Flashcards
Thermo formulas
Cards in this deck (20)
- 1Mixing of vapour and gasx2 = s2-sf/sg-sf
- 2approx state at the pump exith3+Wp/m== h3+v3(p4-p3)
- 3Turbine work (Rankine)Wt/m =h1-h2
- 4Condensor Heat transfer (Rankine)Qout/m =h2-h3
- 5Pump work (Rankine)Wp/m =h4-h3
- 6Heat in to boiler (Rankine)Qin/m = h1-h4
- 7Thermal efficiency of Rankine cycle(Wt/m -Wp/m)
/Qin/m
== (h1-h2)-(h4-h3)
/h1-h4 - 8Thermal efficiency (alternate)1-(h2-h3)/(h1-h4)
- 9Back work ratioRatio of pump work input to work developed by the turbine
bwr= (wp/m)/(wt/m)
= (h4-h3)/(h1-h2) - 10Evaluating pump work (as no irreversibility)(Wp/m)int,rev = v3(p4-p3)
- 11Rankine vs. carnotR has a lower thermal efficiency
In C combustion products are cooled at the most to TH
C requires pumps that handle 2 phase mixtures - 12Turbine efficiency (irreversible)n = (Wt/m)/(Wt/m)s = (h1-h2)/(h1-h2s)
- 13Pump efficiency (irreversible)n = (Wp/m)s/(Wp/m)
= (h4s-h3/ (h4-h3) - 14Reheat systemTwo turbines
No pressure drop at reheating
After 2nd turbine steam expands to compressor pressure - 15Open feedwater heaterInsetropic through turbines and pumps with no pressure drop.
Heat addition takes place state 7-1 - 16mass flow rate (open feed heater)m2 + m3 =m1
=> m2/m1 + m3/m1 =1
=> m3/m1 =1-y
where y is fraction of state extracted at state 2 - 17Fraction of total flow extracted at state 2 (Open feedheater)y = (h6 -h5)/(h2-h5)
- 18Turbine work (open feedheater)Wt/m = (h1-h2) +(1-y)(h2-h3)
- 19Pump work (open feedheater)Wp/m =(h7 -h6) +(1-y)(h5-h4)
- 20heat energy out (open feedheater)Qout/m = (1-y)(h3-h4)
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- University EM2 Flashcards on Thermo formulas, created by kedy3gei on 17/12/2013.
- Created by
- kedy3gei · Dec 2013
- Updated
- Feb 19, 2016
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