Derive an expression for the minimum speed for starting a centrifugal pump.
What is priming? Why it is necessary?
A three stage centrifugal pump has impellers 40 cm40 \text{ cm}40 cm in diameter and 2 cm2 \text{ cm}2 cm wide at outlet. The vanes are curved back at the outlet at 45∘45^\circ45∘ and reduce the circumferential area by 10%10%10%. The manometric efficiency is 90%90%90% and the overall efficiency is 80%80%80%. Determine the head generated by the pump when running at 1000 rpm1000 \text{ rpm}1000 rpm, delivering 50 liters per second50 \text{ liters per second}50 liters per second. What should be the shaft power?
Explain the working principle of air lift pump with neat sketch.
Write short notes on Hydraulic accumulator and hydraulic Intensifier.
Find the number of pumps required to take water from a deep well under a total head of 156 m156 \text{ m}156 m. Also the pumps are identical and are running 1000 rpm1000 \text{ rpm}1000 rpm. The specific speed of each pump is given as 202020 while the rated capacity of each pump is 150 liters/s150 \text{ liters/s}150 liters/s.
Explain the effects of blade profile on the working of a centrifugal compressor.
What are the methods adopted to increase the efficiency of the centrifugal pump by altering the shape of the casing of chamber surrounding the impeller? Briefly explain with neat sketches.
A three-stages centrifugal pump has impeller 40 cm in diameter and 2 cm wide. If the blade angle at outlet is 45∘45^\circ45∘ and the area occupied by the thickness of the vanes may be assumed 8% of the outlet area. If the pump delivers 3.6 m3/min3.6 \text{ m}^3/\text{min}3.6 m3/min when running at 920 rpm, determine (i) power of the pump, and (ii) Manometric head.
Starting from the Euler equation, show that the manometric efficiency of a centrifugal pump is a function of tangential velocity, flow velocity and the vane angle at the out let of the impeller.
Discuss with the help of neat sketch, different heads and main components of a centrifugal pump.
Water is transported from tank A to a tank B by a pump. The dimensions of the system are show in Fig. Q.8(c). The total length of the suction pipe and the delivery pipe are 30 m and 20 m, respectively. The total head losses in the suction pipe and the delivery pipe are 1 m and 2 m, respectively. Determine the water power of the pump needs to deliver if the flow rate is 40 liters/sec. Neglect the velocity head.
What is cavitation in pump? What are its consequences? How can cavitation be avoided?
Show that the maximum acceleration head in a reciprocating pump, without air vessel is given by the relation Ha=(lg)×(Aa)×w2rH_a = \left( \frac{l}{g} \right) \times \left( \frac{A}{a} \right) \times w^2 rHa=(gl)×(aA)×w2r, where, l=length of pipe, A/a=ratio of cylinder area to pipe area and w=angular velocity of crankshaftl = \text{length of pipe, } A/a = \text{ratio of cylinder area to pipe area and } w = \text{angular velocity of crankshaft}l=length of pipe, A/a=ratio of cylinder area to pipe area and w=angular velocity of crankshaft.
A double acting reciprocating pump has a bore of 175 mm175\text{ mm}175 mm and a stroke of 350 mm350\text{ mm}350 mm. The suction pipe has a diameter of 150 mm150\text{ mm}150 mm and is fitted with an air vessel. Determine the crank angle, at which there is no flow of water to or from the vessel. Assume crank speed at 150 rpm150\text{ rpm}150 rpm and plunger has simple harmonic motion.
Explain why priming is necessary in a centrifugal pump.
Discuss the various methods adopted to increase the efficiency of a centrifugal pump by altering the shape of the casing of chamber surrounding the impeller.
A centrifugal pump delivers 30 liters30\text{ liters}30 liters of water per second against a head of 12 m12\text{ m}12 m and running at 1500 rpm1500\text{ rpm}1500 rpm requires 6 horse power6\text{ horse power}6 horse power. Determine the discharge, head of the pump and power required if the pump runs at 1800 rpm1800\text{ rpm}1800 rpm.
Discuss the basic working principle of hydraulic press with neat sketches. A hydraulic press has a ram of 500 mm500\text{ mm}500 mm and a plunger of 50 mm50\text{ mm}50 mm diameter. What force is required on the handle to lift a load of 20 kN20\text{ kN}20 kN, if the leverage is 1:101:101:10?
It is required to deliver 0.048 m3/s0.048\text{ m}^3\text{/s}0.048 m3/s of water to a height of 24 m24\text{ m}24 m through a 150 mm150\text{ mm}150 mm diameter pipe and 120 m120\text{ m}120 m long, by a centrifugal pump. If the overall efficiency of the pump is 75%75%75% and coefficient of friction, f=0.01f = 0.01f=0.01 for the pipe line, find the power required to drive the pump.
What is the specific speed of a centrifugal pump? Prove that the specific speed is Ns=NQH3/4N_s = \frac{N \sqrt{Q}}{H^{3/4}}Ns=H3/4NQ.
A double acting reciprocating pump has a stroke of 300 mm and a piston of diameter 150 mm. The delivery and suction heads are 26m and 4m respectively including friction heads. If the pump is working at 60 rpm, find the actual power required to drive the pump with 80% efficiency.