G. Prakash Narayan^a, Karan H. Mistry^a, Mostafa H. Sharqawy^a, Syed M. Zubair^b, John H. Lienhard V^a,†

Frontiers in Heat and Mass Transfer, Vol.1, No.2, pp. 1-13, 2010, DOI:10.5098/hmt.v1.2.3001

Abstract Simultaneous heat and mass exchange devices such as cooling towers, humidifiers and dehumidifiers are widely used in the power generation, desalination, air conditioning, and refrigeration industries. For design and rating of these components it is useful to define their performance by an effectiveness. In this paper, several different effectiveness definitions that have been used in literature are critically reviewed and an energy based effectiveness which can be applied to all types of heat and mass exchangers is defined. The validity and the limitations of the various effectiveness definitions are demonstrated by way of several examples including direct and indirect contact,… More >

Bengt Sundén^*, Jinliang Yuan

Frontiers in Heat and Mass Transfer, Vol.1, No.1, pp. 1-20, 2010, DOI:10.5098/hmt.v1.1.3008

Abstract Depending on specific configuration and design, a variety of physical phenomena is present in fuel cells, e.g., multi-component gas flow, energy and mass transfer of chemical species in composite domains and sites. These physical phenomena are strongly affected by chemical/electrochemical reactions in nano-/micro-scale structured electrodes and electrolytes. Due to the electrochemical reactions, generation and consumption of chemical species together with electric current production take place at the active surfaces for all kinds of fuel cells. Furthermore, water management and twophase flow in proton exchange membrane fuel cells (PEMFCs) and internal reforming reactions of hydrocarbon fuels in solid oxide fuel cells… More >

Patrick H. Oosthuizen^*, Jane T. Paul

Frontiers in Heat and Mass Transfer, Vol.1, No.1, pp. 1-8, 2010, DOI:10.5098/hmt.v1.1.3006

Abstract Natural convective heat transfer from narrow vertical plates which have a uniform surface heat flux has studied. With a narrow plate the heat transfer rate is dependent on the flow near the vertical edges of the plate. The magnitude of the edge effects will depend on the conditions existing near the edges of the plate. Three situations have here been considered these being a heated plate imbedded in a large plane adiabatic surface, the surfaces of the heated plane and the adiabatic surface being in the same plane, a heated plate with plane adiabatic surfaces above and below the heated… More >

Harumi Toriyama^*, Yutaka Asako

Frontiers in Heat and Mass Transfer, Vol.1, No.1, pp. 1-6, 2010, DOI:10.5098/hmt.v1.1.3005

Abstract Effects of a magnetic field on aeration through porous medium compost have been investigated numerically. Some composts yield heat over 60 degrees Celsius in fermentation process. That exothermic reaction produces a considerable amount of heat, which could be a potential heating source. Fermentation reaction requires aeration, sufficient supply of paramagnetic oxygen gas and exhaust of metabolized diamagnetic carbon dioxide gas. Continuous and forced air supply is more efficient rather than conventional manual turns or stirrings as aeration means. In magnetoaero-dynamics, the magnetizing force acting on a paramagnetic oxygen gas is applied for the enhancement of airflow, heat and mass transfer.… More >

Moran Wang^a, Bin-Yang Cao^b, Zeng-Yuan Guo^b,*

Frontiers in Heat and Mass Transfer, Vol.1, No.1, pp. 1-8, 2010, DOI:10.5098/hmt.v1.1.3004

Abstract The thermomass theory regards heat owning mass-energy duality, exhibiting energy-like features in conversion and mass-like features in transfer processes. The equivalent mass of thermal energy is determined by the mass-energy equivalence of Einstein, which therefore leads to the inertia of heat in transfer. In this work, we build up a thermomass gas model based on this theory to describe the fluid-flow-like heat conduction process in a medium. The equation of state and the governing equations for transport for the thermomass gas have been derived based on methodologies of the classical mechanics since the drift speed of thermomass gas is generally… More >

