dr. ekin Özgirgin yapıcı fall 2016 Çankaya university ...me211.cankaya.edu.tr/uploads/files/me...
Post on 11-Mar-2018
215 Views
Preview:
TRANSCRIPT
Name, Surname: Prof. Dr. Nevzat Onur ID No: Dr. Ekin Özgirgin Yapıcı Fall 2016
1
Çankaya University
Faculty of Engineering
Mechanical Engineering Department
ME 211 Thermodynamics I
Closed Notes and Bookes
Midterm 1 Exam
Solution
Q-1 Net work of a power cycle shown in the figure is 10000 kJ and the thermal efficiency is 0.64.
Determine the heat transfers Qin and Qout, each in kJ.
Solution:
Name, Surname: Prof. Dr. Nevzat Onur ID No: Dr. Ekin Özgirgin Yapıcı Fall 2016
2
Q-2 A piston cylinder arrangement with a linear spring shown in the figure given below contains R-
134a at 16 0C, x = 0.4 and a volume of 0.02 m3. It is heated to 60 0C at which point the pressure is
8 bar. Find; (a) the work, (b) the heat transfer in the process.
Hint: You do not need a spring constant. show the process on a p-v diagram.
Solution:
Name, Surname: Prof. Dr. Nevzat Onur ID No: Dr. Ekin Özgirgin Yapıcı Fall 2016
3
Q-3 A piston -cylinder device initially contains 0.3 m3 of nitrogen gas at 350 kPa and 35 ºC. An
electric heater within the device is turned on and is allowed to pass a current of 2 A for 6 min from
a 120 V source. Nitrogen expands at constant pressure, and a heat loss of 3000 J occurs during the
process. Determine the final temperature of the nitrogen. (Average cP for Nitrogen is 1.039 kJ/kgK
and molecular weight of Nitrogen is 28.01 kg/kmol.)
Solution:
V1=0.3 m3
P1=350 kPa
T1= 35ºC
3000 J
Name, Surname: Prof. Dr. Nevzat Onur ID No: Dr. Ekin Özgirgin Yapıcı Fall 2016
4
Q-4 A rigid 20 Liter vessel initially contains a mixture of liquid water and vapor at 95 ºC with 0.15
(15%) quality. The mixture is then heated until its temperature is 140 ºC. Calculate the heat
transfer required for this process.
Water
20 L, 95 ºC x=0.15
Qin
Name, Surname: Prof. Dr. Nevzat Onur ID No: Dr. Ekin Özgirgin Yapıcı Fall 2016
5
top related