Tube side friction factor, heat exchanger

Figure 10-137. Heating and cooling in tube bundles—tube-side friction factor. (Used by permission Kern, D. Q. Process Heat Transfer, 1 Ed., p. 836, 1950. McGraw-Hill, Inc. All rights reserved. Using nomenclature of Standards of Tubular Exchanger Manufacturers Association.)...

Determine the friction factor and pressure drop for the low-pressure side of a coiled-tube heat exchanger where the fluid flows past 100 tubes in a staggered-tube arrangement. An air flow rate of 0.5 kg/s enters the low-pressure side of the heat exchanger at 0.121 MPa and 183 K. The outside diameter of each tube is 10 mm while the minimum flow area between each tube is 0.0125 m. The transverse pitch is 0.0003 m. 

Heat-transfer coefficient for cross flow over an ideal tube bank Fouling coefficient on outside of tube Heat-transfer coefficient in a plate heat exchanger Shell-side heat-transfer coefficient Heat transfer coefficient to vessel wall or coil Heat transfer factor defined by equation 12.14 Heat-transfer factor defined by equation 12.15 Friction factor... 

It is to be noted that the ratio of the friction factor / to the heat transfer factor J for compact ribbon-packed heat exchangers is approximately equal to the ratio of / to j reported in the present work. F rom this it may be concluded that more compact heat exchangers can be designed with helically finned and coiled tubing, which also represents a Collins type of heat exchanger, without any sacrifice in shell-side pressure drop. 

Flows are usually turbulent on both the tube and shell sides of coiled tube heat exchangers. To calculate pressure drops for single-phase tube side flows, it is simplest to use the normal Fanning friction factor correlation for... 

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