Turbines and recipocating pumps and miscellaneous hydraulic machines

Netaji Subhas University of
Technology
Dwarka New Delhi 110078
Department of Mechanical
engineering
Project on Fluid Mechanics
Under the Guidance of Mr. Manish Kumar
Prepared by Mohit Yadav ( 2019UME5555 )

Contents
Topic covered
1. Turbines
2. Centrifugal Pumps
3. Reciprocating Pumps
4. Miscellaneous Hydraulic
Machines.
Covered in pages
3-26
27-40
41-54
55-95

What is a TURBINE???
 A turbine is a rotary mechanical device that extracts energy
 from a fast moving flow of water, steam, gas, air, or other
 fluid and converts it into useful work.
 A turbine is a turbo-machine with at least one moving part
 called a rotor assembly, which is a shaft or drum with blades
 attached.
 Moving fluid acts on the blades so that they move and impart
 rotational energy to the rotor.

WORKING PRINCIPLE:
The working principle is very much simple.
 When the fluid strikes the blades of the
turbine, the blades are
 displaced, which produces rotational energy.
 When the turbine shaft is directly coupled to
an electric gene-
 -rator mechanical energy is converted into
electrical energy.
 This electrical power is known as
hydroelectric power.

Basic types of turbines
 HydraulicTurbine
 Steam Turbine
 Gas Turbine
 Wind Turbine
Although the same principles apply to all turbines, their specific
designs differ sufficiently to merit separate descriptions.

1] DEFINATION OF HYDRAULIC TURBINE
2] CLASIFICATION
3] TYPES
3.1] Pelton turbine
3.2] Kaplan turbine
3.3] Francis turbine
4] DIFFERENCE BETWEEN PELTON , KAPLAN ,
FRANCIS TURBINES.
CONTENT

INTRODUCTION
 A water turbine is a rotary
machine that converts kinetic
energy and potential energy of
water into mechanical work
 and rotates the shaft to
produce electric energy.
Basic working principle:-
Hydraulic turbine converts the
potential energy of water into
mechanical work.

CLASSIFICATION
 Based on head
 a) High head turbines
 b) Medium head turbines
 c) Low head turbines
 Based on hydraulic action of water
 a) Impulse turbines
 b) Reaction turbines
 Based on direction of flow of water in the runner
 a) Tangential flow turbines
 b) Radial flow turbines
 c) Axial flow turbines
 d) Mixed flow turbines

Three most popular turbines are
 PELTON WHEEL { PELTON TURBINE }
 KAPLAN TURBINE {PROPELLER TURBINE }
 FRANCIS TURBINE

PELTON WHEEL
 The Pelton wheel is an impulse type water
turbine. It was invented by Lester Allan Pelton
in the 1870s.
 This turbine is used for high heads.
Specifications
 Power generation is about 400MW.
 The speed rate ranges from 65 to 800rpm.
 The efficiency is about 85%.
 The runner diameters is between 0.8 t0 6.0m.
 The operational head is from 15 to 1800m.

MAIN COMPONENTS
 1] Nozzle and spear
 2] Runner and bucket
 3] Casing
 4] Breaking jet
 1] Nozzle :- It controls the amount of
water striking the vanes of runner.
 2] Casing :- It is used to prevent splashing
of water.
 3] Runner and Bucket :- It is circular disc
on the periphery on which evenly spaced
bucket are fixed.
 4] Breaking jet :- Its function is to stop the
runner in a short time period.

WORKING
1. The flow of water is tangential to the runner. So it is a tangential
flow impulse turbine.
2. The runner consists of a single wheel mounted on a horizontal shaft.
3. Water falls towards the turbine through a pipe called penstock and
flows through a nozzle.
4. The high speed jet of water hits the buckets (vanes) on the wheel and
causes the wheel to rotate.
5. A spear rod which has a spear shaped end can be moved by a hand
wheel.
6. This movement controls the flow of water leaving the nozzle before it
strikes the bucket.
7. The bucket or vane is so shaped that when the water strikes, it gets
split into two and gives it an impulse force in the center of the bucket.
This bucket is also known as splitter.

