The Effect of Surface Triangular Roughness Inspired by Nature with Different Angles on the Interaction between Free Convection and Surface Radiation in a Square Cavity

This paper focused on finding ways to reduce the amount of heat that escapes through surfaces by using rough walls inspired by the design of silver ant's hair with triangular geometry and researching the impact of triangular roughness with changing angles on the internal thermal environment of the cavity. The thermal performance of square cavities is studied with isolated horizontal walls (upper and lower), where the left wall has a higher temperature than the right wall. The convection and radiation heat transfer in these cavities are simulated using ANSYS Fluent program. The length and height of the square cavities have four dimensions, implying four different Rayleigh numbers. The Nusselt number inside these cavities is determined when the right surface is smooth and rough, with a triangular shape roughness, in addition to studying the impact of the Rayleigh number, which is influenced by the fluid properties and the applied temperatures. According to the results, surface roughness significantly affects the thermodynamic and hydrodynamic behavior of the fluid inside the cavity, with the Nusselt number becoming low with the triangular roughness and the head angles being less than 85°. As a result, the total heat transfer decrease by a maximum of 49.9%.