Numerical Simulation Of Rotary Fluid Pressure Energy Exchanger

This paper mainly studys the performance of RPE (Rotary Pressure Exchanger) based on the background of Seawater Reverse Osmosis. When RPE designed, the two most important things are controlling fluid plug and face seal. So this paper's research is on these two major issues using the CFD.In this paper, firstly, the main purposes of researching fluid plug are to build reasonable numerical computional model, analyze the fluid plug's forming processes and characteristics, research the effection of each parameter and get quantitative methods used in controlling it when RPE designed. Secondly, the main purposes of researching face seal are to build numerical computional model of face seal, explain the principle of face leaking and controlling effectively the pressure and leakage of current experimental device.Based on the above main purposes, a deep research on RPE is made in this paper and the main contents of which are following:I. The basic principles and characteristics of typical devices of all kinds of pressure energy recovery are summarized in this paper.II. The forming mechanism of fluid plug and the basic principles of face seal" are explained in this paper on the base of basic theories.III. The geometric model and parameters are analyzed based on the former theoretical studying; meanwhile, numerical computational models of fluid plug and face seal are setup by the CFD software FLUENT repectively.IV. The existence and effectiveness of fluid plug are identified by use of the result of calculation on NaCl density distribution. Then, the effection of parameters on the fluid plug and face meal are analyzed by Orthogonal Experiment; experiential formula is gotten by fitting dimensionless parameter to volume efficiency.V. The fitting result between the flowing field distribution imitated by the face seal model and that of numerical solution is analyzed. Then, the comparison with experimental result proves that the calculation quality of leaking is reasonable. The relationship between pressure and clearance is analyzed in labototary. The relationship between leakage, pressure and clearance is fitted using in controlling leakage.The final result of this study explains: Firstly, fluid plug is existent, steady and can be effectively controlled. And the key factors of influencing volume efficiency are that the entrance flow and the rotational speed. Meanwhile, the relation between every parameter and the volume efficiency can be quantitatively expressed by empirical formula. Secondly, the main mechanism of face seal is that the laminar flow flowing can be kept inside the gap at high pressure. And in the existing experiment condition, sealed pressure can reach 6MPa when the clearance is controlled to 0.04mm. The leakage can be controlled by the fitting equation of leakage, pressure and clearance.