7. The bucket or vane is so shaped that when the water strikes, it
gets split into two and gives it an impulse force in the center of the
bucket. This bucket is also known as splitter.

KAPLAN TURBINE
 The Kaplan turbine is a propeller-type water
turbine which has adjustable blades. It was
developed in 1913 by Austrian professor Viktor
Kaplan.
 It is mainly used for low-head applications.
SPECIFICATIONS
 The head ranges from 10–70 metres.
 The output varies from 5 to 200 MW.
 Runner diameters are between 2 and 11 metres.
 The rotational speed rate ranges from 69.2 rpm
to 429 rpm
 It gives highest efficiency which is over 90%.

THE MAIN COMPONENTS ARE :
 1] Scroll casing
 2] Guide vanes
 3] Draft tube
 4] Runner
 5] Hub
 1] Scroll casing: It is the casing which guides the
water and control the water passage.
 2] Guide vanes : It is the vanes which guide the water
and perform same function that by scroll.
 3] Draft tube:- It discharges the water to trail race
through gradually expanding tube.
 4] Runner :- It is connected to shaft of the generator.
 5] Hub:- It part on which runner is mounted

WORKING
 The water from the penstocks
enters the scroll casing and then
moves to the guide vanes.
 From the guide vanes, the water
turns through 90° and flows
axially through the runner.
 For Kaplan Turbine, the shaft of
the turbine is vertical. The lower
end of the shaft is made larger
and is called ‘Hub’ or ‘Boss’.
 The vanes are fixed on the hub
and hence Hub acts as runner for
axial flow turbine.

FRANCIS TURBINE
 The Francis turbine is an inward-flow reaction
turbine that combines radial and axial flow
concepts.
 It was developed by James .B. Francis.
SPECIFICATION
 They operate in a water head from 40 to 600 m
(130 to 2,000 ft).
 The power generated is 800MW.
 The speed range of the turbine is from 75 to 1000
rpm.
 It give efficiency of about 90%.
 The runner diameters are between 0.91 to 10.6 m.

THE MAIN PARTS ARE:
 1] Spiral casing
 2] Guide vanes
 3] Runners
 4] Draft tube
 1] Spiral casing :- It guides the water to
the guide vanes and also control the
flow.
 2] Guide vanes :- They guide the water to
runner and get closed on increase in
flow.
 3] Runner :- They are heart of the turbine
and rotate on the impact of flow.
 4] Draft tube :- It is place from where the
water is discharged from the turbine

WORKING
 Penstock conveys water from the
upstream to the turbine runner. Spiral
Casing constitutes a closed passage
whose cross-sectional area gradually
decreases along the flow direction; area
is maximum at inlet and nearly zero at
exit.
 The vanes direct the water on to the
runner at an angle appropriate to the
design, the motion of them is given by
means of hand wheel.
 Runner Blades move due to the driving
force on the runner which is due to
impulse and reaction effect.
 Draft Tube is gradually expanding tube
which discharges water, passing through
the runner to the tail race.

INTRODUCTION
 It converts mechanical energy into hydraulic energy (pressure energy) by virtue of
centrifugal force.
 Flow is in radial outward direction.
 It works on principle of forced vortex flow.
 Common uses include water, sewage, petroleum and petrochemical pumping.
PRINCIPLE
 It works on the principle of forced vortex flow means when a certain mass of
fluid is rotated by external torque rise in pressure head takes place.
 Conversion of energy occur by virtue of two main parts of the pump:
a) Impeller b) Casing.
 Impeller converts driver energy into the kinetic energy & diffuser converts the
kinetic energy into pressure energy.

Components of centrifugal pump
 I. A rotating component comprised of an impeller and a shaft.
Impeller: The impeller is the main rotating part that provides
the centrifugal acceleration to the fluid.
Shaft: Its purpose is to transmit the torques encountered when
starting and during operation. Supports the impeller & other
rotating parts.

