Numerical Investigation of Heat Transfer of Water/Nano-Encapsulated Phase Change Materials in a Cavity Including a Rotating Cylinder

Document Type : Research Article

Authors

صنعتی ارومیه-مهندسی مکانیک

Abstract

In the present paper, heat transfer in a cavity containing a mixture of water + phase change materials surrounded by nanoparticles is investigated. The left and right walls are fixed at hot and cold temperatures, respectively, and horizontal walls are assumed to be adiabatic. There is a circular rotating cylinder in the center of the hole that can rotate clockwise or counterclockwise. The problem is considered two dimensional and fundamental governing equations such as continuity, momentum, and energy are solved in a coupled manner utilizing the finite element method (FEM). To check the accuracy of the numerical results, a comparison with the outputs of others is provided, which indicates a very good agreement of the results. The parameters studied in this study are: dimensionless radius of the cylinder (R), Rayleigh number (Ra), dimensionless melting temperature of the phase change material (θfu), Stephan number (St) and dimensionless angular velocity of the rotating cylinder (Ω). By increasing the dimensionless radius of the cylinder from R = 0.1 to R = 0.4 Ω = -300, the heat transfer rate enhances by 23.37%. On the other hand, with R = 0.4 and considering no-rotation case, the heat transfer rate will decrease by about 59.7% compared to the cavity without the cylinder. Which indicates the importance of rotation of the cylinder inside the cavity in the heat transfer rate enhancement.

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