Inverse design method of non-axisymmetric natural laminar flow nacelle and natural laminar flow nacelle

Abstract

The invention discloses a reverse design method of a non-axisymmetric natural laminar flow nacelle and a natural laminar flow nacelle, and relates to the technical field of nacelle design, which includes nine steps, and forms the final non-axial flow through the respective design of different reference planes. Symmetrical natural laminar flow nacelle, based on the generative topology mapping model, with pressure distribution as the goal, the entire process is implemented using an objective method without relying on the experience of the designer; through the design, matching and fusion of multiple datums, the non-axisymmetric short The three-dimensional flow effect of the cabin is throughout; and the required number of samples is small and the calculation cost is low.

Description

technical field [0001] The invention relates to the technical field of laminar flow nacelle design, in particular to a reverse design method for a non-axisymmetric natural laminar flow nacelle and a natural laminar flow nacelle. Background technique [0002] High bypass ratio engines are currently the main power engines for civil airliners around the world. They have the advantages of low noise, high fuel efficiency, and long service life. They can provide excellent thrust-to-mass ratio and occupy a dominant position in the field of air transportation. Generally, the nacelle resistance accounts for about 5% of the total resistance of the aircraft, while the engine nacelle with a high bypass ratio increases its proportion in the total resistance of the aircraft due to the increase in geometric size. In the cruising state, the flow on the surface of the nacelle is divided into two types: laminar flow and turbulent flow, and the frictional resistance of turbulent flow is much h...

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Problems solved by technology

This design method relies too much on the designer’s experience, and requires reciprocating modeling, which has a high time cost. Compared with the axisymmetric laminar flow nacelle, the laminar flow range of the non-axisymmetric nacelle obtained by the combination of various datums will also be slight loss

[0005] Second, on the basis of the shape of the initial non-axisymmetric nacelle, using the idea of ​​optimal design, the transition position maximization or resistance minimization optimization is performed on the axisymmetric nacelles corresponding to the multiple reference planes of the non-axisymmetric nacelle , it should be emphasized that in the optimization process, the numerical simulation of two-dimensional shape plus axisymmetric boundary conditions is carried out for each datum plane, and finally the shape of the non-axisymmetric natural laminar flow nacelle is obtained according to the configuration combination of each datum plane. The method has a certain automation function, but similar to the first method, it ignores the three-dimensional characteristics of the non-axisymmetric nacelle. Compared with the axisymmetric laminar flow nacelle, the layer of the non-axisymmetric nacelle There will be a slight loss of streaming range

This type of method needs to consider many design variables, and the design parameters are coupled with each other. Whether using gradient optimization algorithm or non-gradient optimization algorithm, the number of sample points required is very large, and the calculation cost is unacceptable.

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