Faculty Publications

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    Synergestic approach for the simultaneous estimation of heat transfer coefficient and heat flux using fin from steady state heat transfer experiments
    (Begell House Inc., 2015) Kumar, H.; Kumar, S.; Srinivasa Sagar, K.; Gnanasekaran, N.
    This paper reports simultaneous estimation of heat transfer coefficient and heat flux from natural convection fin heat transfer. The experimental setup contains rectangular mild steel fin of dimensions (250×154×6 mm) and an aluminium base plate of dimensions (250×150×8 mm). A slot of 4mm depth is created at the center of aluminium plate along its length (250mm) and mild steel fin is press fitted into this slot. Eighteen calibrated K-type thermocouples are used to record the temperature of the base plate and the fin. Beneath the base plate, a heater is placed with the dimensions of the base plate. To restrict the heat loss, bottom and sides of the heater are insulated with glass wool. Steady state experiments are carried out for different heat input. The problem considered is an inverse problem where in heat transfer coefficient and heat flux can be estimated simultaneously for the given temperature data from experiments/surrogate data. The forward model uses Asymptotic Computational Fluid Dynamics (ACFD) to obtain temperature distribution for the assumed inputs (heat transfer coefficient and heat flux). A powerful Markov Chain Monte Carlo method along with Metropolis-Hastings algorithm is used to minimize the objective function. Finally, the estimated values of heat transfer coefficient and heat flux are reported in terms of mean. © 2021, Begell House Inc. All rights reserved.
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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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    A synergistic combination of Asymptotic Computational Fluid Dynamics and ANN for the estimation of unknown heat flux from fin heat transfer
    (Elsevier B.V., 2018) Kumar, H.; Gnanasekaran, N.
    This paper deals with conjugate heat transfer from a rectangular fin. The problem consists of mild steel (250 × 150 × 6 mm) fin placed vertically on aluminium base (250 × 150 × 4 mm). The aluminium plate is subjected to an unknown heat flux at the base. The fin set-up is modelled using ANSYS fluent 14.5. The fin geometry is surrounded by extended domain filled with air so as to account for natural convection conjugate heat transfer. Grid independence study is carried out to fix the number of grids. A simple correlation using Asymptotic Computational Fluid Dynamics (ACFD) is developed and the same is used as a forward model to obtain the temperature distribution considering heat flux as the input. The problem is treated as an inverse problem in which a non-iterative method, ANN is used as the inverse model to estimate the unknown heat flux from the information of temperature. The results of the forward model and the ANN predicted values are in close agreement with error less than 1%. Effect of noise on the unknown parameter is also studied extensively. © 2017 Faculty of Engineering, Alexandria University