Investigation of the effect of a cylindrical heater on saturated pool boiling heat transfer

Boiling heat transfer is extensively employed in diverse engineering fields because of its superior heat transfer characteristics. Pool boiling on a heated plane or around a heated wire has received significant attention. However, the combination of both a heated plane and a heated wire in a pool boiling system has not been sufficiently investigated. In this study, a hybrid lattice Boltzmann (LB) method is employed to investigate the boiling heat transfer characteristics of a system, where a cylindrical heater (heated wire) is placed above a horizontal smooth flat heater. The flow field is simulated using the pseudopotential LB model, and the temperature field is simulated using the finite -difference (FD) method. In the simulation, the conjugate heat transfer involving both the solid and fluid phases is considered. The numerical results show that the boiling curve for different positions of the cylindrical heater is significantly different compared with the case without the cylindrical heater. However, the boiling curve is slightly affected by variations in the temperature of the cylindrical heater. Different boiling phases, including the onset of nucleate boiling (ONB), the critical heat flux (CHF), and film boiling are clearly observed. By moving the cylindrical heater away from the flat heater, the CHF value of the flat heater increases, and the CHF value corresponding to superheating decreases. When the distance between the two heaters is small, the CHF value is lower than that in the case without the cylindrical heater. The lowest CHF value is observed when the cylindrical heater is attached to the flat heater. During the steady film boiling phase, the heat transfer performance is less affected by the cylindrical heater when the distance between the two heaters is large. However, by placing the cylindrical heater to an optimal position, the heat transfer performance during the steady film boiling phase can be significantly improved.