Numerical investigation on natural convection inside closed cavity to create thermally active region with periodic heating/cooling

Analysis of free convection inside an enclosure is important as it has several industrial and domestic applications. In this present paper, the thermal and fluid flow phenomena of air inside an enclosure have been thoroughly inspected numerically with periodic heating/cooling of the bottom wall. The objective is to create a thermally active zone near the bottom surface, which can be tuned based on the requirement, especially for the design of thermally sensitive chemical reactors. The main advantages that are derived from this investigation are twofold. The temperature variations in the domain can be controlled precisely within a specified temperature band, and the zone of influence can also be tuned precisely. The flow behaviors have been critically analyzed with the aid of temperature distribution (isotherms), entropy production maps, vortex (stream functions), and Nu along the bottom wall. From the present investigation, it is observed that there is a critical Ra beyond which the convection starts inside the cavity. Entropy production significantly varies with Ra and periodic length of the cavity. The optimum periodic length is 4 owing to high heat transfer rate and moderate value of entropy generation.

Automated summary

This paper numerically analyzes the thermal and fluid flow phenomena of air inside an enclosure with periodic heating/cooling of the bottom wall. The study reveals the influence of periodic heating/cooling on temperature variations and flow behaviors, and provides key insights for optimizing the design.