterized in that, The relationship curves between turbine efficiency, flow area, reaction force, axial force and turbine speed ratio under various pressure ratio conditions in the turbine output characteristic test of the turbine product were obtained by least squares fitting, and the fitted curves are quadratic curves.