1. Saturated steam at 4 bars absolute pressure with a mean velocity of 3 m/s flows through a horizontal SS304 stainless-steel pi
pe whose inner and outer diameters are 55 and 65 mm, respectively. The heat transfer coefficient for the steam flow is known to be 11,000 W/m2 -K. (a) If the pipe is covered with a 25-mm-thick layer of 85% magnesia insulation and is exposed to atmospheric air at 25°C in cross-flow with U[infinity]=15 m/s, determine the rate of heat transfer by forced convection to the room per unit length of the pipe. (b) If the steam is saturated at the inlet of the pipe, estimate its quality at the outlet of a pipe 30m long. (c) Determine the temperature of the outer surface of the insulation. Is it safe to touch?
1 answer:
You might be interested in
Answer:
A) attached below
B) 743 KJ
C) 1.8983 KJ/K
Explanation:
A) Diagram of system schematic and set up states
attached below
<u>B) Calculate the amount of work received from the paddle wheel </u>
assuming ideal gas situation
v1 = v2 ( for a constant volume process )
work generated by paddle wheel = system internal energy
dw = mCv dT . where ; Cv = 0.743 KJ/kgk
= 5 * 0.743 * ( 500 - 300 )
= 3.715 * 200 = 743 KJ
<u>C) calculate the amount of entropy generated ( KJ/K )</u>
S2 - S1 = 1.8983 KJ/K
attached below is the detailed solution
Answer:
The critical radius is -1.30 nm
Explanation:
Temperature for homogenous nucleation of copper,
Melting point of copper,
Latent heat of fusion,
Surface free energy,
Critical radius, r = ?
The formula for the critical radius is given by:
The critical radius is -1.30 nm