Begell House Inc.
Journal of Enhanced Heat Transfer
JEH(T)
1065-5131
22
2
2015
ARE WE AT A NEW FRONTIER OF NEW AND TRANSFORMATIVE KNOWLEDGE GENERATION . . . OR SIMPLY PUBLISHING FOR ITS OWN SAKE?
v-vii
10.1615/JEnhHeatTransf.2015015955
Raj M.
Manglik
Thermal-Fluids and Thermal Processing Laboratory, Mechanical and Materials Engineering, University of Cincinnati, 2600 Clifton Ave, Cincinnati, OH 45220, USA
Editorial
Editorial for JEHT, Vol. 22, No. 2, 2015.
PERSONAL REFLECTIONS ON FIFTY YEARS OF CONDENSATION HEAT TRANSFER RESEARCH
89-120
10.1615/JEnhHeatTransf.2015012451
John W.
Rose
School of Engineering and Materials Science, Queen Mary, University of London, London E1 4NS, UK
two-phase convection
treated surfaces
extended surfaces
microchannels
dropwise condensation
Marangoni condensation
This paper discusses some of the experimental and theoretical work on condensation heat transfer with which I have been involved over many years. The explosion in publications in recent years precludes a comprehensive survey of the general field. The paper is based on an unpublished presentation I gave at the 8th Experimental Heat Transfer, Fluid Mechanics and Thermodynamics Conference (ExHFT-8) held in Lisbon, Portugal, in 2013. It focuses on the topics of dropwise condensation, which has recently again become fashionable after many years, and condensation of metals. In both of these fields the interface temperature discontinuity plays a crucial role. Also discussed is work on condensation on integral finned tubes, in microchannels, and finally on Marangoni condensation of mixtures.
A CASE STUDY OF USING ENHANCED INTERCONNECT CHANNEL GEOMETRIES ON HEAT AND MASS TRANSFER CHARACTERISTICS OF ANODE-SUPPORTED PLANAR SOFC
121-145
10.1615/JEnhHeatTransf.2015015645
Yogesh N.
Magar
Thermal-Fluids & Thermal Processing Laboratory, Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, OH 45221-0072
Raj M.
Manglik
Thermal-Fluids and Thermal Processing Laboratory, Mechanical and Materials Engineering, University of Cincinnati, 2600 Clifton Ave, Cincinnati, OH 45220, USA
extended surfaces
swirl-flow devices
single-phase flow
suction and injection
porous media
fuel cells
The role of enhanced heat transfer inside interconnect channels for improved convective cooling and thermal management of planar solid oxide fuel cells (SOFCs) is investigated. A case study of two different geometries (sinusoidal wavy or corrugated walls and offset-and- interrupted walls) is presented for a uniform electrochemical reaction rate with constant flow of moist hydrogen and air. The coupled heat and mass transfer is modeled by three-dimensional, steady-state equations for mass, momentum, energy, species transfer, and electrochemical kinetics, in which the porous-layer flow is in thermal equilibrium with the solid matrix and is coupled with the electrochemical reaction rate. The heat and mass transfer rates through the interconnect ducts as well as the electrodes on both the anode and cathode sides are computationally obtained. The temperature field and species mass distributions, along with variations in the friction factor and heat transfer coefficients describe the performance of the two flow-channel geometries. The relative thermal and hydrodynamic behavior is compared with that in plain rectangular-duct interconnects to evaluate their convective-cooling performance. The results demonstrate that the offset interrupted-wall geometry yields better cooling of the SOFC module.
COMPUTATIONAL INVESTIGATION OF DIMPLE EFFECTS ON HEAT TRANSFER AND FRICTION FACTOR IN A LAMILLOY COOLING STRUCTURE
147-175
10.1615/JEnhHeatTransf.2015013956
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
structured roughness
dimple depth-to-diameter ratio
extended surface
jet impingement
single-phase flows
gas-turbine cooling
Good heat transfer performance with a moderate pressure drop penalty contributes to the gas turbine engine lifetime and guaranteeing engine efficiency. In this study, the dimple effects for a Lamilloy® (Allison Advanced Development Corporation, Indiana, IN, USA) cooling structure on the heat transfer and friction factor are numerically investigated. The dimple is positioned directly under the jet impingement nozzle. The Reynolds number ranges from 10,000 to 70,000, the dimple normalized depth is between 0 and 0.3, and the dimple normalized diameter varies from 1 to 2.5. The results for the flow field, target surface heat transfer, pin fin surface heat transfer, friction factor, and solid domain outer-wall temperature are included. For comparison, a Lamilloy cooling structure without the dimple is considered as the baseline. The results show that the dimple significantly increases the local heat transfer due to flow reattachment and recirculation. With an increase in the normalized dimple depth, the heat transfer on the target surface is first augmented due to the increase of flow reattachment and recirculation, and then it is decreased due to the large toroidal vortex. However, an increase in the dimple depth results in reduction of the pin fin surface heat transfer. As the dimple diameter increases, the target surface heat transfer is also first augmented due to the increase in the flow reattachment and recirculation, and then it is decreased as the flow separation increases. The thermal performance indicates that the intensity of the heat transfer enhancement depends on the depth and diameter of the dimple.