Begell House Inc.
Heat Transfer Research
HTR
1064-2285
47
4
2016
EXACT SOLUTION FOR PERISTALTIC FLOW OF A COUPLE STRESS FLUID IN AN ASYMMETRIC CHANNEL UNDER CONVECTIVE CONDITIONS
327-342
Tasawar
Hayat
Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000, Pakistan; Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Faculty of Science,
King Abdulaziz University, P.O. Box 80257, Jeddah 21589, Saudi Arabia
Humaira
Yasmin
Majmaah University
Ahmed
Alsaedi
Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Department of
Mathematics, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi
Arabia
This article considers the heat transfer effects in peristaltic flow of a couple stress fluid. An incompressible fluid is considered in a channel under convective boundary conditions. This study is motivated by investigations of physiological flow through particle size effect. The long wavelength and low Reynolds number approach is adopted. Effects of various physical parameters reflecting the couple stress parameter and Brinkman and Biot numbers on the velocity
profile, streamlines pattern, temperature profile, pumping action, and trapping are studied. Computational results are presented in a graphical form. It is revealed that pressure rises and axial velocity decreases with increase in the couple stress parameter. The temperature also decreases by increasing the Biot number.
SIMULATION OF VEHICLE COOLING LOADS AT DIFFERENT ORIENTATIONS
343-357
Mohamad Firdaus
Sukri
Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru,
Johor Malaysia; Efficient Energy and Thermal Management Research Group, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia
M. N.
Musa
UTM-Ocean Thermal Energy Center (UTM-OTEC), Universiti Teknologi Malaysia,
Jalan Semarak, 54100 Kuala Lumpur, Wilayah Persekutuan Kuala Lumpur, Malaysia
K.
Sumeru
Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru,
Johor Malaysia
M. Y.
Senawi
Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru,
Johor Malaysia
Henry
Nasution
Automotive Development Centre (ADC), Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor,
Malaysia
This paper presents a numerical simulation of the effect of vehicle orientation on the hourly vehicle cooling load profile. This profile enables prediction of a maximum cooling load and hence maximum cooling capacity to be supplied for equipment selection. The correlations and equations proposed by ASHRAE and previous researchers and compressed Singapore weather data from the open literature were used. Four vehicle orientations: North, East, South, and West were considered for a
1.6L Proton Wira Aeroback passenger car. The steady-state heat balance concept was adopted for the cooling load model. A validation exercise indicates that the simulation results are within 6% of published results. In this study, the cooling load profile predicts a maximum load between 12.00 noon and 1.00 pm for all typical days due to high values of solar radiation intensity and outdoor air dry bulb temperature compared to other hours. The highest cooling load occurs when the front wind screen is facing East in March/April at 2.71 kW. Thus, with a 5% safety factor, the highest cooling load is estimated at 2.85 kW. When the cooling capacity is estimated at 10% higher than this maximum cooling load, the proposed design evaporator coil cooling capacity is then estimated at 3.13 kW. This cooling load/capacity provides a basis for new vehicle air-conditioning system development, especially for future full electric vehicles.
FLOW STRUCTURE AND HEAT TRANSFER IN MULTIPLE IMPINGING JETS
359-382
Nabil
Kharoua
Mechanical Engineering Department, The Petroleum Institute, P.O. Box 2533, Abu Dhabi, United Arab Emirates
Lyes
Khezzar
Mechanical Engineering Department, The Petroleum Institute, P.O. Box 2533, Abu Dhabi,
United Arab Emirates
Zoubir
Nemouchi
Laboratoire d'Energetique Appliquee et de Pollution, Université des Frèses Mentouri, Constantine, Algeria
Large eddy simulation of flow and heat transfer of multiple turbulent round jets in an in-line array impinging on a flat plate is conducted. To capture the interactions between the jets, the full geometry is meshed and used in the simulation of nine jets. The single jet Reynolds number based on the nozzle diameter of 13 mm, jet initial average velocity of 23.88 m/s,
and the properties of air at room temperature is equal to 20,000. The computations of the mean vertical and horizontal components of the velocity vector, in selected planes, show very good agreement with experiments. The flow behavior of the jets agrees with experimental findings in terms of vortices surrounding the jets and the appearance of the asymmetry on, and close to, the flat impingement plane. The predicted mean surface Nusselt number on the flat heated plate shows also excellent agreement with experiments and a relative maximum between the jets in the region of the upwash fountain flow where the wall jets collide, not seen in the experiments, but captured by the numerics. It is believed that the present contribution provides an additional insight into the physics of important flow characteristics such as the individual paths of the central, side, and the corner jet streams. In particular, their effect on the nonhomogeneous cooling of the target wall, efficient in the corner regions and degraded in the central region, is also addressed.
