Question

A shell and tube type of heat exchanger with one shell pass and two tube passes will be designed to provide the given heat transfer rate Q(kW) to cool hot water by using cold river water . The hot water flows through the shell and the cold water flows through the tubes. The inlet and outlet temperatures of the hot water and the cold water are given as Thi, The and Tci, Tce in degrees Celcius. Design the shell and tube heat exchanger by making necessary assumptions to calculate the dimensions of the heat exchanger. Q= 10 KW Hot Fluid( Water) Thi= 70 Celcius The= 40 Celcius Cold Fluid ( Water) Tci= 5 Celcius Tce= 15 Celcius 1) Assume the tube diameter and tube length . 2) Assume fouling coefficient based on inside and outside tubes, hdi and hdo . 3) Select the material of construction for the tubes to determine the thermal coefficient. 4) Find the Log Mean Temperature Difference (LMTD) . 5) Obtain the Correction Factor F. 6) Calculate the Mean Temperature Difference. 7) Assume the Overall Heat Transfer Coefficient “U” as initial guess according to type of heat exchanger. 8) Calculate the provisional area. 9) Calculate the number of tubes based on the assumed tube diameter, thickness of the pipe and tube length L. 10) Calculate the tube pitch and bundle diameter. 11) Obtain the bundle diameter clearence. 12) Select the minimum Shell thickness according to nominal shell diameter. 13) Calculate the shell inside diameter 14) Calculate the baffle spacing. 15) Calculate the area for cross flow for the hypothetical row of tubes at the shell equator ( at the shell diameter plane). 16) Calculate the shell side mass flow velocity. 17) Calculate the shell side equivalent diameter ( hydraulic diameter) 18) Calculate the shell side Reynolds number. 19) Calculate or obtain the Prandtl number. 20) Calculate the shell side heat transfer coefficient. 21) Read the friction factor from Jf tablet for the calculated Shell side Reynolds number in order to calculate the shell side pressure drop. 22) Calculate the number of tubes per pass. 23) Calculate the tube-side mass velocity. 24) Calculate the tube-side velocity. 25) Calculate the Prandtl and Reynolds numbers for fluids inside the tubes. 26) Calculate the heat transfer coefficient hi. 27) Calculate the overall heat transfer coefficient “U”. 28) Compare the calculated “U” with that assumed in step 7). If the difference is large , start iteration by changing the tube length till the difference is small enough. 29) Calculate the tube-side pressure drop.

Answer 1