Correction method of high-altitude propeller wind tunnel test data for the influence of Reynolds number

Abstract

The invention provides a data correction method of a high-altitude propeller wind tunnel test for influence of Reynolds number. The data correction method comprises the following steps: according to the similarity criterion of an advance ratio and a tip Mach number, experimental parameters of the high-altitude propeller scale model wind tunnel test are determined; the wind tunnel test of the propeller scale model is carried out; a tension coefficient experimental value C<T,exp> and a power coefficient experimental value C<P,exp> are measured; the tension coefficient experimental value and thepower coefficient experimental value are corrected; and a corrected propeller propulsion efficiency is calculated according to a propeller propulsion efficiency formula. The invention takes into account the difference between the Reynolds number experimental value under the condition of the equal advance ratio and the equal tip Mach number and the Reynolds number under the real working condition of the high-altitude propeller; more accurate aerodynamic performance experimental data such as the high-altitude propeller tension coefficient, the power coefficient and the propulsion efficiency is obtained by using the proposed correction method; so reliable basic data is provided for designing a propulsion system and an energy system of a high-altitude low-dynamic aircraft.

Description

technical field [0001] The invention belongs to the technical field of propeller wind tunnel tests, and in particular relates to a high-altitude propeller wind tunnel test data correction method aimed at the influence of Reynolds number. Background technique [0002] When using the ground constant pressure wind tunnel to verify the aerodynamic performance of the high-altitude propeller scale model, according to the similarity theory of aerodynamics, it is necessary to satisfy the equal forward ratio, equal Reynolds number, and equal tip Mach number at the same time. The measured pull coefficient and power coefficient And propulsion efficiency is the actual performance of the corresponding full-size propeller under real working conditions. Moreover, to verify the aerodynamic performance at different heights, the diameters of the scaled models used in wind tunnel tests should also be different, and the resulting problems are: [0003] (1) It is necessary to process a set of h...

AI Technical Summary

Problems solved by technology

[0003] (1) It is necessary to process a set of high-altitude propeller scale models for each height, which increases the test cost, and there is uncertainty in the error caused by the processing accuracy of high-altitude propeller scale models of different sizes;

[0004] (2) The tension and torque of propeller scale models of different sizes vary greatly. If the same balance is used, the balance errors will be inconsistent; if balances with different ranges are used, the error rules of the entire test system will be inconsistent, and there are still uncertainties;

[0005] (3) The installation time of the propeller scale model is increased during the wind tunnel test, especially when the balance needs to be replaced according to the range, the installation and debugging time is longer, and the test cost is also increased;

[0006] (4) At certain altitudes (such as below 11km), the size of the propeller scaled model that satisfies equal forward ratio, equal Reynolds number, and equal tip Mach number is too large (for example, at a height of 5km, the diameter of a high-altitude propeller with a diameter of 5m, the diameter of the scaled model up to 3.3m), which exceeds the size of the wind tunnel test section and cannot be tested

The resulting problem is: if the tip Mach number of the high-altitude propeller is greater than 0.5 in real working conditions, the tip Mach number of the scaled propeller is close to the speed of sound, or even supersonic speed.

[0011] In short, limited by the actual conditions such as model size, minimum stable wind speed, measurement equipment, test cost, and test difficulty, the current domestic and foreign research on the aerodynamic performance test verification of high-altitude propellers usually All of them satisfy the conditions of equal forward ratio and equal tip Mach number, but ignore the influence of Reynolds number, resulting in the measured propeller pull coefficient, power coefficient, propulsion efficiency test data cannot accurately reflect the propeller aerodynamic performance under the real working conditions at high altitude, and The lower the Reynolds number, the greater the deviation

Images