Unsteady periodic natural convection in a triangular enclosure heated sinusoidally from the bottom using CNT-water nanofluid
Zahurul Islam, A.K. Azad, Md. Jahid Hasan, Rumman Hossain, R. Saidur
Abstract
This research examines the natural convection phenomena in a triangular enclosure, assumed as a mechanical chamber. Water-based CNT-nanofluid was used as the fluid. The nature of the flow is unsteady, and a sinusoidal heat source is situated at the bottom of the triangle. The inclined two walls of the triangle are assumed as cold temperature. Based on the finite element method, dimensionless nonlinear governing equations were obtained employing the Galerkin weighted residual method. Brownian motion of nanoparticles was considered to determine the thermal conductivity and dynamic viscosity. Rayleigh number (Ra), oscillation period τp, and dimensionless time τ are assumed as primary controlling factors, and nanofluid concentration is considered as constant φ = 0.04. The result indicates that the heat transfer rate displays varied patterns varying the Rayleigh number, and it rises as the oscillation period increases. The fluid temperature and flow fields exhibit periodic behavior due to the sinusoidal heat source. The findings of this work can be utilized to build an effective cooling or heating system for the mechanical chamber, ensuring that temperature distributions are effective and consistent.