含固体颗粒流体用安全阀自动冲洗装置的研究_齐亚茹.pdf

Thesis Submitted to Hebei University of Technology for The Master Degree of Chemical Process Equipment STUDY ON AUTOMATICALLY FLUSHING DEVICE FOR SAFETY VALVE USED IN FLUID WITH PARTICLES by Qi Yaru Supervisor:Prof.Gao Bingjun June 2011 河北工业大学硕士生论文 i 含固体颗粒流体用安全阀自动冲洗装置的研究含固体颗粒流体用安全阀自动冲洗装置的研究 摘摘 要要 安全阀用于煤直接液化工业的油煤浆输送管路时，当安全阀泄压后，密封面上往往残存煤颗粒，使阀瓣和阀座间存在缝隙，造成阀门关不死，从而产生内泄漏，同时颗粒的存在会加剧阀瓣和阀座密封面的磨损，影响安全阀的密封性能。有效地清除密封面上的固相颗粒，是解决此问题的关键。为此本课题提出了一种含固体颗粒流体用安全阀的自动冲洗装置，并应用 FLUENT 软件的欧拉模型对冲洗过程进行了三维数值模拟，初步探讨了方案的可行性。通过对不含油源设备的在线冲洗装置冲洗过程进行模拟研究发现，对冲洗油管路与阀门连接管路的连接三通的角度进行合理地选择，设定了合理的冲洗油管路入口的压力，对阀门冲洗过程进行模拟计算发现，冲洗一定的时间后，密封面上的煤粉颗粒体积率低于10-6，可认为密封面已被冲洗干净。同时，分析了液固两相流在冲洗装置中的流动特点，讨论了由冲洗过程对油煤浆输送系统造成影响。对以气液式蓄势器为油源设备的冲洗结构进行了研究。在不同压力下，对连接蓄势器和安全阀入口管路的三通采用不同角度，分别对不同装置的冲洗过程进行数值模拟，分析了三通角度和蓄势器压力对冲洗过程的影响。冲洗一定时间后，阀瓣与阀座间颗粒相体积率低于 10-6，且总耗油量在蓄势器出油容量之内，可认为上述装置能够完成对阀门密封面的冲洗。比较发现，相同压力下，60斜三通装置对煤浆系统的影响最小，45斜三通装置次之；不同压力下，45斜三通装置可完成冲洗的压力较低，总耗油量及进入油煤浆体系的油量小，优于 60斜三通装置。关键词：关键词：安全阀，在线冲洗，液固两相流，欧拉模型，数值模拟 含固体颗粒流体用安全阀自动冲洗装置的研究 ii STUDY ON AUTOMATICALLY FLUSHING DEVICE FOR RELIEF VALVE USED IN FLUID WITH SOLID PARTICLES ABSTRACT Relief valve was wildly used in direct coal liquefaction.After a pressure relief,there always had coal partials on the seal set.A small gap between the disc and the nozzle was made,and the relief valve can not be closed,so inside leaks happened.And then,the seal set was worn much more intensively between the disc and the nozzle,the sealed capability of the relief valve was reduced.Flushing away the particles on the seal set efficiently is the key to solve the problem.So a type of automatically flushing device for relief valve used in fluid with solid particles was proposed,and the flushing process was simulated with Eularian model by FLUENT.The process of flushing online was simulated for the device without oil source.The flushing pipe and relief valve was connected by a three-way tube,chosing a appropriate angle for the tube and setting a reasonable pressure for flushing pipe-inlet were very impotent