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 >

Po Ting Lin, Hae Chang Gea, Yogesh Jaluria^*

Frontiers in Heat and Mass Transfer, Vol.1, No.1, pp. 1-20, 2010, DOI:10.5098/hmt.v1.1.3003

Abstract Thermal systems play significant roles in the engineering practice and our lives. To improve those thermal systems, it is necessary to model and optimize the design and the operating conditions. More importantly, the design uncertainties should be considered because the failures of the thermal systems may be very dangerous and produce large loss. This review paper focuses on a systematic strategy of modeling and optimizing of the thermal systems with the considerations of the design uncertainties. To demonstrate the proposed strategy, one of the complicated thermal systems, Chemical Vapor Deposition (CVD), is simulated, parametrically modeled, and optimized. The operating conditions,… More >

Chen Fang^*, Milnes David, Anita Rogacs, Kenneth Goodson

Frontiers in Heat and Mass Transfer, Vol.1, No.1, pp. 1-11, 2010, DOI:10.5098/hmt.v1.1.3002

Abstract Vapor-venting microchannel heat exchangers are promising because they address the problems of high pressure drop, flow instability, and local dryout that are common in conventional two-phase microchannel heat sinks. We present a 3D numerical simulation of the vapor-venting process in a rectangular microchannel bounded on one side by a hydrophobic porous membrane for phase-separation. The simulation is based on the volume of fluid (VOF) method together with models for interphase mass transfer and capillary force. Simulation shows the vapor-venting mechanism can effectively mitigate the vapor accumulation issue, reduce the pressure drop, and suppress the local dry-out in the microchannel. Pressure… 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 >

Channarong Wantha^a, Kriengkrai Assawamartbunlue^a,*

Frontiers in Heat and Mass Transfer, Vol.2, No.4, pp. 1-8, 2011, DOI:10.5098/hmt.v2.4.3006

Abstract This paper presents a study of the impact of the resonance tube on performance of a thermoacoustic stack. The resonance tube is a key component of a standing-wave thermoacoustic refrigerator. The appropriated resonance tube’s length leads to an increase of performance of the stack in terms of the temperature difference. The results also indicate that the optimal operating frequency differs from the design based on the equation of a half-wavelength. The resonance tube length is elongated to compensate for some effects that occur in the resonance tube, especially when the stack is placed in the resonance tube. The relationship of… More >

A. Valan Arasu^a,*, Agus P. Sasmito^b,†, Arun S. Mujumdar^b

Frontiers in Heat and Mass Transfer, Vol.2, No.4, pp. 1-7, 2011, DOI:10.5098/hmt.v2.4.3005

Abstract The heat transfer enhancement of paraffin wax, a cheap and widely used latent heat thermal energy storage material, using nanoparticles is investigated. The effects of nanoparticle volume fraction on both the melting and solidification rates of paraffin wax are analysed and compared for Al₂O₃ and CuO nanoparticles. Present results show that dispersing nanoparticles in smaller volumetric fractions increase the heat transfer rate. The enhancement in thermal performance of paraffin wax is greater for Al₂O₃ compared with that for CuO nanoparticles. 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 >