Evaluation of thermal hydraulic flow and enhancement of heat performance in different 3D dimpled tube configurations according to design of experiment analysis

The existing numerical research is concentrated on studying pressure drop, various velocity components, and heat performance behavior of heat exchanger pipe fitted with dimple on the inner pipe wall. Three-dimensional computational calculations using the CFD technique are conducted to study the influence of four geometrical parameters, including the distance between dimples, number of dimples, dimple diameter, and dimple pitch on the enhancement of thermo-hydraulic heat transfer. Also, the effects of the following parameters are optimized using the design of experiments (DOE) approaches combined with both Taguchi and Response Surface Methods. The results revealed different patterns of flow field and heat performance due to the use of dimples on the inner pipe surface. Moreover, utilized dimples can rise heat performance due to the interactions between the dimpled wall surfaces and swirling flow; hence, that can rise in area of heat transfer. Detailed flow analysis between dimples and pipe wall is demonstrated to describe the mechanisms of heat performance and pressure drop change. The orthogonal experiment outcomes revealed that the optimal design of the dimpled pipe has improved by about 35.75% and 36.1%. The numerical outcomes indicate that high value for the overall evaluation factor (PEF) is higher than 1. Based on the above findings, it can be found that hydrodynamic analysis flow, enhancement of heat transfer performance, and dimple optimization are required for different design applications.