Je-Chin Han^*, Akhilesh P. Rallabandi

Frontiers in Heat and Mass Transfer, Vol.1, No.1, pp. 1-21, 2010, DOI:10.5098/hmt.v1.1.3001

Abstract Film cooling is widely used to protect modern gas turbine blades and vanes from the ever increasing inlet temperatures. Film cooling involves a very complex turbulent flow-field, the characterization of which is necessary for reliable and economical design. Several experimental studies have focused on gas turbine blade, vane and end-wall film cooling over the past few decades. Measurements of heat transfer coefficients, film cooling effectiveness values and heat flux ratios using several different experimental methods have been reported. The emphasis of this current review is on the Pressure Sensitive Paint (PSP) mass transfer analogy to determine the film cooling effectiveness.… More >

Seyfolah Saedodin, M.S. Motaghedi Barforoush, Mohsen Torabi^*

Frontiers in Heat and Mass Transfer, Vol.2, No.4, pp. 1-4, 2011, DOI:10.5098/hmt.v2.4.4001

Abstract In this paper, a simplifying approach for calculating the radiant energy is achieved using the concept of net radiation heat transfer and provides an easy way for solving a variety of situations. This method has been applied to calculate the net radiation heat transfer between two long concentric semi-cylinders. Then this method used to calculate reduction heat transfer when radiation shields with temperature-dependent emissivity applied between these objects. Moreover, using this method the percentage reduction in heat transfer between two surfaces was calculated. The findings reveal that, one radiation shield with lower emissivity can reduce the net heat transfer even… More >

Aravind Sathyanarayana^a, Pramod Warrier^b, Yogendra Joshi^a,*, Amyn Teja^b

Frontiers in Heat and Mass Transfer, Vol.2, No.4, pp. 1-7, 2011, DOI:10.5098/hmt.v2.4.3007

Abstract Electrical and chemical compatibility requirements of electronic components pose significant constraints on the choice of liquid coolants. Dielectric coolants such as Novec fluids and fluoroinerts are plagued by poor thermal properties. This necessitates the development of new heat transfer fluids. In this study we examine mixture formulations that provide an avenue for enhancing the properties of existing heat transfer fluids. Mixture formulations of Novec fluid (HFE 7200) with Methanol and Ethoxybutane are considered. Pool boiling experiments are performed on a copper nanowire surface. The results show an improvement of 24% and 11% in the CHF of HFE 7200 – Methanol… More >

Antti Lehtinen^a, Reijo Karvinen^b,∗

Frontiers in Heat and Mass Transfer, Vol.2, No.4, pp. 1-6, 2011, DOI:10.5098/hmt.v2.4.3004

Abstract Analytical solutions for three different flat plate conjugate heat transfer cases are presented. The cases are as follows:transient heat transfer of a thin plate with uniform heat generation; the Luikov problem in which one plate surface is kept in a constant temperature and the other one is cooled by forced convection ; and a modified Luikov problem with heat generation on one surface and convection on both surfaces of the plate. All the cases are solved for both laminar and turbulent flows with P r ≥ 1. The solutions in the paper are based on the superposition principle and analytical… More >

Muthasim Fahmy^†, Zhifa Sun

Frontiers in Heat and Mass Transfer, Vol.2, No.4, pp. 1-14, 2011, DOI:10.5098/hmt.v2.4.3003

Abstract A gas-liquid solute transfer process initiated in a closed vessel can exhibit Rayleigh-Bénard-Marangoni (RBM) convection enhanced mass transfer. For short exposure times experimental and theoretical results demonstrate that for deep liquid systems prior to solute penetration across the depth of the fluid, the stability thresholds of the system decreases with time. For thin liquid layers at longer exposure times the mass transfer enhancement under RBM convection can be affected in two ways: (1) solute penetration to the bottom liquid-solid boundary causing a departure from a penetration type concentration profile; (2) solute penetration to the top gas-solid boundary in the gas… More >