Begell House Inc.
Heat Transfer Research
HTR
1064-2285
48
7
2017
NONLINEAR ANALYSIS OF A NON-FOURIER HEAT CONDUCTION PROBLEM IN A FIN HEATED BY CONSTANT HEAT SOURCE
571-584
10.1615/HeatTransRes.2016014323
Mohammad Javad
Noroozi
Faculty of Mechanical Engineering, Semnan University, Semnan, Iran
Seyfolah
Saedodin
Department of Mechanical Engineering, Semnan University, Semnan, Iran
Davood Domiri
Ganji
Department of Mechanical Engineering, Babol Noshirvani University of Technology, P.O. Box
47166-85635, Babol, Iran
non-Fourier
nonlinear analysis
C-V model
ADM
fin
Heat transfer phenomenon within a one-dimensional finite fin subjected to the action of a constant heat source was studied in this paper. The Cattaneo−Vernotte non-Fourier heat conduction model was used for thermal analysis. The thermal conductivity was assumed temperature-dependent which resulted in a nonlinear equation. The obtained equations were solved using the approximate-analytical Adomian Decomposition Method (ADM). It was concluded that the method used in this study is a powerful tool for solving non-Fourier PDEs. It was also found that the nonlinear analysis is important in non-Fourier heat conduction problems. Significant differences were observed between the Fourier and non-Fourier solutions which stresses the importance of non-Fourier solutions in similar problems. The weak role of convection heat transfer was also specified.
CONVECTIVE HEAT TRANSFER OVER A FLAT PLATE IN THE WAKE OF A TURBULENCE GENERATOR
585-606
10.1615/HeatTransRes.2016011984
Iman
Arianmehr
Turbulence & Energy Lab, Centre for Engineering Innovation, University of Windsor, Windsor, Ontario, Canada
David S.-K.
Ting
Turbulence & Energy Lab, Centre for Engineering Innovation, University of Windsor, Windsor, Ontario, Canada
S.
Ray
Essex Energy Corporation, Oldcastle, Ontario, Canada
photovoltaic
flat plate
cooling
turbulence
An experimental investigation was carried out to study the heat transfer and turbulent flow over a flat plate in a wind
tunnel. The turbulence was generated by a turbulence generator with a finite height mounted perpendicular to and on the leading edge of the flat plate. Instantaneous velocity measurements were performed with a 1D hot-wire anemometer to investigate the behavior of the flow a short distance downstream of the perforated plate. Temperature distribution and heat flux along the centerline of the plate with and without the perforated plate at the leading edge were measured. The results showed that significant wind blockage limited the turbulence generator (TG) to be effective in lowering the flat plate temperature
to within a short distance downstream. Detailed flow measurements revealed that the orifice perforated plate that
generated flow turbulence is superior in augmenting the Nusselt number. To realize its full potential, however, the drastic blockage caused by the current turbulence generator design needs to be mitigated.
LATTICE BOLTZMANN SIMULATION OF NATURAL CONVECTION IN CUBICAL ENCLOSURES FOR THE BINGHAM PLASTIC FLUID
607-624
10.1615/HeatTransRes.2016007507
Abdelkader
Boutra
Faculté de Génie Mécanique et de Génie des Procédés, Université des Sciences et de la Technologie Houari Boumediene USTHB, B.P. 32, El-Alia Bab-Ezzouar, 16111 Algiers, Algeria
Youb Khaled
Benkahla
Faculté de Génie Mécanique et de Génie des Procédés, Université des Sciences et de la Technologie Houari Boumediene USTHB, B.P. 32, El-Alia Bab-Ezzouar, 16111 Algiers, Algeria
Djamel Eddine
Ameziani
Faculté de Génie Mécanique et de Génie des Procédés, Université des Sciences et de la Technologie Houari Boumediene USTHB, B.P. 32, El-Alia Bab-Ezzouar, 16111 Algiers, Algeria
Rachid
Bennacer
LEEVAM,
University de Cergy-Pontoise, 5, Mail Gay Lussac, Neuville sur Oise, 95031 Cergy-Pontoise Cedex, Paris, France
Bingham fluid
natural convection
multiple relaxation time
lattice Boltzmann method
cubic cavity
cube-shaped obstacle
The purpose of this work is the study of the hydrodynamic and thermal characteristics of a Bingham plastic fluid contained in a differentially heated cubic cavity, at the center of which a cube-shaped obstacle has been placed. The effect of some parameters in this kind of configuration, such as the Rayleigh number Ra, Bingham number Bn, and the obstacle size e in the cavity, are very important in heat exchange. The study consists in analyzing those parameters at a fixed value of the Prandtl number Pr = 10, while Ra, Bn, and e vary in the ranges 10+3–10+6, 0–20, and 0–0.75, respectively. In order to resolve the dynamic governing equations, we use the multiple relaxation time scheme of the lattice Boltzmann method (LBM/MRT) incorporating the Papanastasiou exponential modification approach. The Finite Difference Method (FDM) is used for the energy equation discretization. The obtained results show that the buoyancy intensity leads to considerable modifications on streamlines and isotherms. Concerning the influence of the viscoplasticity of the Bingham fluid, we note a diminution of central cells and a modification of the Nusselt number evolution due to the increase of the Bingham number.