 II. A stationary component comprised of a casing, casing cover, and
bearings.
Casing: The main purpose of casing is to convert kinetic energy into
pressure energy.
Casings are generally of three types:
a) Volute : Used for higher head, eddy currents formed
b) Vortex : Eddy currents are reduced.
c) Circular : Used for lower head.
 Volute casing :A volute is a curved funnel increasing in area to the
discharge port. As the area of the cross-section increases, the volute
reduces the speed of the liquid and increases the pressure of the liquid.
 Vortex Casing :A circular chamber is introduced between casing and
impeller. Efficiency of pump is increased
 Circular casing :Circular casing have stationary diffusion vanes
surrounding the impeller periphery that convert velocity energy to
pressure energy.
Conventionally, the diffusers are applied to multi-stage pumps.

Priming
 It is the process of filling suction pipe, casing and delivery pipe upto
delivery valve with water. Used to remove air from these parts.
 It is of 2 types:
a) Positive Priming:-The one which speeds up processing.
b) Negative Priming:-The one which slows down the processing.

Working
 Liquid forced into impeller.
 Vanes pass kinetic energy to liquid:
liquid rotates and leaves impeller.
 Volute casing converts kinetic energy
into pressure energy.
 It consists of an IMPELLER rotating
within a casing.
 Liquid directed into the center of
the rotating impeller is picked up by
the impeller’s vanes and accelerated
to a higher velocity by the rotation
of the impeller and discharged by
centrifugal force into the casing .

Work done
 Work is done by the impeller on the water
 W=[ Vw2U2 -Vw1U1 ]/g
 where,
W=work done per unit wg. of water per sec.
Vw2=whirl component of absolute vel. of jet at outlet.
U2=tangential vel. of impeller at outlet.
Vw1 =whirl component of absolute vel. of jet at inlet.
U1 =tangential vel. of impeller at inlet.
 As water comes radially :
Guide blade angle at inlet α=900
Vw1=0 then W=Vw2U2/g

Heads in Centrifugal Pumps
 Suction Head:- Vertical height of
center line of centrifugal pump above
the water surface to the pump from
which water to be lifted.
 Delivery Head:- Vertical distance
between center line of the pump and
the water surface in the tank to which
water is delivered.
 Static Head:- Sum of suction head and
delivery head.
 Manometric Head:- The head against
which a centrifugal pump has to work.
Hm =hs+hd+hfs+hfd+(Vd *Vd )/2g

Efficiencies
 Manometric efficiency:-The ratio of manometric head to
the head imparted by impeller.
=Hm/(Vw2 u2/g)
 Mechanical efficiency :-The ratio of power delivered by
the impeller to the liquid to the power input to the
shaft.
=(WVw2u2/g)/(power input to the pump
shaft)
 Overall Efficiency:-Ratio of power output of the pump to
power input to the pump or shaft.
= wQHm/P =WHm/P

Multistage Centrifugal Pump
 It consists of two or more impellers at a time.
There are two types as follows:
a) SERIES :To produce high head.
b) PARALLEL :To discharge large quantity of liquid.

Cavitation
 It is a phenomena of formation of vapour bubble
where the pressure falls below the vapour
pressure of flowing liquid .
 Collapsing of vapour bubble causes high pressure
results in pitting action on metallic surface.
 Erosion, noise & vibration are produced.
Effects of Cavitation:
 Metallic surface are damaged & cavities are
formed.
 Efficiency of pump decreases.
 Unwanted noise and vibrations are produced.

Introduction
 Pumps are used to increase the energy level of water by virtue of which
it can be raised to a higher level.
 Reciprocating pumps are positive displacement pump, i.e. initially, a
small quantity of liquid is taken into a chamber and is physically
displaced and forced out with pressure by a moving mechanical
elements.
 The use of reciprocating pumps is being limited these days and being
replaced by centrifugal pumps.
 For industrial purposes, they have become obsolete due to their high
initial and maintenance costs as compared to centrifugal pumps.
 Small hand operated pumps are still in use that include well pumps,
etc.
 These are also useful where high heads are required with small
discharge, as oil drilling operations

Main components
 A reciprocation pumps consists of a plunger
or a piston that moves forward and
backward inside a cylinder with the help of
a connecting rod and a crank. The crank is
rotated by an external source of power.
 The cylinder is connected to the sump by a
suction pipe and to the delivery tank by a
delivery pipe.
 At the cylinder ends of these pipes, non-
return valves are provided. A non-return
valve allows the liquid to pass in only one
direction.
 Through suction valve, liquid can only be
admitted into the cylinder and through the
delivery valve, liquid can only be discharged
into the delivery pipe.

