A method for measuring internal flow resistance in wind tunnel tests

Abstract

The invention relates to a method for measuring the resistance of an internal flow of an air vehicle in a wind tunnel at high precision, and belongs to the technical field of the wind tunnel test. Aiming at the problem that the traditional technique for measuring the resistance of the internal flow through the change of pipe flow is not accurate, the invention provides the novel high-precision internal flow resistance measurement method, the method comprises three steps of measuring PIV (Particle Image Velocimetry) of a three-dimensional velocity vector field of the cross section of an outlet,measuring the static pressure-total pressure through a movable pressure measurement rake in a sweeping way, and implementing postprocessing of data. The three-dimensional velocity vector field in thecross section area of the outlet of an inner runner is accurately acquired through the PIV measurement technology, the boundary of the internal flow and an external flow is accurately divided, and the measurement value of a total pressure / static pressure probe is corrected through the three-dimensional velocity vector angle. By moving a controllable pressure measurement rake mechanism to scan andmeasure the pressure in a sweeping way, the data acquisition densities of the total pressure and static pressure measurement points in the cross section area of the outlet of the inner runner are greatly improved, the precision of the whole internal flow resistance measurement method is comprehensively improved from aspects of the quantity of information of test data and the data correction.

Description

technical field [0001] The invention relates to a method suitable for high-precision measurement of the internal flow resistance of an aircraft in a wind tunnel, and belongs to the technical field of wind tunnel tests. Background technique [0002] The internal flow resistance of the aircraft is closely related to the overall aerodynamic characteristics of the aircraft, and its measurement accuracy directly affects the evaluation of the aerodynamic performance of the aircraft. At the same time, with the improvement of the flight Mach number (Ma), the size of the engine relative to the airframe continues to increase, and the proportion of the entire internal flow path resistance to the entire aircraft continues to rise. Therefore, how to measure the internal flow resistance with high precision is of increasing importance to the development of aircraft. significance and value. [0003] At present, there are three main types of measurement methods for internal flow resistance ...

AI Technical Summary

Problems solved by technology

The second method is mainly limited by the influence of the arrangement density of the pressure measuring points on the wall of the inner flow channel and cannot obtain high-precision internal flow resistance. For example, the wall thickness of the model cannot arrange pressure measuring points near the front edge, It is also difficult to effectively arrange pressure measuring points near the complex curved surface of the inner flow channel

In recent years, preliminary research has been carried out and certain results have been achieved. However, the two-dimensional PIV technology is mainly used to measure the velocity field of the longitudinal section at the outlet of different internal flow channels, and a large number of total pressure probes are arranged at the outlet to measure rakes. The pressure measurement error caused by the limited number of pressure rake probes and the airflow deflection angle and the accurate distinction between the inner and outer outlet boundaries are still unresolved, and new test methods need to be explored for research

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