Gas Turbine

Gas turbines use up high pressure gas to produce 

energy.These turbines are not used for producing 

electricity but they are used to propel jet engines.Gasturbines are the latest types of turbines. Their structure is advanced but the principle is same

Wind Turbines

Wind Turbines

Wind turbines use up the moving wind to produce electricity.These turbines might not be as popular as water and steam turbines but in many parts of the world like in Scotland and some parts of America this turbine is used to produce electricity.Long egg beater- like shafts, possessing bow shaped blades, are placed high in the sky. These blades move with the moving wind to produce electricity.Producing electricity from wind may sound a good option as wind is a resource which can never end; however this process has huge restrictions as wind is as reliable as water.It can only be applicable in parts of the world where wind moves fast continuously.

Water Turbine

Water turbines work on the same principle as the steam turbines but the difference is that they use water instead of steam. The water used by these turbines comes from lakes and rivers.Dams which are built in these huge water bodies store the water at one end, at the other end they posses hydraulic turbines which posses a shaft bearing

Steam Turbine

Steam turbines were the first turbines ever produced by man.These turbines are composed of shaft blades and a rotor engine.The steam which is produced by the burning of coal, oil or from nuclear reactor is made to pass through blades which spin at a very high speed to drive the generator which produces energy.The principle on which it works is that the thermal energy which is extracted from the steam is converted into mechanical energy.Although

what is turbine ?

A turbine is a type of engine that can extract energy from a fluid, such as water, steam, air, or combustion gases. It can be contrasted with a piston engine, which uses a piston instead of a turbine to extract energy.

The physical makeup of a turbine is a series of blades, typically made of steel but sometimes ceramic, which can withstand higher temperatures. The fluid goes in one end, pushing the blades and causing them to spin, then gets ejected out the other end. The fluid leaves the turbine with less energy than it had going in - a portion of the difference is captured by the turbine.

single acting and double acting reciprocating pump.

In single acting pump, there is one suction valve and one delivery valve. On the backward stroke of the piston, the suction valve opens and water enters into the cylinder space. On the forward stroke, the suction valve closes and delivery valve opens, the water is

Bernoulli’s theorem and it's assumptions

Bernoulli’s theorem states that in a steady flow of ideal incompressible fluid, the sum of pressure head, velocity head and potential head is constant along a stream line provided no energy is added or taken out by external source. Bernoulli’s equation

convective, flow net and local acceleration,circulation

• Convective acceleration is the instantaneous space rate of change of velocity.

Stream function and Potential function and these properties

Stream function:-
It is defined as the scalar function of space and time, such that its partial derivative with respect to any direction gives the velocity component at right angles to that direction. 

Streamlines,Path lines,Streak lines

A stream line at any instant can be defined as an stationary curve in the flow field so that at any point represents the direction of the instantaneous velocity at that point. 

compressible and incompressible flow and rotational and irrotational flow

Compressible flow is that type of flow in which the density of the fluid change from point to point.

uniform and non uniform flow and laminar and turbulent flow

• When velocity of fluid at any instant of time do not change from point to point in a flow field, the flow is said to be uniform. 

Dimension of flow,Steady flow,Unsteady flow

Dimension of flow:-
A fluid flow is said to be one, two or three dimensional depending upon the number of independent space coordinates. 

FOLLOWER AND THEIR CLASSIFICATIONS

classification of follower :-

(i) According to follower shape
(ii)according to motion of follower

roller follower:In place of a knife edge roller is provided at the contacting end of the follower

Spherical follower :In the contacting end of the follower is of spherical shape

CAM AND THEIR CLASSIFICATION

Cam :-

Cam is a rotating mechanical member used for transmitting desired motion to a follower by direct contact.

Classification of cam 

(i) according to cam shape 
(ii) according to follower movement 
(iii) according to manner of constraint of the follower.

Kinematics of motion

• kinematic link based on relative motion between links
• important definitions in kinematic.

Fluid Mechanics

Pressure and its unit.

