旋转式压力能交换器的数值模拟

Numerical simulation of rotary pressure exchanger

旋转式压力能交换器是反渗透海水淡化过程中的重要设备之一,在降低能耗及系统运行成本方面具有重要作用。本文针对具有双环、类扇形转子结构的旋转式压力交换器,运用Fluent软件对其内部质量传递过程进行了数值模拟,分析了转子孔道盐水浓度分布,及进口流速、转速和孔道长度对孔道浓度分布的影响规律。结果表明:在转子旋转的一个周期内,海水与盐水的混合区域在转子孔道内做一次上下往复运动,海水的品质受转子孔道中混合区域溢出程度的影响;进口流速越大、转子转速越小,混合区域流体溢出程度增大,出口海水品质降低;孔道长度越长,混合区域流体溢出程度及高压出口盐水浓度呈减小趋势。

Rotary pressure exchanger is one of the most important equipment of reverse osmosis desalination process, which plays an important role in reducing energy consumption and system operation cost. Therefore, the software Fluent was employed in this paper to simulate the internal mass transfer process in a particular type of rotary pressure exchanger which had a double loop fan rotor structure. To be Specific, the brine concentration distribution was analyzed when the inlet velocity, rotation speed and the duct length varies. The results showed that in a rotating cycle, the mixed area of sea-water and salt-water was moving up and down in the duct for once and the quality of sea-water was affected by the spillover degree of mixed area; It also indicated that a faster inlet flow rate and a slower rotor speed would lead to an increase in spillover degree of mixed area and a reduce in the quality of outlet sea-water; Meantime, the longer the channel length was, the lower the mixed degree of overflow and the brine concentration in high pressure outlet would be.