传热效率——强化传热的新评价指标

Transport Efficiency of Thermal Energy—a New Performance Evaluation Criteria of Heat Transfer Enhancement

本文从热耗散的角度出发,提出了一种新的衡量热量传输过程效率的物理撼.随后,本文利用最小热耗散优化原理对圆管管内空气对流换热问题进行了优化计算,同时从层流和湍流两种情况进行了优化前后的传热效率的比较.结果表明,对于管内对流换热问题,与不优化的光管相比,优化后的圆管的传热效率远高于前者,并且传热效率与努塞尔数的趋势一致.因此,本文提出的传热效率能够很好地应用于管内强化传热的评价.

Based on the unavailable heat consumed in heat transfer process, a new physical quantity defined as transport efficiency of thermal energy was presented. Then, the approach of mininmm heat consumption was applied to optimize the laminar and turbulent convective heat transfer of air in the circular tube. Furthermore, the transport efficiency was calculated and compared in these cases. It can be found that the transport efficiencies of optimized circular tubes are much higher than the pure tubes for the convective heat transfer in the tube, so is the Nu number. Therefore, the transport efficiency of thermal energy is a good criteria to evaluate the heat transfer enhancement in the tube.