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Δ S of Pure Substances, Isentropic Processes, and Property Diagrams. Δ S of Pure Substances. Can be calculated from defining equations However, very complicated. Generally use tables or EES Be careful mixing methods. can have different reference states. T-s diagram for water.
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ΔS of Pure Substances,Isentropic Processes,and Property Diagrams
ΔS of Pure Substances • Can be calculated from defining equations • However, very complicated. • Generally use tables or EES • Be careful mixing methods. • can have different reference states.
Isentropic Process An adiabatic reversible process will be constant entropy. However, an isentropic process is not necessarily an adiabatic reversible process.
Ideal pumps, turbines, nozzles, and diffusers are isentropic and enable us to assign idealized efficiencies. Because the turbine is isentropic, s2 = s1 can help us find the final state.
Use of T-s diagrams Entropy definition can be rearranged to: δQint rev = TdS Similar to dw = Pdv is area under P-v curve.
One Trivial Example: Isothermal processes are also easy to integrate.
h-s diagram Δh part indicates the work out of a steady- flow adiabatic turbine Δs part indicates the irreversibilities of the process
T-s diagram of a carnot heat engine Wnet = QH - QL