| As one of the most important controlled quantities in aero-engines and measured quantities in its ground tests, fuel flowrate is of great importance in both estimating engine operation state and maneuvering aircraft. Turbine flowmeter is always chosen as the flowrate measurement device in ground tests for its high accuracy, good repeatability and other advantages. It has significant value doing research on dynamic calibration of turbine flowmeters.In order to meet the demands of performance evaluation in dynamic measurement of fuel flowrate, a dynamic flowmeter calibration method utilizing nozzle flapper valve was proposed based on a thorough understanding of flowmeter dynamic model. The differential pressure between two ends of fixed orifice was regarded as standard signal. The mathematical models aiming at two different driving solutions were established. Simulations based on AMESim and Simulink platform were carried out respectively under various working conditions. According to the time lag effect between excitation signal, pressure difference and flowmeter output, the dynamic characteristics of the calibration system was analyzed. The simulation results show that piezoelectric stack driven system has faster and more stable output compared with the torque motor system. Besides, the dynamic calibration test rig was designed and constructed. The test rig was controlled through upper computer, which was able to adjust the opening of nozzle-flapper assembly. The experiment results demonstrate that the system principle is correct and test rig is feasible. As the experiment results show, dynamic meter coefficient of the calibrated flowmeter is around 0.11 mL. |
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