Examining the Impact of Using Hemispherical Dimples-protrusions on Heat Transfer and Pressure Drop in the Finned-tube Heat Exchanger with Different Configurations

In comparison to a plain fin, the addition of dimples or protrusions to the fins of a finned tube heat exchanger significantly affects the promotion of heat transfer. The impact of the number of dimples or protrusions and the arrangement of inline and staggered configurations on pressure drop and heat transfer is examined numerically in this research. The outcomes demonstrate that increasing the number of dimples and protrusions significantly affects heat transfer magnitude and pressure drop. Increasing the number of dimples and protrusions within the Reynolds number range of 150-1200 enhances the friction coefficient and heat transfer by 108%-163% and 16%-112%, respectively, in contrast to the plain fin. In evaluating the result of the arrangement of inline and staggered configurations, the heat transfer amounts of these two models are almost the same, and the friction coefficient is higher in the model that uses the arrangement of inline. In the inline arrangement model utilizing dimples-protrusions, the resultant heat transfer and friction coefficient increase 11%-92% and 64%-113% within the Reynolds number range of 150-1200, respectively, compared to the plain fin.