Abdulmajeed Saeed Al-Ghamdi

Evaluation of the FTn Finite Volume Method for Transient Radiative Transfer in Anisotropically Scattering Medium

In this paper, we formulated, applied, and tested the FTn Finite Volume Method (FTn FVM) for transient radiative transfer in three-dimensional absorbing, emitting, and anisotropically scattering medium. Both the STEP and the Curved-Line Advection Method (CLAM) are introduced for spatial discretization of the transient radiative transfer equation. The results show that FTn FVM reduces largely the ray effects and it is more accurate than the standard FVM. Also, using both STEP and CLAM schemes, FTn FVM has smaller convergence time than the standard FVM for all cases. On the contrary, the STEP scheme is faster than the CLAM scheme but it has less accuracy. Then, the effects of optical thickness, scattering albedo, and anisotropy factor on incident radiation and radiative flux are presented and discussed.

Evaporation of water/ammonia binary liquid film falling down on one plate of a vertical channel

AbstractA numerical study was conducted to investigate the coupled heat and mass transfer during the evaporation of a water/ammonia liquid film under mixed convection. This binary liquid film is falling down on one plate of a vertical channel. The wetted plate is adiabatic while the dry plate is isothermal. Parametric computations were performed to investigate the effects of the inlet parameters of the water/ammonia binary liquid film on the temperature at the liquid–gas interface and on the mixture evaporation rate.

Numerical simulation and analysis of confined turbulent buoyant jet with variable source

In this work, experimental and numerical investigations are undertaken for confined buoyant turbulent jet with varying inlet temperatures. Results of the experimental work and numerical simulations for the problem under consideration are presented. Four cases of different variable inlet temperatures and different flow rates are considered. The realizable k-ε turbulence model is used to model the turbulent flow. Comparisons show good agreements between simulated and measured results. The average deviation of the simulated temperature by realizable k-ε turbulent model and the measured temperature is within 2%. The results indicate that temperatures along the vertical axis vary, generally, in nonlinear fashion as opposed to the approximately linear variation that was observed for the constant inlet temperature that was done in a previous work. Furthermore, thermal stratification exits, particularly closer to the entrance region. Further away from the entrance region the variation in temperatures becomes relatively smaller. The stratification is observed since the start of the experiment and continues during the whole course. Numerical experiments for constant, monotone increasing and monotone decreasing of inlet temperature are done to show its effect on the buoyancy force in terms of Richardson number.

Improved finite volume method for three-dimensional radiative heat transfer in complex enclosures containing homogenous and inhomogeneous participating media

ABSTRACT The paper presents a modified finite volume method for the solution of the radiative transport equation, which implements the FTn angular discretization along with the bounded high-resolution curved line advection method to alleviate ray effect and false scattering, respectively, and consequently improve the accuracy of the final results. Using the blocked-off-region procedure, the present formulation is capable of treating blockage effects caused by inner/outer obstructing bodies. The developed methodology based on the combination of the above methods is evaluated against five three-dimensional test cases considering either homogenous or inhomogeneous participating media. For all cases, the predictions reveal the mitigation of false scattering and ray effects consequently the improvement of accuracy, employing this model for solving radiation heat transfer in industrial applications. In industrial application, the radiative heat transfer problem is solved for a unity boiler furnace where an inhomogeneous medium is assumed. The effects of the scattering albedo, walls emissivity and walls temperature are investigated.

Numerical study of falling binary liquid film evaporation: liquid film thickness

aLaboratory of Thermal and Energy Systems Studies, Monastir University, Ibn Eljazzar Street, 5019 Monastir, Tunisia, Tel. +966 1252 700 70; Fax: +966 1252 700 27; emails: abdelaziz.nasr@ymail.com (A. Nasr), sassi.bennasrallah@yahoo.fr (S. Ben Nasrallah) bMechanical Engineering Department, College of Engineering, Umm Al-Qura University, P.O. Box 5555, Makkah, Saudi Arabia, emails: alghamdi10@hotmail.com (A.S. Al-Ghamdi), mssoufi@uqu.edu.sa (M.S. Alsoufi) cLaboratoire Génie de l’Energie, Matériaux et Systèmes (LGEMS), B.P. 1136, ENSA-Agadir, Morocco, email: m.feddaoui@uiz.ac.ma