Working of Peciprocating Pump
 When the piston moves from the left to the right, a
suction pressure is produced in the cylinder. If the
pump is started for the first time or after a long
period, air from the suction pipe is sucked during
the suction stroke, while the delivery valve is
closed. Liquid rises into the suction pipe by a small
height due to atmospheric pressure on the sump
liquid.
 During the delivery stroke, air in the cylinder is
pushed out into the delivery pipe by the thrust of
the piston, while the suction valve is closed. When
all the air from the suction pipe has been
exhausted, the liquid from the sump is able to rise
and enter the cylinder.
 During the delivery stroke it is displaced into the
delivery pipe. Thus the liquid is delivered into the
delivery tank intermittently, i.e. during the
delivery stroke only.

Classification of Reciprocating pumps
 Following are the main types of reciprocating pumps:
 According to use of piston sides
 Single acting Reciprocating Pump: If there is only one
suction and one delivery pipe and the liquid is filled only on
one side of the piston, it is called a single-acting reciprocating
pump.
 Double acting Reciprocating Pump: A double-acting
reciprocating pump has two suction and two delivery pipes,
Liquid is receiving on both sides of the piston in the cylinder
and is delivered into the respective delivery pipes.

 Single acting Reciprocating Pump  Double acting Reciprocating Pump

Discharge through a Reciprocating Pump
Discharge in case of Single acting pump
Let, A = cross sectional area of cylinder
r = crank radius
N = rpm of the crank
L = stroke length (2r)
 Discharge through pump per second= Area x stroke length x rpm/60
QTH=ALN/60
Discharge in case of double acting pump
 Discharge/Second =QTH=[ ALN/60 + (A-AP)LN/60 ]
Where, AP = Area of cross-section of piston rod
However, if area of the piston rod is neglected
Discharge/Second = 2ALN/60

 Thus discharge of a double-acting reciprocating pump is twice than
that of a single-acting pump.
 Owing to leakage losses and time delay in closing the valves, actual
discharge Qa usually lesser than the theoretical discharge Qth.

Slip
 Slip of a reciprocating pump is defined as the difference between the
theoretical and the actual discharge.
i.e. Slip = Theoretical discharge - Actual discharge
= QTH - Qa
= QTH – QACT
QTH
Slip can also be expressed in terms of %age and given by
=(1-QACT/QTH)100 = (1 – CD )100
Where Cd is known as co-efficient of discharge and is defined as
the ratio of the actual discharge to the theoretical discharge.
Cd = Qa / Qth
Value of Cd when expressed in percentage is known as volumetric efficiency
of the pump. Its value ranges between 95---98 %. Percentage slip is of the
order of 2% for pumps in good conditions.

EXAMPLE:
 Problem-1: A single-acting reciprocating pump discharge 0.018 m3/s of water per second
when running at 60 rpm. Stroke length is 50 cm and the diameter of the piston is 22 cm. If
the total lift is 15 m, determine:
a) Theoretical discharge of the pump
b) Slip and percentage slip of the pump
c) Co-efficient of discharge
d) Power required running the pump
Solution: L = 0.5 m , Qa = 0.018m3/s , D = 0.22 m , N = 60 rpm , Hst = 15 m
(a) QTH = ALN/60 = (π/4)x(0.22)2x(0.5x60/60)
= 0.019 m3/s
(b) Slip = Qth - Qa
Slip = 0.019 – 0.018 = 0.001 m3/s
Percentage slip = (Qth - Qa )/ Qth = (0.019-0.018)/0.019 = 0.0526 or 5.26%
(c) Cd = Qa / Qth = 0.018/0.019 = 0.947
(d) Power Input = ρ g HstQth(Neglecting Losses) = 1000 x 0.019 x 9.81x 15 = 2796 w or 2.796 kW

