An uninsulated steam pipe with a wall temperature of 140 °Cpasses through a room of quiescent air of 14 °C. The pipe ishorizontal and has an outer diameter of 20 cm. Find the following(include units if needed):
a) The temperature to evaluate properties = __________
b) The Rayleigh number, _____________
c) The heat transfer coefficient, h = ____________
d) q’ along the pipe = ________________
e) The pipe diameter is decreased by 50%. If all otherparameters remain the same, will the heat transfer coefficientincrease, decrease or stay the same? ___________. Justify youranswer mathematically. For air: ν = 20.92 x 10-6 m2/s, α = 29.9 x10-6 m2/s, 30 x 10-3 W/m·K, Pr = 0.7