Kinematic,viscosity,Cavitation,Surface Tension,Capillarity

Pressure and its unit.

If the fluid is stationary, then the force (dF) exerted by the fluid on the area is normal to the surface (dA). This normal force per unit area is called pressure.P = ( dF / dA) The unit of pressure is N/m2. 

Kinematic viscosity,Cavitation,Surface Tension,Capillarity

• Kinematic viscosity is defined as the ratio of dynamic viscosity to density. n = m / r The unit of kinematic viscosity is m2/s .

compressibility,vapor pressureof a liquid

• Compressibility of substance is the measure of its change in volume under the action of external forces, namely, the normal compressive forces. The measure of compressibility of the fluid is the bulk modulus of elasticity (K) K = lim DV - 0 (- DP) / (DV/V) The unit of compressibility is N/m2 .

Different manometer used in fluid mechanics

A manometer is a transparent tube containing a liquid of known density used for the purpose of measuring the fluid pressure. The common fluids used are mercury, alcohol.

Simple manometer, one end is connected to the point at which the pressure is to be measured and the other end is open to atmosphere.

classifications of fluid

Real fluid:- The fluids in reality have viscosity m > 0 hence they are termed as real fluids and their motion is known as viscous flow. (ex) Air , water, kerosene, blood, milk .

Viscosity and Newton’s law of viscosity

The viscosity can be defined as the property of fluid which resist relative motion of its adjacent layers. It is the measure of internal fluid friction due to which there is resistance to flow, The unit of viscosity is Ns/m2. 

Density,Specific volume,Specific weight,Specific gravity (SG)

Density is defined as the mass of a substance per unit volume. 
If a fluid element enclosing a point P has a volume dV and dm , then the density is given by r = lim dV - 0 (dm / dV) = (dm / dV) The unit of density is kg/m3 . 

Differentiate solid and fluid

Fluid :-

The fluid deforms continuously when subjected to a shear stress. When the shear stress disappears the fluid never regain in to original shape. 

Define fluid

A Fluid is a substance that deforms continuously when subjected to a shear stress no matter how small that shear stress may be. 

BASIC UNITS DIMENSION UNIT SYMBOL

Length ------------------meter --------------m 

Mass --------------------kilogram ----------kg

Time--------------------- second ------------s 

kinematic link based on relative motion between links

1)Sliding pair.In a sliding pair minimum number of degree of freedom is only one.

2)Turning pair.In a turning pair also degree of freedom is one.when two links are connected such that one link revolves around another link it forms a turning pair.

3)Cylindrical pair.In a cylindrical pair degree of freedom is two.If one link turns and slides along another link it forms a cylindrical pair.

important definitions in kinematic

Degree of freedom.Of mechanism.It is defined as the minimum number of input parameters which must be independently controlled in order to bring the mechanism into a useful engineering purpose.
Grashoff’s law.Sum of shortest link length and sum of longest link length is not greater than the sum of remaining link length.

some important mechanism in kinematic

1. Inversion of mechanism.The method of obtaining different mechanism by fixing different links in a kinematic chain is known as inversion of mechanism.
2. Mechanical advantage of mechanism.It is defined as the ratio of output torque to the input torque also defined as the ratio of load to effort.

Kinametics link,Kinematic pair,Kinematic chain

• Kinematic link It is a resistive body which go to make a part of a machine having relative motion between them.

turbulence and its effects

It is the zig-zag motion of the air-fuel mixture in the combustion chamber. The turbulence of the mixture is due to admission of fuel-air through comparatively narrow sections of the intake pipe, valves, etc. during the suction stroke. Turbulence plays a very vital role in combustion phenomenon The turbulence can be increased at the end of the compression by suitable design of combustion chamber. The effects of turbulence are:-

stages of combustion in a CI engine

1. First stage : Ignition Delay Period

During the first stage some fuel has been admitted but has not yet been ignited. The ignition delay is counted from the start of injection to the

factors affecting the flame propagation in S.I. engines

1. Fuel-air ratio : The composition of the working mixture influences the rate of combustion and the amount of heat evolved. With hidrocarbon fuels the maximum flame velocities occur when mixture strength is about 10% rich than stoichiometric. The velocity of flame decreases when the mixture is made leaner or is enriched still more than 10%.

