1. Pumps & tURBINES ME 170: Fundamentals of Mechanical Engineering
Bangladesh University of Engineering and Technology (BUET)
ME 170: Fundamentals of Mechanical Engineering
(Model Lab)
Lecture 4
Pumps & tURBINES
Md. Muntasir Alam
Lecturer
Department of Mechanical Engineering,
BUET, Dhaka-1000
address: ,
Md. Muntasir Alam (BUET)

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Hydraulic Energy
Hydraulic energy is what is produced by the water which is stored in reservoirs and lakes at a high altitude (so that it has gravitational potential energy). If at a given moment it falls to a lower level, this energy is transformed into kinetic energy and afterwards into electrical energy in the hydroelectric plant.
Kinetic Energy
Pressure Energy
Potential Energy

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Turbo Machinery
Turbo machines are dynamic fluid machines that either extract energy from a fluid (as in turbines) or add energy to fluid (as in pumps) as a result of dynamic interactions between the device and fluid.

4. Classification of Turbo Machines
Bangladesh University of Engineering and Technology (BUET)
Classification of Turbo Machines

5. Based on energy addition/extraction:
Bangladesh University of Engineering and Technology (BUET)
Classification of Turbo Machines
Based on energy addition/extraction:
1. Absorb energy to increase fluid pressure e.g. pumps, fans, compressors
2. Producing energy by expanding flow to lower pressures. e.g. turbines
Turbine
Pump
Compressor

6. Classification of Turbo Machines
Bangladesh University of Engineering and Technology (BUET)
Classification of Turbo Machines
Based on direction of fluid flow:
1. Axial Flow: E.g. Kaplan Turbine 2. Radial Flow: E.g. Francis turbine old version 3. Mixed Flow: E.g. Francis Turbine

7. Based on type of fluid handled: 1. Incompressible fluid: E.g. Pumps
Bangladesh University of Engineering and Technology (BUET)
Classification of Turbo Machines
Based on type of fluid handled:
1. Incompressible fluid: E.g. Pumps
2. Compressible fluid: E.g. Compressors
Based on no. of stages:
1. Single stage – single row of blades/impellers
2. Multi stage – multiple row of blades/impellers

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Pumps

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Pumps
It is a mechanical device which transfers energy from an external source to the liquid flowing through a conduit.
MECHANICAL ENERGY  HYDRAULIC ENERGY

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Pump Classification

11. Positive Displacement Pumps
Bangladesh University of Engineering and Technology (BUET)
Positive Displacement Pumps
A Positive Displacement Pump makes a fluid move by trapping a fixed amount and forcing (displacing) that trapped volume into the discharge pipe. The volume is constant through each cycle of operation.
Rotary type: Gear, screw, lobe, vane pumps
Reciprocating type: Piston, plunger, diaphragm pumps

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Reciprocating Pump
A Reciprocating pump is a positive displacement pump which is driven by power from an external source and consists of a cylinder in which a piston is moved forwards and backwards. The movement of the piston creates alternately a vacuum pressure and positive pressure by means of which the water is raised.

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Gear Pump
A Gear Pump uses the meshing of gears to pump fluid by displacement. Gear pumps are widely used for hydraulic fluid power applications and in chemical installations to pump high viscosity fluids. As the gears rotate they separate on the intake side of the pump, creating a void and suction which is filled by fluid. The fluid is carried by the gears to the discharge side of the pump, where the meshing of the gears displaces the fluid.
External Gear Pump
Internal Gear Pump

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Lobe Pump
Lobe Pumps are used in a variety of industries including pulp and paper, chemical, food, beverage, pharmaceutical and biotechnology. Lobe pumps are similar to external gear pumps in operation in that fluid flows around the interior of the casing. Unlike external gear pumps, the lobes do not make contact. Lobe contact is prevented by external timing gears located in the gearbox.

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Centrifugal Pump
A Centrifugal Pump is a machine which converts mechanical energy into kinetic and pressure energy through centrifugal force.
A centrifugal pump consists of two main parts:
a rotating element, including an impeller and a shaft.
a stationary element made up of a casing, stuffing box and bearings.
Impellers

16. Centrifugal Pump–Why Priming?
Bangladesh University of Engineering and Technology (BUET)
Centrifugal Pump–Why Priming?
Total head, H = Suction head, hs + Delivery head, hd
Priming is done in pumps to remove any air present in the suction side. For removing air water is filled in suction pipe, casing and into a portion of delivery pipe. As the head developed by the pump is directly proportional to the density of fluid to be handled, so with the presence of air it is not possible to create pressure. So, if impeller runs in air, very low pressure will be developed due to low density of air. As a result, no liquid will be lifted by the pump.

