Question

Water at 15°C enters a tube of 2 cm of diameter with flow rate 3953 kg/h. Assume the ratio L/D>10, and the wall temperature is constant at 80-C. The outlet temperature is 50°C The properties of water at the film temperature are density rho = p = 985 kg/m3, specific heat Cp = 4180 J/kgk, conductivity k = 0.651 W/mK, dynamic viscosity mu= u = 4.71 × 10- kg/ms, At the wall temperature of 80°C we have dynamic viscosity muw= Hw = 3.55 x 10-*kg/ms

1. Calculate the average velocity, U

2. Calculate Reynolds number Rep

3. Determine the flow regime

4. Calculate Prandti number Pr Calculate the rate of heat transfer, q

5. Calculate the mean temperature Tm 5.

6. Calculate Nusselt number Nup

7. Calculate convection heat transfer coefficient h

9. Calculate the length of the tube L

10. Calculate the ratio L/D

Answer #1

A 1.5cm inside diameter tube has water flowing in it at a flow
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a) the amount of heat transfer required to achieve a
10oC increase in water temperature (in W)
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Heat capacity of gas phase: 0.036+4.23
x10-5T (in kJ/moleoC, T is
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s) 0.721 0.029
130oC 1.93x10-5kg/(m
s) 0.738 0.025
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s) 0.755 0.020
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