Study the influence of concavity shapes on augmentation of heat‐transfer performance, pressure field, and fluid pattern in three‐dimensional pipe

Abstract

AbstractIn this current study, the heat‐transfer augmentation mechanism and pressure drop with flow field structures over different dimple arrays in turbulent flow of three‐dimensional circular tube are investigated based on computational fluid dynamics numerical methods using the standard k − e turbulent model. The water is the working fluid over the range of Reynolds numbers from 1500 to 24,000, with three different tubes dimpling arrangements are analyzed. The numerical simulation results are validated through available experimental data, and they show good agreement results between them. The numerical analysis results showed that the flow fields are symmetric within the middle cross‐sectional direction in the pipe with and without dimples. Also, the flow near or close to the dimples is chaotic and including small vortexes and eddies. The results found that the temperature difference in the dimple tube with 2 mm diameter at low flow range 0.56 L/min was higher than that of smooth pipe, dimple tube 0.75 and 1.5 mm by 26.8%, 10.57%, and 3.68%, respectively. It can be concluded that using dimples in heat‐exchanger tubes can provide rates of heat transfer that is higher than that without dimpled tubes at the same operating conditions. Hence, this is an important enhancement in process industries for the energy conversion applications.