Republic of the Philippines
BOHOL ISLAND STATE UNIVERSITY, MAIN CAMPUS
COLLEGE OF ENGINEERING AND ARCHITECTURE
Tel no. 038-411-3289 Telfax: 038-5017516
6300, Tagbilaran City
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Student’s Name: Althea Iris S.Dano
Year and Section: BSME 2B
Subject: Engineering Thermodynamics 1
Instructor: Engr. Juanito Origines
GENERAL, CARNOT, STIRLING & ERICSSON
1. The thermal efficiency of a particular engine operating on an ideal cycle is 30%. Determine (a)
the heat supplied per 1200W-hr of work developed, (b) the ratio of heat supplied to heat rejected,
and (c) the ratio of work developed to heat rejected.
A.
B.
C.
2. Consider a Carnot cycle executed in a closed system with 0.003 kg. of air. The temperature limits
are 300 and 900 K, and the minimum and maximum pressures that occur during the cycle are 20
and 2000 kPaa. Assuming constant specific heats, determine the net work output per cycle.
PRESSURE AT STATE 2
( )
( )
(
)
ENTROPY CHANGE DURING PROCESS 1-2
( )
(
HEAT DURING ISOTHERMAL PROCESS 1-2
THERMAL EFFICIENCY
WORK OUTPUT PER CYCLE
( )
)
(
)
3. Consider a Carnot cycle executed in a closed system with air as the working fluid. The maximum
pressure in the cycle is 800 kPa while the maximum temperature is 750 K. If the entropy increase
during isothermal heat rejection process is 0.25 KJ/kg.K and the net work output is 100 kJ/kg,
determine (a) the minimum pressure in the cycle, (b) the heat rejection from the cycle, and (c) the
thermal efficiency of the cycle. (d) If an actual heat engine cycle operates between the same
temperature limits and produces 5200 kW of power for the air flow rate of 90 kg/s, determine the
second law efficiency of the cycle.
GIVEN:
CONSTANT SPECIFIC HEATS
A. MINIMUM PRESSURE
( )
( )
(
(
)
( )
(
)
)
B. HEAT REJECTION
C. THERMAL EFFICIENCY
D. SECOND LAW OF EFFICIENCY
̇
4. Show that the thermal efficiency of the Carnot cycle in terms of the isentropic compression ratio
(ratio of the volume before and after compression during isothermal process)
is given by
.
( )
(
)
5. Assume 2 lb of nitrogen actuate a Stirling cycle between the temperature limits of 240 and 160 for cryogenic use. If the maximum pressure in the cycle is 200 psia and the isothermal
compression ratio is, determine (a)
(b)
(c)
(d)
and (f)
or MEP (Mean Effective
Pressure)
GIVEN:
A.
( )
(
)
(
)
B.
( )
(
)
(
)
C.
( )
( )
D.
(
(
)
)
E.
(
(
)
)