安全阀超压泄放过程动力学参数分析与测试

Analysis & testing on dynamic parameters of safety valve during the overpressure relief process

对3D模型安全阀的超压泄放机理及气体动力学过程进行了模拟分析和试验验证。利用区域分组法和路径分析法,对开启部件在超压泄放过程中的稳态流场参数进行了详细整理,研究了速度、压力参数在内外流场选定路径上的分布以及开启部件的动态力平衡情况。对竖直(Y)方向各种力平衡问题的研究和比较,证明了升力测试值为总力,包括静态力和动态力两部分,其中,静态力占绝对优势;反冲(升)力中,动态力起很大作用,间隙力属于自平衡力系。动态力主要来源于密封面和反冲盘折边出口附近的高速气体流动。阀芯反冲(升)力也主要来源于静态力,动态力影响较小。水平(X)方向力平衡参数研究结果表明,对于反冲盘与阀芯分离结构,阀芯处于严格的动态平衡中,而反冲盘则可能存在水平方向的不平衡力,可能导致阀芯开启和回座过程偏载。无论阀芯与反冲盘是整体还是分离式设计,此偏载均可能导致开启回座偏差,甚至引发颤振、频跳或密封面损坏。利用试验装置和新研制的传感器,获取了试验开启过程中阀芯压力、升力、开启高度和反冲盘测点压力,进一步计算了反冲盘和阀芯反冲(升)力的数值。试验和模拟结果对比表明,数值模拟结果与传感器测试数据吻合,为进一步研究内外流场及其动作机理奠定了基础。

With the numerical simulation and the experiment methods,the safety valve overpressure relief process and the gas dynamic problem are studied. The relief valve interior steady flow field of moving parts was analyzed by using the domain decomposition and paths analysis methods,the dynamic force balance,the distribution of velocity and the stress characteristics of the paths in the interior and external flow field were studied as well. The results showed that according to the balance of vertical（Y）direction force,experimental lift data came from total pressure,of which the static force was the main part. The dynamic force was important to the recoil force. The clearance force was balanced. The dynamic force mainly came from the high speed gas in the sealing surface and the disc holder ruffled. The static force was the main part of the valve core lift. The research on balance of horizontal（X） direction force showed that valve core was dynamically balanced,but unbalanced horizontal vibration force may exist in the disc holder,leading to a partial load during the open and return process. This partial load may lead to displacement deviation,flutter, chatter and damage the sealing surface,whether combining the valve core and the disc holder into one element or not. By using the experimental setup and the new sensor,the valve core pressure,lift,lifting height and the data of disc holder in monitoring points were successfully obtained, and the recoil force was calculated. The results showed that the 3D simulation was consistent with the sensor testing data.