旋转压力交换器内间隙泄漏和润滑特性研究

The Research on Internal Leakage and Lubrication Property of Gap in Rotary Pressure Exchanger

旋转式压力能交换器是利用正位移原理进行流体压力能交换的装置,被广泛应用于反渗透海水淡化系统。旋转压力交换器内复杂间隙的液膜对转子起到润滑和支撑作用,同时也是内泄漏的通道。为研究压力交换器内间隙泄漏和润滑特性,为间隙流道结构的设计提供参考,对压力交换器内间隙进行三维建模,基于Fluent对间隙内三维流动进行定常计算,并利用试验结果验证了计算模型的准确性,分析了不同轴向端面间隙、环向间隙、环向间隙长度下的间隙泄漏量和液膜润滑特性。由结果可知,压力交换器内同时存在环向间隙轴向泄漏通道和轴向间隙端面泄漏通道,作为连接环向和轴向液膜的润滑槽压力分布是影响两条泄漏通道的流量大小和分配的关键因素;其中轴向端面间隙对润滑槽压力分布影响最大,而环向间隙及其长度主要影响环向泄漏通道的流量,而对端面泄漏通道的流量影响很小。

Rotary pressure exchanger （RPE） is a kind of energy recovery equipment based on the principle of positive displacement, which is widely employed in the seawater reverse osmosis （SWRO） system. The liquid films located in complex gaps of RPE play the roles of lubrication, support of the rotor and the internal leakage channels. In order to provide design reference for gap structure, a 3-D model was built to simulate the three dimensional flow in the gaps based on Fluent, and the simulation results were confirmed by the experiment. At the present work, leakage properties and fluid film lubrication properties were researched with different parameters of end clearance, circumferential clearance and its length. The results show that both the axial leakage in circumferential gap and end-face leakage in axial gap exist in the RPE at the same time. And the pressure distribution of lubrication groove joining the end film and circumferential film greatly influences on the flux and distribution of two leakage paths. The simulation results show that the end clearance influences the pressure distribution of lubrication groove mostly, while circumferential clearance and its length principally impact on the circumferential leakage, but have little to do with end-face leakage.