共查询到18条相似文献,搜索用时 125 毫秒
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推进剂供应系统的充填特性对发动机起动过程控制具有重要意义,而供应系统管路系统复杂,需要具有边界协调性好、计算精度高、稳定性好的WENO格式。为了模拟充填过程液体压力的瞬变特性,将流动控制方程进行坐标变换解决移动边界的问题。针对坐标变换后的流体瞬变流动控制方程,获得带源项的双曲方程组,利用基于特征变量的Roe类型高阶有限差分WENO格式建立了适用于推进剂充填过程的一维瞬变流动仿真模型。考虑稳态摩擦的情况下,对带气垫的推进剂充填过程利用WENO格式和显式特征线法进行了仿真,结果表明WENO方法的耗散小、预测结果更好。考虑了介质物性、摩擦系数、频率相关摩擦、多变过程指数等对充填过程的影响,研究结果表明瞬态摩擦模型和多变过程指数对水击压力的峰值和衰减过程有显著的影响。 相似文献
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燃气管路气流脉动特性是影响补燃循环多推力室液体火箭发动机安全运行的因素之一,气流脉动压力强度剧烈时将影响管路下游燃烧室燃烧稳定性及发动机的正常工作。为探究液体火箭发动机燃气管路气流脉动压力特性,对燃气管路进行了模化试验,分析了进口流量分别为额定值模拟流量65%,100%和108%下无导流装置和有导流装置的气流脉动压力变化特征。结果表明,带导流装置的燃气管路分叉处气流脉动压力标准差值减少约38%~50%,脉动压力功率谱能量减少约66%~88%;两出口管间气流脉动压力标准差相对大小值减少约11%~22%。导流装置在抑制气流脉动及改善气流稳定性方面效果显著,对燃气管路设计及气流优化具有参考价值。 相似文献
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由喷嘴连接的燃烧室到供应系统压力振荡传递过程研究 总被引:4,自引:2,他引:2
为了研究在压力振荡由液体火箭发动机燃烧室传递到供应系统的过程中喷嘴所起的作用,从理论上分析了压力振荡由燃烧室到供应系统通过喷嘴的传递过程,推导了振荡传递过程的传递函数.讨论带有各种喷嘴的供应系统的动态特性,对供应系统管路长度、燃烧室压强、喷嘴种类、喷嘴压降及喷嘴结构尺寸对燃烧室压力振荡引起供应系统压力振荡的影响进行了计算,得到了喷嘴以及工况参数在传递过程中的影响规律. 相似文献
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基于谱方法的管路充填过程仿真 总被引:4,自引:1,他引:3
基于一维瞬变流理论,建立了推进剂供应系统管路充填过程数学模型.提出采用Fourier谱方法求解充填管道中液体瞬变流控制方程的新方法.利用坐标变换方法,很好地处理了解算管内气液移动边界时,非线性迭代收敛速度较慢这一难题.对由贮箱、隔离阀、管道组成的系统充填过程进行了仿真计算,并将计算结果与已发表的采用特征线方法获得的结果进行对比分析,表明该方法和仿真结果可信.进一步研究了预存气体压力、贮箱压力、多变指数等影响因素对最大充填压力峰的影响规律. 相似文献
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In order to obtain the dynamic characteristics of a differential piston warm gas selfpressurization system for liquid attitude and divert propulsion system, a transient model is developed using the modular modeling method. The system includes the solid start cartridge,pressure-amplified tank with liquid monopropellant, liquid regulator, gas generator, and pipes.The one-dimensional finite-element state-variable model is applied to the pipes and the lumped parameter method is adopted for the other modules. The variations of the system operation parameters over time during the startup, steady-state, and pulsing operational processes are obtained from the transient model, and the characteristics of starting time changing with different system parameters are also analyzed. It is shown that the system startup process can be divided into three distinct processes. The starting time monotonically changes with variations of the liquid regulator parameters, first decreasing and then increasing with the mass change of the solid propellant charge of the start cartridge, initial gas cavity volume of the pressure amplified tank and initial gas cushion of the propellant tank. The starting time can be reduced to less than 1.0 s(0.68–0.75 s for the current system). For meeting the deviation requirements of ±10% of the steady-state propellant tank pressure, the positive deviation requirement is assured by the self-locking pressure and the negative deviation can be assured within an allowable maximum propellant tank volume flowrate(1.6 times the design value for the proposed system) for downstream thrusters for a designed system. The results from the simulation are useful as a guide for further system design and testing. 相似文献
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针对航空涡轮发动机部件的过渡态,提出了一种基于压气机部件三维模型的过渡态性能计算方法,采用动态边界条件,以转速和出口静压为过渡过程的控制参数,二阶向后欧拉法求解三维非定常雷诺平均Navier-Stokes方程组,通过三维非定常模拟获得压气机的过渡态性能和内部非定常流场特征。以NASA跨声速压气机Rotor 67转子为模型,采用该方法模拟了压气机从60%设计转速加速至100%设计转速的过渡过程,获得了压气机过渡态性能及转子内部详细的激波结构与演变过程。对比通用特性结果,在整个过渡曲线上,总压比相对误差最大值小于6%,绝热效率相对误差最大值小于2%,验证了该方法的可靠性。结论表明:基于动态边界的三维非定常模拟方法能够准确模拟压气机的过渡态性能,并反映出过渡态的非定常流场详细信息。 相似文献
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Cavitation caused by insufficient suction is a major factor that influences the life of aircraft pumps. Currently, pressurizing the tank can solve the cavitation problem under steady large-flow conditions. However, this method is not always effective under transient conditions (from zero flow to full flow in a very short time). Moreover, to apply and design other measures, such as a boost impeller, the suction dynamics during the transient period must be investigated. In this paper, a novel approach based on the pressure wave propagation theory is proposed for predicting the inlet pressure of an aircraft pump under transient conditions. First, a dynamic model of a typical aircraft pump is established in the form of differential equations. Then, the transient flow model of the inlet line is described using momentum and continuity equations, and the governing equations are discretized by the method of characteristics and the finite difference method. The simulated results are in good agreement with the results from verification tests. Further simulation analysis indicates that the wave velocity and transient time may influence the inlet and reservoir pressure as well as the size of the inlet line. Finally, solutions for upgrading the inlet pressure are discussed. These solutions provide guidelines for designing inlet installations. 相似文献
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航天器推进系统水击及其抑制方法 总被引:2,自引:1,他引:1
针对航天器推进系统充填和关机过程水击这一动力学问题,基于已建立的航天器推进系统仿真模型,开展了某型推进系统的仿真研究,并重点分析了节流孔、弯管对推进剂供应管路水击的抑制作用.研究结果表明:①在推进系统充填和关机过程中,其不同位置均出现了明显的水击现象,充填过程水击频率较低,而关机过程水击频率较高,关机过程的水击峰值压力显著高于充填过程;②节流孔可显著削弱充填过程中的压力和流量振荡,关机过程的水击需要由较小的节流孔才能有效抑制;③弯管可明显削弱充填过程中的压力和流量振荡,对流量振荡的抑制效果尤为显著,但弯管对关机过程水击的抑制效果不明显. 相似文献
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