一回路主止回阀结构优化及流体力学分析

发布时间：2019-05-27 19:00

【摘要】：船用核动力装置与民用核动力装置相比,由于其特殊的工作环境和性能要求,所以在结构上有所不同。为了保证船用核动力装置在特殊情况下工作的稳定性,其一回路设计有备用回路。备用回路和主回路之间通过止回阀进行连接,它们之间可以互相切换工作。在切换的过程中,不但要求阀门能够稳定可靠的工作,而且还要求它不能完全关死。否则不工作的回路会因为水温过低而影响反应堆的稳定性。这就对止回阀的性能提出了更多的要求。本文所要研究的止回阀就是针对上述问题设计制造的。它有别于传统意义上的止回阀,由于其对冲原理可以大大减小阀的水击作用。本文的研究是在前人研究的基础上,针对对冲式止回阀原理样机在实验中出现低流量关不上关不严的问题,对主止回阀的结构提出了改进。应用AutoCAD和Pro/E对止回阀改进结构的流道进行建模,并且用GAMBIT划分完网格,最后用CFD软件FLUENT对阀的关闭过程进行数值模拟。计算出阀门在关闭过程中压力变化云图、速度变化云图、阀头阀座的受力变化曲线以及速度变化曲线,通过这些参数来判断阀门的工作状态,找出止回阀存在的问题的根源并加以解决。最后通过实验验证理论分析的结果,对比理论值与实际值之间的差距并分析原因。通过动态模拟得到了阀头阀座的受力曲线、速度曲线以及流量变化曲线。计算的结果表明,在各种工况下阀门都能够自动关闭,阀座的受力和运动速度都明显大于阀头的。阀头阀座的受力和运动速度都是随着时间的增大而增大。逆流压差的大小直接影响回流量的大小和阀门的关闭速度以及阀头阀座的受力。压差越大,阀头阀座的受力和运动速度越大,回流量越大。
[Abstract]:Compared with civil nuclear power plant, marine nuclear power plant is different in structure because of its special working environment and performance requirements. In order to ensure the stability of marine nuclear power plant under special circumstances, a backup circuit is designed. The standby circuit and the main circuit are connected by check valves, and they can switch to each other. In the process of switching, not only the valve is required to work stably and reliably, but also it is not completely closed. Otherwise, the circuit that does not work will affect the stability of the reactor because of the low water temperature. This puts forward more requirements for the performance of check valve. The check valve to be studied in this paper is designed and manufactured in view of the above problems. It is different from the traditional check valve, because its hedge principle can greatly reduce the water hammer effect of the valve. On the basis of previous studies, this paper puts forward an improvement on the structure of the main check valve in order to solve the problem that the low flow rate can not be closed strictly in the experiment of the prototype of the counterimpact check valve. AutoCAD and Pro/E are used to model the flow channel of the improved structure of the check valve, and the grid is divided with GAMBIT. Finally, the closing process of the valve is simulated by CFD software FLUENT. The pressure change cloud picture, the speed change cloud picture, the stress change curve and the speed change curve of the valve head seat during the closing process are calculated, and the working state of the valve is judged by these parameters. Find out the root cause of the problem of check valve and solve it. Finally, the results of theoretical analysis are verified by experiments, and the gap between theoretical value and actual value is compared and the reasons are analyzed. The stress curve, velocity curve and flow curve of valve head seat are obtained by dynamic simulation. The calculation results show that the valve can be closed automatically under all kinds of working conditions, and the force and movement speed of the seat are obviously larger than those of the valve head. The force and speed of the valve head seat increase with the increase of time. The countercurrent pressure difference directly affects the return flow, the closing speed of the valve and the force of the valve head seat. The greater the pressure difference, the greater the force and movement speed of the valve head seat, and the greater the return flow.
【学位授予单位】：哈尔滨工程大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH134

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