Desirable properties of I.C. engine fuels

The desirable properties of IC. engine fuels are :-

1. High energy density.

2 Good combustion qualities

3 High thermal stability.

4. Low deposit forming tendencies.

5. Compatibility with the engine hardware.

6. Good fire safety. 

7 Low toxicity.

Ignition lag , After burning , Flame propagation , Auto-ignition

(a) Ignition Lag is the time interval between the point of spark ignition and point of combustion It can be decreased by increasing compression ratio decreasing speed and using rich mixtures.

ignition advance,Willan’s line ,scavenging,compression ratio

Ignition Advance : is the angle between the occurrence of the ignition spark and the TDC position of the piston (ignition of the charge).

detonation,squish,cetane number,octane number

• Detonation in S I Engines It is due to auto-ignition of the fuel before the spark actually occurs.

knocking in S I engine and different factor effecting it

Phenomena of knocking in SI Engines In a SI engine combustion is initiated between the spark plug electrodes and then spreads across the combustible mixture A definite flame front which separates the fresh mixture from the products of combustion travels from the spark plug to the other end of the combustion chamber

HUCR (highest useful compression ratio )

The highest useful compression ratio (HUCR) is the highest compression ratio at which a fuel can be used without detonation in a specified test engine under specified operating conditions and the ignition and mixture strength being adjusted to give best efficiency.

Supercharging

Supercharging: is the process of supplying greater mass of air to engine cylinder by compressing intake air initially with a view to obtain higher power. This is essential for aircraft at high altitudes where density of air is less. It promotes knocking.

Different between two-stroke and four-stroke engines

some basic different between two-stroke and four-stroke engines are give below :-

POWER PLANT ENGINEERING

POWER PLANT ENGINEERING 

• How does a Circulating Fluidized Bed Boiler Work ?
• How does a Power Plant Boiler work?
• How does a Gas Turbine Power Plant Work?

Automobile Engineering

Automobile Engineering

• crankcase ventilation
• transmission system
• oil cooler

Strength of Materials

Strength of Materials

• Column and it's type
• POWER TRANSMITTED
• Torsion Formula
• DEFINITIONS of Simple Bending of Beams
• Sign conventions in Bending Moment and Shear Force diagram

Heat Transfer

Heat Transfer

• perpetual motion machine of second kind
• What do you mean by the entropy?
• working of Carnot cycle
• steady flow equation in Steam nozzle

perpetual motion machine of second kind

It is defined as a machine which continuously absorbs heat from a single thermal reservoir and converts this heat completely into work.

What do you mean by the entropy?

Entropy is a function of a quantity of heat which shows the possibility of conversion of that heat into work.

working of Carnot cycle

This cycle consists of two adiabatic and two isothermal processes, as shown in the P-V and T-S diagrams of the Fig. (a) & (b).

steady flow equation in Steam nozzle

Nozzle is a device with varying x-sectional area through which the pressure energy of

 flowing fluid decreases and the K.E. increases.

      The main aim is to produce a jet of very high velocity

      In the nozzle,

steam power plant numerical

The following data pertaining to a steam power plant are given for each state corresponding to Fig. shown below. Determine heat transfer in each process and turbine work.

steady flow energy equation

Fig. shows a steady flow process

      Let us consider an open system through which the working substance flows at a steady rate.

steady flow energy equation for a steam turbine

It is assumed in the turbine:

        It is insulated so that no heat enters or leaves the system i.e. flow of fluid through the turbine is adiabatic.

therefore,   q = 0                                        ……….. (1)

Joule’s law

Joule’s law states that the internal energy of a perfect gas is the function of absolute temperature only. Therefore, U = f (T).

