Question

A hot fluid passes through a thin-walled tube of 10-mm diameter at 18 kg/h at a temperature of 85 C. On the outside, coolant flows across the tube at a velocity of 3 m/s at a temperature of 25 C. Neglecting the thermal resistance of the metal wall, calculate 1. (a) The two heat transfer coefficients, (b) Overall heat transfer coefficient, and (c) Cooling rate (in W/m) achieved in the given configuration Assume hot fluid properties are constant at the given temperature range: density-1079 kg/m3, Cp 2640 J/kg K, viscosity 0.0034 N-s/m2, k-0.026 W/m K. Assume coolant fluid properties are constant in the given temperature range: density-995 kg/m, Cp-4640 J/kg K, viscosity 0.002 N-s/m2, k-0.02 W/mK. suggestion: calculate tube side transfer coefficient using Dittus-Boelter or Seider-Tate correlation; for shell side use flow-across cylinder correlation; using thermal circuit analysis, calculate overall heat transfer resistance and then overall heat transfer coefficient. Cooling rate then can be calculated by overall coefficient area*temperature difference.]

Answer 1

n 2 Type 념乩u, inside tube, Re- 20 , S g 65%tos o.8

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