A Method for Measuring Surface Friction with Double Friction Balance
A measurement method and balance technology, applied in the field of wind tunnel testing, can solve problems such as friction measurement error and friction balance measurement interference, and achieve the effect of eliminating errors, reducing errors and improving overall efficiency
Active Publication Date: 2020-02-21
中国空气动力研究与发展中心超高速空气动力研究所
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Problems solved by technology
In most cases, there is a pressure gradient in the flow direction of the measurement environment pressure acting on the friction balance measurement surface. When there is a pressure gradient on the friction balance measurement surface, the resultant force point of the measurement environment pressure must deviate from the friction balance measurement surface. The center of the friction balance is equivalent to an eccentric moment acting on the measurement surface of the friction balance. This eccentric moment will interfere with the measurement output of the friction balance, which will inevitably bring errors to the friction measurement. Therefore, it is urgently needed Develop a friction measurement method that can eliminate the error caused by eccentric torque
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Embodiment 1
[0026] The first step is to select two friction balances with good calibration results from the number of friction balances that have been produced and preliminarily calibrated according to the requirements of the wind tunnel test measurement points for the surface friction measurement of the test model 1; according to Wind tunnel test model design specification design and figure 1 Similar to test model 1, according to the requirements of the number of measurement points in the wind tunnel test for surface friction measurement of test model 1 and the selected friction balance structure size, determine the position of the measuring point on test model 1 and the form of the opening measurement hole. The shape of the measuring head of the resistance balance is rectangular or circular. The opening form of the surface friction measuring hole I2 of the test model 1 is consistent with the shape of the measuring head of the friction balance. The size of the opening of the friction meas...
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The invention discloses a double-friction balance measurement method for the surface friction. The measurement method is used for measuring the friction resistance of a test model surface in a tunneltest. According to the measurement method, friction balances in a pair are arranged at a longitudinal symmetric surface of a test model symmetrically, so that an error caused by a torque generated bya measurement environment pressure intensity or pressure intensity gradient on the measurement surfaces of the friction balances is eliminated; the pressure intensity interference calibration link isreduced and the overall efficiency of the measurement study is improved; and error occurrence caused by the asymmetry of the wind tunnel flow field is reduced.
Description
technical field [0001] The invention belongs to the field of wind tunnel tests, and in particular relates to a method for measuring surface frictional resistance of a test model. Background technique [0002] Surface frictional resistance, that is, frictional resistance, greatly limits the performance of hypersonic vehicles. The research results of C. P. Goyne, R. J.Stalker, and A. Paull in "Shock tunnel skinfriction measurement in a supersoniccombustor" (AIAA -98-0943) show that: In the test model of fuel ramjet engine, its frictional resistance can account for about 28% of the total resistance. During the flight of a hypersonic vehicle, in addition to the induced resistance, the resistance it encounters is mainly composed of two parts, one is the resistance generated by the shock wave, that is, wave resistance; the other is the resistance generated by friction, that is, friction. The wave resistance is related to the flight Mach number, while the frictional resistance is ...
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IPC IPC(8): G01M9/06
CPCG01M9/062
Inventor 吕治国赵荣娟黄军
Owner 中国空气动力研究与发展中心超高速空气动力研究所