不同流程布置风冷式冷凝器的数值研究

Numerical Study on Air-cooled Condenser with Different Circuit Arrangements

为了节省实验资源并缩短实验周期,本文应用三维分布参数模型对风冷式冷凝器的4种流程布置和5组不同制冷剂流量工况的流动换热性能进行数值研究,并通过实验验证了模型的可靠性。仿真模型对制冷剂换热量的预测与相同工况下的实验值的相对误差在±10%以内;制冷剂压降的预测值相对误差在±15%以内。模拟结果表明:为了使换热量尽量大的同时熵产数小,流程布置合流次数为0、2、3时所对应的最佳质量流量范围分别为511~540 kg/h、472~511 kg/h和432~472 kg/h。研究发现在低质量流量区域,选择有合流的管路更具优势;在高质量流量区域,则选择无合流的管路具有更好的传热特性。

To save experimental resources and shorten the experimental cycle,a three-dimensional distributed parameter model was used to study the heat transfer performance of air-cooled condensers.Four kinds of circuit arrangements and five groups under different refrigerant flow conditions were compared,and the reliability of the model was experimentally verified.The relative error of the simulation model for predicting the heat transfer of refrigerants was less than±10%,compared with the experimental values under the same working conditions,and the relative error of the predicted value of refrigerant pressure drop was less than±15%.Simulations demonstrated that the optimal mass flow rate ranges corresponding to the confluences number of the circuit arrangements of 0,2,and 3 were 511~540kg/h,472~511kg/h,and 432~472kg/h,respectively,reflecting ahigh heat transfer and low entropy production.The pipeline with confluence exhibited more advantages in the low mass flow rate area,while the non-confluence pipeline exhibited better heat transfer characteristics in the high mass flow rate area.