نتایج جستجو برای: heat transfer efficiency

تعداد نتایج: 822919  

Journal: :iranian journal of hydrogen & fuel cell 2015
elham omidbakhsh amiri

a micro-channel heat exchanger reactor with different micro-baffle shapes has been studied numerically. governing equations were solved base on the finite volume method with fluent software. in upper section, oxidation reaction of methanol was occurred and in lower section, steam reforming of methanol was done. two sections were separated with solid part which played as heat exchanger and trans...

Journal: :energy equipment and systems 0
ali reza yousefnejad department of mechanical engineering, najafabad branch, islamic azad university, najafabad, iran mohammad mahdi heyhat faculty of mechanical engineering, tarbiat modares university, tehran, iran amir homayoun meghdadi department of mechanical engineering, najafabad branch, islamic azad university, najafabad, iran

the present study investigated the effect of distilled-water/ silver nanofluid on heat transfer in a closed cooling system of one of the electrical energy generation units at isfahan power plant. the difference between this study and previous researches refers to silver properties which have a high thermal conductivity and is non-toxic, hydrophilic and eco-friendly. distilled water/ silver nano...

2014
Yuan Tian Changying Zhao Alexei Lapkin

Cascaded thermal storage, consisting of multiple Phase Change Materials (PCMs) with different melting temperatures, has been proposed to solve the problem of poor heat transfer caused by unavoidable decrease of temperature differences during heat exchange process. This paper conducts a theoretical study of the overall thermal performance for a cascaded thermal storage system. Both heat transfer...

L. Nourpour M. Alizadeh M. Sh. Mazidi V. Shojaee Shal

In the design of heat exchangers, it is necessary to determine the heat transfer rate between hot and cold fluids in order to calculate the overall heat transfer coefficient and the heat exchanger efficiency. Heat transfer rate can be determined by inverse methods. In this study, the unknown space-time dependent heat flux imposed on the wall of a heat exchanger internal tube is estimated by app...

This paper reports the thermal performance of a new cylindrical solar collector based on an experimental investigation with this difference that instead of the collector tube with absorbent coating, coil into a spiral copper tube is placed in the center of the collector. The spiral shape of the tube, heat transfer without disruption or increase the heat transfer area, is increasing. In this cas...

Azarikhah, P., Qasemian, A., Shojaeefard, M.H.,

Heat transfer in internal combustion engines is one of the most significant topics. Heat transfer may take place through thermal conduction and thermal convection in spark ignition engines. In this study, valve cover heat transfer and thermal balance of an air-cooled engine are investigated experimentally. The thermal balance analysis is a useful method to determine energy distribution and effi...

Journal: :journal of particle science & technology 2015
vahid madadi avargani amir rahimi touraj tavakoli gheinani

an experimental and theoretical energy and exergy analysis was conducted for a cylindrical cavity receiver employed in a parabolic dish collector. based on simultaneous energy and exergy analysis, the receiver average wall temperature and overall heat transfer coefficient were determined. a simplified nusselt number for heat transfer fluid (htf) through the receiver as a function of reynolds an...

Heat transfer coefficient and thermal efficiency of γ-Al2O3/water nanofluids flowing through a double tube heat exchanger were experimentally investigated. The nanoparticles were well dispersed in distilled water at 0.05–0.15 %vol. A large number of experiments were performed at different fluid flow rates under turbulent flow regime (18,000<Re<40,000) and various nanofluid...

Journal: :energy equipment and systems 0
behrang sajadi school of mechanical engineering, college of engineering, university of tehran, tehran, iran pedram hanafizadeh school of mechanical engineering, college of engineering, university of tehran, tehran, iran samar bahman school of mechanical engineering, college of engineering, university of tehran, tehran, iran ghazale hayati school of mechanical engineering, college of engineering, university of tehran, tehran, iran

plate heat exchangers are widely used in industries due to their special characteristics, such as high thermal efficiency, small size, light weight, easy installation, maintenance, and cleaning. the purpose of this study is to consider the effect of depth, angle, and pitch of hemispheric chevrons on the convective heat transfer coefficient and pressure drop. in the simulation of the heat exchan...

The thermal balance analysis is a useful method to determine energy distribution and efficiency of internal combustion (IC) engines. In engines cooling concepts, estimation of heat transfer to brake power ratio, as one of the most significant performance characteristics, is highly demanded. In this paper, investigation of energy balance and derivation of specific heat rejection is carried out e...

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