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Unformatted text preview: Quiz#6 ME 300 Fall 2008 Your NAME: 60LUTlO NS Answer all questions. Please DO NOT consult text book, class notes, HW solutions, or your
neighbor students. Strict penalties for violations will be imposed, as per university rules. 1. Steam enters a turbine operating at steady state with a mass flow rate of 4600 kg/h.
The turbine develops output of 1000kW. The enthalpy at the inlet to the turbine is 3177.2 kJ/kg while the exit enthalpy is 2345.4 kJ/kg. Neglecting KE and PE effects,
calculate the heat transfer to the surroundings. {Q .. ‘4‘) «Yb (hl’hl) cv "' CV '
Bhoo : \oc>0 * — caeskw 2. Air enters a compressor at steady state at a pressure of 1 bar and temperature of 290
K. At the exit, the pressure is 7 bars and temperature is 450 K. The compressor is well
insulated. The mass flow rate is 0.8 kg/s. Use a specific heat at constant pressure of 1.0 kJ/(kg.K). Find the rate of work in kW required to run the compressor. Neglect
changes in KE and PE. . . , . a T #1,
O: QC.\,WCV +m£hp~ln¢3 : oww+mc\a(. a.) _. \29 WW 54c“ : (0.3)Q\.o)(1qo—+5o) : wave. WM 3 \acgkw 3. A heat exchanger has heat transfer between two fluid streams. Fluid A enters the heat
exchanger with a mass flow rate of 40 kg/s and an inlet enthalpy of 200 kJ/kg. Fluid B
enters the heat exchanger with an inlet enthalpy of 500 kJ/kg and leaves the
exchanger with an enthalpy of 300 kJ/kg. The mass flow rate of Fluid B is 25 kg/s.
What is the exit enthalpy of Fluid A? Neglect the effects of KE and PE changes, and
also consider the heat exchanger to be wellinsulated. . z 0
2 me (he) ‘I‘ Z malt heh" (hA)'(h') 4&9» ; “nab * Unﬁdehe“ . maf
L > .p (as) l 300) he’s: 0 +053 (5°05 " (“0) Uh” (403 (200} : O
s k:
as (SM3w) . aoo H25 :32 __.
h2A  9‘00 ‘T (2’: ’ “S 4. A wellinsulated throttling device samples steam flowing through a pipe at a pressure
of 10 bars. The exhaust from the steam is to the atmosphere at 1.01 bars. The
temperature of the steam after the throttle valve is 120 °C, for which the enthalpy is
2700 kJ/kg. Determine the quality of the steam in the pipe if the following values are
given for 10 bars. hf: 800 kJ/kg and h g = 2800 kJ/kg .. h
\n\ = \“D. > \“9. F “aka; "' 0 x) h.
in : Q100 .— 860 _ o ‘ M ...
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 Spring '08
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 Thermodynamics, Mass flow rate, 3W, 1 bar, Fluid B

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