CE/SE方法在点火管一维两相流数值计算中的应用

介绍了CE／SE方法。该方法不同于以往的一些计算格式，在计算中它把时间和空间同等对待，具有格式构造简单、计算方便和对激波间断分辨率高等优点。运用适合点火管一维两相流控制方程的CE／SE方法来计算点火管内的一维两相流流动，源项采用四阶Runge-Kutta方法进行处理。数值计算的结果与实验数据的比较表明，CE／SE方法能对两相流进行有效的数值模拟。     

航空活塞发动机进排气管路改进设计研究

针对小型航空飞机的动力性及安全性要求,采用CFD技术,建立了某型航空活塞发动机缸内与增压管路系统仿真模型,探讨了航空活塞发动机进排气管路系统性能评价方法,揭示了进排气管路结构参数对各缸进气均匀性、充气效率、排气倒流及涡轮特性的影响规律.通过对进排气管路系统的改进设计,有效改善了进排气系统性能及整机动力性能.所采用的改进设计研究方法为今后航空活塞发动机进排气管路设计奠定了基础.     

基于带源项非结构网格CE/SE方法的PDRE爆轰排气流场中尾喷管特性研究

为了研究非定常两相脉冲爆轰发动机爆轰和排气流场中尾喷管的特性,推导了带源项非结构三角形网格求解元守恒元数值方法(CE/SE方法)的计算格式,应用该方法数值研究了满填充工况下带不同结构尾喷管火箭式脉冲爆轰发动机的内外流场和爆轰推进性能。研究表明:该非结构网格CE/SE方法可有效捕捉变截面管中强间断和复杂波系结构。各类喷管中,含收敛段喷管排气时间增长,气流在收敛段喉部发生壅塞;含扩张段喷管内出现斜激波过膨胀现象。当环境压力为0.1 MPa、填充率为1时,单次爆轰模式下带不同类型喷管的汽油/空气两相脉冲爆轰发动机的推进性能:除40°角扩张喷管外,其他各类喷管在爆轰和排气进程中均能提高发动机的冲量。     

Study on Effects of Diesel Engine Cooling System Parameters on Water Temperature

A simulation model for a certain diesel engine cooling system is set up by using GT-COOL. The backwater temperature response in different operating conditions is simulated numerically. The effects of single or multiple system parameters on the water temperature are analyzed. The results show that, changing different single parameters, the time taken for the steady backwater temperature is different, but relatively short;and if multiple parameters are changed, the time will be longer. Referred to the thermal balance test, the simulation results are validated and provide a basis for the intelligent control of the cooling system.     

Design and Experiment for Exhaust Pipes of Pressure Wave Supercharged Diesel Engine

NOx and soot emissions from diesel engines can be greatly reduced by pressure wave supercharging （PWS）. The diesel engine matched with PWS needs redesigning its exhaust pipes. Except for meeting the installation requirements, the exhaust gas must be stable in pressure before rushing into PWS. In this paper the lateral and center ported divergent exhaust pipes are designed, modeled geometrically and analyzed structurally based on a 3-D design software-CATIA to determine the structure of two exhaust pipes having the required inner volume. Then flow analysis for two exhaust pipes is done using a flow analysis software-ANASYS. Moreover, the optimal exhaust pipes are determined comprehensively and cast for engine test. Engine test results show that PWS is superior to turbocharging at low engine speeds and inferior to turbocharging in power and emissions at medium-to-high engine speeds. The performance of PWS engine under high speed operating conditions can be improved by contriving larger surge volume intake and exhaust nines.     

Application of Two-dimensional Viscous CE/SE Method in Calculation of Two-phase Detonation

The method of two-dimensional viscous space-time conservation element and solution element (CE/SE) can be used to calculate the gas-liquid two-phase interior flow field in pulse detonation engine (PDE). In this paper, the evolution of the detonation wave and the distribution of its physical parameters were analyzed. The numerical results show that the change of axial velocity of gas is the same as that of detonation pressure. The larger the liquid droplet radius is, the longer the time to get stable detonation wave is. The calculated results coincide with the experimented results better.