What is throttling ?

It is an irreversible steady flow expansion process in which fluid is allowed to move through a restricted passage (such as porous plug, sudden reduction in x-section of flow or a partially opened valve).

Steady and Unsteady flow processes

Steady flow process: A process is said to be steady flow process, if the conditions in the control volume remains unchanged with time.

flow and non flow processes

Flow processes : The processes occurring in open system which permit the transfer of mass as well as energy across its boundaries are known as flow processes.

isobaric process

In an isobaric process, both volume and temperature change, where as pressure is kept constant. The volume and temperature increases when heat is supplied to system and decreases when heat is rejected by the system.

non-flow process

The processes taking place in a closed system which do not permit the transfer of mass across their boundaries are known as non-flow processes.

first law of thermodynamics

First law of thermodynamics states that, “If a system passes through a cycle of processes so that it returns to its initial state the sum of heat and work effects will be zero.

Column and it's type

Column. A bar or a member of a structure inclined at 90° to the horizontal and carrying an axial compressive load is called a column.

Slenderness ratio. The ratio of the equivalent length of the column to the least radius of gyration is called the slenderness ratio.

POWER TRANSMITTED

The  power transmitted by a shaft is given by:

Torsion Formula

Consider a circular shaft of length 1 and diameter d subjected to torque T, as shown in Fig. 5.1 (a). One end of the shaft is rigidly fixed. A line AB on the surface of the shaft, which is parallel to the axis before twisting, takes up the form of a helix AC after twisting. Let 4’ be the angle of shear strain on the surface. Then

DEFINITIONS of Simple Bending of Beams

Axis of Beam (or Centroidal axis). It is a line passing through centroids of all cross-sections of the beam. Line EF is the axis of beam.

Sign conventions in Bending Moment and Shear Force diagram

BENDING MOMENT AND SHEAR FORCE

Bending Moment

The bending moment (B.M.) at any point along a loaded beam is the algebraic sum of the moments of all the vertical forces acting to one side of the point abcut the point. Consider a simply supported beam AB carrying concentrated loads as shown in Fig. 3.1 Lé R and RB be the

FACTOR OF SAFETY

It is the ratio of the maximum permissible stress to which a member can be subjected to the allowable or working stress. For ductile materials,

STRESS-STRAIN DIAGRAM FOR MILD STEEL

The stress-strain diagram for a ductile material like mild

 steel is shown in Fig. 1.13. The curve starts from the origin , showing thereby that there is no initial stress of strain in the specimen. Upto point A, Hooke s law is obeyed and stress is

proportional to strain.Therefore, OA is a straight line. Point A is called the limit of proportionality. Upto point B, the material remains elastic, i.e. on removal of the

VOLUMETRIC STRAIN

It is the ratio of the change in volume V of the body to its original volume V0, when subjected to hydrostatic stress.

POISSON’S RATIO

The ratio of the lateral strain to the longitudinal strain is called the Poisson’s ratio. It is denoted by v (Greek letter Nue). Thus

LONGITUDINAL AND LATERAL STRAINS

Consider a circular test specimen of diameter d and length L If a tensile load P is applied to the specimen its length increases. The increase in length per unit length is called the longitudinal strain. Since the

BASIC DEFINITIONS OF STRENGTH OF MARTIAL

Stress: All bodies offer an equal internal resistance to the externally applied forces. The magnitude of the resisting force per unit area is called stress. Its SI units are N/mm2 or N/rn2.

Tensile (or ultimate) strength: It is the ratio of maximum load to original area of cross-section.

crankcase ventilation

During combustion of oil in combustion chamber there is possibility of acid formation due to sulphur present in the fuel which cause corrosion to engine parts e.g. cylinder walls, piston pins and gear etc.

transmission system

Transmission system consists of clutch, gear box giving different types of ratios of torque output to applied input. The output torque is then transmitted to gear beam and then to differential beam from which it is transfers to in rear wheel if vehicle is in rear wheel drive. It transmits the required torque according to the vehicle drive. So it is a main part without which we cannot imagine variation of speed and torque.