Comparison of Centrifugal and Reciprocating
Pumps
Centrifugal Pumps
 1. Steady and even flow
 2. For large discharge, small heads
 3. Can be used for viscous fluids e.g. oils,
muddy water.
 4. Low initial cost
 5. Can run at high speed. Can be coupled
directly to electric motor.
 6. Low maintenance cost. Periodic check
up sufficient.
 7. Compact less floors required.
 8. Low head pumps have high efficiency
 9. Uniform torque
 10. Simple constructions. Less number of
spare parts needed
Reciprocating Pumps
 1. Intermittent and pulsating flow
 2. For small discharge, high heads.
 3. Can handle pure water or less viscous
liquids only otherwise valves give frequent
trouble.
 4. High initial cost.
 5. Low speed. Belt drive necessary.
 6. High maintenance cost. Frequent
replacement of parts.
 7. Needs 6-7 times area than for centrifugal
pumps.
 8. Efficiency of low head pumps as low as 40
per cent due to the energy losses.
 9. Torque not uniform.
 10. Complicated construction. More number
of spare parts needed.

4.
MISCELLANEOUS
HYDRAULIC MACHINES

Introduction:
There are a lot of hydraulic machines. In all of these machines
power transmitted with the help of a fluid which may be a liquid (
water / oil ) These devices are :
 1- Hydraulic accumulator
 2- Hydraulic intensifier
 3- Hydraulic press
 4- Hydraulic crane
 5- Hydraulic lift
 6- Hydraulic ram
 7- Hydraulic coupling
 8- Hydraulic torque converter
 9- Air lift pump

Hydraulic accumulator :
 Is a device used to stored the energy Of liquid under pressure
and make this energy available to hydraulic machines , such as
lifts presses and cranes.
 This accumulator used to supplied the fluid to the cranes or
lifts…etc.
Some uses of hydraulic accumulator
 emergency functions and safety functions
 To absorb shock
 To supplement pump flow

Types of hydraulic accumulator :
1- Simple hydraulic accumulator
The hydraulic accumulator is a device used for
storing energy of a liquid in the form of
pressure energy, which may be supplied for any
sudden or intermittent requirement.
• In hydraulic lift or the hydraulic crane, a
large amount of energy is required when lift or
crane is moved upward.
• This energy is supplied from hydraulic
accumulator.
• when the lift is moving in the moving in the
upward direction, no large external energy is
required and at that time, the energy from the
pump is stored in the accumulator

CAPACITY OF HYDRAULIC ACCUMULATOR
 It is defined as the maximum amount of a hydraulic energy stored in a
accumulator. •
 Expression for the capacity of accumulator is obtained as,
A=Area of the sliding ram
L=stroke or lift of the ram
P=intensity of water pressure supplied by the pump
W=weight placed on the ram
W=intensity of pressure * area of ram
The work done in lifting the ram=W*lift of the ram=W*L
=P*L*A
Therefore the capacity of accumulator =work done in lifting the ram
=P*A*L
capacity of accumulator=P*volume of accumulator(A*L=volume)

2-Differential hydraulic
accumulator
 • It is a device in which the liquid is
stored at a high pressure by a
comparatively small load on the ram.
 • It consists of a fixed vertical cylinder of
small diameter.
 • The fixed vertical cylinder is surrounded
by closely fitting brass bush , which is
surrounded by an inverted moving cylinder
, having circular projected collar at the
base on which weights are placed.

