2.57 - (3) U = m ( u 2-u 1 ) change in internal energy of...

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2.57 Equations Problem Set 5: 2-57 5 kg of steam contained in a piston-cylinder assembly expands from state 1 where u 1 =2709.9 kJ/kg to state 2 where u 2 =2659.6 kJ/kg. During the process there is heat transfer of 80 kJ to the steam and a paddle wheel transfers 18.5 kJ of work to the steam. Determine the work done by the steam on the piston. System: Steam in cylinder m = 5 [kg] mass of steam (1) Q = 80 [kJ] heat input to steam (2) W pw = - 18 . 5 [kJ] paddle-wheel work ( < 0) since it is an energy input to the system
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Unformatted text preview: (3) U = m ( u 2-u 1 ) change in internal energy of the steam (4) u 1 = 2709 . 9 [kJ / kg] initial specic internal energy (5) u 2 = 2659 . 6 [kJ / kg] nal specic internal energy (6) Q-W pw-W piston = U energy balance to determine W piston (7) $TabStops 0.2 3.0 in Solution U =-251 . 5 [kJ] m = 5 [kg] Q = 80 [kJ] u 1 = 2710 [kJ / kg] u 2 = 2660 [kJ / kg] W piston = 350 [kJ] W pw =-18 . 5 [kJ]...
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