Three vessels that are open to the atmosphere contain three

Three vessels that are open to the atmosphere contain three different fluids. The atmospheric pressure was measured at 101 kPa. Calculate both the absolute pressure (psia) and the gage pressure (psig) at the bottom surface of each container.

Vessel A is 6 ft. wide 15 ft. high and is filled with crude oil (Density= 56.2 ibm/ft^3)

Vessel B is 4 ft. wide 10 ft. high and is filled with a water based fluid (Density= 62.4 ibm/ft^3)

Vessel C is 5 ft. wide 8 ft. high and is filled with a oil based fluid (Density= 49.9 ibm/ft^3)

(Thermodynamics\'s question), please try to answear with explanation. Thanks!

Solution

Answer:

Pabs = Patm + Pgauge

Patm is the pressure caused by the weight of the earth’s atmosphere. Often atmospheric pressure is called Barometric Pressure

Pgauge is pressure relative to atmospheric pressure

Pabs is total pressure

VESSEL A

Patm = 14.79 psi, Pgauge = 0.032 x 386 x 180 = 2223.36

Pabs = 2238.15

VESSEL B

Patm = 14.79 psi, Pgauge = 0.0361 x 386 x 120 = 1672.15

Pabs = 1686.94

VESSEL C

Patm = 14.79 psi, Pgauge = 0.028 x 386 x 96 = 1037.56

Pabs = 1052.35

The gauge pressure of the vessel only depends on height not on size.