近地低速飞行时旋翼尾涡系的畸变及其诱导速度

本文用一简化自由涡模型模拟旋翼尾涡系,用一简单涡模拟地面涡,对近地低速飞行时旋翼尾涡系的畸变及其引起的诱导速度变化作了研究。在地面涡和地面的影响下,桨盘附近的尾涡几何位置发生很大变化,导致桨盘处的诱导速度发生很大变化。尾涡畸变在桨盘处引起的诱导速度变化远远大于地面涡和地面在桨盘处直接产生的诱导速度。考虑尾涡畸变后计算出的诱导速度在桨盘处的分布和实验符合很好。     

风量与风机的安全运行

本文阐明了离心式通风机在通风除尘(或排毒净化)系统中的作用,以及离心式通风机产生风压.风量的工作工程,从而引出风机的性能参数风量L、风压P、功率N、效率η等.文章突出地论述了风量对风压、功率、效率的影响;详尽地分析了离心式通风机的性能曲线,特别是N—L曲线;根据性能曲线分析得知,风量L为零(L=0)时,风消耗的功率N最小.从而得出结论;系统中的离心式通风机必须是在关闭状态下启动,以确保通风机的安全运行.     

一个方便实用的旋翼数据库

本文介绍了一个以EXCEL和EXCEL VB建立的旋翼数据库。并以一个分库为例介绍了建立和使用方法。     

利用气动式溜车—管路系统实现散状物料的输送

气动式溜车－管路系统是近年来兴起的一种高效的中,长距,离输送装置,它克服了常规运输系统运费高,噪声大和污染环境的缺点,在工程上有着良好的应用前景。本文对该系统的原理和原理和结构进行了较为细致的分析,并介绍了一个应用实例。     

关于模糊逻辑系统及其建模函数的数学描述

模糊逻辑系统按真值化处理与推量规则导出最优系统数学表达式。在线性定常状态下,分别建立起连续与间断系统的数学模型,归纳出模糊控制的等效解法。并应用模糊数学算法,对一非线性实例绘制出双模控制框图。     

航空母舰液压拦阻系统拦阻力建模与仿真

以国内外普遍使用的某型航空母舰液压拦阻系统为研究对象,从其组成和工作原理出发.针对产生拦阻力的主要元器件,根据液压系统的传动基本理论建立了液压拦阻系统的拦阻器系统和滑轮缓冲系统的数学模型.利用该模型结合舰载机着舰动力学模型和拦阻索动力学模型进行了拦阻动力学的数值仿真,对比了仿真值与试验值的区别,分析计算了某型舰载机以不同重量、速度着舰的拦阻动力学过程.验证了滑轮缓冲系统能有效减缓拦阻索张力,且通过改变控制阀口通油面积可以实现不同质量飞机在基本相同的距离上实现安全拦阻,说明模型的合理性.     

Conceptual design of a bioregenerative life support system containing crops and silkworms

This article summarizes a conceptual design of a bioregenerative life support system for permanent lunar base or planetary exploration. The system consists of seven compartments – higher plants cultivation, animal rearing, human habitation, water recovery, waste treatment, atmosphere management, and storages. Fifteen kinds of crops, such as wheat, rice, soybean, lettuce, and mulberry, were selected as main life support contributors to provide the crew with air, water, and vegetable food. Silkworms fed by crop leaves were designated to produce partial animal nutrition for the crew. Various physical-chemical and biological methods were combined to reclaim wastewater and solid waste. Condensate collected from atmosphere was recycled into potable water through granular activated carbon adsorption, iodine sterilization, and trace element supplementation. All grey water was also purified though multifiltration and ultraviolet sterilization. Plant residue, human excrement, silkworm feces, etc. were decomposed into inorganic substances which were finally absorbed by higher plants. Some meat, ingredients, as well as nitrogen fertilizer were prestored and resupplied periodically. Meanwhile, the same amount and chemical composition of organic waste was dumped to maintain the steady state of the system. A nutritional balanced diet was developed by means of the linear programming method. It could provide 2721 kcal of energy, 375.5 g of carbohydrate, 99.47 g of protein, and 91.19 g of fat per capita per day. Silkworm powder covered 12.54% of total animal protein intakes. The balance of material flows between compartments was described by the system of stoichiometric equations. Basic life support requirements for crews including oxygen, food, potable and hygiene water summed up to 29.68 kg per capita per day. The coefficient of system material closure reached 99.40%.     

惯导测试设备及其检测

阐述了惯导测试设备的作用、种类,介绍了其典型结构及基本精度指标的概念。说明了惯导测试设备的发展趋势;总体布局向卧式发展;轴系结构向有源磁悬浮发展;台体向复合材料球形壳体发展;输电装置向滚环发展;分度元件采用高精度的感应同步器。列举了检定技术的实例,说明了其发展方向:不断提高检定精度;开展动态检定;改善测量设备对三轴空间位置的适应性。此外,管理上要制度化,名词术语与数据处理要标准化,设计与检定要相协调。     

Progress of continuously rotating detonation engines

Continuously rotating detonation engine (CRDE) is a focus for concern in the field of aerospace propulsion. It has several advantages, including one-initiation, high thermal efficiency and simple structure. Due to these characteristics, it is expected to bring revolutionary advance-ments to aviation and aerospace propulsion systems and now has drawn much attention throughout the world. In this paper, an overview of the development of CRDE is given from several aspects:basic concepts, applications, experimental studies, numerical simulations, and so on. Representative results and outstanding contributions are summarized and the unresolved issues for further engi-neering applications of CRDE are provided.