冷凝器流程布置方案的研究与探讨

Study on Refrigerant Circuitry Design for Condensers

基于传热单元法,建立了冷凝器的稳态分布参数模型。经与前人的实验研究结果进行对比,数值模拟结果与实验结果吻合良好。运用该模型详细分析了六种不同流程布置的二排管冷凝器的换热和流动特性。研究结果表明:单回路冷凝器中,逆流布置换热最好,错流其次,顺流最差;对任一流程布置的冷凝器,当风量不变时,必然存在一最佳冷媒流量使冷凝器性能达到最佳;当冷媒流量保持不变时,也相应存在一个最佳风量,使冷凝器性能最佳。冷凝器流路布置中,重力的影响不可忽略。针对单回路冷凝器进出口总压降过大,沿程压降、热阻及换热系数分布不均匀,提出了一些实用性的分流原则,如双“N”流路,相变点分流等并进行了深入细致的讨论。该研究方法为冷凝器流程布置的优化设计提供了理论基础和指导方向。

Based on the, a steady state distributed parameters model was established in the numerical simulation of refrigerant circuitry in condensers. The calculation results are in agreement with the experiments in the previous literature. The heat transfer and flow characteristics of six different two- rows condensers were studied with the present model. The research results show that the counter- flow condensers have a better performance than other arrangements condensers. When the front velocity is constant, there must be an optimum refrigerant mass velocity, leading to the best performance for the condensers. Similarly, when the refrigerant mass velocity is constant, there must be an optimum front velocity. In addition, the influence of gravity force cannot be ignored. Some practical refrigerant circuitry branching and joining principals were proposed and extensively studied, considering the pressure, heat resistance, and heat transfer coefficient distribution along the heat tubes.