# Pressure Cooker and Mass Flow Rate

Steam is leaving a pressure cooker whose operating pressure is 30 psi. It is observed that the amount of liquid in the cooker has decreased by 0.4 gal in 45 minutes after the steady operating conditions are established, and the cross-sectional area of the exit opening is 0.15 in^2. Determine (a) the mass flow rate of the steam and the exit velocity, (b) the total and flow energies of the steam per unit mass, and (c) the rate at which energy is leaving the cooker by steam.

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Solution:

I prefer to work in SI units, there will be no problem to convert back to any other system of units.

a) The volume flow rate is 0.4 gal per 45 min, that means

0.4 gal = 0.4*3.785 = 1.514 L --> volume rate = 1.514/45 =

= 0.0336 L/min = 0.0336/60 = 0.00056 L/s

By looking in a steam table (you can find a lot of steam tables on Internet), we will find on saturation line:

p = 30 psia = 2.0685 bar --> T = 394.4 K = 121.2 deg C

ro(L) = 942.1 kg/m3 = 0.9421 kg/L

where ro(L) is density of water at liquid state

Since ...

#### Solution Summary

This complete answer includes calculations and explanation. 400 words.