Heat transfer from gas flow through pipe
Here's a question:
A gas flows in a pipe at a rate of 1 kg/s. The pressure and temperature at one section
of the pipe are 0.6 MPa and 527K. At the second section of the pipe, the pressure is
0.5MPa and temperature is 320K. The specific volume of the inlet gas is 0.249 m3/kg
and at the second section, it is 0.24 m3/kg. Assume that the specific heat at constant
volume is 1.33 kJ/kg ºC. If no shaft work is done by the gas and the velocities are
small, determine the magnitude and direction of the heat transfer. Assume the pipe to
be horizontal, and neglect velocity terms.
Could you please tell me which of the following answers is correct and why?
1)
2)
h = u + Pv and u = Cv.T
h1 = (1.33 x 527) + (0.6 x 103 x 0.249) = 850.31 kJ
h2 = (1.33 x 320) + (0.5 x 103 x 0.24) = 545.6 kJ
W = m(h2 – h1)
-304.71 kW (Loss)
Many thanks