![]() ![]() ![]() The length of the tube (2800 mm) is only the length of the straight portion of the tube. The tube length field is mandatory and a value must be entered. However please make sure that the shell length is consistent. The user can specify a value of the shell but it is not necessary as software calculates it. Length of each tube required for the second case = 1.Shell length in the heat exchanger is derived from the tube length value entered in the Bundle tab in Shell and Tube Heat Exchanger Properties dialog box.įor the BEU type exchanger, the entered value of tube length is 2800 mm Substituting for Q 1/C from Equn.1 in Equn.2, I.e., 'A' is directly proportional to 'L'įor a given diameter and number of tubes it can be written as, Since there is no change in physical properties of fluid compared to the first case, overall heat transfer coefficient U will be the same for both the cases. Therefore, outlet temperature of water = 300 + 75 = 375 KĪnd heat transfer rate for the second case will be 50% more than that of the first case, since there is a 50% increase in temperature drop. Since the flow rates are not changed, for a change of 60 K (i.e., = K) in oil temperature the corresponding change in water temperature = 60 x 50 / 40 = 75 K Outlet temperature of water is obtained from the following proportionality factor.įor 40 K change in oil temperature, there is a change of 50 K in water temperature. Assume that the physical properties remain unchanged. Calculate the length of each tube required for this purpose. ![]() It is now desired to cool the oil to 390 K (instead of 410 K) while maintaining the flow rate of oil, flow rate of water, inlet temperature of oil and water, and the number of tubes at the same values as before. The exchanger consists a number of tubes of 1 m length each. In a counter-current heat exchanger, an oil stream is cooled from 450 K to 410 K by water inlet and outlet temperatures of 300 K and 350 K respectively. ![]()
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