风扇转子叶片周向积叠的三维气动优化设计

为了研究优化环境对优化结果的影响,利用商业软件NUMECA对某风扇第一级转子叶片进行了气动优化设计,并对比研究了第一级转子单排叶片的优化及其在整级环境中的优化结果。研究发现．单叶排优化后．虽然能提高整级风扇的效率,但是由于匹配的原因,整级风扇在整个流量范围内总压比都比优化前的有所减小;在级环境中优化后,该级风扇的效率和稳定工作范围都扩大了,且保证了级压比不变,其优化效果比单叶排的优化效果好。     

An adaptive integration surface for predicting transonic rotor noise in hovering and forward flights

In this paper, a new permeable adaptive integration surface is developed in order to evaluate transonic rotor noise in accordance with FW-H_pds equations(Ffowcs Williams-Hawkings equations with penetrable data surface). Firstly, a nonlinear near-field solution is computed on the basis of Navier-Stokes equations, which is developed on moving-embedded grid methodology.The solution calculated through the present CFD method is used as the input for acoustic calculations by FW-H_pds equations. Then, two criteria for constructing integration surfaces are established based on the analysis of the quadrupole source strength and the nonlinear characteristic.A new surface is determined adaptively by the pressure gradient or density in a given flowfield,eschewing the uncertainties associated with determining cylinder-shaped integration surfaces. For varying hover cases, transonic noises are simulated with new integration surfaces for a UH-1 model rotor. Furthermore, numerical results of the new integration surface derived from the density perturbation value conform better to experimental data than results derived from the pressure gradient.Finally, the integration surface given by jrqj being 0.1, which is an applicable criterion obtained from hover cases, is used to predict transonic rotor noise in forward flight. The computational accuracy of the new integration surface method has been validated in predicting transonic rotor noise of an AH-1 model rotor at different advance ratios.     

风扇翼型气动性能的实验研究

在西北工业大学NF-3风洞二元实验段内对两种风扇翼型的气动性能进行了对比实验研究,实验采用表面测压和尾排型阻测量技术。结果表明:在风扇的工作范围内,新设计的风扇翼型的升阻比要比传统的风扇翼型增大20%左右;通过两翼型翼面弦向压力分布特性的比较,可以推知,前者的气动噪声将会比后者小。     

升力风扇垂直起降无人机死重分析

针对升力风扇垂直起降无人机为了实现垂直起降功能而产生附加的结构重量,以及为加大功率而附加的动力系统重量问题,从总体设计的角度出发,建立了附加重量数学模型,并针对各种设计影响因素进行了分析.研究结果可为升力风扇垂直起降无人机的总体参数设计提供参考.     

Computational study of wing deformation and sting interference effects with the CAE-AVM test case

A modern transonic computational fluid dynamics test case is described in this paper, which is the Aerodynamic Validation Model (AVM) from the Chinese Aeronautical Establishment (CAE). The CAE-AVM is a representation of a modern transonic business jet aircraft with a design Mach number of 0.85. Numerical simulations for the AVM are conducted for two geometries: one baseline geometry, and one geometry that includes the applied model support system of the wind tunnel as well as the deformed wing shape that occurred during wind tunnel testing. The combined influence of wing deformation and model support interference on local and integral aerodynamic features is presented. Comparisons between CFD and experimental results are made; reasons of discrepancy between results from considered cases are analyzed.     

叶片弯掠组合设计对风扇气动噪声的被动控制

转子尾迹与静子叶片干涉是产生风扇离散噪声的主要噪声源之一。环形叶栅几何对于声源项的求解以及管道内的声传播都有重要影响,因此在讨论叶片弯掠组合设计对于风扇噪声的被动控制作用时需要重点强调三维效应的影响。本文利用三维升力面理论,建立了可以考虑叶片弯掠组合影响的气动声学模型。相比数值计算方法,三维升力面理论不存在频散耗散影响,求解快速高效,更加有利于初始阶段的优化设计,以及为数值计算模型提供验证。通过与已有结果的对比,进一步阐述了叶片后掠和周向倾斜对于风扇离散噪声的影响机制。而弯掠组合设计算例的计算结果表明,在某些条件下,选取合适的叶片弯掠造型能够获得很好的降噪效果。由于轴向传播波数的影响,前传声场和后传声场对于弯掠组合的变化趋势存在一定的差异性。     

世界垂直起降动力装置的演进和展望

介绍了半个世纪以来世界垂直起降动力装置发展的概况,阐述了垂直起降动力装置的类型、演进情况并展望了其发展前景.     

应用S2流面准三元计算程序分析小型发动机的跨音压气机气动特性

应用Ｓ２流面准三元计算程序，对两台典型小型发动机压气机（Ｉ型机、Ⅱ型机）的气动性能进行了分析。更加真实地揭示了它们内部的流动情况，并分析了它们的改进思想和方法。其中Ｉ型机是应用“平均设计”思想设计的早期跨音压气机，Ⅱ型机是其成功的改型机。     

高负荷风扇级的特性实验与流场分析

为了探索高负荷风扇级的流场特性,积累这方面的设计经验,在压比和效率特性之外,还分别利用三孔针和总压耙对所实验风扇级的出口有关参数进行了测量。同时,为了辅助分析问题,借助了CFD研究了转静根部的匹配问题。对根部区域的实验和计算现象进行了重点讨论,并指出了不足和进一步改进的方向。