EME lab practical- GTU

G.I.D.C. DEGREE ENGINEERING COLLEGE, NAVSARI

CERTIFICATE This is to certify that Mr. /Miss

___________________________________________of Branch_____________in Sem._________, Enrollment No._____________has satisfactorily completed his/her term work for subject Elements of Mechanical Engineering (2110006) during term 20___.

DATE:______________

Sign of Faculy Head of the department


TABLE OF CONTENTSR NO

.EXPERIMENTS PAGE

NO.

DATE OF

PERFORMANCE

DATE OF

CHECKINGSIGN MARKS

1 To study different configurations of steam generators

2 To study different boiler mountings & accessories

3 Study of different calorimeters used for measurement of steam quality

4 To study different I.C. engines.

5 Study of different types of pumps.

6 Study of different type of compressors.

7 Study of refrigeration and air conditioning systems.

8 Study of elements of motion and power transmission.

9 Study of Clutches, Couplings & Brakes.

10 To study the engineering materials.

AVERAGE MARKS


EXPERIMENT NO.1

OBJECTIVES To understand the phenomenon of evaporation. To study different configurations of steam generators.

THEORY

Steam generator is basically a heat exchanger that generates steam under the desired conditions of pressure & temperature, by facilitating heat exchange between water and flue gases generated upon the combustion of fuel.

A steam generator thus needs to have necessary heat transfer surfaces, space for storage of water & steam, furnace for burning the fuel and necessary equipment for control of its operation.

Steam generators can be classified in several ways viz. according to tube content, orientation of boiler shell, method of circulation of water, operating pressure, applications etc.

The following configurations will be studied; • Simple vertical boiler • Cochran boiler • Locomotive boiler • Babcock & Wilcox boiler • Lancashire boiler

EXERCISES

1. Explain evaporation phenomenon with sketch. 2. Differentiate between:

Fire tube & water tube boilers 3. Define boiler. Discuss various classifications of boilers.4. Give name of basic parts of boiler and write function of each. 5. Describe with the help of a neat sketch the working of:

Cochran boiler Babcock & Wilcox boiler Lancashire boiler


EXPERIMENT NO.2

OBJECTIVE To study different boiler mountings & accessories.

THEORY

A steam generator is employed to generate steam under desired conditions of pressure & temperature. Different devices are a part of the steam generator which are called as mountings or accessories.

Mountings

Mountings are the fittings & devices, which are necessary for the complete controlled operation and safety of a boiler.

Some of the important boiler mountings are; • Safety valve • Pressure gauge • Water level indicator • Steam stop valve • Feed check valve • Blow off cock • Fusible plug, etc.

Accessories

Accessories are the appliances installed to enhance the performance of the boiler. These are optional components and a boiler can be operated without accessories.

The important boiler accessories are; • Super heater• Economizer • Air preheater

EXERCISES

1. What are boiler mountings and accessories? 2. How is draught created in the various boilers that you have studied?


3. Explain what is meant by:(a) Boiler efficiency(b) Equivalent evaporation.

4. With the help of neat diagrams explain the location and working of following mountings:

1. Safety valve (all four types)2. Pressure gauge 3. Water level indicator 4. Steam stop valve 5. Blow off cock 6. Feed check valve 7. Fusible plug

7. Explain Working of following accessories: 1. Economizer 2. Super heater 3. Air preheater

4. Exhaust steam feed water heater


EXPERIMENT NO.3

OBJECTIVE Study of different calorimeter used for measurement of steam quality

(dryness fraction).

THEORY

Dryness fraction of steam is defined as the ratio of mass of vapor present in a sample of wet steam to the total mass of the steam sample. Steam dryness fraction is denoted by X, and can take any value between 0to 1.

Where: mv =mass of vapourml =mass of liquid

Dryness fraction of 1 indicated that the steam sample is dry saturated where as dryness fraction value of 0 indicate saturated liquid state.

The determination of the dryness fraction of steam driving the turbine is very important as excessively wet steam may cause erosion and corrosion of turbine blades, thereby shortening the life of the turbine.

For safe operation of turbine the dryness fraction of the steam has to be greater than 0.88.

TASK

Study of following calorimeter used for measurement of steam quality:(a) Separating calorimeter(b) Throttling calorimeter(c) Separating Throttling calorimeter

EXERCISES

1. Define dryness fraction. 2. Explain with help of neat sketch the working of following calorimeter:

a) Bucket or Barrel calorimeterb) Separating calorimeterc) Throttling calorimeter


d) Combined throttling & Separating Calorimeter

EXPERIMENT NO.4

OBJECTIVE Study of different Internal Combustion (I.C.) engines.

THEORY

Heat engines are the devices that first convert chemical energy stored in the fuel, into heat energy and then thermal into mechanical energy.

