Question

thermodynamics

(5) Write the first law for a closed system, steady form, ignore kinetic and potential energy. (does it use enthalpy or internal energy?) (6) Write the equation to evaluate the work for a closed system (p-v work) for processes where po" = constant. (7) What is the name of a reversible power cycle? What can you assume about the efficiency of this cycle?

Answer 1

For closed - system under going a cycle The net head transfer is equal to net work transfer u L Q = { w A & dQ = $dw - For closed system under going a process da = det du do- net heat transfer dw- net work transfer de wet energy change

dE= d (k. Et d P E) + du Change in Kivetic energy Change in potential energy Change in internal energy By reglecting write it d R.E) and as dp.E) , we can d Q = dut dw

6 Polytropic process Ideal gas eq. foo polytropie Process Praca hao Polytropic index lokner We Pixir P2 V2 n-

WHERE GAMMA(γ) IS THE RATIO OF SPECIFIC HEATS

engine is a reversible power | carnot Cycle isotherma hot. Trotz = Thigh ladiabatic y adiabatic iso thern . Iz = T = Tow Carnot so The cannot efficiency is the theoretical mar efficieny that can achieve when a heat engine is operating between two temperature.