Begell House Inc.
Heat Transfer Research
HTR
1064-2285
43
5
2012
NUMERICAL SIMULATIONS OF MHD FLUID FLOW AND HEAT TRANSFER IN A LID-DRIVEN CAVITY AT HIGH HARTMANN NUMBERS
383-404
Dipin
Kalapurakal
Department of Mechanical Engineering, The University of Akron, Akron, OH 44325-3903, INDIA
Abhilash
Chandy
Indian Institute of Technology Bombay
Numerical calculations of the 2D steady incompressible magnetohydrodynamic (MHD) driven cavity flow and heat transfer are presented. The Navier−Stokes equations in the stream function and vorticity formulation, and the energy equation are solved numerically using a uniform mesh of size 601 × 601. The effect of magnetic field in terms of the Hartmann number (Ha ≤ 1000) are studied for steady incompressible driven cavity flow for various Prandtl numbers (0.001 < Pr < 10). Contours of stream function, vorticity, and temperature, and profiles of centerline velocities and Nusselt number (Nu) at the hot boundary are presented to assess the MHD effects. While the magnetic field makes all flows one-dimensional with stretching observed in the direction of the magnetic field, its effect on heat transfer is more pronounced only with increased Pr.
AN EXACT SOLUTION FOR THERMAL ANALYSIS OF A CYLINDRICAL OBJECT USING A HYPERBOLIC HEAT CONDUCTION MODEL
405-423
Seyfolah
Saedodin
Department of Mechanical Engineering, Semnan University, Semnan, Iran
Mohammad Sadegh Motaghedi
Barforoush
Faculty of Mechanical Engineering, Semnan University, Semnan, Iran
The purpose of the present paper is to carry out the non-Fourier effect subjected to a special heat-flux boundary condition. The governing equation is expressed in cylindrical coordinates and is solved by deriving the analytical solution. The temperature layers and profiles of sample calculations are performed. It is found that, as much as the Vernotte number is higher, a point can get to higher temperature during the process. Also, it can be perceived that the temperature of different points of the object becomes even lower than the initial temperature.
INTERFACIAL SHEAR OF CO-CURRENT STEAM−WATER FLOW ESTIMATION − II. ENHANCED SINGLE-PHASE FLUENT MODEL IN CONJUNCTION WITH MEASURED PROFILES OF STEAM VELOCITY AND LONGITUDINAL WATER TEMPERATURE
425-442
Stasys
Gasiunas
Lithuanian Energy Institute, 3 Breslaujos str., LT-3035 Kaunas, Lithuania
Marijus
Seporaitis
Lithuanian Energy Institute, 3 Breslaujos g., Kaunas, LITHUANIA, LT-44403
Benediktas B.
Cesna
Lithuanian Energy Institute, Kaunas, Lithuania
Mindaugas
Valincius
Lithuanian Energy Institute, 3 Breslaujos str., LT-3035 Kaunas, Lithuania
Raimondas
Pabarcius
Lithuanian Energy Institute, 3 Breslaujos str., LT-3035 Kaunas, Lithuania
Darius
Laurinavicius
Lithuanian Energy Institute, Kaunas, Lithuania
The results of condensation implosion tests (Almenas et al., 2006) and slug flow occurrence (Chun and Yu, 2000) lead to the conclusion that condensation may have some serious impact on steam−liquid interface stability. To explore this in detail a special test facility was constructed and the FLUENT 3D model (single phase with condensation simulation) is developed at the Lithuanian Energy Institute. The following investigation seeks to determine the condensation influence on the stability of a horizontal two-phase flow interface and the overall purpose of the program is to employ transitional behaviors with positive feedback between momentum and energy transfer in real systems.
This paper presents the experimental test facility developed at LEI and the methodology of the experiments whose results were employed to adapt and verify the FLUENT 3D model. Preliminary results of modeling show that both the boundary-layer thickness and interfacial shear strongly depend on condensation.
HEAT TRANSFER IN THE INITIAL PART OF THERMAL STABILIZATION OF HELICAL CHANNELS IN AIR FLOW
443-460
Povilas
Poskas
Lithuanian Energy Institute, Branduolines inzinerijos problemas laboratorija, Breslaujos str. 3, LT-44403 Kaunas, Lithuania
Vytautas
Simonis
Lithuanian Energy Institute, Branduolinës inzinerijos problemø laboratorija, Breslaujos str. 3, LT-44403 Kaunas, Lithuania
Experimental results, their analysis and generalization are presented for local heat transfer from
the convex and concave surfaces of rectangular helical channels in the initial part of thermal
stabilization in air flow over a wide range of operating (Re =103−4·105) and geometrical (D/h
= 5−90, b/h = 2−20) parameters in one-side heating.
It was established, according to the helical channels length, that heat transfer from a convex surface decreases and that from a concave surface increases approaching the stabilized values, which in the channel of the highest curvature (D/h = 5.5) reach up to −50% for a convex surface and up to +60% for a concave surface versus those in a straight flat channel. With a decrease of channel curvature (an increase of the parameter D/h), heat transfer intensity from both surfaces decreases in comparison with a straight flat channel. Also, heat transfer stabilization on a convex surface occurs later than on a concave surface or in a straight flat channel.
Correlations were obtained for changes of heat transfer from convex and concave surfaces of helical channels in the initial part of thermal stabilization, in comparison with stabilized heat transfer.
NUMERICAL STUDY OF MIXED CONVECTION IN A LID-DRIVEN CAVITY WITH PARTIAL HEATING/COOLING AND INTERNAL HEAT GENERATION
461-482
V.
Sivakumar
Department of Mathematics, Knowledge Institute of Technology, Salem 637 504, India
Sivanandam
Sivasankaran
Department of Mathematics, King Abdulaziz University, Jeddah 21589, Kingdom of Saudi Arabia
P.
Prakash
Department of Mathematics, Periyar University, Salem 636 011, India
The aim of the numerical study is to analyze the effect of partial heating/cooling and internal heat generation or absorption on mixed convection in a lid-driven cavity. Portions of the left and right walls are considered to be heating and cooling regions, respectively. Both (heating/cooling) regions are located at three different places on their respective walls. The remaining portions of the left and right walls and the horizontal walls of the cavity are taken to be adi-abatic. The results are shown graphically in the form of streamlines, isotherms, and velocity profiles to understand the influence of different locations of heating and cooling regions, different Richardson numbers, and internal heat generation or absorption parameters. It is observed that high heat transfer is found while locating the heating and cooling regions at Top-Top in the forced convection-dominated regime. It is also observed that heat transfer decreases in the presence of internal heat generation whereas it increases in the presence of internal heat absorption for all heating and cooling locations.