Investigation on flow and heat transfer characteristics of latent functionally thermal fluid for axisymmetric flows

Abstract

The utilization of heat exchangers in energy and industrial production is vital for heat exchange and transfer. The latent functionally thermal fluid (LFTF), due to its exceptional properties, can be effectively utilized in double-pipe heat exchanger as a heat transfer fluid. This study delves into the convective and heat transfer characteristics of LFTF in symmetric flow conditions. Employing the lattice Boltzmann method (LBM), various dimensionless parameters are examined, including the height-to-diameter ratio (HDR) and inner diameter size. The results show that higher Rayleigh and Stefan numbers lead to more intense reactions and heat transfer processes. Additionally, a phase change temperature of 0.7 results in a total melting time that is 1.5 times longer than at a phase change temperature of 0.1. As the inner diameter increases, the average Nusselt number decreases faster, resulting in a shorter total melting time. Specifically, when the HDR is 0.5, the total melting time is 47.61% shorter compared to an HDR of 2. This is due to the fact that the temperature collects in the upper part of the study area resulting in faster melting in the upper part and hence shorter complete melting time the smaller the HDR. In summary, understand these relationships is crucial for optimizing heat transfer processes in industrial applications.