CAPACITY OF HYDRAULIC ACCUMULATOR
 • Let
p=intensity of pressure of liquid supplied by pump
a=area of brass-bush L=vertical lift of the moving cylinder
W=total weight placed on the moving cylinder
W=p*a
p=W/a
From this equation it is clear that pressure intensity can be increased by making the
area small.
Now the total energy stored in the accumulator
= Total weight*Vertical lift
Energy stored in accumulator=W*L Nm

Hydraulic Intensifier
 FUNCTION: It is used to increase the
intensity of pressure of liquid by
energy available from a large
quantity of water at a low pressure.
 CONSTRUCTION: It consist of fixed
ram surrounded by a sliding cylinder
which is itself surrounded by a larger
fixed cylinder as show in figure.
The sliding cylinder contains water
at high pressure which is supplied to the
machine through fixed ram. The large
fixed cylinder contains water from the
main supply at a low pressure.

Calculation
 Let, P1= intensity of pressure of low pressure liquid.
P2= intensity of pressure of high pressure liquid.
A1= cross sectional area of sliding cylinder=𝜋/4 𝐷1 2 .
A2= cross sectional area of fixed ram= 𝜋/4 𝐷2 2 .
D1= Outer Diameter of sliding cylinder.
D2= Outer Diameter of fixed ram.
Force exerted by low pressure liquid on the sliding cylinder (in downward
direction) =𝐹1=𝑃1𝐴1
Force exerted by high pressure liquid on the sliding cylinder(in upward direction)
=𝐹2 = 𝑃2𝐴2
Equating the upward and downward forces
𝑃1𝐴1 = 𝑃2𝐴2
Intensity of high pressure liquid 𝑃2 = 𝑃1𝐴1/𝐴2
𝑃2 = 𝑃1 × ( 𝐷1/𝐷2 )2

Hydraulic press
 • The hydraulic jack/Press is a device used for lifting heavy loads by the application of much
smaller force.
 • It is based on Pascal’s law, which states that intensity of pressure is transmitted equally in
all directions through a mass of fluid at rest.
Working
 Let • W= Weight to be lifted , • F = Force applied on the plunger,
• A = Area of ram , • a = Area of plunger. Working
• Pressure intensity produced by the force F,
p = F/Area of plunger = F/a
• As per Pascal’s law, the above intensity p will be equally transmitted in all directions. •
Therefore,
The pressure intensity on ram = p = F/a = W/A or W= F(A/a)

Hydraulic crane
Introduction
 The hydraulic crane is used for transferring or raising heavy loads.
 It can be used up to loads 2500 kN.
 It is widely used in loading and unloading ship, warehouses, workshop, heavy
industries and dock sidings.
Construction
 The jib and tie are attached to the vertical post .jib is hinged near the foot of the
vertical post .
 Hydraulic jigger consist of a movable ram sliding in a fixed cylinder . The sliding
ram , one end is connected to set of movable pulley block and other end is contact
with water.
 One end of wire rope fixed with cylinder body is taken round all the pulley of the
two sets of pulley and at the end passes round the guide pulley block.
 The free end of the wire rope is attached with a hook for suspending the load.

Application
 Hydraulic crane used for lowering workshop, foundary, loading
and unloading of ship and Railway wagons and heavy industries.

Hydraulic lift
 Hydraulic lift is a device used for carrying passenger or goods from one floor
to another in multi- storied building to raise heavy objects.
PRINCIPLE OF HYDRAULIC LIFT
 Pascal's law is a principle in fluid mechanics that states that pressure exerted
anywhere in a confined incompressible fluid is transmitted equally in all
directions throughout the fluid such that the pressure variations (initial
differences) remain the same.
 This law is applied to lifts.
TYPES OF HYDRAULIC LIFTS
 DIRECT ACTING HYDRAULIC LIFT
 SUSPENDED HYDRAULIC LIFT

DIRECT ACTING HYDRAULIC LIFT
 When fluid under pressure is forced into the cylinder,
the ram gets a push upward. The platform carries
loads or passengers and moves between the guides.
At required height, it can be made to stay in level
with each floor so that the good or passengers can be
transferred.
 In direct acting hydraulic lift, stroke of the ram is
equal to the lift of the cage.
Components of direct acting hydraulic lift:
 Fixed cylinder: It is fixed with the wall of the floor,
where the sliding ram reciprocate when we apply the
pressure.
 Cage: It is fitted on the top of the sliding ram where
the load is placed (i.e. lifted load).
 Sliding ram: It is fitted in the fixed cylinder which is
reciprocate (upward or downward direction) when
we applied the pressure (i.e. reaches the floor wise.)