The growth of the obstacle size was found to decrease the heat transfer rate. This diminution is proportional to the growth of the Bingham number.
MODELING OF FLUID FLOW AND HEAT TRANSFER OF AA1050 ALUMINUM ALLOY IN A MODERN LOW-HEAD DIRECT-CHILL SLAB CASTER
625-656
10.1615/HeatTransRes.2016013742
Latifa
Begum
Department of Mining and Materials Engineering, McGill University, M.H.
Wong Building, 3610 University Street,Montreal, QC, H3A 0C5, Canada
Mainul
Hasan
Department of Mining and Materials Engineering, McGill University, M.H. Wong Building, 3610 University Street,Montreal, QC, H3A 0C5, Canada
vertical DC casting
solidification
3D modeling
open-top melt feeding
laminar/turbulent melt flow
mushy fluid
A low-head hot-top mold is modeled for the vertical direct-chill casting (DCC) process where the melt is assumed to have been delivered through the entire top cross section of the caster. The previously verified in-house 3D Computational Fluid Dynamics (CFD) code is extended to model an industrial-sized AA1050 slab for the above caster for steady-state operation. For the generalization of the predicted results, nondimensional parameters governing this problem were identified. To keep consistency with the industrial cooling strategy, a stepwise change of the cooling water temperature in the mold, in the impingement
and in free streaming regions was considered. A series of parametric studies were conducted by varying the important DCC process parameters, namely the casting speed ranging from 60 to 180 mm/min, inlet melt superheat, ranging from 16°C to 64°C, as well as the effective heat transfer coefficient (HTC) at the metal–mold contact region, varying from 0.75 to 3.0 kW/(m2·K). The velocity field, the temperature distributions, and the local surface temperature profiles are presented and discussed. The sump depth and the mushy thickness at the ingot center are seen to increase linearly with the increasing casting speed, whereas the shell thickness at the exit of the mold decreases linearly with the casting speed. The thickness of the solid shell at the mold exit is increased by about 4% for the aforementioned increase in HTC. Correlations of the above-mentioned quantities with casting speed are reported to provide useful guidelines for vertical DCC design engineers and operators.
EFFECTS OF PIN FIN CONFIGURATIONS ON HEAT TRANSFER AND FRICTION FACTOR IN AN IMPROVED LAMILLOY COOLING STRUCTURE
657-679
10.1615/HeatTransRes.2016013575
Lei
Luo
National Key Laboratory of Science and Technology on Advanced Composites in Special
Environments Center for Composite Materials and Structures, Harbin Institute of Technology,
Harbin, 150080, China; School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China
Chenglong
Wang
Division of Heat Transfer, Department of Energy Sciences, Lund University, Box 118, Lund,
SE-2 2 100, Sweden
Lei
Wang
Division of Heat Transfer, Department of Energy Sciences, Lund University, Box 118, Lund,
SE-2 2 100, Sweden
Bengt
Sunden
BS Heat Transfer and Fluid Flow
Songtao
Wang
School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China
Lamilloy
pin fin
heat transfer
friction factor
cone-shaped
In this study, numerical simulations are conducted to investigate the effects of pin fin location, pin fin diameter, and pin fin shape on the target and pin fin surfaces heat transfer as well as friction factor in an improved Lamilloy cooling structure. The pin fin normalized location is varied from 0.35 to 0.65 while the pin fin diameter is changing from 15 mm to 60 mm. Cone-shaped pin fins are introduced, and the root to roof diameter ratio of the cone-shaped pin fin is ranging from 0.5 to 2.
The Reynolds number is between 10,000 and 50,000. Results of the target and pin fin surfaces Nu number, friction factor,
and flow structures are included. For convenience of comparison, the Lamilloy cooling structure whose pin fin normalized location is 0.5 with a pin fin diameter of 30 mm is studied as the baseline. It was found that with increase of the pin fin normalized location, the heat transfer on the pin fin surfaces is gradually decreased while the friction factor shows a lower value as the pin fins are positioned either near the impingement center or the film holes. This trend is also found for increasing the pin fin diameter. In addition, the heat transfer on the pin fin surface is increased remarkably by using a cone-shaped pin fin with a slight target surface heat transfer penalty. It was also found that by changing the pin fin location, pin fin diameter, and the pin fin shape, it may reach 7.6% higher values than the baseline thermal performance based on the target surface Nu number while it is 43.58% based on the pin fin surface.