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Unformatted text preview: 7.45 Fluid properties: Ink ink m =60000lbm/hr=16.667lbm/s T 1 =130F T 2 =110F C p =0.44BTU/lbm-R K f =0.0085Btu/hr-ft-R =54.3 lbm/ft 3 =3.558X10-3 ft 2 /hr =0.41C p = 8.563X10-6 lb-s/ft 2 =5.074X10-6 ft 2 /s Pr = 5.134 4.4<V optimum <9.5ft/s Water (properties are evaluated at 65F) w m = unknown t 1 = 65F t 2 = unknown C p =0.9995BTU/lbm-R K f =0.3428Btu/hr-ft-R =62.4 lbm/ft 3 =5.496X10-3 ft 2 /hr =11.53X10-6 ft 2 /s Pr = 7.552 For liquid-liquid heat exchange, we can use a double pipe heat exchanger. Ink has a greater tendency to cause fouling on surfaces it contacts, because it has a larger fouling factor than water. R ink =0.001 ft 2-hr-R/BTU, R water =0.00075 ft 2-hr-R/BTU (Table 7.1). Therefore we route the ink through the pipe and the water through the annulus of the double pipe heat exchanger. Ink Min flow area = max V m ink =0.0323ft 2 Max flow area = max V m ink =0.0698ft 2 From Table 7.3, we choose 4X3 heat exchanger. A p =0.04846ft 2 Tube sizes:...
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- Winter '07