1. What does a nozzle do?
a) decreases the velocity of a fluid at the cost of its pressure gain
b) increases the velocity of a fluid at the cost of its pressure drop
c) increases the velocity of a fluid and also its pressure
d) none of the mentioned
Explanation: A nozzle increases KE of fluid and reduces its pressure
2. What does a diffuser do?
a) increases the pressure of the fluid at the expense of its KE
b) decreases the pressure of the fluid and also increases its KE
c) increases the pressure of the fluid and also its KE
d) decreases the pressure of the fluid and also its KE
Explanation: A diffuser increases the pressure at the expense of its KE.
3. For an insulated nozzle, SFEE of the control surface gives ( considering change in PE is zero and inlet velocity is small compared to exit velocity)
a) V2=sqrt(4*Δh)
b) V2=sqrt(Δh)
c) V2=sqrt(Δh/2)
d) V2=sqrt(2*Δh)
Explanation: dQ/dm=0, dW/dm=0, Δh=h1-h2.
4. Fluid flow through which of the following throttles the flow
a) partially opened valve
b) orifice
c) porous plug
d) all of the mentioned
Explanation: In all of the given cases, there is an appreciable drop in pressure and hence the flow is throttled.
5. In a throttling device, what do we get as SFEE when changes in PE and KE are taken zero?
a) dQ/dm≠0
b) dW/dm≠0
c) h1=h2
d) none of the mentioned
Explanation: Enthalpy of the fluid before throttling is equal to the enthalpy of the fluid after throttling.
6. Turbines and engines ____ positive power output, and compressors and pumps ____ power input.
a) require, give
b) give, require
c) give, give
d) require, require
Explanation: This is the basic information about turbines, engines, compressors and pumps.
7. For a turbine, it is seen that work is done by the fluid at the expense of its enthalpy.
a) true
b) false
Explanation: For a turbine, W/m=h1-h2.
8. For an adiabatic compressor or pump,
a) the enthalpy of fluid remains constant with the amount of work input
b) the enthalpy of fluid decreases by the amount of work input
c) the enthalpy of fluid increases by the amount of work input
d) none of the mentioned
Explanation: For an adiabatic pump or compressor, W/m=h2-h1.
9. A heat exchanger is a device in which heat is transferred from one fluid to another.
a) true
b) false
Explanation: Basic fact about heat exchanger
10. For an inviscid frictionless fluid flowing through a pipe, Euler equation is given by
a) Vdp+VdV+gdZ=0
b) Vdp-VdV+gdZ=0
c) Vdp-VdV-gdZ=0
d) none of the mentioned
Explanation: Euler equation is derived from steady flow energy equation.