不同旋流情况对旋转流线涡燃烧室性能的影响

为探究不同旋流器位置和数目对航空发动机燃烧室性能的影响规律,运用FLUENT软件,采用计算流体力学法对某旋转流线涡燃烧室冷态流场和燃烧性能进行了研究。结果表明:相比于其他位置,旋流器距离燃烧室头部为88 mm时流线涡更稳定、更不易脱落,且燃烧效率最高,火焰长度也最短,燃烧效果最理想;旋流器数量的改变对压力损失和火焰长度的影响并不明显,但3个旋流器产生的涡范围更大,且会使空气与燃料掺混得更好,壁面温度场更加理想,燃烧性能更好。     

Microstructure and Martensitic Transformation Behaviors of Explosively Welded NiTi/NiTi Laminates

The study is a first attempt to prepare bulk NiTi/NiTi shape memory alloy (SMA) laminates with a macroscopic heterogeneous composition by explosive welding and investigate their microstructures and martensitic transformation behaviors. After explosive weld- ing, a perfect interfacial bonding between the two components and a reversible martensitic transformation are realized in the tandem. Results show achievement of a fine granular structure and the maximum value of microhardness near the welding interface because of the excessive cold plastic deformation and the high impact velocity during the explosive welding. Meanwhile, the effects of aging on the transformation of the welded tandem are investigated by differential scanning calorimeter (DSC) and subject to discussion. The trans- formation temperatures of NiTi/NiTi SMAs increase with the rise of the aging temperature. The experimental results indicate the shape memory properties of NiTi/NiTi SMA fabricated by explosive welding can be improved by optimizing the aging technology.     

振动时效对NiTi记忆合金双程记忆应变的影响

研究了振动时效对NiTi形状记忆合金双程记忆效应的影响.结果表明,当预应变较小或较大时,经过振动时效后NiTi合金的双程应变量增加;当预应变适中时,振动时效后NiTi合金的双程应变量减小.这可能是由于振动时效在NiTi合金中产生了微观塑性变形,改变了合金中的双程应力场而导致的.     

CAM后置处理研究

分析了数控加工后置处理技术的特征、面临的问题和当前的发展趋势,介绍了应用通用后置处理器开发定制专用后置处理器的实践。     

航改大功率、高效率舰船燃气轮机的

为适应舰船战术性能和舰船吨位级别提高的要求,迫切需要研究大功率、高效率舰船燃气轮机.通过对国内外战舰主动力装置进行分析,认为中国开发40000kw的大功率燃气轮机是十分必要的,利用现有航空发动机的技术资源优势,采用先进的间冷技术是发展大功率、高效率舰船燃气轮机的1条现实可行的技术途径,既可以提高燃气轮机在设计工况下的功率和热效率,又能保持在低工况下的高效率.     

等离子发生器燃烧流场数值模拟

采用漩涡破碎（EBU）燃烧模型、k-ε双方程湍流模型及SIMPLEC算法,对等离子发生器内部的燃烧流场进行了数值模拟,得到了关于等离子燃烧流场相关特性参数分布。该数值模拟对等离子发生器的研究具有指导作用。     

The Two-step Reverse Martensitic Transformations of TiNi Shape Memory Alloy Based on Solution-treatment and Aging

A TiNi-alloy is solution-treated in a vacuum furnace of 6.7×10-3 Pa at 1 223 K for 3.6 ks, and then aged at 773 K for 1.8 ks. The differential scanning calorimetry (DSC) measurements show that after the heat-treatment, takes place a two-step reverse Martensitic transformation, from which results the two-stage recovery strain in a prestrained Martensitic TiNi-alloy wire during heating. The Vickers microhardness indentation test in cross-sectional areas of the TiNi-alloy wire indicates the compositional heterogeneity between its sur-face layers and its inside. The fact that the sizes of the indentation in surface layers smaller than those in the inside bears witness to the existence of slightly harder surface layers. It is believed that these phenomena are related to the compositional fluctuation caused by the evaporation and oxidization of Ti-element during the solution-treatment and heterogeneity formed during the subsequent aging treat-ment.     

飞机环控系统供气温度、流量和湿度对座舱热负荷的影响

 将歼击机前机身置于电辐射加温器内,当座舱盖温度达６０℃,飞机座舱驾驶杆周围温度稳定在４０℃时,座舱空气调节系统使用不同的供气温度、供气流量、含湿量进行通风降温,观察对座舱温度和人体温度参数的影响。供气温度与座舱三球温度指数（ＷＢＧＴ）和座舱平均舱温（Ｔｄｂ）呈正相关。供气流量３００ｋｇ／ｈ降温效果优于２５０ｋｇ／ｈ。供气温度与２０ｍｉｎ时的平均皮肤温度下降值（ΔＴｓｋ）呈负相关。供气温度高,人体出汗量高,人体热反应明显。ＷＢＧＴ３０℃,使用０℃供气温度在短时间内可使座舱温度和人体Ｔｓｋ降至工效区范围,多数指标可满足国家军用标准的要求。     

Synthesis of TiNi/Ti_2Ni Composite Particles in Molten Salts

A new process of synthesizing TiNi/Ti2Ni composite particles, high temperature molten salts method, is introduced. This method uses molten salts as a reaction medium that does not take part in the chemical reaction and can be easily dissolved in rinsing water. Ac-cording this method, the composite particles were prepared in molten salts at 700 ℃-900 ℃. By means of differential scanning calo-rimetry (DSC), the reversible martensitic transformation of TiNi particles in these composite particles was confirmed.     

浅谈CAD/CAM对高速加工的影响

CAD/CAM软件的使用对高速加工零件精度有很大的影响,本文对相关影响因素进行了分析和研究,并给出了一些建议。