【摘要】 采用分布参数法对平行流冷凝器建立了数学模型,对目前广泛使用的制冷剂R134 a和替代制冷剂R404A以及R410A在平行流冷凝器中的传热和流动性能进行了模拟计算和分析比较.同时,对多元平行流冷凝器7种不同的各流程管数分配方案进行了模拟比较.结果表明:在采用平行流冷凝器的汽车空调工况范围内,R410A和R404A的流动和传热性能均优于传统的R134 a,且R410A比R404A性能更优越,更适宜作为中低温制冷剂用于汽车空调中.具有较好传热和流动性能的管数分配规律是各流程扁管数从前向后依次递减,且递减的速率逐渐加快.由于过冷段对压降的影响较大,扁管数不宜过少.更多还原

【Abstract】 A mathematic model of distributed parameters for parallel-flow type condenser was derived.The simulation and analysis of the heat transfer and the flow characteristics using the refrigerant R134a,the alternative refrigerant R404A and R410A in parallel-flow type condenser were carried out.And the effect of 7 different kinds of flow tube number arrangement on multi-unit parallel-flow condenser was studied.The results show that under the operating conditions of the automobile air-conditioning,R410A and R404A have better flow and heat transfer performances than R134a,and R410A is even better than R404A,which indicates that R410A is more suitable as the alternative refrigerant using in the medium and low temperatures.The arrangement rule which can make the multi-unit parallel-flow condenser have better heat transfer and flow performance is that the tube numbers in every flow should be decreased in turn,and the decreasing speed should be gradually accelerated.Because of the subcooling section’s great impact on pressure drop,the tube numbers in subcooling section shouldn’t be too few.更多还原