Motilal Nahru National Institute of TechnologyApplied Mechanics Department

(2015-2017)

Different types of pumps used for slurry transportation in Multiphase flow

SUBMITTED BY: ABHISHEK SHRIVASTAVA

Centrifugal pump

AXIAL FLOW SLURRY PUMP• They operate at much lower pressures and higher flow rates than centrifugal pumps.• An axial flow pump has a propeller-type of impeller running in a casing. The pressure in an AFP is developed by the flow of liquid over the blades of impeller. The fluid is pushed in a direction parallel to the shaft of the impeller. It allows the fluid to enter the impeller axially and discharge the fluid nearly axially. The propeller of an AFP is driven by a motor.

Advantages• Relatively high discharge (flow rate) at a relative low head.• Easily be adjusted to run at peak efficiency at low-flow/high-pressure and high-flow/low-pressure by changing the pitch on the propeller.• Lower aerodynamic losses and higher stage efficiencies. Applications

• Handling sewage from commercial, municipal and industrial sources.

• In power plants, they are used for pumping water the refrigeration line. In the chemical industry.

Mixed-flow pumps• Mixed-flow pumps function as a compromise between radial and axial-flow pumps. The fluid experiences both radial acceleration and lift and exits the impeller somewhere between 0 and 90 degrees from the axial direction.

• Mixed-flow pumps operate at higher pressures than axial-flow pumps while delivering higher discharges than radial-flow pumps.

• The exit angle of the flow dictates the pressure head-discharge characteristic in relation to radial and mixed-flow.

Application:Waterworks, water supply, and irrigation

Co-Rotated Disk Pump• Disc pump operate on the principle of Boundary layer and viscous drag.

• The boundary layer next to disc surface is stationary relative to discs. As disc rotates, energy is transferred to successive layers of molecule of fluids due to viscous drag which results in velocity and pressure gradients between fluid layers.

• The force that is created by the combination of boundary layer and viscous drag propels the fluid from the pump in the smooth, pulsation free flow.

• The heavier particles are slowly accelerated hence flow in centre of discs hence do not impinges on discs.

Application◦ Used to carry fluids of viscosity of several 100,000c.p.◦ Pumping efficiency increases as viscosity increases.

Archimedes' screw Archimedes' screw consists of a screw (a helical surface surrounding a central cylindrical shaft) inside a hollow pipe.

As the shaft turns, the bottom end scoops up a volume of water. This water is then pushed up the tube by the rotating helicoid until finally it pours out from the top of the tube

Uses◦ transferring water to irrigation ditches◦ draining land that was underneath the sea◦ creation of polders.◦ used in chocolate fountains

Plunger Piston pump

• A plunger pump is a type of positive displacement pump where the high-pressure seal is stationary and a smooth cylindrical plunger slides through the seal. This makes them different from piston pumps and allows them to be used at higher pressures.

• They can deliver high pump pressures and

• Only handles lower flow rates, Pulsating flow.

• Heavy and bulky.

• An axial piston pump has a number of pistons (usually an odd number) arranged in a circular array within a cylinder block. This cylinder block rotates about its axis of symmetry by an integral shaft that is aligned with the pumping pistons.

• One end of the cylinder block is convex and wears against a mating surface on a stationary valve plate. The valve plate has two semi-circular ports that allow inlet of the operating fluid and exhaust of the outlet fluid. The pumping pistons protrude from the opposite end of the cylinder block. The cam is movable, the orientation of which, in combination with shaft rotation, provides the cam action that leads to piston reciprocation and thus pumping.

Axial Piston Pump

Hydraulic ram pumps• A hydraulic ram is a water pump powered by hydropower.

• It takes in water at relatively low pressure and high flow-rate and outputs water at a higher hydraulic-head and lower flow-rate. The device uses the water hammer effect to develop pressure that lifts a portion of the input water.

• Used in a source of low-head hydropower, and a need for pumping water to a destination higher in elevation than the source. The ram is often useful since it requires no outside source of power other than the kinetic energy of flowing water.

