Steam and Gas Turbines Inteview Questions and Answers for freshers on “Nozzle Discharge Coefficients and Calculations”.
1. Coefficient of discharge is the __________ of Actual discharge to the theoretical discharge.
a) ratio
b) product
c) sum
d) none
Answer: a
Clarification: Discharge coefficient is the ratio of actual discharge to the theoretical discharge.
2. Coefficient of discharge is used to measure ___________
a) none of the mentioned
b) pressure exerted by the nozzle on the fluid
c) flow rate allowed by the nozzle
d) resistance offered by the nozzle
Answer: d
Clarification: Coefficient of discharge is used to measure the inaccountable losses of the fluid passing through the nozzle. It is used to measure the resistance exerted by the nozzle.
3. Unit of flow resistance is _________
a) N/m2
b) m2/N
c) KN/Kg
d) No unit
Answer: d
Clarification: Flow resistance is a unit less parameter.
4. Coefficient of discharge is the ____________
a) product of coefficient of velocity and coefficient of contraction
b) arithmetic sum of coefficient of velocity and coefficient of contraction
c) ratio of coefficient of velocity and coefficient of contraction
d) none of the mentioned
Answer: a
Clarification: Cd = Cc*Cv
Where
Cd = Coefficient of discharge
Cc = Coefficient of contraction
Cv = Coefficient of velocity.
5. Coefficient of discharge is _____________
a) directly proportional to coefficient of discharge
b) inversely proportional to square of the coefficient of discharge
c) inversely proportional to coefficient of discharge
d) directly proportional to square of coefficient of discharge
Answer: b
Clarification: Coefficient of resistance is denoted by K and coefficient of discharge is denoted by Cd. Where
K = 1 /Cd2.
6. For sharp edge orifice, coefficient of discharge lies between ___________
a) 0.61 – 0.64
b) 0.87 – 0.89
c) 0.50 – 0.61
d) none of the mentioned
Answer: a
Clarification: For sharp edges coefficient of discharge lies between 0.61 – 0.64.
7. Coefficient of discharge (Cd) can be written as Cd=1/K(0.5).
a) True
b) False
Answer: a
Clarification: Coefficient of discharge is inversely proportional to square root of K.
8. In the equation Cd=1/K(0.5) what does K mean ?
a) Pressure drop inside the nozzle
b) Mass flow rate
c) Flow resistance
d) None of the mentioned
Answer: c
Clarification: Coefficient of discharge is inversely proportional to square root of flow resistance.
9. Coefficient of discharge is inversely proportional to square root of _______
a) flow resistance
b) pressure drop inside the nozzle
c) none the mentioned
d) flow resistance & pressure drop inside the nozzle
Answer: d
Clarification: Coefficient of discharge can also be written as Cd = m/(density*(pressure drop)*Area)(0.5) or else Cd = 1/K(0.5).
10. Coefficient of discharge is directly proportional to mass flow rate.
a) True
b) False
Answer: a
Clarification: When mass flow rate increases coefficient of discharge increases.
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