Physics

POD based modeling on flow and heat transfer of air-cooled condenser influenced by natural wind
Numerous factors, including the meteorological and the geographical conditions as well as the configurations of the fin tube bundles, can affect the performance of an air-cooled condenser (ACC) in a power generating unit. In this work a new model is presented to rapidly and accurately predict the flow and heat transfer characteristics of an ACC under the influence of natural wind. This reduced-...


Theoretical and experimental studies on thermal control by using a novel PTC material with room temperature Curie point
Positive temperature coefficient (PTC) material is a kind of thermo-sensitive material, the resistivity rapidly rises suddenly while the temperature increasing thereafter the Curie point. It can be used as a potential thermal control component to replace the ordinary resistor heater. However, the Curie temperatures of the most PTC materials are much higher than the operating temperature ranges ...
Experimental analysis of heat transfer of supercritical fluids in plate heat exchangers
Heat transfer of a supercritical refrigerant with highly variable properties close to pseudo-critical temperature was experimentally investigated in plate heat exchangers. Two different plate corrugation angles (30° and 60°) were examined while the Reynolds and the Prandtl number range from 800 to 4200 and 3.2 to 4.2, respectively. The results are found to be different from those obtained usi...


Rough surfaces with enhanced heat transfer for electronics cooling by direct metal laser sintering
Experimental evidences are reported on the potential of direct metal laser sintering (DMLS) in manufacturing flat and finned heat sinks with a remarkably enhanced convective heat transfer coefficient, taking advantage of artificial roughness in fully turbulent regime. To the best of our knowledge, this is the first study where artificial roughness by DMLS is investigated in terms of such therma...
Numerical study of the Maisotsenko cycle heat and mass exchanger
This report describes numerical modeling of heat and mass transfer in the Maisotsenko cycle heat and mass exchanger (HMX) used for indirect evaporative cooling. For this purpose an numerical model is developed based on the modified ε-NTU method to perform thermal calculations of the indirect evaporative cooling process, thus quantifying overall heat exchanger performance. The proposed mathemat...


Pressure drop during condensation of R134a flowing inside a multiport minichannel
This paper is a continuation of the authors’ previous work on the condensation of R134a flowing inside a multiport minichannel (Sakamatapan et al., 2013) [22]. The pressure drop’s characteristics during condensation were investigated in an experiment for R134a flowing inside a multiport minichannel. The pressure drop characteristics were observed under mass flux range of 345–685kg/m2, hea...
Numerical modeling of turbulent flow through isotropic porous media
Turbulent flow through porous media is of considerable theoretical and practical interest in various engineering disciplines such as chemical, mechanical, nuclear, geological, environmental, petroleum, etc. In the present work, a numerical study of turbulent flow through porous media was carried out. The porous media was considered to be made of a spatially periodic array of infinite square cyl...

Heat transfer characteristics of phase change nanocomposite materials for thermal energy storage application
Three phase change nanocomposite materials made of stearic acid and different carbon additives (multi-walled carbon nanotube-MWCNT, graphene, graphite) are prepared to enhance the heat transfer performance for thermal energy storage applications. The SEM analysis shows that the carbon additives are uniformly distributed in the based phase change material of stearic acid, and the DSC analysis re...
The role of tides in shelf-scale simulations of the wave energy resource
Many regions throughout the world that are suitable for exploitation of the wave energy resource also experience large tidal ranges and associated strong tidal flows. However, tidal effects are not included in the majority of modelling studies which quantify the wave energy resource. This research attempts to quantify the impact of tides on the wave energy resource of the northwest European she...

The wind energy potential of Iceland
Downscaling simulations performed with the Weather Research and Forecasting (WRF) model were used to determine the large-scale wind energy potential of Iceland. Local wind speed distributions are represented by Weibull statistics. The shape parameter across Iceland varies between 1.2 and 3.6, with the lowest values indicative of near-exponential distributions at sheltered locations, and the hig...
Energy generation from grey water in high raised buildings: The case of India
Energy consumption in developed as well as developing countries is high, especially in the residential and commercial building sectors. Researchers have been working on several technologies for the reduction of energy consumption in buildings; among them, energy-harvesting techniques are quite promising. In this paper, we explore a possibility of harnessing energy from grey water, while it flow...

Experimental investigation of a novel multi-effect solar desalination system based on humidification–dehumidification process
This paper presents an experimental investigation of a novel multi-effect solar desalination based on humidification–dehumidification process. The main objective of this work is to determine the operational and performance characteristics of the system with use of packed porous plastic balls and finned heat exchangers. The effect of operating parameters such as the heating temperature, the se...
Energy and economic assessments of bio-energy systems based on annual and perennial crops for temperate and tropical areas
Bio-energy systems based on dedicated crops depend on efficient and economic feedstock production as a pre-requisite for sustainable development. In this study, 15 annual and perennial species suited for temperate or tropical areas were assessed in terms of energy and financial balan oil and coconut palm, jatropha, castor bean, sunflower and rapeseed (biodiesel); sugar cane, maize and wheat (1s...
Macromolecular Crowding as a Regulator of Gene Transcription
Studies of macromolecular crowding have shown its important effects on molecular transport and interactions in living cells. Less clear is the effect of crowding when its influence is incorporated into a complex network of interactions. Here, we explore the effects of crowding in the cell nucleus on a model of gene transcription as a network of reactions involving transcription factors, RNA pol...
Attraction of Rotors to the Pulmonary Veins in Paroxysmal Atrial Fibrillation: A Modeling Study
Maintenance of paroxysmal atrial fibrillation (AF) by fast rotors in the left atrium (LA) or at the pulmonary veins (PVs) is not fully understood. To gain insight into this dynamic and complex process, we studied the role of the heterogeneous distribution of transmembrane currents in the PVs and LA junction (PV-LAJ) in the localization of rotors in the PVs. We also investigated whether simple p...