Influence of the cross-sectional geometry of the heat exchanger element on heat flow and pressure drop

¹ Kazan State Power Engineering University, 51, Krasnoselskaya str., 420066, Kazan, Russia
² Kazan National Research Technological University, 68, Karl Marks str., 420015, Kazan, Russia

^* Corresponding author: solovyeva.ov@kgeu.ru

Abstract

This paper examines the influence of the geometry of the heat exchanger element on heat flow, pressure drop, outlet temperature and energy efficiency. By numerical modeling in a two-dimensional formulation, we solved the problem of convective heat transfer when air flows transversely around one and three rows of heated elements of different cross-sections. The following cross-sectional shapes of heated elements are: circle, trefoil, trefoil (mirrored), quatrefoil, cinquefoil and cinquefoil (mirrored). Calculations were carried out using ANSYS Fluent v. 19.2 at the following air flow velocities: 0.01; 0.05; 0.25 and 1.25 m/s. The research results showed that when flowing around one row of elements, the highest energy efficiency is provided by elements with a trefoil shape in cross-section. When flowing around three rows of elements at lower air flow velocities (0.01, 0.05, and 0.25 m/s), trefoil-shaped elements also have the best energy efficiency values, and only at an air flow velocity of 1.25 m/s elements with a trefoil cross-section inferior by 3.67% to elements with a cinquefoil (mirrored) cross-section.