摘要
针对快变升速、密封腔压力波动、轴系扰动等扰变工况导致的非接触式机械密封动环与静环碰摩、泄漏加剧及动力失稳等问题,提出了一种内径螺旋槽、外径波锥槽和中间坝区组合的新型表面结构,并将其与螺旋槽、波锥坝槽的降漏减振功效进行了比较。首先,建立了扰变工况下摩擦学与动力学耦合的数学模型;然后,基于给定扰动工况的表征函数,全时间域联立求解含流量因子、接触因子、挤压项与考虑质量守恒空化边界的润滑方程、Jackson-Green接触方程及补偿环轴向动力学方程;最后,以承载力、泄漏量、膜厚为主要指标,对3种表面结构的瞬态响应进行了对比分析。结果表明:新型组合槽在多类扰变工况下具有出色的密封性能与稳定性,启动阶段泄漏量始终保持在最低水平,与波锥槽脱开转速相差500 r/min,压力波动工况下组合槽膜厚振动最大幅值仅为3μm,与螺旋槽相比,轴系扰动工况下其接触冲击载荷减小12 kN,瞬时泄漏量减少400 L/h。研究结果可为扰变工况下表面结构优化设计与稳定性提升提供参考。
A novel surface structure which combines spiral groove(SG)at inner side,wave-tilt(WTD)at outer side and annular dam at center is proposed(SG-WTD)to solve the problem such as surface rub-impact,leakage aggravation and dynamic instability of non-contacting mechanical seals during startup,pressure fluctuation and shafting disturbance.Meanwhile,this new surface structure is compared with traditional SG and WTD for leakage and vibration reducing.A mathematical model coupling tribology and dynamic system under disturbance conditions is established.Then,the Reynolds equation considering JFO boundary,flow factor,contact factor and squeeze item,the Jackson-Green asperity contact equation as well as the dynamic equations of flexible mounted ring are solved simultaneously based on the operating conditions.Finally,the transient responses of three surface structures are analyzed comparatively taking the bearing capacity,leakage rate and film thickness as the main indexes.Results show that the novel SG-WTD structure has excellent sealing performance and stability under various disturbing conditions.Its leakage rate always remains at the lowest level during startup and it has higher separation speed about 500 r/min compared with WTD.SG-WTD structure has significant stability under pressure fluctuations,and the maximum disturbance of film thickness is only 3μm.The contact force and leakage rate are reduced by 12 kN and 400 L/h,respectively,compared with SG.This study may provide a reference for surface structure optimal design and stability improvement under disturbance conditions.
作者
徐鲁帅
王赟磊
张帆
郝木明
袁小阳
XU Lushuai;WANG Yunlei;ZHANG Fan;HAO Muming;YUAN Xiaoyang(Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System,Xi’an Jiaotong University,Xi’an 710049,China;College of New Energy,China University of Petroleum(East China),Qingdao,Shandong 266580,China)
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2020年第1期56-63,共8页
Journal of Xi'an Jiaotong University
基金
国家自然科学基金资助项目(11872289,51775412)
国家自然科学基金青年基金资助项目(51805409)
关键词
机械密封
表面结构
瞬态特性
扰变工况
稳定性
mechanical seal
surface structure
transient characteristics
disturbance condition
stability
