scholarly journals Numerical study of temperature dependent thermal conductivity and homogeneous-heterogeneous reactions on Williamson fluid flow

2020 ◽  
Vol 4 (8) ◽  
pp. 085009
Author(s):  
Aamir Hamid
Author(s):  
Ranjan Das

In this paper an inverse numerical study of a conductive, convective and radiative rectangular fin is carried out with temperature-dependent thermal conductivity. At first, an implicit Runge-Kutta method-based solution is obtained for calculating the temperature distribution, and then an inverse problem is solved for estimation of unknown thermo-physical properties. The convection–conduction parameter, variable conductivity parameter and radiative parameter have been simultaneously predicted for satisfying a prescribed temperature distribution. This is achieved by minimizing a least squares-based objective function using a hybrid differential evolution-nonlinear programming optimization algorithm. The results obtained from the forward method are compared with Adomian decomposition and homotopy analysis methods which are found to be satisfactory. It is observed that many feasible combinations of parameters exist which satisfy the same temperature distribution, thus providing an opportunity for selecting any combination from the available alternatives. The effect of convection–conduction parameter on the temperature distribution is observed to be more than other parameters. A case study of different fin materials is also carried out for demonstrating the application of the present methodology.


2020 ◽  
Vol 9 (1) ◽  
pp. 338-351
Author(s):  
Usha Shankar ◽  
N. B. Naduvinamani ◽  
Hussain Basha

AbstractA two-dimensional mathematical model of magnetized unsteady incompressible Williamson fluid flow over a sensor surface with variable thermal conductivity and exterior squeezing with viscous dissipation effect is investigated, numerically. Present flow model is developed based on the considered flow geometry. Effect of Lorentz forces on flow behaviour is described in terms of magnetic field and which is accounted in momentum equation. Influence of variable thermal conductivity on heat transfer is considered in the energy equation. Present investigated problem gives the highly complicated nonlinear, unsteady governing flow equations and which are coupled in nature. Owing to the failure of analytical/direct techniques, the considered physical problem is solved by using Runge-Kutta scheme (RK-4) via similarity transformations approach. Graphs and tables are presented to describe the physical behaviour of various control parameters on flow phenomenon. Temperature boundary layer thickens for the amplifying value of Weissenberg parameter and permeable velocity parameter. Velocity profile decreased for the increasing squeezed flow index and permeable velocity parameter. Increasing magnetic number increases the velocity profile. Magnifying squeezed flow index magnifies the magnitude of Nusselt number. Also, RK-4 efficiently solves the highly complicated nonlinear complex equations that are arising in the fluid flow problems. The present results in this article are significantly matching with the published results in the literature.


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