某型制导炸弹实时仿真系统设计

采用训练仿真系统进行武器装备的维修和操作训练是当今装备的发展趋势。某型制导炸弹是我军即将装备部队的精确制导武器,为了提高训练质量、节约训练经费和延长装备寿命,迫切需要研制该型弹训练仿真系统。介绍了基于PC/104总线的该型制导炸弹实时仿真系统的软硬件设计与实现。该系统具有操作简单,模拟控制信号精确,检测迅速准确,可扩展性强等特点,满足了部队训练和院校实验室教学的要求。     

航空电子综合火控系统驾驶员操作程序(POP)仿真

驾驶员操作程序(POP)是航电综合设计最重要的顶层设计文件,其仿真对支持总体设计具有不可替代的作用。首先从整个航空火控系统的角度阐述了POP的组成及任务操作,然后介绍了POP仿真模型的建立方法和制作思路,并对某型飞机航电综合火控系统POP进行了仿真实现。其结果可用于评价飞机航电综合火控系统的POP操作逻辑关系的正确性。     

地空导弹弹道仿真模型

地空导弹弹道仿真是地空导弹火力单元作战过程仿真的一个重要环节,仿真模型的合理性、算法的可行性、过程描述的正确性,直接影响防空作战仿真结果.从仿真的实际需要出发,给出不同引导方法下的弹道仿真模型、算法、过程描述及关键问题的解决方法,并通过实际应用验证了模型、算法的合理性、可行性和实用性.     

超声速飞行器流场的并行数值计算及效率分析

基于有限体积方法、TVD差分格式和显式Runge-Kutta迭代方法的框架,针对超声速/高超声速飞行器绕流流场,在超级并行计算机上完成了2~64个CPU并行数值计算工作。通过测试程序在超级计算机上的并行效率,并将并行程序应用于航天飞机绕流流场计算,检验了计算程序进行大规模并行计算的性能。结果表明,在负载平衡的条件下,程序在该超级并行计算机上达到了不同程度的超线性加速比,并行效率最高达到了126%,远远高于微机Cluster并行平台上的结果,适合复杂流场的大规模并行计算。     

Modeling of the whole process of shock wave overpressure of free-field air explosion

The waveform of the explosion shock wave under free-field air explosion is an extremely complex problem. It is generally considered that the waveform consists of overpressure peak, positive pressure zone and negative pressure zone. Most of current practice usually considers only the positive pressure. Many empirical relations are available to predict overpressure peak, the positive pressure action time and pressure decay law. However, there are few models that can predict the whole waveform. The whole process of explosion shock wave overpressure, which was expressed as the product of the three factor functions of peak, attenuation and oscillation, was proposed in the present work. According to the principle of explosion similarity, the scaled parameters were introduced and the empirical formula was absorbed to form a mathematical model of shock wave overpressure. Parametric numerical simulations of free-field air explosions were conducted. By experimental verification of the AUTODYN numerical method and comparing the analytical and simulated curves, the model is proved to be accurate to calculate the shock wave overpressure under free-field air explosion. In addition, through the model the shock wave overpressure at different time and distance can be displayed in three dimensions. The model makes the time needed for theoretical calculation much less than that for numerical simulation.     

Effect of tongue clearance on hydraulic performance of double support vortex pump

In order to study influence of tongue clearance on the hydraulic performance of double support vortex pump, three dimensional flow model with symmetric variable size tongue clearance was established by changing section parameter of tongue clearance, and applied to numerically simulate the steady inner flow in a vortex pump based on fixed working conditions and impeller through ANSYS FLUENT. The numerical results show the influence of tongue channel with two sections (non-uniform and uniform sections) on flow field characteristics in vortex pump. Firstly, the variation of tongue channel section changes the vortex structure distribution in circumferential flow channel. Specifically the spiral forward vortex structure in the circumferential direction shifts to large radius side with increasing tongue width. Secondly, the circumferential velocity gradient and axial pressure gradient both diminish with the increase of the tongue section, and the inlet/outlet pressure difference and velocity distribution also reduce with increasing tongue channel section. Finally, for vortex pump with non-uniform section of tongue channel, the head diminishes and the efficiency remains constant approximately with the increase of the tongue width, while the head and the efficiency both diminish for uniform section of tongue channel.     

A worst‐case formulation for constrained ranking and selection with input uncertainty

In this research, we consider robust simulation optimization with stochastic constraints. In particular, we focus on the ranking and selection problem in which the computing time is sufficient to evaluate all the designs (solutions) under consideration. Given a fixed simulation budget, we aim at maximizing the probability of correct selection (PCS) for the best feasible design, where the objective and constraint measures are assessed by their worst‐case performances. To simplify the complexity of PCS, we develop an approximated probability measure and derive the asymptotic optimality condition (optimality condition as the simulation budget goes to infinity) of the resulting problem. A sequential selection procedure is then designed within the optimal computing budget allocation framework. The high efficiency of the proposed procedure is tested via a number of numerical examples. In addition, we provide some useful insights into the efficiency of a budget allocation procedure.     

太阳观测卫星的数传天线波束及其指向设计

针对三轴稳定对日指向姿态的太阳同步轨道卫星,提出为获得最大对地数据传输时间的天线波束设计及布局方案。根据某型太阳观测卫星的轨道姿态设计方案,建立数传天线对指定地面站的天线波束指向仿真模型;使用卫星工具包STK仿真软件,分析不同波束角方案及其可能的指向对数传时间的影响,发现了对日指向卫星与对地指向卫星在数传时间上的不同规律,找到最优的天线波束布局来获得最大的数传时间;根据星载数传能力与不同天线波束宽度之间的关系,获得传输数据的最佳天线波束宽度,为这类卫星数传天线的波束设计及其布局提供设计依据。     

基于系统构型替换的固冲发动机故障模式半实物仿真

为全面快速验证冲压发动机的故障检测算法,基于构型替换建立了能模拟多种固冲发动机故障的仿真验证平台。基于此平台,搭建了发动机点火故障模型、压强传感器故障模型、设备接口模型,以及与真实控制器中检测算法具有相同外部接口和系统构型的故障检测算法模型等。通过系统构型的切换,将同一个故障模式注入故障检测算法模型和真实发动机系统,并通过对比同一组故障模式下故障检测模型检测结果与发动机控制系统检测结果,来对发动机控制器中的故障检测算法进行快速验证。以无喷管助推器点火的检测为例,讲述了该方法的建模、实验验证及分析过程,此外,该方法还能应用到无喷管助推器关机、进气道前后堵盖打开、燃气发生器点火、燃气流量容错控制等多个故障模式的仿真模拟与验证,具有很强的通用性,能大大地降低控制系统开发与验证的时间成本,具有很强的应用价值。     

超压气球上升过程温度与动力学特性仿真分析

针对带加强筋的超压气球,分析上升过程热环境及受力状态,建立热力学与动力学模型并分析其耦合关系。基于MATLAB开发仿真程序,对超压气球进行仿真分析。分析了气球上升过程中高度、速度、温度变化特性,数据表明上升过程中的热力学环境和动力学特性都对球内气体温度有重要影响,气球上升速度和球内气体温度相互耦合并与自由浮力系数存在相关性。飞行试验实测数据验证了仿真结果的准确性。理论分析结果和仿真模型可为后续超压气球设计和飞行试验提供指导。