০১। 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
ক) 4.4 KPa
খ) 2.94 KPa
গ) 3.7 KPa
ঘ) none of these
০২। A 2" gate valve fitted in a pipe is replaced by a similar globe valve. Pressure drop in gate valve was Δp. For the same discharge, the pressure drop across globe valve is
ক) Δp
খ) < Δp
গ) > Δp
ঘ) Δp2
০৩। A bed consists of particles of density 2000 kg/m3. If the height of the bed is 1.5 metres and its porosity 0.6, the pressure drop required to fluidise the bed by air is
ক) 25.61 kPa
খ) 11.77 kPa
গ) 14.86 kPa
ঘ) 21.13 kPa
০৪। A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun's equation for the above fluid-particle system (in SI units) is given below : Δ P/L = 375 x 103 VOM + 10.94 x 106 V2OM (SI units) If water is to be used as the fluidising medium, in actual operation, the above bed has a height = 1 m. What is the porosity of the fluidised bed ?
ক) 0.2
খ) 0.5
গ) 0.7
ঘ) 0.8
০৫। A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun's equation for the above fluid-particle system (in SI units) is given below : Δ P/L = 375 x 103 VOM + 10.94 x 106 V2OM (SI units) If water is to be used as the fluidising medium, the minimum fluidisation velocity, VOM is
ক) 12 mm/s
খ) 16 mm/s
গ) 24 mm/s
ঘ) 28 mm/s
০৬। A Bingham fluid of viscosity μ = 10 Pa.s and yield stress, τ0 = 10 KPa, is shared between flat parallel plates separated by a distance of 10-3 m. The top plate is moving with a velocity of 1 m/s. The shear stress on the plate is
ক) 10 KPa
খ) 20 KPa
গ) 30 KPa
ঘ) 40 KPa
০৭। A centrifugal pump designed for handling water (μ = 1 cp) will deliver __________ when pumping a thicker oil (μ = 30 cp).
ক) less head & capacity
খ) more head
গ) more capacity
ঘ) less head & more capacity
০৮। A centrifugal pump designed to pump water is employed to pump a more viscous oil. In the later case, the pump
ক) develops a lower head.
খ) capacity is reduced.
গ) requires more power.
ঘ) all (a), (b) and (c).
০৯। 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 new discharge will be __________ litres/minute.
ক) 500
খ) 200
গ) 1000
ঘ) 750
১০। 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.
ক) 0.5
খ) 2
গ) 4
ঘ) 1
১১। 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, then the new head will be __________ metres.
ক) 2
খ) 4
গ) 8
ঘ) 5.5
১২। A centrifugal pump is called a turbine pump, if it is having a
ক) turbine type impeller.
খ) vaned diffusion casing.
গ) rotating vaned volute.
ঘ) none of these.
১৩। A centrifugal pump is used to pump water through a horizontal distance of 150 m, and then raised to an overhead tank 10 m above. The pipe is smooth with an I.D of 50 mm. What head (m of water) must the pump generate at its exit (E) to deliver water at a flow rate of 0.001 m3/s? The Fanning friction factor, f is 0.0062.
ক) 10 m
খ) 11 m
গ) 12 m
ঘ) 20 m
১৪। A centrifugal pump loses prime after starting. The reason of this trouble may be
ক) incomplete priming.
খ) too high a suction lift.
গ) low available NPSH and air leaks in the suction pipe.
ঘ) all (a), (b), and (c).
১৫। A centrifugal pump used to pump water is used to pump an oil with specific gravity of 0.8 at the same rate. The power consumption will now
ক) increase
খ) decrease
গ) remain same
ঘ) data insufficient to predict
১৬। A compressor that takes suction at a pressure below atmospheric and discharge against atmospheric pressure is called a __________ pump.
ক) sump
খ) volute
গ) vacuum
ঘ) submerged
১৭। A conical tank with a bottom opening of cross-sectional area A is filled with water and is mounted on supports as shown in the figure. What is the force F with which plate X must be pushed up to prevent water from leaking ? Assume that the density of air is negligible as compared to the density of water ρL.
ক) ρL . Vg
খ) ρL . A.Hg
গ) ρL . Vg/2
ঘ) ρL .Vg/3
১৮। A differential pressure cell is used for
ক) measuring small pressure difference in gases.
খ) measuring small pressure difference in liquids.
গ) remote recording of pressure difference.
ঘ) measuring the difference of the impact & the static pressure.
১৯। A double acting reciprocating pump compared to a single acting pump (of almost same size working under same pressure levels) would give almost double
