Enhancing the Heat Transfer in the Thermal Chimney by Attaching the Fin under CFD Analysis

Abstract

The primary and secondary heaters in heat exchangers were numerically evaluated at nominal temperatures of 140°C for the primary heaters, 100°C for the secondary heaters, and 20°C for the ambient temperature in order to validate the design idea for enhancing the air temperature. The “convective heat transfer” of air in a thermal chimney built to laboratory size using two different types of electrical heaters and a rectangular cross-section of constant area. Three-dimensional, steady Reynolds-averaged Navier-Stokes equations, the energy equation, and the k − ω turbulence model were used in ANSYS 2021 CFX computational fluid dynamics simulations of air convective heat transfer. It was taken into consideration how much heat was radiated from heater surfaces to chimney walls. In the chimney, measurements were made of the temperature, flow fields, and general thermal and heat transfer characteristics. The boundary condition of the heater surface and thermal radiation between two row heaters were investigated in relation to heat transfer between them. The operating temperatures of the primary and secondary heaters in every chimney design scenario are fixed, as is the row gap ratio of 5d from centre to centre and the fixed horizontal spacing of 1.75d between each heater. The air's estimated temperature agrees with the previous numerical data. In order to raise the air temperature in the current research, attach fins to the primary heaters. When fins are fixed to the heaters, the chimney's thermal qualities are better than those of the basic primary heaters. Numerous jets were present in the gaps between the heaters, and the temperature of each row was monitored.