Numerical investigation of entropy generation induced by assisted mixed convection in a vertical convergent channel: effects of geometric parameters

In this paper, the analysis of the 2nd law of thermodynamics characteristics of assisted mixed convection heat transfer coupled with fluid flow within a vertical convergent isothermal channel is numerically carried out. The numerical model is undertaken for 2D, laminar and steady flow using finite volume approach and air as working fluid. The analysis focused on two pertinent geometric situations namely the variation of the minimal distance (Dmin) of the convergent channel while keeping the convergence angle fixed, and the change of the latter (2°, 10°, and 20°) while Dmin kept unchanged. Whereas, Dmax was used as the characteristic length. The measurements are performed for the following buoyancy-assisted cases: upward/downward flow within hot/cold walls. Several buoyancy parameters are considered ranging from 0.1 to 10 at Reynolds number equal to 100. The effect the aforementioned geometric parameters on entropy production and its distribution is investigated. The results revealed that the energy degradation is dominated by heat transfer irreversibility. Also, this latter is more influenced by Dmin variations.