1. Which is the most common type of Evaporator?
a) Flooded Evaporator
b) Plate Evaporator
c) Coil Evaporator
d) Brine Evaporator
Explanation: The most common type is a coil winding on a plate & so the name ‘plate evaporator’
2. In Rankine Cycle, water is converted to saturated liquid in ___________
a) Evaporator
b) Economizer
c) Superheater
d) Preheater
Explanation: The saturation of water occurs in an Economizer in a Rankine Cycle
3. If Evaporator & Condenser pressures are p & q, the intercooler pressure P is given as?
a) P = pq
b) P = p/q
c) P = (pq)(1/2)
d) P = p2q
Explanation: The relation between Intercooler pressure, Evaporator & Condenser is,
P = (pq)(1/2).
4. Phase change at constant pressure takes place in _____________
a) Economiser
b) Evaporator
c) Superheater
d) Air-Preheater
Explanation: Superheater undergoes a change in phase at constant pressure.
5. Which of these factors don’t cause Internal Irreversibility of a Rankine cycle?
a) Throttling
b) Mixing
c) Fluid Friction
d) Fluid flow
Explanation: The Rankine cycle is an Irreversible cycle. For a cycle to be irreversible naturally throttling, mixing & friction in fluids are the factors that cause this Irreversibility.
6. A gas turbine works on __________
a) Carnot cycle
b) Brayton cycle
c) Dual cycle
d) Rankine cycle
Explanation: A gas turbine works on 2 isentropic and 2 isobaric processes which is nothing else but Brayton cycle.
7. What is the range of Thermal efficiency in the Brayton cycle?
a) 30-35%
b) 40-45%
c) 50-55%
d) 50-60%
Explanation: Efficiency of Brayton cycle in actual working condition is found to be between 35 to 45%
8. What is the maximum possible TIT(Turbine Inlet Temperature)?
a) 1000 K
b) 1500 K
c) 950 K
d) 1300 K
Explanation: The maximum temperature is limited by metallurgical conditions.
9. A simple Brayton cycle uses Helium as the working fluid, has a maximum temperature of 1000 K, and a pressure ratio of 4. At the start of the compression, the Helium pressure and temperature are 50 kPa and 250 K. Based upon cold-air standard analysis assumptions, the thermal efficiency of the cycle is?
a) 0.13
b) 0.23
c) 0.43
d) 0.53
Explanation: Using the pressure ratio = 1 – rp(1 – k) / k.
10. A simple Brayton cycle has a pressure ratio of 5 and a maximum temperature of 900 K. Air enters the compressor at 100 kPa, 300 K. Based upon cold-air standard analysis assumptions, the back-work ratio of this cycle is?
a) 0.23
b) 0.53
c) 0.48
d) 0.36
Explanation: Using the pressure ratio and isentropic process relations, T2 = T1rp(k – 1) / k = 475 K and T4 = T3rp(1 – k) / k = 568 K. Application of the first law to the compressor and turbine processes and substituting the results into the back-work ratio definition produces rb = (T2 -T1) / (T3 -T4) = 0.53