干式壳管式蒸发器内新型分液器的数值模拟

Technical Research of New Dispensers in Dry-expansion Shell and Tube Evaporator

干式壳管式蒸发器内各管间制冷剂的流量分配不均会带来蒸发器换热效果的下降。本文通过CFD商用软件对干式壳管式蒸发器内流量分配情况进行数值模拟研究,提出了一种新型分液器,用于平衡各管间的流量分配情况。数值模拟与可视化实验的流场信息对比,验证了模拟结果的可靠性。搭建了实验台,设计并制造了锥形分液器,将分液器安装于冷水机组上进行了整机性能的多个工况实测实验,结果表明:加装分液器后蒸发器进出口压降由原来的约15 k Pa下降到约3 k Pa,整机COP提高约5%。

Fluid flow maldistribution in each tube of a dry-expansion shell and tube evaporator can cause inefficient heat exchange. In this paper, a numerical simulation of flow distribution in a dry-expansion shell and tube evaporator is carried out using CFD commercial software. A new type of dispenser is proposed to balance the flow distribution between different tubes. A numerical simulation and visualization experiment are compared to verify the reliability of the simulation results. An experimental platform was set up, and a conical liquid distributor was designed and manufactured. The liquid distributor was installed in a chiller. The performance of the chiller under different conditions was tested. The results show that the inlet and outlet pressure drops in the evaporator decreased from about 15 kPa to about 3 kPa, and the entire COP increased by about 5%.