in this research the simulation of an air independent proton exchange membrane fuel cell (pemfc) propulsion system was taken into consideration. the system consists of several parts including pem fuel cell stack, metal hydride and liquid oxygen (lox) tanks, and also pre-heaters of oxygen and hydrogen gases along with other heat exchangers, to ensure proper operation of system. the heat recovery...

In this paper the heat transfer characteristics of a two-phase closed thermosyphon over a wide range of heat transfer rates, system pressure, aspect ratios and filling ratios were studied. The experiments focused on the boiling and condensation heat transfer characteristics of a thermosyphon with a copper tube having 25 and 32 mm inside and outside diameters. Distilled water was used as the wor...

In this paper the heat transfer characteristics of a two-phase closed thermosyphon over a wide range of heat transfer rates, system pressure, aspect ratios and filling ratios were studied. The experiments focused on the boiling and condensation heat transfer characteristics of the thermosyphon. The experimental boiling and condensation heat transfer coefficients inside the thermosyphon were com...

a thermodynamic analysis of the counter flow wet cooling tower (cwct) in the steelmaking unit of the khuzestan steel company (ksc) is performed in this paper. we evaluated both energy and exergy formulations for analyzing the heat and mass transfer, exergy and second-law efficiency in this cooling tower. the lewis factor le f is an indication of the relative rates of heat and mass transfer in a...

The aim of this paper is to enhance thermal performance of a microchannel heat sink by using nanoencapsulated phase change material (NEPCM) slurry as a cooling fluid instead of pure fluid. A threedimensional model of a circular channel using water slurry of NEPCM was developed. The results show a significant reduction in the mean fluid temperature along the channel and heat sink wall temperatu...

conclusions the results showed that the heat stress increased by increasing air velocity and humidity in both groups. the air velocity with high humidity can be considered as a positive factor in the occurrence of heat strain. therefore, the incidence of heat stress decreases with the increase of humidity and reduction of air velocity or with increase of air velocity and reduction of humidity i...

heat stress is well recognized among the hazardous physical agents that might be present during work. this study aims to compare wbgt index at acclimated and unacclimated people to permissible threshold limit value and study the differences between physiological parameters at them. twenty one healthy men were participated in the study. all of the subjects were monitored in two different weather...

in the presented research, heat transfer of a mobile electrolyte alkaline fuel cell (afc) (which the electrolyte has cooling role of system) has been considered. proper control volumes of system with specific qualification have been chosen. consequently, heat and mass transfer in control volumes have been assessed. considerations on them and contributed models lead to approve a double tube heat...