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Turbines

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Turbine
A Turbine is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work.
has at least one set of moving blades attached to a shaft called the rotor assembly.

19. Turbine Classification
Bangladesh University of Engineering and Technology (BUET)
Turbine Classification

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Impulse Turbine
An Impulse turbine is a turbine which is driven by the impulse of water. In case of an impulse turbine water from the dam flows through a pipeline. After passing a guide mechanism it comes out through a nozzle. All the energy of water is converted into kinetic energy. Water in the form of a jet from nozzle impinges on the buckets fixed to the outer periphery of a running wheel. After coming out of buckets water flows with a low velocity. The pressure of water both at entering and leaving the buckets is atmospheric.

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Reaction Turbine
A Reaction turbine is a turbine into which water enters with high pressure and flows over curved blades. A part of pressure head is converted into kinetic energy and the remaining part remains as pressure head. The reaction pressure is responsible for the motion of the runner. The difference of pressure between inlet and outlet point is known as reaction pressure. The entire water passage remains totally enclosed.

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Pelton Wheel

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Pelton Wheel

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Pelton Wheel
Nozzles direct forceful, high- speed streams of water against a rotary series of spoon-shaped buckets mounted on the rim of a wheel. The water jet's momentum is transferred to the wheel and thence to a turbine. Thus, impulse energy does work on the turbine. Used for high head, low flow rate.

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Francis Turbine

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Francis Turbine
Francis turbine is an inward flow reaction turbine where the water under the pressure enters the runner from the guide vanes towards the centre in radial direction and discharges out of the runner axially. This turbine is used for medium head and medium flow rates.

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Kaplan Turbine

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Kaplan Turbine
Kaplan turbine is an evolution of the Francis turbine. It is a propeller type water turbine which has adjustable blades. Since the radial distance from the axis at the inlet and outlet is same, the peripheral velocity is constant. This turbine is used for low heads and high flow rates.

29. Hydroelectric Power Plant
Bangladesh University of Engineering and Technology (BUET)
Hydroelectric Power Plant

30. Hydroelectric Power Plant
Bangladesh University of Engineering and Technology (BUET)
Hydroelectric Power Plant

31. Hydroelectric Power Plant- Components
Bangladesh University of Engineering and Technology (BUET)
Hydroelectric Power Plant- Components
Headpond: a channel which leads water to the turbine.
Reservoir: The place behind the dam where water is stored.
Intake: The gates built on the inside of the dam. Water from reservoir is released and controlled through these gates.
Dam: Dam develops a reservoir of the desired capacity and builds up a head for power generation.
Penstock: carries the water flowing from reservoirs towards the power generation unit.
Draft Tube: allows the turbine to be set above tailrace.
Tailrace: a channel which carries water from the turbine.

32. Generation capacity = 230MW Reservoir size = 777 sq. km
Bangladesh University of Engineering and Technology (BUET)
Karnafuli Hydroelectric Power Plant
Generation capacity = 230MW
Reservoir size = 777 sq. km

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Gas Turbine
A Gas turbine is a type of internal combustion engine. It has an upstream rotating compressor coupled to a downstream turbine, and a combustion chamber in between.

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Turbojet
Turbojet is an airbreathing jet engine, usually used in aircraft.
Consists of a gas turbine with a propelling nozzle.
Compressed air from the compressor is heated by the fuel in the combustion chamber and then allowed to expand through the turbine.
Turbine exhaust is then expanded in the propelling nozzle where it is accelerated to high speed to provide thrust.

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Turbojet

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Turbofan
Turbofan is an airbreathing jet engine, widely used in aircraft propulsion.
Turbo portion refers to a gas turbine engine which achieves mechanical energy from combustion.
A ducted fan uses the mechanical energy from the gas turbine to accelerate air rearwards.
In turbofan, some of the air bypasses the turbine.
A turbofan can be thought of as a turbojet being used to drive a ducted fan, with both of those contributing to the thrust.

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Turbofan

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Turboprop
Turboprop engine is a turbine engine that drives an aircraft propeller.
In contrast to a turbojet, the engine’s exhaust gases do not contain enough energy to create significant thrust, since almost all of the engine’s power is used to drive the propeller.
The propeller is coupled to the turbine thorough a reduction gear that converts the high RPM, low torque output to low RPM, high torque.

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Turboprop

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Turboprop
Airbus Military Cargo Aircraft

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Turboprop
Airbus Military Cargo Aircraft

42. End of Model Lab!!!!!!!!!!! Thanks a Lot!!!!!
Bangladesh University of Engineering and Technology (BUET)
End of Model Lab!!!!!!!!!!! Thanks a Lot!!!!!
Best of Luck for everyone!!!!!!!!
Remember
- The Shawshank Redemption (1994)