A Method of Detecting Surface Errors in Constricted Sections of Wind Tunnels

Abstract

The invention discloses a method of detecting inner type surface and curved surface errors of a wind tunnel contraction section. The method comprises the following steps of using a three-dimensional laser scanner to scan an inner type surface of the wind tunnel contraction section so as to acquire point cloud data; converting a coordinate of the point cloud data in a computer to a coordinate system where a contraction section inner type surface model is located; sectioning the point cloud data of the inner type surface of the wind tunnel contraction section and a pre-designed contraction section inner type surface model, and using a point cloud coordinate and a known standard curve to fit a curvilinear equation of an intersecting line of wind tunnel contraction section inner type surface point cloud and a section cutting plane; calculating a shortest distance from each point on the intersecting line of the wind tunnel contraction section inner type surface point cloud and the section cutting plane to an intersecting line of the contraction section inner type surface model and the section cutting plane, and comparing a maximum value with a maximum allowable deviation value. In the invention, full range detection of the wind tunnel contraction section inner type surface and curved surface errors can be realized; leak detection in a sampling detection method is avoided and an accurate basis is provided for subsequent repairing of the wind tunnel contraction section inner type surface and the curved surface.

Description

technical field [0001] The invention relates to the technical field of wind tunnels in the aerospace technology, in particular to a method for detecting the error of a profile surface in a contraction section of a wind tunnel. Background technique [0002] Wind tunnel refers to a kind of pipeline experimental equipment that can artificially generate and control airflow to simulate the flow of air around aircraft or objects, the function of objects and observe physical phenomena. It is the most commonly used and most effective tool for aerodynamic experiments. During the experiment, the model or object is often fixed in the wind tunnel to obtain the experimental data repeatedly and economically. In order to make the experimental results accurate, the flow during the experiment must be similar to the actual flow state, that is, the requirements of the law of similarity must be met. However, due to wind Due to the constraints of tunnel size and dynamics, it is difficult to simu...

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Problems solved by technology

During the experiment, the model or object is often fixed in the wind tunnel to obtain the experimental data repeatedly and economically. In order to make the experimental results accurate, the flow during the experiment must be similar to the actual flow state, that is, the requirements of the law of similarity must be met. However, due to wind Due to the limitations of tunnel size and dynamics, it is difficult to simulate all similar parameters simultaneously in one wind tunnel

The shrinkage section is an important part of the wind tunnel. The cross-section gradually shrinks along the curve, and the internal flow field changes complicatedly. The quality and accuracy of the inner surface are important factors affecting the quality of the simulated wind field in the wind tunnel. Excessive increase in size will affect the air flow in the wind field and affect the characteristic parameters of the air flow field, resulting in inaccurate results of wind tunnel experiments. Therefore, in the construction of wind tunnel engineering, it has great influence on the surface error of the shrinkage section in the wind tunnel. high requirements

[0003] According to the national military standard "Code for Construction and Acceptance of Conventional Wind Tunnel Installation Engineering", the detection of the curved surface of the wind tunnel mainly uses a sample with a chord length of not less than 1.5m to detect the curved surface. The above detection method must be tested by the detection personnel with detection tools Contact detection on the surface requires a lot of manpower, and the detection area with a high position needs the detection platform to assist detection, and the detection efficiency is low

Generally, there are many shrinkage sections in the wind tunnel structure. The traditional measurement technology is labor-intensive and time-consuming, and cannot realize the large-scale efficient and accurate detection of the special-shaped inner surface of the shrinkage section.

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