For checking vehicle it should be placed on level surface and then suspend plumb

line from four different corners. Mark the point on ground. Then check the diagonals of four point marked on ground. It should not be differ by 7 to 8 mm. If difference is more than percribed limit then frame is misaligned.

oil cooler

The main objective of oil cooler is to dissipate the heat from lubricating oil Fig. 3.1. Oil cooler is a simple heat exchanger oil coolers nd are generally used in heavy vehicles. Where temperature of oil flow raises it cause the

fuel injector

It is known as nozzle, atomises or fuel valve as shown in figure. The main function of injector is to inject the fuel in the cylinder in the vapourised form in theproper quantity.It’s mainly consists of nozzle and nozzle holder. This types of construction helps to replace the nozzle enhances

transmission system

Transmission system consists of clutch, gear box giving different types of ratios of torque output to applied input. The output torque is then transmitted to gear beam and then to differential beam from which it is

Spring and Shock absorber

The spring support the weight of the vehicle and absorb road shocks. It is offour types coil, leaf spring, air spring and torsion bar.

classifaction of the automobiles

Automobiles can be classified by considering the following points.

1. Use:

(a) Auto, cycles, Buses, Car, Jeeps etc.

purpose of a Fin

The purpose of fins is to improve heat dissipation from a surface to surroundings. Fins are widely used in engineering heat transfer
equipment's  Electrical apparatus like transformers and motors in which

Kirchhoff’s law

This law was established in 1860. Kirchhoff’s law states that at any temperature the ratio of the total emissive power E to the absorptivity

What is Emissivity ?

Emissivity (E) : The Emissivity, of a surface is defined as the ratio of the emissive power of the surface to the emissive power of a hypothetical black body at the same temperature.

Maxwell’s theory

Maxwell’s theory : According to this theory, the energy is transferred from a hot body to cold body in the form of electromagnetic waves.

conduction, convection and radiations

Conduction and convection: These two modes of energy transport required the existence of a material medium.

For conduction of heat, there must be temperature inequalities at adjacent points in the material medium. For convection of heat there must be a fluid free to move and transport energy with it.

irreversible process

A process, which involves heat transfer due to finite difference of temperature between the system and surroundings, is known as an irreversible process

open system, close a system and isolated system

Open system: A system in which the transfer of ma as well as energy takes place, is known as an open system Air compressor and a balloon containing air are known s an open system.

Extensive properties and Intensive properties

1. Extensive properties: The properties which are dependent on the mass a system are known as extensive or extsinsic properties. Volume, mass, internal energy, enthalpy and entropy are the examples of extensive properties. 

Internal energy

Energy possessed by a substance because of molecular arrangement and motion molecules is known as Internal energy. It is solely

quasi-static process

Quasi static means ‘almost static” It refers to a process in which a thermodynamic equilibrium state passes through a process in such a way that every state in the process is in thermodynamic equilibrium.

thermodynamic equilibrium

If in a system, the temperature and pressure at all parts is same, also there is no velocity gradient and chemical equilibrium is also attained

Zeroth law of thermodynamics

if the bodies A and B are in thermal equilibrium with a third body C

separately, then the two bodies A and B shall also be in thermal equilibrium with each other.

system, boundary, surroundings and universe

System: A thermodynamic system represents a specified quantity of matter under consideration to analyse a problem, so as to study the change in properties of the specified quantity of matter due to exchange of energy-in the form of heat and work.

Define heat and work.

Heat may be termed as the energy interaction across the system boundary which occurs due to temperature difference only.’

       Work is done when the point of application of a force moves in the direction of force.

Remember These in Thermodynamics

1. Thermodynamics is that branch of science which deals with energy transfer
2. A system may be closed, open or isolated system
3. A homogeneous system is one which consists of a single phase
4. A heterogeneous system is one which consists of two or more phases.