Heat transfer augmentation in a diamond shaped enclosure utilizing CNT-water Nanofluid

Abstract A numerical analysis has been investigated for unsteady natural convection heat transfer problem in diamond shaped cavity. Carbon nanotube (CNT)-water nanofluid is used to analyze the heat transfer and compared with the pure water as working fluid. The lower right wall is kept at heated surface with constant heat flux and upper left wall is kept cold. Both the bottom left and upper right wall are kept adiabatic. The considered physical problem is characterized mathematically by a set of governing equations along with the corresponding boundary conditions. Galerkin weighted residual method of finite element analysis is used to solve the governing equations. Calculations are done for pertinent parameters such as the solid volume fraction (ϕ = 0.0–0.12) and Rayleigh number (Ra = 104–108) at dimensionless times (τ = 0.01 and 1.0) and fixed Pr = 6.2. Obtained results are presented in terms of average Nusselt number and maximum fluid temperature, streamlines and isotherms in graphs, charts and related contours. It has been observed that increase of Rayleigh number and solid volume fraction enhance the heat transfer rate and reduce the maximum fluid temperature. In this investigation the highest amount of overall heat transfer reaches up to 115%.