Internal Combustion (I.C) engines are type of heat engines in which combustion of the fuel and hence conversion of chemical energy stored within the fuel into thermal energy takes place within i.e. inside, the engine.

I.C. engines have evolved over the years, starting from the low speed bulky machines of the early twentieth century to today’s state of the art modern high seed, high performance engines.

Detailed study of several I C engines is to be carried out to meet with the following objectives;

• To identify the type of engine, i.e. 2 stroke or 4 stroke, SI or CI etc. • To understand the technical specifications of engines • To get acquainted with the engine set up i.e. the type of starting

method employed, the type of output power measuring device used, the type of cooling method employed, the type of inlet air flow measuring method used etc.

EXERCISE

1. What is an internal combustion engine? Give detailed classification of I.C. engines.

2. Draw a neat schematic diagram of engine showing its major components.3. Explain the function of I.C. Engine parts.4. Differentiate between:

(a) Two stroke & four stroke I.C engines (b) S.I. & C.I. engines

5. Explain the working of two sroke and four stroke S.I. & C.I. engines.


EXPERIMENT NO.5

OBJECTIVE

To study different types of pumps.

THEORY The pump is a mechanical device which conveys liquid from one

place to another. It can be also define as a machine that transfers the mechanical energy of a motor or an engine in to potential, kinetic, and thermal energy pump belongs to the category of power absorbing machines. Pumping is the addition of energy to move it from one place to another.

The pumps used to handle water are called hydraulic pumps. Other common types of pump are fuel pumps, oil pumps, mud pumps etc.

A pump is defined as a device, which raises or transfer liquids at the expense of power input.

A machine designed to elevate, deliver, and move various liquids. A unit that transfer mechanical energy of a motor of an engine in to

potential and kinetic energy of a liquid. Application area of pump the municipal water works, power plants,

agriculture, transport and many other utility services and industries. According to design and principle of operation, pumps may be

classified in following two categories: Dynamic pumps, which include centrifugal pumps, axial flow and peripheral pumps.Positive displacement pumps, which include reciprocating pumps (piston pump, plunger pump), rotary pumps (gear type, screw type and vane type).

EXERCISE

1. Define pump and classify different types of pumps.2. Explain with neat sketch the following types of Reciprocating Pump.

1) Plunger Pump2) Single Acting Pump3) Double Acting Pump4) Bucket Pump


3. Explain with neat sketch the following types of Rotary Pump.1) Gear Pump2) Screw Pump3) Vane Pump

4. Explain with neat sketch the following types of Centrifugal Pump.1) Volute Pump2) Vortex Pump3) Diffuser Pump

5. What is priming? Why priming is required in centrifugal pump? Also write methods of priming.

6. Explain with neat sketch function of Air Chamber.


EXPERIMENT NO.6

OBJECTIVE

To study different types of compressor.

THEORY The compressor is the machine which handles a compressible fluid and

pressurizes it by doing work on it. The fluid can be air, gas or vapor. It can be also defined as a machine which takes in air at low pressure and compresses it to high pressure which the help of some suitable arrangement. i.e. reciprocating piston and cylinder arrangement or rotary arrangement it is called an air compressor.

Generally an air compressor takes in air at the atmospheric pressure. It is compressed to high pressure and delivered it is to a storage tank. From the storage tank it is taken out for different uses through the pipe lines. The compressor driven with the help of some prime mover.

SYSTEM

The compressor is a single acting, two stage, twin cylinder, stationary reciprocating air compressor. It is mounted directly on a storage tank for storing the air and to deliver it at a constant pressure. The compressor is coupled with a three phase, 1440 rpm; ac motor through a v-belt and the speed is reduced to 800 rpm. The com pressure is supplied with a pressure switch (unloader), an energy meter, a safety valve, pressure gauges, air delivery valve, an arrangement for airflow measurement, a dynamometer etc. The other technical specifications of the compressor are as follows;

- Displacement: 300LPM - Working pressure: 12kg/cm - Storage tank capacity: 160 liters- Bore and stroke of the LP cylinder: 70 X 85 mm - Bore and stroke of the HP cylinder: 57 X 85 mm - Clearance ratio (c): 0.020 for the LP cylinder

0.030 for the HP cylinder


- Speed of the compressor (N) = 900 rpm - Energy meter constant: 200 rev/kWh- Co-efficient of discharge (C) of the orifice: 0.6 - Diameter of the orifice plate: 15 mm

EXERCISE

1. What is compressor? Give its classification.2. Write down use of compressed air.3. Draw sketch of reciprocating compressor and explain its working.4. Define following in context with the compressor:

(i) Capacity (ii) Free air delivery (iii) Multi staging (iv) Volumetric efficiency

3. Sketch a simple centrifugal compressor and explain its working. 4. Sketch an axial flow compressor and explain its working. 5. Compare reciprocating and rotodynamic compressor.


