helppp asappp thanks! 3. (30 points). An inventor claims that the data given bel
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helppp asappp thanks!
3. (30 points). An inventor claims that the data given below for the schematic device at steady- state produces hot and cold streams of air from a single stream of air at an intermediate temperature without energy transfer by work or heat. Verify that both first and second laws of thermodynamics are satisfied mi of air T70P ple 5.1 atm m1 = 0.4 mi 2 Inlet T, = 175"F P2 = 1 atm Hot outle m3 =0.6m Cold outlet 7-0F P I atm 3.1 Does the device satisfy the first law of thermodynamics? a. Yes--No_ _ because b.Ln/dt=0 3.2 The entropy generation is a. S, 045 kkg K a. No of the above C. Sz= 092 kJ/Kg. K 3.3 Does the device satisfy the second law of thermodynamics? a. Yes No because b. s,>0Explanation / Answer
T1=700F=294.11K ;T2=1750F=352.44K ;T3=00F=255.22K
3.1) Yes ,the device satisfies the first law of thermodynamics because
sum of mass flow rate is equla to 0
m1-m2-m3=m1-0.4m1-0.6m1=0
3.2)entropy generation
s2-s1=cp ln(T2/T1) -R ln(P2/P1)
=>1005ln(352.44/294.11)-287ln(1/5.1)=649.4 J/kgK=0.649kJ/kg.K
s3-s1=cpln(T3/T1)-Rln(P3/P1)
=1005ln(255.22/294.11)-287ln(1/5.1)=325 J/kgK=0.325kJ/kg.K
total entropy generation is 0.6494+0.325=0.9744 kj/kg K
SO answer is None of the above
3.3)Yes, the device satisfy the second law of thermodynamics because Sg>0
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