Effect of phase change on performance of spiral groove liquid film seals

doi:10.11949/j.issn.0438-1157.20170299

Abstract

Abstract:

In order to investigate phase change effect of liquid film on sealing performance of spiral groove liquid film seals, phase change model of non-contacting liquid film seals was established on the basis of mass conservation and mass source from Hertz equation. By discretization of governing equations with finite volume method, the effect of liquid film phase change on sealing performance was analyzed. Results show that phase change on sealing performance is closely related to sealing effectiveness. Both groove position and phase distribution in dynamic pressure groove have significant influence on sealing performance and pressure distribution at end face. During phase change in liquid film, seal opening force was increased but leakage was decreased for downstream pump seal, whereas the effect was different for upstream pumping seal. If the slot was close to inner diameter, seal opening force of upstream pumping seal was first increased and then decreased, but leakage was first decreased and then increased and finally decreased. If the slot was close to outer diameter, seal opening force of upstream pumping seal was increased linearly but leakage was first decreased and then increased. Phase transition occurred in groove region could strongly weaken hydrodynamic effects and largely impact on pressure distribution at the end face.

Key words: phase change, liquid film seal, sealing performance, Hertz equation

摘要：

为了探究液膜相变现象对螺旋槽液膜密封性能的影响。基于质量守恒定律，以赫兹方程推导质量源项并建立非接触式液膜密封相变模型。使用有限体积法对控制方程进行离散，分析了液膜相变现象对非接触式机械密封性能的影响。结果表明：相变现象对密封性能的影响与密封功用密切相关，且动压槽开槽位置及槽内相态分布对密封性能与端面压力分布影响显著；液膜发生相变后，下游泵送型密封开启力增大且泄漏量减小；上游泵送型内槽式密封开启力先增大后减小，泄漏量先减小后增大再减小，外槽式密封开启力呈线性增大，泄漏量先减小后增大；相变发生在槽区时，会导致动压效应明显减弱，对端面压力分布影响较大。

关键词: 相变, 液膜密封, 密封性能, 赫兹方程

CLC Number:

TB42

CAO Hengchao, HAO Muming, LI Zhentao, YANG Wenjing, SUN Zhen, WANG Yanhong, REN Fujun. Effect of phase change on performance of spiral groove liquid film seals[J]. CIESC Journal, 2017, 68(8): 3190-3201.

曹恒超, 郝木明, 李振涛, 杨文静, 孙震, 汪艳红, 任付军. 相变对螺旋槽液膜密封性能的影响[J]. 化工学报, 2017, 68(8): 3190-3201.

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