Supersonic plane mixing layer wind tunnel

Abstract

The invention provides a supersonic plane mixing layer wind tunnel which comprises a transition section (1), a stable section (2) and a spray pipe experiment section (3), wherein the transition section (1) is used for inducing an air flow; the stable section (2) is connected at the downstream of the transition section (1) and is provided with a first partition plate (21); and the spray pipe experiment section (3) is connected at the downstream of the stable section (2) and comprises mutually parallel upper peripheral wall (3a) and lower peripheral wall (3b) and two side walls connected with the upper peripheral wall (3a) and the lower peripheral wall (3b). A spray pipe part (31) and a mixing part (32) are formed, wherein a spray pipe fixing block (33) is arranged at the spray pipe part, and the upper surface and the lower surface of the spray pipe fixing block (33) respectively form a spray pipe profile. The supersonic plane mixing layer wind tunnel provided by the invention has good two-dimensional characteristic of a flow field and is convenient to implement the optical testing technology.

Description

technical field [0001] The invention relates to a wind tunnel, in particular to a supersonic plane mixed layer wind tunnel. Background technique [0002] The supersonic planar mixing layer refers to the flow field structure formed by the mixing of two parallel supersonic airflows with different flow parameters in a free or confined space, which widely exists in scramjet engines, supersonic ejectors, high-speed missile air curtain cooling optical windows and In flow fields such as aerodynamic windows of high-energy lasers, the problems involved in flow stability, transition, vortex structure interaction, and turbulence are far more complicated than incompressible mixed layers, which have important engineering and theoretical values, and related research needs to be carried out in depth. [0003] The supersonic planar mixed layer wind tunnel is a necessary experimental device for generating supersonic mixed laminar flow field. Generally, two supersonic nozzles are used to gen...

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Problems solved by technology

[0006] The existing technology uses a flat plate with a certain thickness to separate the upper and lower nozzles. If the width of the dividing plate is too small, the development of the boundary layer on the side wall will reduce the two-dimensional characteristics of the plane mixed layer. It is easy to deform, which will also reduce the two-dimensional characteristics of the flow field

[0007] The existing mixed layer wind tunnel does not take rectification measures to reduce the turbulence of the incoming flow

In particular, the downblown wind tunnel driven by a shock tube or a high-pressure gas tank has a high Reynolds number, the boundary layer between the nozzle wall and the partition plate is a turbulent flow state, and the wall boundary layer disturbance passes through the Mach wave and the mixing layer. interaction, the vortex structure of the boundary layer of the partition plate directly sheds and affects the structure of the mixed layer, and these uncontrollable turbulent characteristics bring great inconvenience to the study of the mixed layer

[0008] Although most of the existing mixed-layer wind tunnels have optical windows, the size and layout of the windows cannot be directly applied to the supersonic planar mixed-layer wind tunnel device, and it is difficult to meet the observation of the entire flow field, especially through the observation of the incoming flow boundary. Laminar Structure Evaluation of History Effects in Mixed Laminar Flow Fields

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