SUSPENDED HYDRAULIC LIFT
CONSTRUCTION:-
 Cage: It is fitted on the top of the sliding ram
where the load is placed (i.e. lifted load).
 Wire rope: It connects the cage to pulley.
 Sliding ram: It is fitted in the fixed cylinder
which is reciprocate (upward or downward
direction) when we applied the pressure (i.e.
reaches the floor wise)
 Pulleys: pulleys are connected to the sliding
ram and fixed cylinder; where one pulley is
fixed and other pulley is movable.
 Hydraulic jigger: It consists of a moving ram
which slides inside a fixed hydraulic cylinder.
 Fixed cylinder-: It is fixed with the wall of
the floor, where the sliding ram reciprocate
when we apply the pressure.

Hydraulic ram
 A hydraulic ram is a cyclic water pump powered by hydropower.
 Its function as a hydraulic transformer. It is a device which raises small
quantity of water without any external power to higher level from large
quantity of water available at lower level.
 It works on the principal of water hammer or inertia force of water in a
pipe line

Working
 Hydraulic ram works on the principal of water hammer as when a flowing water is suddenly
brought to rest the change in momentum of water masses causes a sudden rise in pressure. This
rise in pressure is utilizes to raise a small quantity of water to higher level.
 Initially, the waste valve is open and delivery valve is closed. The water from supply tank start to
flow under the force of gravity and picks up speed and kinetic energy until it forces the waste
valve closed.
 The momentum of the water flow in supply pipe against now closed waste valve causes a water
hammer that raises the pressure in chamber. The high pressure of water opens the delivery valve
and water enters into the air vessel which further compresses the air already preset in the air
vessel.
 The pressure in the air vessel raises which closes the delivery valve ,now water from air vessel is
forced to flow through delivery pipe.
 Under this condition waste valve and delivery valve both remains closed
 Slowly pressure in the valve chamber falls and waste valve again opens allowing the water to flow
through it.
 Now, under this condition, flow through the supply pipe begins again producing water hammer in
the valve chamber. The cycle is repeated.

EFFICIENCY
 Hydraulic ram has two types of efficiencies namely D’ Aubuisson’s efficiency and Rankine’s
efficiency.
1. D’ Aubuisson’s efficiency:
 Let, Q = discharge from supply tank to valve chamber
 q = discharge from valve chamber to delivery tank
 H = height of water in delivery tank raised above the chamber.
 h = height of water in the supply tank above chamber (supply head)
since, Energy supplied to/by the ram per second
 = weight of water supplied per second to chamber × height of fall or rised So,
energy supplied from the supply tank = ρQg.h
 = ωQh ( ⸪m =ρQ and W=mg=ρQg)
Energy delivered to delivery tank= ρqg.H = ωqH
Efficiency of ram,
η = Energy delivered Energy supplied = ρ𝑞gH/ρQgh = 𝒒𝑯/𝑸𝒉

2. Rankine’ s efficiency:
 If the water level in the supply tank is taken as datum. Then the actual height raised
is (H-h).
 Energy supplied to supply tank = ρ(Q-q)gh.
= ω(Q-q)h
 Energy delivered to the delivery tank = ρqg(H-h)
= ωq(H-h)
Efficiency,
η = ωq (H−h) / ω(Q−q) h = 𝐪 (𝑯−𝒉) / 𝑸−𝒒 𝒉
 This is known as Rankine’s efficiency and its value is always less than D’ Aubuisson’s
efficiency

Fluid coupling
 When we want to transfer the rotation
energy or torque of one shaft to another,
we have to connect those two shafts with
such a arrangements which can transfer
the power with maximum efficiency and
as per need.
 In above kind of situations, ”The
couplings” is used.
 The coupling is device which connects the
driving and driven shaft and also transfer
the power.
 A Fluid coupling is used for transmitting
power or torque from one to another
shaft with the help of oil (fluid).
 Without MECHANICAL connection of two
shafts.

