The pressure and power requirement of a gas fan at constant speed & capacity varies ____________ the gas density?

Related Mcqs:

1. Power requirement of fans having constant wheel diameter varies _____________ fan speed?

   A. As square of
   B. Directly as
   C. As cube of
   D. None of these

2. For a specific centrifugal air blower operating at constant speed & capacity, the power requirement and pressure vary_______________?

   A. Directly as square of gas density
   B. Directly as gas density
   C. Directly as square root of gas density
   D. Inversely as gas density

3. In case of centrifugal fan or blower, the gas capacity varies as __________________?

   A. Speed
   B. (Speed)2
   C. (Speed)3
   D. (Speed)0.5

4. A gas (density = 1.5 kg/m3, viscosity = 2 × 10‒5 kg/m.s) flowing through a packed bed (particle size = 0.5 cm, porosity = 0.5) at a superficial velocity of 2 m/s causes a pressure drop of 8400 Pa/m. The pressure drop for another gas, with density of 1.5 kg/m3and viscosity of 3 × 10‒5kg/m.s flowing at 3 m/s will be________________?

   A. 8400 Pa/m
   B. 12600 Pa/m
   C. 18900 Pa/m
   D. 16800 Pa/m

5. Consider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a liquid of constant density at a particular discharge capacity. With decrease in the capacity of the pump, the _______________ decreases?

   A. NPSH required
   B. BHP required by the pump
   C. Head of the liquid pumped
   D. All A., B. and C.

6. The fluid velocity varies as the cube of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop for ____________ fluid?

   A. Newtonian
   B. Pseudo-plastic
   C. Dilatent
   D. Bingham plastic

7. A 0.5 m high bed made up of a 1 mm dia glass sphere (density 2500 kg/m3 ) is to be fluidised by water (density 1000 kg/m3 ). If at the point of incipient fluidisation, the bed voidage is 40%, the pressure drop across the bed is________________?

   A. 4.4 KPa
   B. 2.94 KPa
   C. 3.7 KPa
   D. None of these

8. The speed of sound in an ideal gas varies as the __________________?

   A. Temperature
   B. Pressure
   C. Density
   D. None of these

9. A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, the power consumed now will be _____________ hp?

   A. 0.5
   B. 2
   C. 4
   D. 1

10. The fluid velocity varies as the square of the cylindrical pipe diameter, in case of steady state laminar flow at constant pressure drop, for ______________ fluid?

    A. Newtonian
    B. Dilatant
    C. Pseudo-plastic

    D. Non-Newtonian