Supersonic free vortex mixing layer wind tunnel

Abstract

The invention provides a supersonic free vortex mixing layer wind tunnel. The wind tunnel comprises a transition section (1), a stabilizing section (2) and a spray pipe experimental section (3), wherein the transition section (1) is used for introducing air flow; the stabilizing section (2) is connected to the downstream side of the transition section (1) and is provided with a first separation plate (21) for separating the introduced air flow into two strands of air flow; the spray pipe experimental section (3) is connected to the downstream side of the stabilizing section (2) and comprises a spray pipe part (31) and a mixing experimental part (32); a transparent window is formed on the peripheral wall of the spray pipe experimental section (3); the spray pipe part (31) has a double freevortex spray pipe structure and is used for accelerating the two strands of air flow to form a free vortex state respectively; the mixing experimental part (32) is positioned on the downstream side of the spray pipe part (31) and is used for mixing the two strands of air flow in the free vortex state to form a free vortex mixing layer, so that velocity fields of the two strands of air flow at an inlet of the experimental part of the wind tunnel meet the requirement of supersonic free vortex distribution; therefore, an ideal supersonic free vortex mixing layer can be obtained in the wind tunnel.

Description

Technical field [0001] The invention relates to a wind tunnel, in particular to a supersonic free vortex mixed layer wind tunnel. Background technique [0002] The supersonic free vortex mixing layer refers to a flow field structure formed by mixing two supersonic airflows whose velocity distribution satisfies the free vortex relationship in a free or confined space. It is a typical mixed laminar flow field with flow direction curvature. The supersonic mixing layer affected by curvature is widely present in scramjets, supersonic ejectors, high-speed missile air curtain cooling optical windows, and aerodynamic windows of high-energy lasers. The flow stability, transition, and vortex structure involved are mutually exclusive. Problems such as effect and turbulence are far more complex than planar mixing layers, and have important engineering and theoretical value. Related research urgently needs to be carried out. [0003] The generation of supersonic free vortex mixed laminar flow ...

AI Technical Summary

Problems solved by technology

The existing mixed-layer wind tunnel structure is not conducive to reducing the turbulence of the incoming flow, especially the down-blown wind tunnel driven by the shock tube or high-pressure gas tank has a high Reynolds number, and the boundary layer of the nozzle wall and the partition plate turbulent flow

Turbulent fluctuations in the wall boundary layer interact with the mixed layer through Mach waves, and the vortex structure in the boundary layer of the partition plate directly sheds and affects the structure of the mixed layer. These uncontrollable turbulent characteristics bring great inconvenience to the study of the mixed layer

The existing planar mixed layer wind tunnel has a small width-to-height ratio and obvious sidewall effects. The development of the sidewall boundary layer greatly increases the complexity of the mixed layer flow field, which is not conducive to the study of its fine flow field structure.

The existing mixed-layer wind tunnels lack a good optical measurement environment, especially the influence of the incoming boundary layer is difficult to evaluate, which is also very unfavorable for the study of the historical effect of the mixed layer

[0014] In addition to the above problems, it is difficult to directly extend the existing planar mixed layer wind tunnel design technology to the free vortex mixed layer wind tunnel design

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