![]() ![]() Model numbers of D & R exchangers can be determined easily by assembling a few pertinent factors. Bott provides a good overview of tubular thermal design methods and example calculations.D & R Model "VT" for tube side condensing D & R Model "VS" for shell side condensingĭ & R Model "LL" for liquid to liquid service D & R Model "LLS" for steam to liquid sevice Ĭalculate the shellside heat transfer coefficient (Use Bell- Delaware Method)Ĭalculate tubeside heat transfer coefficient (see, for example, Tubes: Single Phase Heat Transfer In).Ĭalculate tubeside pressure drop (see, for example, Pressure Drop, Single Phase).Ĭalculate wall resistance and overall heat transfer coefficient (see Overall Heat Transfer Coefficient and Fouling).Ĭalculate mean temperature difference (see Mean Temperature Difference).Ĭompare area required with area of assumed geometry and allowed tubeside and shellside pressure drop with calculated values.Īdjust assumed geometry and repeat calculations until Area required is achieved within the allowable pressure drops.īooks by E. A floating head exchanger is suitable for the rigorous duties associated with high temperatures and pressures but is more expensive (typically of order of 25% for carbon steel construction) than the equivalent fixed tubesheet exchanger.Ĭonsidering each header and shell type in turn:Ĭalculate the shellside flow distribution. ![]() There are several rear header types that can be used but the S-Type Rear Head is the most popular. The use of a floating head means that thermal expansion can be allowed for and the tube bundle can be removed for cleaning. The tubesheet at the rear header end of the shell is of slightly smaller diameter than the shell, allowing the bundle to be pulled through the shell. The tubesheet at the Front Header (tube side fluid inlet end) is of a larger diameter than the shell and is sealed in a similar manner to that used in the fixed tubesheet design. In this type of exchanger the tubesheet at the Rear Header end is not welded to the shell but allowed to move or float. Floating Head Exchanger (P, S, T and W Type Rear Headers) ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |