MAE 204 Lecture Notes - Lecture 21: Wfed, Wnet, Superheating

• School: University at Buffalo
• Department: Mechanical & Aerospace Engr
• Course: MAE 204
• Professor: Salac David

Document Summary

They are heat engines where the working fluid changes phase must poker plants use this cycle. The ideal vapor power cycle is the rankine cycle nth=1-qout/qin. Each of these steps in a simple ideal rankine cycle are reversible. Pump and turbie are no isentropics np<1 nt<1. Boiler and condenser not isobaric np<1 nt<1 not isobaric more commom for anaysis is isobaric 2-3 and 4-1, but np<1 and nt<1. A rankine cycle consist of 4 open steady flow, reversible systems. Generic mass + enegery balacne dm/dt =m. in-m. out de/dt = q. i -w. out +m. in -m. out . Q. in - w. out = m. (hout-hin) of ke and pe neglacted qin - wout = hout-hin-- true for all devices. If you know t1,p1 and t2,pw => use tables for h1 and h2 if tables not available, use h2 = hf +vf(p-psat) => need t2. If t2 not available, recall that 1-2 is a reversible open system.