H. M. T. Khaleed

Analysis of Heat and Mass Transfer in a Vertical Annular Porous Cylinder Using FEM

The present study is intended to study heat and mass transfer in a vertical annular cylinder embedded with saturated porous medium. The inner surface of cylinder is maintained at uniform wall temperature and uniform wall concentration. The governing partial differential equations are non-dimensionalised and solved by using finite element method (FEM). The porous medium is discritised using triangular elements with uneven element size. Large number of smaller-sized elements are placed near the walls of the annulus to capture the smallest variation in solution parameters. The results are reported for both aiding and opposing flows. The effects of various non-dimensional numbers such as buoyancy ratio, Lewis number, Rayleigh number, aspect ratio, etc on heat and mass transfer are discussed. The temperature and concentration profiles are presented.

Finite element analysis and experimental validation of flashless cold forging of propeller hubs and blade of autonomous underwater vehicle

Abstract In this paper three-dimensional finite element method analysis and experimental flashless cold forging of aluminium front and back hubs, and the blade of an autonomous underwater vehicle propeller are presented. The rigid—plastic finite element simulation is performed using Deform F-3V6.0, to estimate the optimum load required for the flashless cold forging. The complex profiles of the hubs and blade are modelled using Solidworks SP4.02007, which is also used for the modelling of the workpiece and die-punch assembly. The workpiece used is of AISI AL6061 and the die material is die steel (AISI D2). The process is optimized to form the propeller back and front hubs, and the blade. For all the models, three workpieces with different specifications are selected and investigated to obtain the optimum workpiece that gives flashless cold forging with no underfilling. Based on the simulation results, the flashless cold forging is successfully done on a 100 tonne C-type machine. The experimental forged samples conform well with the simulated models.

Heat transfer in a conical porous medium due to inner and top surface heating: Effect of cone angle

The present study investigates the heat transfer behavior in a conical porous annular cylinder subjected to 2 surfaces heating. The boundary conditions are such that the inner radius and top surface of cone is maintained at hot isothermal temperature Th and outer surface is cooled to temperature Tc. Effect of varying the cone angle is investigated.

Double Diffusive Flow in a Porous Medium Embedded with Vertical Annulus with Power Law Heating

The present paper deals with the evaluation of double diffusive flow in a porous medium fixed with vertical wall. The boundary conditions are such that the vertical plate is heated with power law coefficient and far away medium is maintained at lower temperature Tc. The vertical plate is maintained at higher concentration Cw and far away medium is subjected to low concentration Cc. The study is carried out to know the heat and mass transfer behavior inside the porous region due to power law heating. The heat and mass transfer behavior is explored with respect to various parameters such as Lewis number, buoyancy ratio, Rayleigh number etc.

Soret effect due to opposing flow in square porous annulus

The present work is undertaken to investigate the behavior of opposing flow in porous medium under the influence of Soret effect in a square porous annulus. The boundary conditions are such that the outer walls of annulus are maintained at higher temperature and concentration as compared to inner walls. This heat and mass transfer phenomenon is governed by three partial differential equations. The differential equations are converted into a matrix form of equations by the application of finite element method and then solved using iterative algorithm. The results are presented in terms of isotherms, iso-concentration and streamlines indicating the thermal energy, concentration and fluid velocity inside the porous medium under applied boundary conditions. It found that the maximum value of stream function in porous medium decreases with decrease in buoyancy ratio.

Heat transfer in porous duct: Effect of horizontal outer wall heating

Heat transfer in porous medium is one of the important areas of research for last few decades. The current work is considered to investigate the effect of top and bottom wall heating of a square duct that contains porous medium between its inner and outer boundaries. The other six surfaces of duct are cooled to isothermal temperature Tc. The resulting momentum and energy equations that govern the heat and fluid flow behavior in porous medium are solved with the help of finite element method. It is observed that the heat transfer and fluid flow behavior of horizontal wall heating is quite different from other cases being reported in literature. It is found that the fluid flows in multiple circulation cells around corners of the duct giving a unique flow pattern. The isotherms tend to concentrate on lower and upper section of duct with huge middle area of cavity having least thermal energy.

Opposing flow in square porous annulus: Influence of Dufour effect

Heat and mass transfer in porous medium is very important area of research which is also termed as double diffusive convection or thermo-solutal convection. The buoyancy ratio which is the ratio of thermal to concentration buoyancy can have negative values thus leading to opposing flow. This article is aimed to study the influence of Dufour effect on the opposing flow in a square porous annulus. The partial differential equations that govern the heat and mass transfer behavior inside porous medium are solved using finite element method. A three node triangular element is used to divide the porous domain into smaller elements. Results are presented with respect to geometric and physical parameters such as duct diameter ratio, Rayleigh number, radiation parameter etc. It is found that the heat transfer increase with increase in Rayleigh number and radiation parameter. It is observed that Dufour coefficient has more influence on velocity profile.