内燃机活塞温度场的轴对称组合边界元分析

采用常数-线性组合边界元计算轴对称热传导问题,既可减小奇异点计算的困难性,又提高了计算精度。本文运用FORTRAN77算法语言编制了包含有三种类型边界条件在内的轴对称组合边界元分析程序,具体分析了6135ZG柴油机活塞的温度分布。结果表明,应用边界元法分析轴对称活塞温度场,计算工作量比有限元的计算量显著减少,而计算结果同有限元结果吻合得较好,与实际测量结果相比,最大相对误差仅为1％。     

旋转自洁式空滤器固体颗粒的运动特性与性能分析

应用数值计算和试验的方法研究旋转自洁式空气滤清器固体颗粒的运动特性，采用Lagrange分析方法推导滤清器内颗粒的运动控制方程，在气相三维流场计算的基础上，计算了不同情况下的固体颗粒的运动轨迹以及分级效率。试验测试了不同几何参数下滤清器的滤清效率，计算与测试结果吻合良好。     

Kinetic characteristic for a synchronal rotary compressor

The synchronal rotary compressor is si mple instructure,but it has stronger adaptability for a vari-ety of working medium,so it is a good type as aircompressor,oil pump andrefrigerationsystemcom-pressor.The geometric theory and structure charac-teristics of this mechanis m are introduced[1].Itgives the designing background for the synchronalrotary compressor.The calculational methods of arotary speed of cylinder and relative speed bet weenthe cylinder and bladed rotor are deduced in detail;the…     

MODEL AND SIMULATION FOR A BRUSHLESS AC GENERATOR WITH AROTARY RECTIFIER

Objective For a brushless AC generator with a rotary rectifier, it is necessary and significant to model and simulate at normal and fault operation states. Methods Two new concepts, namely, Simulink signals and PSB (Power System Blockset) variables, are proposed, and the difference between the two concepts is clarified. Based on the new model for synchronous machines, a simulation model for a brushless AC generator with a rotary rectifier is constructed by Matlab/Simulink/PSB. This new model, which has a speed input terminal and an exciting voltage input one, can simulate the real electrical characters and direct mechanical connection between two synchronous machines perfectly. The rotary rectifier is a three-phase full-wave bridge rectifier which consists of six diodes. The model for the diodes is a macro-model which possesses much better accuracy than an ideal one of switches. Results Based on the present model, some simulation results such as exciting current waveform, phase current waveform and phase voltbge waveform are afftained at several operation conditions. Conclusion The simulation for a brushless AC generator with a rotary rectifier is demonstrated at normal and fault operation states, respectively. The results confirm the presented method.     

关于汽车液压制动器轮缸孔与活塞的配合间隙

汽车液压制动器轮缸(以下简称:轮缸)缸孔与活塞滑动面之间的配合间隙,关系着制动器的工作状况和使用寿命.     

干式缸套柴油机活塞温度的试验测量与数值仿真

对4112型干式缸套柴油机的活塞温度进行了实验测量,以测量的结果为已知边界条件对其进行了有限元的数值模拟,得出了柴油机活塞的温度场．对测量和仿真的结果进行了分析和研究,了解了4112型柴油机活塞的热负荷状况和承接热负荷的耐受能力,并提出了相应的改进措施,为改进活塞结构、提高其承载能力提供了理论依据．     

高性能沥青路面（Superpave）的技术初探

采用旋转压实新技术,用PG等级和常规指标评价SBS改性沥青的技术性能。从原材料、配合比设计、现场施工等方面简略介绍了Superpave技术在沪蓉高速公路成都段的首次应用,为今后Superpave技术推广应用提供借鉴。     

THE EDDY LOSSES OF A MAGNETIC THRUST BEARING

Accurate calculations of losses associated with the operation of magnetic bearings are particularly important for high speed applications where the rotor losses are expected to be large and for some particular applications where even low power losses will be critical. Power losses in the magnetic thrust bearing is often neglected, but if there is misaligned in the rotor and bearing, the magnetic field in the thrust bearing is no longer axisymmetric one, or the dynamic control current in the winding is time dependent one, eddy currents are caused to flow inside the conducting material, then the power losses are very important for magnetic bearing design. This paper presents an analytical model of a thrust magnetic bearing, and the magnetic fields, forces and losses of thrust magnetic bearing are calculated. In the calculations the frequency of dynamic control current is up to 1 000 Hz, rotating speed is from 60 rpm to 1 200 rpm, and the non-linearity of material is also taken into consideration. The results shows that if the magnetic field is not saturation, the eddy losses is proportional to dynamic control current frequency and a square function of dynamic control current, and also 5/2 power function of shafts speed.     

粉喷桩处理软土地基施工技术

粉喷桩加固软土地基的原理是：利用压缩空气携带着粉体固化材料，经过橡胶软管输送到钻头，借助叶片在旋转提升时产生的空隙喷出，喷出的混合气体在空隙中压力急剧降低，促使固化材料粘附在旋转叶片切开空隙的土中，地基土固化材料通过水泥的水解和水化作用、离子交换、硬化反应、碳化反应后，形成坚硬稳定的土体，从而达到加固软土地基的目的。其施工工艺流程见图1。