一种特型燃气舵数值模拟分析

介绍了一种由活动体和固定体组成的特型燃气舵.为了解该燃气舵的相关特性及其与普通燃气舵的区别,分别对该特型燃气舵和普通燃气舵进行了数值模拟.根据数值模拟的结果,从流场、热效应、固体颗粒影响及气动性能4个方面进行了分析.与普通燃气舵相比,特型燃气舵具有抗侵蚀能力强、结构质量轻和阻力小等优点,但也有升力小的缺点.     

Analysis and control of inter-electrode gap during leveling process in counter-rotating electrochemical machining

The inter-electrode gap (IEG) is an essential parameter for the anode shaping process in electrochemical machining (ECM) and directly affects the machining accuracy. In this paper, the IEG during the leveling process of an oval anode workpiece in counter-rotating ECM (CRECM) is investigated. The variation of the minimum IEG is analyzed theoretically, and the results indicate that rather than reaching equilibrium, the minimum IEG in CRECM expands constantly when a constant feed speed is used for the cathode tool. This IEG expansion leads to a poor localization effect and has an adverse influence on the roundness of the machined workpiece. To maintain a small constant IEG in CRECM, a variable feed speed is used for the cathode based on a fitted equation. The theoretical results show that the minimum IEG can be controlled at a small value by using an accelerated feed speed. Experiments have been conducted using a specific experimental apparatus in which the cathode tool is designed as a combined structure of two sectors and a thin sheet. By detecting the machining currents flowing through the minimum IEG, how the latter varies is obtained indirectly. The results indicate that using an accelerated feed speed is effective for controlling the IEG, thereby improving the roundness of the machined workpiece.     

低压涡轮导叶内环结构设计

为实现低压涡轮导叶内环初步方案快速设计、降低低压涡轮工作叶片冷气相对总温和提高冷却效率,以某型低压涡轮导叶内环为研究对象,提出了 1 种基于等熵过程的低压涡轮导叶内环设计方法和流程,并采用 3 维数值仿真方法对设计结果进行了分析和验证,得到了不同预旋喷嘴径向高度对转、静子腔内的流动影响规律。结果表明:提出的低压涡轮导叶内环设计方法和流程能够满足初步方案的设计要求;预旋喷嘴的径向高度对工作叶片和涡轮盘表面的相对总温影响较大,工程上需综合考虑。     

复合式气冷涡轮导叶综合冷效试验研究

介绍了复合式气冷涡轮导叶的冷却效果试验研究。试验结果表明，导叶在宽广的冷气流量比范围内，具有良好的冷却特性，经模化分析，在发动机状态下，叶片中截面相对冷却效果为0．69，达到了设计指标。     

进口边界层对采用弯叶片的平面扩压静叶栅流场性能的影响

给定不同型式的进口边界层,在两种不同亚音速条件下对一平面扩压静叶栅的弯叶片流场进行了数值模拟。结果表明弯叶片对扩压叶栅的改善的能力受进口边界层的特征影响。这种影响分为两个方面:(1)边界层厚度的影响和(2)边界层动量损失厚度的影响。边界层越厚或动量损失厚度越大,在低马赫数条件下弯叶片对吸力面角区密流增加越明显,从而更大程度地提高了端区的流动性能,降低了叶栅损失。在高马赫数条件下,若边界层越厚或动量损失厚度越大,角区密流虽变化不大,但因端区损失较大,其性能的提高会给叶栅总性能的改善带来较大的收益。      

单级轴流大小叶片压气机非定常流场数值研究

通过数值模拟方法对单级轴流大小叶片压气机与常规叶栅压气机的非定常压力场进行分析与对比,结果表明:由于小叶片的分隔效应,使得转子通道的非定常压力和单叶片非定常负荷脉动大大增强,并促进了压力波向上游的传播;但转、静子单元的整体扭矩和轴向力脉动降低;绝对坐标系下转子入口处的压力波动是转子势扰动、动静干扰产生的压力波和此波在周向的不均匀性的综合作用,不同的入口周向位置,压力波的幅值相位存在较大差别,小叶片的存在强化了这种差别.     

Ni3Al基IC6高温合金工程应用研究

IC6合金是在"863"计划支持下,由北京航空材料研究院研制成功的一种定向凝固Ni3Al基高温合金.选用该合金试制某新型航空发动机整体定向凝固Ⅱ级导向器叶片.由于该叶片尺寸大、形状复杂,给铸造工艺带来很大难度.经过合理设计浇注系统,实现了定向柱晶从叶身向缘板平滑过渡弯晶生长,有效地消除了叶身和缘板转接处的晶界裂纹,使叶片的毛坯合格率由原来的5%攀升到62%,超过了"863"计划规定的50%的指标.在此基础上,对Ⅱ级导向器叶片的铸造工艺稳定性,真空热处理工艺,叶片表面防护涂层工艺,返回料的应用进行了系统的工程应用研究.该叶片已通过技术鉴定,转入批生产,目前已生产65台叶片,在使用中工作正常,没有出现任何材料质量问题.     

基于ADAMS的静叶联调机构参数化设计

针对压气机静子叶片调节机构空间运动关系复杂、设计难度大的问题,提出了1种以3维参数化仿真为核心,进行压气机静叶联调机构方案设计的方法.基于ADAMS平台建立调节机构的简易模型,利用软件参数化分析模块研究了模型中决定机构性能的关键设计变量的确定方法;在此基础上,以某型压气机调节机构为例,利用参数化方法进行了该机构的方案设计.结果表明:在方案设计阶段,参数化分析方法可快速、有效地进行调节机构结构参数选取与优化,使模型的运动/动力学仿真结果满足设计要求.     

某小型发动机高压涡轮导向器环吹试验研究

介绍了某小型发动机高压涡轮导向器的环吹试验，初步研究了该导向器的特点。试验结果表明，试验的高压涡轮导向器流场周期性较好，导向器的性能达到了设计指标。     

Assembly Variation Identification of High Pressure Spool by Response Surface Based Model Updating Using IV-optimal Designs

This article, in order to improve the assembly of the high-pressure spool, presents an assembly variation identification method achieved by response surface method (RSM)-based model updating using IV-optimal designs. The method involves screening out non-relevant assembly parameters using IV-optimal designs and the preload of the joints is chosen as the input features and modal frequency is the only response feature. Emphasis is placed on the construction of response surface models including the interactions between the bolted joints by which the non-linear relationship between the assembly variation caused by the changes of preload and the output frequency variation is established. By achieving an optimal process of selected variables in the model, assembly variation can be identified. With a case study of the laboratory bolted disks as an example, the proposed method is verified and it gives enough accuracy in variation identification. It has been observed that the first-order response surface models considering the interactions between the bolted joints based on the IV-optimal criterion are adequate for assembly purposes.