A Method for Controlling the Scale of Aircraft Surface Defects with Reduced Effects on Flow Transition

Abstract

The invention provides a method for controlling the size of aircraft surface defects that reduces the impact on flow transitions. First, the theoretical analysis method or ground test method is used to conduct flow transition research on the aircraft, and the surface defects that satisfy the boundary layer transition without being affected are obtained. Then carry out a joint simulation analysis of aerodynamic heating, structural temperature field and deformation field for the section where the defect occurs, and extract the thermal deformation data of each section where the defect occurs during the flight from the calculation results of the structural deformation; finally use the initial The defect scale counteracts the thermal deformation strategy, and the defect scale that should be initially processed is designed according to the constraint range and thermal deformation data, so as to ensure that the actual defect scale meets the constraint range during flight. The invention can reasonably and effectively control the surface defect scale of the aircraft, reduce the possibility of inducing premature transition of the surface, and ensure the reliable operation of the thermal protection system of the aircraft.

Description

technical field [0001] The invention relates to a method for controlling the size of aircraft surface defects that reduces the influence on flow transitions, and is suitable for the steps, gaps or sags formed by the installation of antenna windows on the docking steps or gaps of surface cabins in hypersonic aircraft flight tests, and the installation of sensors. The control of defect scales such as protrusions or depressions in order to reduce its influence on the flow transition of the aircraft surface belongs to the technical field of hypersonic aircraft transition. Background technique [0002] A hypersonic vehicle spans a wide flight airspace and speed domain. As the Reynolds number of the incoming flow increases, the flow on the surface of the vehicle will undergo a boundary layer transition. Since the wall friction coefficient / heat transfer coefficient of the laminar boundary layer and the turbulent boundary layer are significantly different, the boundary layer transit...

AI Technical Summary

Problems solved by technology

[0004] At present, there is no mature method to control the surface defect scale of the aircraft to reduce its impact on the transition. In the engineering development, the process control of the processing, manufacturing and assembly links is mainly used to keep the defect scale of the surface steps and gaps at a small size. The magnitude of (eg 0.2mm)

However, in practical engineering applications, this method has some shortcomings, and it cannot fully meet the requirements of the aircraft surface transition control on the surface defect scale.

On the one hand, the constraint range of defect scales such as surface steps and gaps that are not affected by the surface transition of the aircraft may be relatively strict, subject to the influence of manufacturing and assembly technology levels, especially for composite materials, the existing technology level may not be able to Ensure that the dimensions of steps and gaps meet the constraint range

On the other hand, due to the different materials and sizes of the sections that produce steps and gaps, the thermal response of each component after being aerodynamically heated during the actual flight is also inconsistent, and the thermal deformation of each section is different, which will make the initial step , cracks, etc. scale changes, which may cause the defect scale not to meet the constraint range

This makes it difficult to reasonably control the scale of defects such as steps and gaps on the surface of the aircraft, and increases the possibility of inducing premature transition and endangering the reliable operation of the thermal protection system.

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