Evaluation of thermal-hydraulic performance of dimpled tube from the perspective of skewness and kurtosis

The flow characteristics and heat transfer performances of tube with ellipsoidal dimples are numerically investigated in this present work. Skewness and kurtosis of dimpled tube wall surface are calculated by discrete method. Effects of dimple cross section shape, number, cross distribution angle and pitch on thermal-hydraulic performance and roughness parameters are discussed. These results show that compared with the smooth tube, the dimpled tube has a better thermal-hydraulic performance due to the flow mixing and flow separation are significant increase. In addition, the influence law of dimple cross section shape, number and pitch on skewness, kurtosis and thermal-hydraulic performance is the larger skewness and smaller kurtosis, the better thermal hydraulic performance. However, it is unable to evaluate the effect of dimple cross distribution angle on thermal-hydraulic by using skewness and kurtosis.