Доступ предоставлен для: Guest
Главная ICHMT DL Текущий год Архив Исполнительный Комитет ICHMT

EFFECTS OF ASPECT RATIO ON NATURAL CONVECTION OF BINGHAM FLUIDS IN RECTANGULAR ENCLOSURES WITH DIFFERENTIALLY HEATED HORIZONTAL WALLS HEATED FROM BELOW

DOI: 10.1615/ICHMT.2014.IntSympConvHeatMassTransf.280
pages 387-401

Sahin Yigit
School of Mechanical and Systems Engineering, Newcastle University, Newcastle-Upon-Tyne, United Kingdom

Robert J. Poole
School of Engineering, University of Liverpool, Brownlow Hill, Liverpool, L69 3GH, UK

Nilanjan Chakraborty
School of Mechanical and Systems Engineering, Newcastle University, Newcastle-Upon-Tyne, NE17RU, United Kingdom

Аннотация

In this analysis the effects of aspect ratio AR (height: length) on natural convection of yield stress fluids obeying the Bingham model within rectangular enclosures has been investigated for 1/ 4 ≤ AR ≤ 4 . A nominal Rayleigh number range 103Ra ≤ 105 (Ra defined based on the height) for a single representative value of nominal Prandtl number (i.e. Pr = 500) in a configuration with differentially heated horizontal walls subjected to constant wall temperatures with heated bottom wall has been studied. It has been found that the convective transport strengthens with increasing nominal Rayleigh number Ra for both Newtonian and Bingham fluids but the mean Nusselt number Nu for Bingham fluids remains smaller than the value obtained for Newtonian fluids for a given set of values of Ra and Pr due to augmented viscous resistance arising from yield stress in Bingham fluids. For Bingham fluids Nu decreases with increasing Bingham number Bn (non-dimensional yield stress) and thermal transport becomes principally conductiondriven for large values of Bn. The relative contribution of convection to the overall thermal transport diminishes (strengthens) with increasing (decreasing) AR for a given set of values of Ra and Pr for both Newtonian and Bingham fluids. Thus, the thermal transport takes place principally due to conduction for tall enclosures. A detailed scaling analysis has been carried out to explain the effects of AR. This scaling analysis, in turn, has been utilised here to propose a correlation, which has been demonstrated to predict Nu obtained from simulation data for 1/4 ≤ AR ≤ 4, 103Ra ≤ 105 and Pr = 500.

ICHMT Digital Library

Bow shocks on a jet-like solid body shape. Thermal Sciences 2004, 2004. Pulsed, supersonic fuel jets - their characteristics and potential for improved diesel engine injection. PULSED, SUPERSONIC FUEL JETS - THEIR CHARACTERISTICS AND POTENTIAL FOR IMPROVED DIESEL ENGINE INJECTION
View of engine compartment components (left). Plots of temperature distributions in centreplane, forward of engine (right). CHT-04 - Advances in Computational Heat Transfer III, 2004. Devel... DEVELOPMENT AND CURRENT STATUS OF INDUSTRIAL THERMOFLUIDS CFD ANALYSIS
Pratt & Whitney's F-135 Joint Strike Fighter Engine under test in Florida is a 3600F class jet engine. TURBINE-09, 2009. Turbine airfoil leading edge stagnation aerodynamics and heat transfe... TURBINE AIRFOIL LEADING EDGE STAGNATION AERODYNAMICS AND HEAT TRANSFER - A REVIEW
Refractive index reconstructed field. (a) Second iteration. (b) Fourth iteration. Radiative Transfer - VI, 2010. Theoretical development for refractive index reconstruction from a radiative ... THEORETICAL DEVELOPMENT FOR REFRACTIVE INDEX RECONSTRUCTION FROM A RADIATIVE TRANSFER EQUATION-BASED ALGORITHM
Two inclusion test, four collimated sources. Radiative Transfer - VI, 2010. New developments in frequency domain optical tomography. Part II. Application with a L-BFGS associated to an inexa... NEW DEVELOPMENTS IN FREQUENCY DOMAIN OPTICAL TOMOGRAPHY. PART II. APPLICATION WITH A L-BFGS ASSOCIATED TO AN INEXACT LINE SEARCH