摘要
为提升瑞利台阶型机械密封的泄漏控制能力和丰富其零/负泄漏设计方法,通过建立有限元数值模型,对比研究了端面环形槽的空化诱导机理及诱导空化区对密封性能的影响规律与水平。结果表明环形槽在较大槽深下仅存在流体静压效应且静压力较低,可极大改变端面流体膜压分布,限制并分离正向瑞利台阶处液膜高压区从而在反向瑞利台阶区域诱导生成空化效应,其量纲一化深度超过20后限制分离作用水平趋于稳定。环形槽诱导作用最大使空化区长度增加82%从而有效提升密封空化抽吸水平,扩大负泄漏工况区域。反向瑞利台阶主槽深度显著影响环形槽诱导作用,其优选范围为8~15,该范围内空化长度比与反向抽吸率的相对改变量均小于2%,这使密封在一定端面磨损量下仍具有良好的泄漏控制能力。
To improve the leakage controlling capability and enrich the design method of zero/negative leakage in mechanical seals with Rayleigh steps,it was comparatively studied by developing the finite element numerical model that the cavitation induction mechanism of annular groove at sealing face and the influencing law and level of induced cavitation zone on sealing performance.The results indicate that there is only the hydrostatic effect and the hydrostatic pressure is lower at the annular groove zone under the larger groove depth.it greatly changes the film pressure distribution at sealing face,namely,restricts and separates the high-pressure zone of liquid film at forward Rayleigh steps,thus the cavitation effect is induced significantly in the reverse Rayleigh steps.The restriction and separation level tends to be stable when its dimensionless depth exceeds 20.The length of cavitation zone is increased by up to 82%due to the induction effect of annular groove,which effectively improves the cavitation suction level and increases the operating range with negative leakage.The main groove depth of reverse Rayleigh step significantly affects the induction effect of annular groove and its optimum range is 8~15,in which the relative changes of cavitation length ratio and reverse suction rate are less than 2%.It makes the mechanical seals remain a good leakage-controlling capability in a certain amount of wear for end faces.
作者
马学忠
孟祥铠
MA Xuezhong;MENG Xiangkai(College of Petrochemical Engineering,Lanzhou University of Technology,Lanzhou 730050;College of Mechanical Engineering,Zhejiang University of Technology,Hangzhou 310032)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2022年第13期166-174,共9页
Journal of Mechanical Engineering
基金
国家自然科学基金(52005236)
兰州理工大学博士科研启动基金(02-061907)资助项目。
关键词
机械密封
环形槽
空化诱导
负泄漏
有限元分析
mechanical seal
annular groove
cavitation induction
negative leakage
finite element analysis
