Steam and Gas Turbines Multiple Choice Questions on “Critical Pressure Ratio”.
1. Pressure ratios below 20 are used in _____________ engines.
a) steam turbine
b) aero derivative engines
c) heavy frame engines
d) none of the mentioned
Answer: c
Clarification: Lower pressure ratios are maintained in heavy frame engines.
2. Heavy frame engines are physically ___________
a) medium
b) large
c) small
d) none of the mentioned
Answer: b
Clarification: Heavy frame engines are physically large.
3. Aeroderivative engines have pressure ratios ___________
a) greater than 30
b) lesser than 30 and greater than 20
c) greater than 50
d) none of the mentioned
Answer: a
Clarification: Higher pressure ratios of greater than 30 are used in aeroderivative engines.
4. Aeroderivative engines are used where ____________ power units are required.
a) larger
b) smaller
c) optimum
d) none of the mentioned
Answer: b
Clarification: Aeroderivative engines are used where smaller power units are required.
5. Aeroderivative engines are larger.
a) True
b) False
Answer: b
Clarification: Aeroderivative engines are compact and smaller in size.
6. Aeroderivative engines release higher emissions.
a) True
b) False
Answer: a
Clarification: Aeroderivative engines are smaller and produce high output as a result of which they release higher emissions.
7. Gas turbines operate at pressures ________ than critical pressure ratio.
a) higher
b) lesser
c) does not depend on pressure ratio
d) none of the mentioned
Answer: b
Clarification: Gas turbines operate at pressures less than critical pressure ratio.
8. Critical pressure ratio is ratios of pressures at _________ discharge.
a) minimum
b) none of the mentioned
c) optimum
d) maximum
Answer: d
Clarification: Critical pressure ratio is the ratios of pressure at maximum discharge.
9. Ratio of critical pressure to inlet pressure in known as ___________
a) none of the mentioned
b) pressure ratio
c) critical pressure ratio
d) isoentropic pressure ratio
Answer: c
Clarification: Ratio of critical pressure to inlet pressure is called as critical pressure ratio.
10. In De Laval Nozzle critical pressure ratio is given by (2/y+1)^(y/y-1).
a) True
b) False
Answer: a
Clarification: Critical pressure ratio of De Laval nozzle is derived theoretically.