【作者】 王威；

【导师】 叶建军；

【作者基本信息】 华中科技大学 ， 新能源科学与工程， 2023， 硕士

【摘要】 液氢储运目前在大规模、远距离的氢能储运方面具有明显的优势,液氢球阀作为液氢储运系统的关键部件,在控制液氢流量、压力、流向等方面起着重要的作用。在液氢球阀的启闭过程中,阀门开度的变化极易导致其内部的低温液氢介质在流经阀门时出现空化现象,影响阀门和管道的性能及可靠性。本文基于Mixture多相流模型和修正过后的Zwart-Gerber-Belamri空化模型,结合滑移网格技术,研究了液氢球阀启闭过程中的流动规律和空化特性,揭示了不同运行工况和阀芯结构参数对流道内空化特性的影响规律。本文具体研究内容如下:建立了液氢球阀启闭过程中的数值模型,研究了不同开度下启闭过程中内部流动规律,揭示了启闭过程中空化现象发生的机理,分析了压力、速度、流量流阻系数、气体体积分数等随阀芯开度的变化规律。研究表明关闭过程中流道内的空化现象要比开启过程更加严重,并且会形成更长的空穴流。在特定工况下,分别研究了阀门入口压力和阀芯关闭速度对于液氢球阀关闭过程中空化特性的影响规律。结果表明,减小阀门的入口压力能够降低流道内的空化现象。对于阀芯关闭速度而言,在关闭过程中可采用先快后慢的方式降低流道内的空化现象。通过改变阀芯出口面积和阀芯流道结构,研究了液氢球阀关闭过程中阀芯结构参数对流道内空化特性的影响,得到了不同结构下流道内气体体积分数、温度和能量损失的变化规律。研究发现,增大阀芯出口面积能够降低流道内的空化现象,此外O型流道结构具有最小的流阻系数,而缩径流道结构对于液氢球阀的抗空化效果最好。更多还原

【Abstract】 As a key component of the liquid hydrogen storage system,the liquid hydrogen ball valve plays an important role in controlling the flow,pressure and direction of the liquid hydrogen.During the opening and closing of the liquid hydrogen ball valve,the variation of the valve opening degree will easily lead to the cavitation of the cryogenic liquid hydrogen medium inside the valve when it flows through the valve.And it will affect the performance and reliability of the valve and pipeline.Based on the Mixture multiphase flow model and the modified Zwart-Gerber-Belamri cavitation model,this paper investigates the flow law and cavitation characteristics of the liquid hydrogen ball valve during the opening and closing process.And the influence of different operating conditions and spool structure parameters on the cavitation characteristics in the fluid channel is studied.The details of the research in this thesis are as follows:A numerical model in the opening and closing process of a liquid hydrogen ball valve is established.And the internal flow law in the opening and closing process is studied.Then,the mechanism of cavitation phenomenon in the opening and closing process is revealed.Meanwhile,the variation law of pressure,velocity,flow coefficient,flow resistance coefficient and hydrogen volume fraction with the opening of spool opening are analyzed.The study shows that the cavitation phenomenon in the closing process is more serious than that in the opening process,and longer cavity flow will be formed.Under the specific working conditions,the influence of valve inlet pressure and spool closing speed on the cavitation characteristics in the closing process of liquid hydrogen ball valve is studied.The results show that the cavitation phenomenon in the fluid channel can be reduced by reducing the inlet pressure.For the closing speed of the spool,the cavitation phenomenon in the fluid channel can be reduced by the way of first fast and then slow in the closing process.By changing the spool outlet area and the spool channel structure,the influence of the spool structure parameters on the cavitation characteristics in the fluid channel during the closing process of liquid hydrogen ball valve is studied.The changes of hydrogen volume fraction,temperature and energy loss in the fluid channel with different structures are obtained.It is found that increasing the spool outlet area can reduce the cavitation phenomenon in the fluid channel.In addition,the O-type structure has the smallest flow resistance coefficient,while the reduced diameter structure has the best cavitation resistance effect for liquid hydrogen ball valves.更多还原