A Numerical Analysis of Cylindrical and Conical Pin Fins Configurations for Enhancing Heat Exchanger Performance

In this paper, a study was performed for the effect of fins shape, spacing and arrangement on the inner pipe of a double pipe heat exchanger (DPHE).The DPHE models considered consist of concentric tubes with water and air as the hot and cold fluids in the inner and outer pipes, respectively.Computational fluid dynamics (CFD) simulation was incorporated to analyze the considered DPHE models with two different types of fins having the same surface area, cylindrical and conical pin fins.The distinction between cylindrical and conical pin fins is significant because their shapes influence the heat transfer and fluid flow characteristics within the heat exchanger.Therefore, understanding these differences is crucial for optimizing the design and performance of the double pipe heat exchanger.The numerical model was validated against experimental data from the available literature.Parameters such as fins spacing and arrangement were optimized to select the optimal configuration.The results showed that the cylindrical shaped pin fins are superior to the conical shaped fins although having the same overall surface area.The cylindrical and conical fins increased the airside Nusselt number by 20.22% and 13.95% compared to that of a smooth pipe DPHE, respectively.Additionally, increasing the fins spacing with a reduced number of fins decreased the airside Nusselt number but improved the overall performance of the DPHE by reducing the friction factor.Between 25 mm and 100 mm with increments of 25 mm, the fins spacing was optimized at 75 mm where the highest thermal performance factor was acquired.Finally, a staggered arrangement of the fins showed a negative impact on the hydrothermal performance of the DPHE as compared to an inline arrangement.