自旋转式压能回收装置内部流动机理与能量转化机制研究

Hydraulic-driven self-rotary energy recovery device can efficiently recovery the high pressure energy of concentrated salt water and reduce the running costs of desalination. Therefore, it is widely used in the desalination projects. In this application project, the non-valve-regulated rotary energy recovery device is taken as the main research object. The description method of high-speed rotor is explored, and the 3D fluid-structure coupling numerical simulation technology of hydraulic-driven rotor is established. The experiments and numerical simulation studies are carried out, and the transient characteristics of flow in the rotor and liquid collection channels during instant starting, running and stopping processes are analyzed. On this basis, the generation mechanism and evolution law of unsteady flow structure in the flow passage components are revealed. Then the forms and processes during the energy conversion of high and low pressure fluids are studied. Also, the relationship between the flow characteristics and the pressure energy recovery efficiency within the unsteady flow is investigated, and the energy conversion mechanism in the energy recovery process is clarified. In the end, orthogonal simulation experiments are conducted to achieve the primary and secondary factors affecting the energy conversion efficiency. Then, the relationships between the various factors are determined by the dimensional analysis method. With the research carried out, the performance prediction methods and control theory of self-rotary pressure energy recovery system can be improved. The research achievements can be used as the basis for the design and optimization of high-pressure energy recovery device, and also be a basis for the control theory of hydraulic-driven rotary devices.

液力驱动自旋转式能量回收装置可高效回收浓盐水中的高压余能，降低海水淡化的运行成本，因此被广泛的应用于海水淡化工程领域。本项目以非阀控自旋转式能量回收装置为研究对象，探索高速转子内湍流场的描述方法，建立液力驱动转子的流-固耦合三维数值模拟方法；开展内部流动实验和数值模拟研究，分析瞬时启动、运行及停机过程中，转子和集液槽流道内呈现的瞬态流动特性，揭示不同运行过程中各过流部件内非定常流动结构产生的机理和演化规律；分析流道内高、低压流体能量转化的形式和过程，探讨非定常流场的流动特征与压能转化效率之间的相互关系，阐明压能回收过程中能量的转化机制；通过正交仿真实验掌握影响能量转化效率的主次因素，采用量纲分析方法确定各个因素之间的相互关系，完善自旋转式压能回收装置性能预测方法和控制理论，为高效压能回收装置的设计和优化提供依据，为液力驱动式旋转装置的控制提供理论基础。

液力驱动自旋转式能量回收装置可高效回收浓盐水中的高压余能，降低海水淡化的运行成本，因此被广泛的应用于海水淡化工程领域。本项目主要是通过数值模拟方法来研究能量回收装置内部流动特性及能量转换机理研究。建立了一种适用于能量回收装置内流机理研究的非线性PANS湍流模型，并利用该模型展开本项目的研究。建立三维模型研究了转子孔道内非定常流动特性分析，揭示了转子转速和进口流速对液柱活塞的影响规律，分析了转子孔道长度对孔道内浓度的影响，设计了不同的集液槽结构并研究了其对装置性能的影响，同时研究了能量回收装置端面液膜的密封机理，建立了微米级间隙的三维计算模型，通过分析端面密封问题的特点，探索了转速、流速、间隙大小、操作压力、密封压力等参数对端面密封性能的影响。本项目的研究结果可为高效压能回收装置的设计和优化提供依据，为液力驱动式旋转装置的控制提供理论基础。