EXPERIMENT NO.7

OBJECTIVE

To understand the working principle of refrigeration and air conditioning systems.

THEORY

Refrigeration is defined as the process of reducing temperature of a body, making it less than the surrounding temperature and maintaining it.

The device that helps perform process of refrigeration is known as a Refrigerator and the working cycle le on which the device (refrigerator) works is knows as a Refrigeration Cycle .

Refrigeration system find application in variety of areas like preservation of food items, storage of medicines at low temperature, for comfort air conditioning, manufacturing of ice, liquefaction of gases like oxygen etc.

Air conditioning is defined as simultaneous control of temperature, humidity, air movement, oxygen content and cleanliness of air.

Complete air conditioning process includes following:

(a) Cooling or heating of air (b) Addition of moisture (Humidification) or removal of moisture

(Dehumidification) of air (c) Control of air movement (d) Control of quantity of oxygen in air (e) Maintaining air cleanliness

The two main application of air conditioning are:

(a) For generation of conditions where a human body feels comfortable. This is known as comfort air conditioning.

(b) For providing conditioned air for some industrial application like manufacturing of paper, textile industry etc. This is known as


industrial air conditioning

TASK

To understand Vapor Compression Refrigeration (VCR) system and identify its main system components.

Represent the VCR cycle on a P-h and T-s diagram To understand working of different devices like a house hold refrigerator, a

water cooler, an ice making plant etc. working on VCR cycle. To understand the basic air conditioning process like heating, cooling,

humidification, dehumidification etc. To identify the main system components and understand the working of

following air conditioning equipments: (a) A window air conditioner (b) A split air conditioner

EXERCISE

1. Define refrigeration and refrigerant. Write down properties of good refrigerant.2. Define COP for a refrigeration system & one ton of refrigeration.3. Draw a neat schematic of a VCR system and explain its working with T-s and

p-h charts.4. With help of neat sketch explain the working of Domestic VCR system & VAR

system.5. Define air conditioning. Explain the principle of air conditioning.6. With a neat sketch explain the working of a window air conditioner and a split

air conditioner. Also discuss their relative merits and demerits.


EXPERIMENT NO.8

OBJECTIVE Study of elements of motion transmission and power transmission

THEORY

Mechanical systems often need motion or power to transmit from prime mover to a machine or from one shaft to another shaft. The sources of power generally used are electrical motors, internal combustion engines, or steam hydraulic and gas turbines.

The drive may be individual drive from a captive motor or group drive from a line shaft. Further the transmission may be through a flexible system like belts, ropes and chain drive or a positive drive like gear or clutch drive. Belts and ropes are normally flexible in nature and they are used when the shafts are comparatively large distance apart. Gears are used between shafts having relatively smaller center distance. Chains are used for relatively large centre distance between shafts. Unlike belts and ropes, chains and gear are positive drive elements which transmit power without slip.

Belt and Rope Drives: To transmit the power from one shaft to another, pulleys are mounted on the two · shafts. The pulleys are then connected by an endless belt or rope passing over the pulleys. The connecting belt or rope is kept in tension so that motion of one pulley is transferred to the other without slip. The speed of the driven shaft can be varied by varying the diameter of the pulleys.

Types of belt: Flat belt, V-belt, Circular belt or Rope

Type of flat belt drives: Open belt drive Crossed or twisted belt drive

Chain drives: To avoid slippage, steel chains are used. The chain is made up of a rigid links which are hinge d together in order to provide the necessary


flexibility for wrapping around the driving and driven wheels. The wheels have projecting teeth and fit into the corresponding recesses, in the links of the chain. The wheel and the chain are thus constrained to move together without slipping and ensure perfect velocity ratio. The toothed wheels are known as sprocket wheels or simply sprockets. These wheels resemble to spur gears.

Gear Trains: A gear train is a combination of gears used to transmit motion and power from one shaft to another. It becomes necessary when it is required to obtain large speed reduction with in a small space. The following are main types of gear trains.

Simple gear train : 1. A pair of mating external always moves in opposite direction 2. All odd numbered gears move in one direction and all even

numbered gears move in opposite direction. 3. Speed ratio is the ratio of the speed of the driving to the driven shaft,

is negative when the input and output gears rotate in opposite direction and it is positive when the two rotate in same direction. Reciprocal of speed ratio is known as the train valve of the gear train.

4. All the gears can be in a straight line or arranged in zigzag manner.

Compound gear train : When a series of gears are connected in such a way that two or more gears rotate about an axis with the same angular velocity, it is known as compound gear train. In this type, some of the intermediate shafts, i.e. other than the input and output shafts carry more than one gear.

