Excitation of flows in parallel plates with cavities using natural convection

Abstract

This study proposes and numerically analyzes a novel method for generating thermal drift using natural convection in a flat parallel plate channel. Unlike conventional approaches that rely on wavy walls and sinusoidal temperature distributions, the proposed method uses rectangular cavities and uniform temperature distributions. This structurally simple yet effective method offers enhanced practicality and industrial applicability. The analysis focuses on the formation of horizontal flows driven by natural convection. Rectangular cavities introduced in the lower plate have their vertical walls subjected to differential heating, generating efficient horizontal flows. Numerical simulations revealed that these flows arise from fluid circulation within the cavities, moving toward the heated wall relative to the cavity. Systematic investigations were conducted to examine the effects of cavity width and height, as well as throat width and height, on flow and heat transfer characteristics. Results showed that the ratio of flow rate to heat transfer could be optimized under specific geometric conditions. The formation, disappearance, and interaction of vortices with the channel’s upper wall were found to play a significant role in influencing these characteristics. The dimensionless results were converted into dimensional quantities based on realistic temperature differences and fluid properties, demonstrating the feasibility of applying this method to practical devices such as heat exchangers and thermal management systems. The use of natural convection eliminates the need for auxiliary power sources like pumps, enabling energy savings and cost reductions. This study highlights new possibilities for designing energy-efficient thermal-fluid systems that leverage natural convection. The findings are expected to contribute to the development of sustainable thermal management technologies and next-generation energy solutions.