نتایج جستجو برای: Cooling
تعداد نتایج: 54410 فیلتر نتایج به سال:
یکی از روشهای متداول برای جلوگیری از تغییر شکل و خواص قطعات در تماس با گازهای داغ، از قبیل پره توربین و دیواره محفظه احتراق، استفاده از تکنیک سرمایش لایه ای (film cooling) می باشد. در روش سرمایش لایه ای شکافی (slot film cooling) سیال خنک کن مانع مانع از انتقال حرارت بین گازهای داغ و سطح فلز می شود. در این حالت می توان تحلیل جریان را به صورت دوبعدی انجام داد. اما در روش سرمایش لایه ای تک سوراخه ...
run-out-table (rot) is located between last finishing stand and down coiler in a hot strip mill. as the hot steel strip passes from rot, water jets impact on it from top and bottom and strip temperature decreases approximately from 800-950 °c to 500-750°c. the temperature history that strip experience while passing through rot affects significantly the metallurgical and mechanical properties, s...
the present paper describes the designing of a thermally and economically optimum mechanical draft counter-flow wet cooling tower. the design model allows the use of a variety of packing materials in the cooling tower toward optimizing heat transfer. once the optimum packing type is chosen, a compact cooling tower with low fan power consumption is modelled within the known design variables. mor...
temperature restrictions on aqueous effluents dictate that streams with a temperature higher than the permitted level needed to pass through cooling systems to reduce the effluent temperature before discharge. in this study, by considering the grouping design rules based on pinch technology, an optimum design for a distributed effluent cooling system, has been developed. a counter-flow wet cool...
background: the phase change materials (pcms) have the appropriate properties for controlling heat strain. one of the well-known pcms is paraffin. this study aimed to design the cooling vest from the cheap commercial paraffin compound and evaluation of its effectiveness under laboratory hot conditions. methods: the cooling vest was made of the polyester fabric and it had 17 aluminum packs. the ...
Introduction: One way to reduce the level of heat strain is to use personal evaporative cooling coats. such as the wrist, ankle, head and neck. The purpose of this study is to design, construct, and determine the cooling power of local cooling coatings and evaluate their efficiency in improving perceptual indicators in the laboratory. Materials and Methods: Initially, the design and constructio...
gas turbines play an important role in supplying power for the country especially in peak electricity load. the main disadvantages are the turbines, they produce large changes are a result of climate change. however, in times of peak electricity grid and at the same time warm months, can produce gas turbines under the effect of ambient temperature, the amount of reduced considerably. the method...
The present paper describes the designing of a thermally and economically optimum mechanical draft counter-flow wet cooling tower. The design model allows the use of a variety of packing materials in the cooling tower toward optimizing heat transfer. Once the optimum packing type is chosen, a compact cooling tower with low fan power consumption is modelled within the known design variables....
Parametric study of the influence of cooling channel dimensions on PEM fuel cell thermal performance
In a polymer membrane fuel cell more than half of the chemical energy of hydrogen is converted to heat during generation of electricity. This causes an increase in the cell temperature. The Cooling field design has a significant role in cell cooling. The cell's performance and stability are reduced due to inappropriate heat dissipation. In this paper, the cooling flow and heat transfer in cooli...
background heat is a harmful factor in workplaces that causes physiologic and cognitive changes in workers. objectives the purpose of this study was to investigate the effect of cooling vest on heat strain and reaction time while wearing chemical-biological-nuclear protective clothes. methods twelve male students with mean age of 25 ± 2 and body mass index (bmi) of 23 ± 1.5 were recruited in th...
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