A testing system and testing method for unsteady pressure on the surface of a vibrating blade

Abstract

The invention provides a system and a method for testing unsteady surface pressure of a vibrating blade. A direct-current shunt motor drives a tested turbine blade to carry out three-dimensional bending vibration, so that a blade vibration phase is locked by a photoelectric detection system, thereby triggering an external pressure sensor to acquire periodic unsteady blade surface pressure relateddata; and the data is analyzed; the distortion influence of a connecting pipe between a measurement point and the sensor on a measuring signal is corrected through a connecting pipe transfer function, so that the unsteady pressure of each measurement point on the surface of the tested vibrating blade and a phase difference between the unsteady pressure and the vibration displacement of the blade are obtained, therefore, the chordwise local aerodynamic damping and radial aerodynamic damping of the vibrating blade and the aerodynamic damping of the whole blade are determined and the aerodynamicelastic stability of the vibrating blade is judged through calculation by using an offline data analysis system. The system and the method are capable of improving the space resolution of the unsteady surface pressure measurement of the vibration blade, thus improving the accuracy of the integral aerodynamic damping of the blade.

Description

technical field [0001] The invention relates to a testing system and testing method for unsteady pressure on the surface of a vibrating blade, in particular to a testing system and a testing method for unsteady pressure on the surface of a vibrating blade based on an external pressure sensor and tube transfer function signal correction. Background technique [0002] The unsteady pressure on the surface of the vibrating blade is a periodic aerodynamic pressure induced by blade vibration that changes with time, and the unsteady pressure test system is a necessary test system to obtain the key parameter in the aeroelastic analysis of the vibrating blade of rotating machinery - aerodynamic damping. [0003] Usually, the traditional foreign blade surface unsteady pressure test system uses a miniature high-frequency pressure sensor built in the blade to be tested, and uses an accelerometer to synchronize the vibration displacement and measure the phase difference between the pressu...

AI Technical Summary

Problems solved by technology

The accuracy of the overall aerodynamic damping value of the vibrating structure given by the pressure signal obtained by this test system cannot fully meet the accuracy requirements for quantitative analysis of blade vibration stress in engineering and judgment of aeroelastic stability, nor can it fully meet the accuracy requirements for Checking accuracy requirements of computational fluid dynamics (CFD) numerical simulation models

The main disadvantages are as follows: the size of the miniature high-frequency pressure sensor required to measure the unsteady pressure on the blade surface limits the number of embedded pressure sensors on the blade surface, so that the spatial resolution of the acquired unsteady pressure on the blade surface is low, so that the Reduced accuracy of overall aerodynamic damping

Moreover, the installation of the miniature high-frequency pressure sensor cannot maintain the shape of the original profile of the blade, which will affect the flow state of the fluid; additional work is required to eliminate the temperature, installation stress and vibration acceleration for the measurement accuracy and durability of the miniature high-frequency pressure sensor The price of the miniature high-frequency pressure sensor is very expensive; especially the method of using the accelerometer to synchronize the phase difference between the vibration displacement and the pressure signal, on the one hand, occupies a limited number of measurement channels, on the other hand, increases the measurement data Post-processing difficulties

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