Advantages of gear train: 1. It transmits exact velocity ratio. 2. It may be used to transmit large-power 3. It has high efficiency 4. It has compact layout

Disadvantages of gear train: 1. The manufacture of gears requires special tools and equipment 2. The error in cutting teeth may cause vibrations and noise during operation

EXERCISE


1. Give Comparison the individual drive and group drive. 2. Name the methods by which power from one shaft to another shaft is

transmitted. 3. Explanation the different type of belts drive and pulleys with neat sketch.4. Discussion the gear drive, chain drive and friction drive with neat sketch. 5. What is bearing? Classify the bearing and draw sketch of the thrust bearing. 6. What is the function of gear trains in automobiles? 7. What is the function of the stepped pulley and idler pulley? 8. What is V-belt drive? How it differs from a flat belt drive?


EXPERIMENT NO.9 OBJECTIVE

To study the working and applications of Coupling, Clutch and Brake.

THEORY Coupling

Couplings are used for joining sections of long transmission shafts. They are also used for connecting the shaft of a driving machine to the shaft of a separately built machine so as to give an effect of continuous shaft.

1. Rigid coupling Rigid couplings are used connect two shafts when they are in perfect axial alignment • Sleeve or Box or Muff coupling • Split muff or clamp coupling • Flange couplings

2. Flexible coupling These types of couplings are used protect the driving and driven machines from effect of shocks excesses stresses due to deflection and vibrations, which may arise from misalignment of shafts.


• Bush pin type flange coupling • Oldham coupling • Universal coupling • Clutch

The flow of mechanical power is controlled by means of a clutch. The clutch is a mechanical device, which is used to connect or disconnect the source of powerfrom the remaining parts of the power transmission system s at the will of the operator An automotive clutch can permit the engine to run without driving the car. This is desirable when the engine is to be started or stopped or when the gears are to be shifted.

Single plate friction clutch Multi disc clutch Centrifugal clutches

• Brake A brake is a mechanical device by means of which artificial resistance is applied to a moving system or machine in order to slow down or completely stop the motion of a machine. In performing this function, the brake absorbs either kinetic energy of moving members such as rotating drum, machine, automobile vehicle or potential energy given up by objects being lowered by hoists, elevators. The energy absorbed by a brake is converted into heat energy and dissipated in the surroundings air. There are two distinct functions of vehicle brakes. To stop or slow down the vehicle in the shortest possible distance in

emergencies. To control the vehicle to be retained when descending a hill.

Types of brakes:According to the means used for transforming the energy by the braking elements the brakes are classified as hydraulic brakes electric brakes Mechanical brakes

Depending upon the shape of the friction material the mechanical brakes are classified as block brake, internal or external shoe brakes and band brakes.


EXERCISE

1. What is coupling? Classify the couplings. 2. What is difference between rigid coupling and flexible coupling? 3. Explain the following couplings with neat sketch.

a. Oldham’s coupling b. Flange coupling c. Bush pin flexible coupling

4. What is clutch? State its function and classify the clutches. 5. Explain the following clutches with neat sketch.

1. Disc clutch 2. Cone clutch

6. What is brake? How it differs from clutch? 7. Classify the different type of Brakes. 8. Explain an internal expanding shoe brake and a band brake with neat sketch.


EXPERIMENT NO.10

OBJECTIVE To study the different types of engineering materials.

THEORY All the Engineering of any disciplines should have the proper knowledge of engineering materials for the successful design and working of any engineering system. Proper material should be selected with functional, service and economical considerations. For the selection of proper materials for the products, knowledge about the materials and their properties may be very useful. The important mechanical properties are as below:

1. Strength 2. Elasticity 3. Plasticity 4. Malleability 5. Ductility 6. Impact strength 7. Hardness 8. Toughness 9. Brittleness 10. Resilience 11. Creep 12. Fatigue

Classification of Materials: The engineering materials can be broadly classified as follows:

1. Metallic a. Ferrous (Iron, steel and their alloys) b. Non-ferrous (copper, zinc, lead, aluminum etc. and their alloys)

2. Non Metallic (Plastic, rubber, timber, ceramics, polymers, glass etc.)

EXERCISES 1. Define the following properties of material. Strength, Elasticity, Plasticity, Malleability, Ductility, Impact strength, Hardness, Toughness, Brittleness, Resilience, Creep and Fatigue 2. Define ferrous and non-ferrous materials. 3. State and classify steels. Give at least one example of their applications. 4. Give the examples of non-ferrous materials with their application. 5. What is ceramic? State at least two its properties and practical applications. 6. What are abrasive materials? State their applications.

EME lab practical- GTU

Engineering

Transcript of EME lab practical- GTU