航空发动机圆套状尾喷管流场温度场数值模拟

NUMERICAL SIMULATION OF FLOW AND TEMPERATURE FIELDS IN DOUBLE CONVERGENT NOZZLES

对某机型双收缩圆环套状尾喷管内，冷热气流相互掺混的流动传热过程，作了数值模拟。用ＳＩＭＰＬＥ思想在曲线系中进行程序设计。该程序可以对任意形状的两股流有（无）掺混时的流场、质量场、温度场、辐射通量场进行模拟，对二维流动传热问题比ＳＩＭＰＬＥ程序更具有通用性。最后对某机型的实际情况（形状尺寸），用区域拼装法生成曲线网格作了模拟。结果说明，引射的冷空气与热主流在双收敛喷管内掺混，确实能降低尾喷管内气流温度、降低红外辐射。

A numerical simulation was employed to study the flow and temperatare fields of hot exhaust gas mixing with cold air in exhaust ejector.In the calculation the algebraic stress model (ASM) with the effect of buoyancy forces as turbulence model was adopted.Four heat radiation flux model was taken as heat radiation model.Due to complicated geometry of the nozzles the boundary fitted curvilinear coordinates were employed and curvilinear mesh was generated with the help of TTM method,then the blocks were put together under the given boundary conditions.A new general numerical method is developed on the basis of SIMPLE (Sami-Implicit Method for Pressure Linked Equations),and a general software was compiled in the boundary fitted curvilinear coordinate system.This software can be used widely for numerical simulation of flow fluid,heat and mass transfer,combustion,radiation in mixed flow with arbitrary boundary shapes.The results for some aeroplanes illustrate that the double convergent walls of the nozzles can intensify the mixing of hot and cold flows,and the violent mixing can greatly reduce the heat radiation flux and the temperature of aeroengine exhaust gas in double convergent nozzles.