Aircraft surface defect scale controlling method capable of reducing influence on flow transition

Abstract

The invention provides an aircraft surface defect scale controlling method capable of reducing the influence on the flow transition. The aircraft surface defect scale controlling method capable of reducing the influence on the flow transition comprises the steps that first, a theoretical analysis method or a ground test method is used for performing a flow transition study on an aircraft, and a constraint range of the surface defect scale meeting the requirement that the boundary layer transition is not affected is obtained; then the joint simulation analysis of aerodynamic heating, a structural temperature field and a deformation field is carried out on the section where the defect is generated, and the thermal deformation data of each section where the defect is generated during the flight is extracted from the structural deformation calculation result; the strategy of initial defect scale offsetting the thermal deformation is adopted, and based on the constraint range and thermal deformation data, the initial defect scale to be processed is designed to ensure that the actual defect scale meets the constraint range during the flight. The aircraft surface defect scale can be reasonably and effectively controlled, the possibility of inducing surface transition in advance is reduced, and the reliable operation of an aircraft thermal protection system is ensured.

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.

Images