Working
 When the driving shaft with pump impeller is rotated, the oil
starts moving from the inner radius to outer radius of the
pump impeller by centrifugal action.
 Due to centrifugal action and the speed of impeller, the
pressure and kinetic energy of oil at outer radius increases.
The oil then enters the turbine runner at the outer radios of
the runner and flows inwardly to the inner radios of the
runner. It will exert force and make it run.
 The magnitude of the torque increases with an increases in
the speed of driving shaft.
 And cycle will continue.

Efficiency
 In actual prectice, the speed of driven shaft is always less then the
driving shaft by 2% to 4% due to friction and turbulence loss in the
impeller and runner passage, which is known as SLIP.
 The efficiency of the power transmitted by fluid coupling is about 98%.
 In fluid coupling the driven shaft is free from engine vibrations.
Applications
 Industrial
 Rail transportation
 Fluid couplings are found in some Diesel locomotives as part of the
power transmission system.
 semi-automatic transmissions and automatic transmissions. Since the
late 1940s.
 Aviation

Hydraulic torque converter
 The fluid torque convertor is
used for transmitting variable
(increased or decreased)
torque from one shaft to
another shaft.
 A fluid torque convertor is
nothing but a improved FLUID
COUPLING.
 The different torque( +/-) is
achieved by adding third
member (reaction member)
between pump impeller and
turbine runner.

Working
 When oil flowing from the pump impeller to
turbine Runner exerts the torque on the
stationary guide vanes which change the
direction of oil. As result of this, the oil
reacts upon the turbine runner and reduces
the speed of turbine runner.
 As we know, P is directly proportional to NT.
 Hence, if the T at the driven shaft is to be
increased, the corresponding value of the
speed at the same shaft should be
decreased.
 The speed of driven shaft is decreased by
decreasing the velocity of oil, which is flow
from pump impeller to the turbine runner
and then through the STATOR which change
the direction of oil, therefore the convergent
is possible.

Application
 Automatic transmissions on
automobiles, such as cars,
buses, and on/off highway
trucks.
 Forwarders and other heavy
duty vehicles.
 Marine propulsion systems.
 Industrial power transmission
such as conveyor drives, almost
all modern forklifts, winches,
drilling rigs, construction
equipment, and railway
locomotives.

Air lift pump
 An airlift pump is a device used to lift water from a deep well or sump by
utilizing the compressed air.
The main component are :
 1.Air compressor to supply compress air
 2.Air pipe fitted with one or more nozzles
 3.Delivery pipe
Working
It is well known that the density of water is more than the density of air. So the
main principle used in air-lift pumps is the density difference between water and
air. Air is made to mix with the water and thus allowed to form froth. Froth here
consists of mixture of water and air. So the density of this mixture is less than that
of the water. It is the mixture of air which makes the density less than water. Thus
a very small column of pure water can balance a very long column of air-water
mixture. This is the working principle of air-lift pumps.

Advantages
 1.No moving parts.
 2.Less maintenance.
 3.Simple & reliable.
 4.No mechanical parts below ground
level.
 5.It can pump solid without any
damage to the system.
 6.It can handle mud, sand, and
gritty water too.
 7.This pump can raise more water
through a bore hole of given
diameter than any other pump
types.

Diadvantages
 Worst efficiency, 20 to 40% operating
efficiency, when compared
to expenditure of energy in compressing
air.
 Running cost of an air-lift pump is
high in terms of energy expenditure
terms.
 Bore holes have to be drilled very deep
in order to get enough static head. If
not, the discharge will be less and
probably no discharge. Boring is
considerably a costly operation.
 It is suitable for draining water in the
mines where compressor than any units
are already installed.

Thanks you
For Patience
 Date of submission
30-November -2020

Turbines and recipocating pumps and miscellaneous hydraulic machines

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