• Initially, the waste valve [4] is open, and the delivery valve [5] is closed. The water in the inlet pipe [1] starts to flow under the force of gravity and picks up speed and kinetic energy until the increasing drag force closes the waste valve. The momentum of the water flow in the inlet pipe against the now closed waste valve causes a water hammer that raises the pressure in the pump, opens the delivery valve [5], and forces some water to flow into the delivery pipe [3].

Air Operated Double Diaphragm Pump

It is a Positive displacement pump that uses a combination of the reciprocating action of a teflon diaphragm and suitable valves on either side of the diaphragm to pump.

Diaphragm pump characteristics:• Have good suction lift characteristics, some are low pressure pumps with low flow rates; others are capable of higher flow rates, dependent on the effective working diameter of the diaphragm and its stroke length. They can handle sludges and slurries with a relatively high amount of grit and solid content.• Suitable for discharge pressure up to 1,200 bar• Have good dry running characteristics.• Can be used to make artificial hearts.• Can be up to 97% efficient.• Have good self priming capabilities.

• A double-acting piston-diaphragm pump with a hose as the diaphragm.

• This hose is compressed by a hydraulic liquid which also restores its original shape.

• While the hose is compressed, the slurry inside is displaced and flows out. Ball valves on the top and bottom of the hose ensure that the flow is in one direction only.

Piston-Diaphragm Pump

Double Disc Pump• Double Disc Pump combine the performance features of a positive displacement pump and the principle of “Induced Flow” to provide superior versatility in fluids handling.

• Based on a “Free-Diaphragm” technology, the pump utilize a unique principle of operation where the discsperform the duties of both diaphragm and valve,providing a double acting, non clogging, pumpingaction.

Progressive cavity pump• It moves fluid by means of rotor turning within stationary stator. It transfers fluid by means of the progress, through the pump, of a sequence of small, fixed shape, discrete cavities, as its rotor is turned. The flow rate is proportional to the rotation rate of the pump.

• This action squeezes material out of the end of the pump.

• These are frequently used to pump sludge. It is used to meter large volumes of chemicals in a precise manner.

Orbital lobe pumps• Orbital lobe pump displaces the liquid trapped between two long helical rotors, each fitted into the other when perpendicular at 90°, rotating inside a triangular shaped sealing line configuration, both at the point of suction and at the point of discharge.

• This design produces a continuous flow with equal volume and no vortex. It can work at low pulsation rates, and offers gentle performance that some applications require.

Applications include:

• High capacity industrial air compressors.

• Used in Internal Combustion Engine as Supercharger.

Flexible impeller• A flexible impeller pump is a positive-displacement pump that, by deforming impeller vanes, draws the liquid into the pump housing and moves it to the discharge port with a constant flow rate.

• The flexibility of the vanes enables a tight seal to the internal housing, making the pump self-priming, while also permitting bi-directional operation.

• The output from these pumps tends to be smooth or gentle when compared to the operation of a reciprocating pump

Particularly suitable for transfer of viscous, delicate, and slurry fluids even with high solid content. Widely used in the oenological field, food processing, chemical industry, cosmetic and marine field

Gear pump• This is the simplest of rotary positive displacement pumps.

• It consists of two meshed gears that rotate in a closely fitted casing.

• The tooth spaces trap fluid and force it around the outer periphery. The fluid does not travel back on the meshed part, because the teeth mesh closely in the center.

• Gear pumps see wide use in car engine oil pumps and in various hydraulic power packs.

Peristaltic pump• The fluid is contained within a flexible tube fitted inside a circular pump casing (though linear peristaltic pumps have been made).

• A rotor with a number of "rollers", "shoes", "wipers", or "lobes" attached to the external circumference of the rotor compresses the flexible tube.

• As the rotor turns, the part of the tube under compression is pinched closed thus forcing the fluid to be pumped to move through the tube.

• Used in heart-lung machines to circulate blood during a bypass surgery

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