This work investigates the effect of Joule heating and viscous dissipation due to electric double layer (EDL) and electroosmotic effect on steady fully developed electromagnetohydrodynamic flow in a porous microchannel. Dimensionless formulations of the Poisson-Boltzmann, momentum, and energy equations are derived for the electric potential, velocity profile and temperature distribution in the microchannel. Exact solutions for the temperature distributions and velocity profile were obtained using the method of undeterminate coefficients. The Debye-Hückel linearization is used to get exact solution for the electric potential. The results showed that Brinkmann number ( Br ) , Joule heating parameter ( J ) , Debye-Hückel parameter ( Κ ) , Hartmann number ( M ) , electric field ( E z ) and suction/injection parameter ( S ) have a substantial impact on flow formation and heat transfer. Using MATLAB software, graphical simulations are provided in order to deliver a greater understanding of the influence of relevant parameters on the results achieved.
Slag entrapment from metal-slag interface during continuous casting operation has been a major area of concern for steelmakers globally. The presence of inactive regions in the upper region of the mold poses another challenge. Proper flow behavior of the molten metal coming out of the nozzle in the mold is required to overcome these challenges. Nozzle design greatly affects the flow pattern of the molten steel inside the mold. The present investigation is an attempt to study the flow and solidification behavior in a slab caster mold with the use of a novel designed hexa-furcated nozzle (HFN) using numerical investigation results. The casting speed and submerged entry nozzle (SEN) depth are varied to study the effect of these parameters on minimizing the inactive zones in the mold and the steel/slag interface fluctuations. The results show that the interface fluctuation increases at higher casting speed and lower SEN depth. The RTD analysis is also performed for different cases to investigate the flow behavior. The validation of the fluid flow and RTD curve inside the computational domain is carried out with the use of physical modeling.
The impacts of vertical throughflow, rotation, cross-diffusion, and vertical heterogeneous permeability on the double-diffusive convection in a finite rotating vertical porous cylinder have been studied. The fluid in the cylinder is warmed and salted from beneath, and its top and lower walls are taken to be isothermal, isosolutal and permeable. In the model formulation, the Brinkman model was adopted, coupled with the Boussinesq approximation. The normal mode technique is used to perform linear stability analysis and single term Galerkin technique is employed to solve the eigenvalue problem. Further, the influence of vertical heterogeneity, vertical throughflow, thermal and solute Rayleigh, Taylor, and the Soret and Dufour numbers on the fluid system instability has been investigated. We found, among other results, that vertical heterogeneity may either stabilize or destabilize the fluid system. The Dufour number delays both the stationary and oscillatory convection onsets. The positive Soret number is found to have a stabilizing effect on the stationary convection case, with a destabilizing effect on the oscillatory convection case.
This study's primary objective is to demonstrate how diffusion-thermo and thermal diffusion influence of peristaltic flow processes with slip boundaries when joule heating happens from the interior. Several operational factors and their impacts on the system were analysed, along with the corresponding graphs. As slip parameters rise, the axial pressure gradient fluid flow tends to drop. The pressure rate is demonstrated to drop in the backward and peristaltic pumping regions as the quantity of the second order slide parameter rises, whereas it rises in the co-pump zone. As slip parameters rise, fluid temperature and concentration tend to drop. Changes in the thermal diffusion and thermo diffusion factors cause changes in the fluid's temperature and concentration. The Nusselts number can be increased by increasing the Prandtl number, the thermo-diffusion constraint, the dufour number, and the Schmidt number. However, this will result in fewer Sherwood number.
The main focus of the current study is to examine the impact of melting heat transfer and chemical reactions on MHD micropolar fluid flow over a sheet that is exponentially stretching and immersed in a porous medium in which the source of heat is not uniform. Also taken into consideration are slip phenomena and thermal radiation. The governing PDEs are converted to a system of ODEs via similarity transformation and the necessary boundary conditions. These nonlinear ODEs are resolved with the help of shooting techniques and an RK-4 iterative strategy. Also, solved this problem using the Bvp4c approach for validating the results of the RK-4 method. Both outcomes are consistent with previously published data. With the help of tables and graphs, we examine the influence of multiple physical parameters on velocity, thermal profile, microrotation, concentration profiles, Nusselt number, Sherwood number, coefficient of skin friction, and Wall couple stress. We see that the temperature distribution and velocity profiles decrease when the melting parameter increases. The temperature profile boost when the heat source parameter is increased.
The main purpose of this study is to investigate numerically the thermal performance of a parabolic trough solar collector’s absorber tube that contains a novel kind of inserts with the objective to improve the heat transfer between the heat transfer fluid and the absorber tube. In the first part of this paper, the diameter and the length of the cylindrical inserts are investigated based on Finite Volume Method and Monte Carlo Ray Tracing method for Reynolds number ranges from 2.36∙10^4 to 7.09∙10^4. In the second part, the eccentricity of the cylindrical inserts is investigated under the same operating conditions. The Therminol ®VP1 is the HTF that used in this investigation intermediate fluid. The numerical simulation indicates that the perturbators enhance the thermal behavior of receiver and reduces the absorber tube’s temperature difference.
The current study focuses on the thermal distribution in the boundary layer of a wedge with a variable surface temperature. The governing equations of MHD flow for variable wall temperature conditions can be converted to ODE by using similarity solutions, and the Hartmann number (Ha) from 1 to 3 can be solved via the colocation method. This method’s results are compared to those of the numerical method, and it is then evaluated and validated. As the angle or Ha increases, the width of the hydrodynamic boundary layer decreases, and the slope of the boundary layer increases, increasing the coefficient of friction on the surface. The results are obtained for variable wall temperature (n), Prandtl number (Pr) and Eckert number (Ec), where they are 0.5≤n≤1.5, 0.5≤Pr≤5, and 0.001≤Ec≤0.002, and at a certain angle. It is observed that when Ha, Pr, and n increase, the thermal boundary layer grows faster than before; thus, thickness decreases and the Nusselt number (Nu) rises; however, as the Ec adds, the Nu decreases on the wall.