University of Sistan and Baluchestan, Iranian Society Of Mechanical Engineers Challenges in Nano and Micro Scale Science and Technology 2821-000X 1 1 2013 01 01 Natural Convection and Entropy Generation in Γ-Shaped Enclosure Using Lattice Boltzmann Method 1 18 991 10.7508/tpnms.2013.01.001 EN E. Fattahi Faculty of Mechanical Engineering, Babol University of Technology Babol, Iran M. Farhadi Faculty of Mechanical Engineering, Babol University of Technology Babol, Iran K. Sedighi Faculty of Mechanical Engineering, Babol University of Technology Babol, Iran Journal Article 2013 06 29 This work presents a numerical analysis of entropy generation in Γ-Shaped enclosure that was submitted to the natural convection process using a simple thermal lattice Boltzmann method (TLBM) with the Boussinesq approximation.  A 2D thermal lattice Boltzmann method with 9 velocities, D2Q9, is used to solve the thermal flow problem. The simulations are performed at a constant Prandtl number (Pr = 0.71) and Rayleigh numbers ranging from 10³ to 10⁶ at the macroscopic scale (Kn = 10^-4). In every case, an appropriate value of the characteristic velocity is chosen using a simple model based on the kinetic theory.  By considering the obtained dimensionless velocity and temperature values, the distributions of entropy generation due to heat transfer and fluid friction are determined. It is found that for an enclosure with high value of Rayleigh number (i.e., Ra=10⁵), the total entropy generation due to fluid friction and total Nu number increases with decreasing the aspect ratio. https://chal.usb.ac.ir/article_991_ed33fb88310481a59b7edd67542621f9.pdf