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

Abstract

The invention provides a high-altitude propeller wind tunnel test data correction method aiming at the influence of a tip Mach number, which comprises the following steps of: determining test parameters of a wind tunnel test of a high-altitude propeller scaling model according to an advance ratio and a Reynolds number similarity criterion; performing the wind tunnel test on the propeller scaling model to obtain a tension coefficient test value C<T, exp> and a power coefficient test value C<p, exp>; and correcting the tension coefficient test value and the power coefficient test value, and calculating according to a propeller propulsion efficiency formula to obtain a corrected propeller propulsion efficiency. According to the high-altitude propeller wind tunnel test data correction method,the difference between a tip Mach number test value under the conditions of equal advance ratio and equal Reynolds number and a tip Mach number under the real working condition of a high-altitude propeller is considered, and the provided high-altitude propeller wind tunnel test data correction method is utilized to obtain accurate aerodynamic performance test data such as a tension coefficient, apower coefficient, a propulsion efficiency and the like of the high-altitude propeller, so that reliable basic data are provided for the design of 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 correction method for high-altitude propeller wind tunnel test data aimed at the influence of tip Mach 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 ...

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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 above 11km), the size of the propeller scale model that satisfies the equal advance ratio, equal Reynolds number, and equal tip Mach number is too small (for example, at a height of 20km, the diameter of the high-altitude propeller with a diameter of 3m, the diameter of the scaled model Only about 0.25m), it is difficult to ensure that the geometric shape of the propeller scale model is strictly proportional to the geometric shape of the full-scale propeller

[0010] 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 meet the conditions of equal forward ratio and equal Reynolds number, without considering the influence of propeller tip Mach number, resulting in the measured propeller pull coefficient, power coefficient, propulsion efficiency test data cannot accurately reflect the propeller aerodynamic performance under real working conditions at high altitude, And the larger the tip Mach number, the larger the deviation

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