Question

A closed, rigid steel tank contains 1 lbm of water, initially at 260 F and a quality of 60%. The tank is fitted with a paddle wheel and the water is stirred until the temperature is 350 F. The tank is well insulated on the outside and the steel is in thermal equilibrium with the water. The mass of the steel tank itself (not including water) is 60 lbm and the specific heat of the tank is 0.115 Btu/lbm·R. Changes in kinetic and potential energy are negligible.

1)Determine the pressure of the water at the final state, in lbf/in^2

2) Determine the work done, in Btu

3) Determine the amount of entropy produced for a system including both the water and the steel tank, in Btu/degrees R.

Answer #1

A closed, rigid steel tank contains 1 lbm of water, initially at
260F and a quality of 60%. The tank is fitted with a paddle wheel
and the water is stirred until the temperature is 350F. The tank
is well insulated on the outside and the steel is in thermal
equilibrium with the water. The mass of the steel tank itself (not
including water) is 60 lbm and the specific heat of the tank is
0.115 Btu/lbm·R. Changes in kinetic...

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of a saturated liquid-vapor mixture of water at 100 kPa and half of
the mass is in the liquid phase. An electric resistance heater
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c. Find the final energy of the tank (Btu)
d. Compute the heat (Btu)
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