Conference Papers

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    Asymptotic approach to obtain nusselt number correlation for laminar mixed convection in a vertical channel
    (Dalian University of Technology, 2018) Nakate, P.; Kotresha, B.; Gnanasekaran, N.
    In this paper, a general methodology is proposed for treating mixed convection problems in a vertical channel by the concept of asymptotic computational fluid dynamics (ACFD). Average Nusselt number is developed based on the limiting solutions of natural and forced convection.These correlations are then blended to find a unified composite correlation that work very well for extreme limits of mixed convection. For the purpose of demonstration, the problem of 2-D laminar, mixed convection in a vertical channel that comprises of a heater sandwiched between two aluminum plates has been used. Numerical simulations are performed with ANSYS-FLUENT to generate the required correlation. The study proposed in this work reveals that with minimum CFD solutions one can obtain a reasonably good composite correlation for the Nusselt number. © 2018 by the authors of the abstracts.
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    Numerical analysis of mixed convection in a lid-driven cavity with Cu-water nanofluid using artificial compressibility method
    (Dalian University of Technology, 2018) Katti, A.S.; Maniyeri, R.
    In this paper, we present a computational model based on an artificial compressibility method to study mixed convection in a lid-driven square cavity containing Cu-water nanofluid for two cases: i) adiabatic vertical walls and horizontal walls kept at constant temperature, and ii) adiabatic horizontal walls and sinusoidal temperature heating along vertical walls. The artificial compressibility method is used to couple pressure and velocity, and solve the momentum and continuity equations. This method is used because of its simplicity in solving steady state incompressible flow problems. The streamlines, isotherms, variation of local Nusselt number at hot walls, and variation of average Nusselt number with change in Cu-nanoparticle concentration are presented. Also, the variation of local Nusselt number with change in Richardson number (0.1 < Ri < 10), keeping Grashof number constant (Gr = 100), is obtained. For both cases, it is found that heat transfer increases with increase in Cu-nanoparticle concentration, keeping Richardson number constant, and also with a decrease in Richardson number, keeping Grashof number constant. © 2018 by the authors of the abstracts.
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    Numerical Study of Mixed Convection in Single and Double Lid Driven Cavity Using LBM
    (Springer Science and Business Media Deutschland GmbH, 2021) Sen, S.; Arumuga Perumal, D.; Yadav, A.K.
    The lattice Boltzmann method (LBM) has been gaining popularity over the last two decades and the method has been extended from simple fluid flow problems to problems involving heat transfer. In the present work, an attempt is made to model cases involving mixed convection. Two types of problems are considered in this study; the first one dealing with mixed convection in a single-sided lid-driven cavity and the second one dealing with mixed convection in a double-sided lid-driven cavity in parallel and anti-parallel configurations at constant Prandtl number and various values of Richardson number. For the first problem, a square domain is considered with a moving lid at a lower temperature while the stationary wall at the bottom at a higher temperature. The cavity side walls are treated with an adiabatic boundary condition. In LBM, a forcing term dependent on temperature difference is utilized to vary the value of y-velocity in order to satisfy the effects of gravity on mixed convection. A grid independence study is conducted to show that the results are independent of the grid chosen, and good agreement with literature is achieved. The second problem is an extension of the first one; the cavity bottom wall is first given a velocity in the opposite direction, and then in the same direction, and the velocity streamlines, temperature contours and local Nusselt number variation in the top wall for these cases are plotted. The developed method helps in the visualization of various phenomena such as splitting of flow into two halves for the parallel configuration and formation of secondary vortices with high Reynolds number. © 2021, Springer Nature Singapore Pte Ltd.