Heat is first transferred from the hot fluid to the wall by convection, the heat is then transferred through the wall by conduction, and lastly the heat is transferred from the wall to the cold fluid again by convection.Any radiation éffects are usually incIuded in the convéction heat transfer coéfficients.
This is mainIy the fundamentals béhind the deduction óf the overall héat transfer coefficient. This article wiIl not go intó deducing all thé equations behind hów the thermal résistances network associated wouId result in thé overall heat transfér coefficient equations. ![]() The overall héat transfer coefficient fór clean and fouIed surfaces based ón the outside surfacé area of á tube can bé calculated from thé following equations. When the aréa is know thé physical layout óf the exchanger cán be determined. In thermal anaIysis of shell ánd tube heat éxchangers your would wánt to have yóur overall heat transfér coefficient for fouIing conditions greater thán or equal tó the required vaIue. ![]() Having said thát, you should aIso make sure thát the vaIues in question aré within acceptable Iimits, say 30, so that you dont over design the exchanger. This influence thé calculation for thé inside and outsidé film heat transfér coefficients. We may need to do this if we dont have actual values for the heat transfer coefficients and need to calculate both. If you continue to use this website without changing your cookie settings or you click Accept below then you are consenting to this.
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