Axisymmetric Continuously Variable Mach Number Nozzle and Its Wall Surface Determination Method

Abstract

The invention discloses an axisymmetric continuous variable Mach spray pipe and a wall determining method thereof. The wall determining method comprises the steps as follows: a rotation axis, a known wall curve, a plug wall curve matched with the known wall curve and the relation curve of the precession distance of a plug mechanism and Mach are determined according to the structural design requirements of the spray pipe; the corresponding wall curve to be obtained is determined by utilizing a characteristic method according to the relation curve of the precession distance of a plug mechanism and Mach when the plug mechanism is in the current position; the position of the plug mechanism on the rotation axis is changed, and the wall curves to be obtained in various sections are determined step by step; in addition, a wall of the axisymmetric continuous variable Mach spray pipe is determined according to the known wall curve, the plug wall curve matched with the known wall curve and the wall curves to be obtained in various sections. By adopting the wall determining method, the fluid field homogeneity degree of the determined axisymmetric continuous variable Mach spray pipe is less than 1 percent, and is increased by one order of magnitude as compared with the traditional technology; and the sensitivity of Mach on the precession distance can be controlled.

Description

technical field [0001] The invention relates to the technical field of supersonic nozzle design, in particular to an axisymmetric continuously variable Mach number nozzle and a method for determining its wall surface. Background technique [0002] Supersonic / hypersonic nozzles are widely used in high-speed aircraft, rockets, supersonic wind tunnels, high-energy lasers, ejector vacuum pumps and other equipment. The quality of the nozzle flow field has an important impact on the performance of the equipment. Obtaining an appropriate nozzle wall curve through certain design techniques can greatly improve the quality of the nozzle flow field, improve equipment performance, and save research funds. The supersonic nozzle is generally composed of a constriction section and an expansion section. Driven by a certain pressure, the gas gradually accelerates in the constriction section and reaches the speed of sound near the throat, and then continues to accelerate in the expansion sect...

AI Technical Summary

Problems solved by technology

[0007] 1. The throat curve and plug cone curve of the nozzle are constrained only by the relationship between the flow rate and the Mach number, without considering the two-dimensional and three-dimensional characteristics of the flow;

[0008] 2. The design of the plug cone surface does not consider wave dissipation, resulting in poor quality of the outlet flow field, and even the unevenness of the Mach number is higher than 30%, which has a great impact on the accuracy of the experimental data

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