CONJUGATE NATURAL CONVECTION IN AN INCLINED SQUARE POROUS ENCLOSURE WITH FINITE WALL THICKNESS AND PARTIALLY HEATED FROM ITS LEFT SIDEWALL
383-402
Sameh Elsayed
Ahmed
Department of Mathematics, Faculty of Science, Abha, King Khalid University, Saudi Arabia; Department of Mathematics, Faculty of Science, South Valley University, Qena, Egypt
Ahmed Kadhim
Hussein
College of Engineering, Mechanical Engineering Department, Babylon University, Babylon City, Hilla, Iraq
M. M. Abd
El-Aziz
Department of Mathematics, Faculty of Sciences, South Valley University, Qena, Egypt
Sivanandam
Sivasankaran
Department of Mathematics, King Abdulaziz University, Jeddah 21589, Kingdom of Saudi Arabia
The analysis of conjugate natural convection heat transfer in a square inclined enclosure filled with a porous medium and adjacent to the walls of finite thickness is investigated numerically using the finite volume method. While a uniform heat source is located on a part of the left inclined sidewall of the enclosure, the right inclined sidewall is maintained at a constant low temperature. The top and bottom walls are assumed adiabatic together with the remaining parts of the
left inclined sidewall. Numerical computations are performed in wide ranges of the thermal conductivity ratio, enclosure inclination angle, dimensionless wall thickness, and dimensionless heat source length. The results are presented to give a parametric study showing the influence of these parameters on the flow and the heat transfer characteristics inside the enclosure. The results of the present work explain that the local Nusselt number of fluid phase increases when the thermal
conductivity ratio increases, while the local Nusselt number along the heat source decreases as the thermal conductivity ratio increases. On the other hand, the average Nusselt number at the solid walls and fluids increases when the inclination angle increases from φ = 0° to φ = 45°, decreases slightly at φ = 60°, and decreases significantly when φ = 90°. Moreover, the fluid circulation intensity within the porous medium can be improved when considering a small wall thickness, high thermal conductivity ratio and when the heat source length increases. The results are compared with other published results and they found to be in good agreement.
NATURAL CONVECTION IN A HORIZONTAL ANNULUS WITH A DIFFERENT NUMBER AND ARRANGEMENTS OF DISCRETE HEAT SOURCE−SINK PAIRS
403-421
M.
Mastiani
Department of Ocean and Mechanical Engineering, Florida Atlantic University, 777 Glades Road,
Boca Raton, FL 33431, USA
H.
Mirzaei
Department of Mechanical Engineering, Urmia University of Technology, Urmia, Iran
S. S.
Sebti
Department of Mechanical Engineering, Urmia University of Technology, Urmia, Iran
Abdolrahman
Dadvand
Department of Mechanical Engineering, Urmia University of Technology, Urmia, Iran
Sina
Kashani
Department of Mechanical Engineering, Islamic Azad University, Gorgan Branch, Kordkoy Center, Golestan, Iran
Laminar natural convection in an air-filled two-dimensional cylindrical annulus with discrete heat source-sink pairs is investigated numerically. Two and three heat source-sink pairs with different arrangements are considered. The sources and sinks are located on the inner and outer cylinders, respectively, and they are assumed as constant temperature boundary conditions. The remaining portions of the annulus are considered to be insulated. The emphasis is mainly placed on the effects of the number, size, and arrangement of the source-sink pairs on the fluid flow and heat transfer features. The goerning equations are solved on a nonuniform O type mesh using a pressure-based finite volume method. The results are presented in terms of streamlines, isotherms, local and average Nusselt number. It is found that the cases with two source-sink pairs give rise to the higher average Nusselt number as compared to those with the three source-sink pairs. In addition, the
local Nusselt number decreases as the size of the heat source-sink pairs increases. Finally, the highest thermal performance of the enclosure is obtained by radially collinear arrangement of the source-sink pairs.