Consider a rigid, pressurized stainless-steel (SS-304) propane tank that weighs 18 lbs. (empty) and is initially at thermal equilibrium (Eq.) with its surroundings (1atm, 22°C). The inner dimensions of the propane tank are roughly a cylinder (height: 13¼", diameter: 10¼"). The tank is 99% filled with propane and x=0.05. The welded handle and stand on the tank weighs 1 lbs. (combined) and valve on the tank weighs 1.5 lbs. and has an exit area of 1 cm2. NOTE: for this problem you will need to look up the thermodynamic properties of propane and SS-304. Show your calculations!
a) List below your references for the properties of propane and SS-304?
b) What is the wall thickness of the propane tank in mm? _________ mm
c) What is inner volume of the propane tank in mL and gallons? _________ mL _________ gallons
d) What is the pressure inside the tank in psi and kPa? _________ psi _________ kPa
e) What is the mass of liquid propane in the tank in kg and lbs.? _________ kg _________ lbs.
f) What is the volume of gaseous propane in the tank in mL? _________ mL
At t0 = 0 seconds, the valve on the tank is instantly opened until equilibrium (Eq.) is reached @ t = tEq.
g) What is the mass of air (in kg) in the tank @ Eq.? _________ kg
h. Draw a schematic of the system @ t = t0, identifying all the key properties of the system, boundary, surroundings, etc.
At some intermediate time t = t1, the pressure in the tank is equal to Psurr.
i) Draw a schematic below of the system @ t = t1, identifying all the key properties of the system, boundary, surroundings, etc.
j) In equation form, what is the net amount of heat transferred between the tank and its surroundings between t=t0 and t=t1? (make sure you identify all of your assumptions). Show your derivation on the blank pages.
k) In equation form, what is the entropy generated between t=t0 and t=t1?
l) In equation form, what is the entropy generated between t=t1 and t=tEq?
m) Qualitatively plot the temperature of the tank from t=t0 to t=tEq. Assume that SS-304 has the same temperature as its contents. No detailed calculations are needed, but make sure you label the axes, including the notable initial, final, maximum, and minimum temperatures of the system.
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n) Qualitatively plot the rate of heat transfer from t=t0 to t=tEq. No detailed calculations are needed, but make sure you label the axes and include the notable initial, final, maximum, and minimum rates of heat transfer.
o) Below: Qualitatively plot the rate of entropy generated due to heat transfer (SQ), mass transfer (Sm), and changes in the system from t=t0 to t=tEq. NOTE: the system should consist of both the SS tank and its contents. Again, no detailed calculations are needed, but use the same plotting recommendations as that requested in parts m and n).