Mechanical

Important Questions for Mechanical Those were asked to me in interview 2019?

      Q1. What was your last profile?

      Ans.I was a technical trainer in training division.

      Q3. Draw the cooling & lubrication system diagram in engine?

      Q4. What is  adiabatic process?

      Ans. An adiabatic process occurs without transfer of heat or mass of substances between a                           thermodynamic system and its surroundings. In an adiabatic process, energy is transferred 

               the  surroundings only as work.

        Q5. What is otto cycle?

         Ans. An Otto cycle is a thermodynamic cycle that describes the functioning of a  spark ignition  engine.

Q6. What is diesel cycle?

        Ans.  An Diesel cycle is a thermodynamic cycle that describes the functioning of a  compression    ignition  engine.The Diesel cycle is assumed to have constant pressure during process.

Q7. Working of oil strainer and oil sump?

        Ans. The oil pump forces the engine oil through the passages in the engine to properly distribute  oil to different  engine components.
Strainer  removes some of the larger dust particles.

Q8. Types of engine ?

       Ans. Internal combustion engines and external combustion engines.

Q9. What is EC and IC engine?

      Ans.External engines are those in which the working fluid is ignited by the the external sources and  In IC engines fuel is ignited inside the cylinder.

Q10. Why diesel engine is called CI engine?

      Ans.as compression of the air is used to Ignite the fuel so diesel engines are referred as a CI  engine.

Q11. Compression ratio for  diesel engine?

      Ans. 15:1-23:1

Q12. How Engine works?

      Ans. The engine converts Chemical energy into Heat Energy then Mechanical Energy by Completing four strokes.

Q13. What is stroke?

       Ans. A stroke refers to the full travel of the piston along the cylinder.

Q14. How petrol engine works?

      Ans.A two-stroke engine contains two processes:

Compression stroke: The inlet port opens, the air-fuel mixture enters the chamber and the piston moves upwards compressing this mixture. A spark plug ignites the compressed fuel and begins the power stroke.

Power stroke: The heated gas exerts high pressure on the piston, the piston moves downward (expansion), waste heat is exhausted.

Q15. What is TDC & BDC?

       Ans. Top dead center and bottom dead center.

Q16. What is combustion chamber?

       Ans. In which the fuel burns.

Q17. Difference between Cam shaft and Crank shaft?

        Ans. Crank shaft convert the reciprocating motion into rotary motion and cam shaft operates the Valves.

Q18. Working of oil separator?

       Ans. The function of an oil separator is to separate oil from the hot gas in the discharge line and return it to the compressor crankcase or to the oil reservoir.

Q19. Bolt tightening sequence?

       Ans. It should be crossing symbol type.

Q20. What is torque and types of toque wrench?

       Ans. Torque is the twisting force that tends to cause rotation.
The point where the object rotates is known as the axis of rotation. Mathematically, torque can be written as

 T=f*r

●        Dial type

●        Click type

●        Beam type

●        Digital type

Q21. How to change torque of torque?

       Ans. Adjust the torque specification on the wrench by turning the handle of the torque wrench while holding the shaft of the torque wrench. The dial indicator will move up or down the inch-pound, foot-pound or N-m scale as you turn the handle clockwise or counterclockwise.

For get it in details please click on the blow link

https://youtu.be/3v3hLvuO_KU

Q22. What was your polytechnic project?

       Ans. Air Cooler.

Q23. What is Connecting Rod?

       Ans. Which connects the piston to the Crank shaft.

Q24. Bearing used in  connecting rod?

       Ans. Sleeve bearing.

Q25. Working of Piston Pin?

       Ans. It connects the piston and connecting rod.

Q26. Types of bearing?

       Ans.      

●        Plain bearings

●        Ball bearing

●        Roller bearing

●        Fluid bearing

●        Magnetic bearing

Q27. Working of bearing?

        Ans. Bearings reduce friction and it is used for specific purposes and designed to carry specific types of loads, radial or thrust.

Q28. What is friction bearing?

        Ans. Friction is the force that opposes motion between any surfaces that are in contact. 
There are four types of friction: static, sliding, rolling, and fluid friction. Static, sliding, and rolling friction occur between solid surfaces. Fluid friction occurs in liquids and gases.

Q29. Explain ohm’s law?

       Ans. V=IR

Q30. Newton’s third Law?

        Ans. Newton's third law is: For every action, there is an equal and opposite reaction.

Q31. What are current and voltage?

       Ans. current is the rate of flow of electric charge.

Voltage is what makes electric charges move. It is the 'push' that causes charges to move in a wire or other electrical conductor.

Q32. What is tappet setting?

       Ans.Tappet clearance is the clearance between the rocker arms and the point where they rest on the valves.

Q33. How to Check tappet setting?

       Ans. By using filler Gauge.

Q34. What is battery?

       Ans. Batteries are a collection of one or more cells whose chemical reactions create a flow of electrons in a circuit.
All batteries are made up of three basic components: an anode (the '-' side), a cathode (the '+' side), and some kind of electrolyte (a substance that chemically reacts with the anode and cathode.

Batteries that must be thrown away after use are known as primary batteries. 

Batteries that can be recharged are called secondary batteries.

Q35. What kind of tools did you used?

       Ans.

●        Mallet

●        Hammer

●        Screw driver

●        Wrenches

●        Tension meter

●        Spanners

●        pneumatic & electric guns etc

Q36. Some HR questions?

        Ans. Family background etc.

 If there is any doubt & Mistakes please ask and comment

Source _Google_&_Self👴

16012020:10PM

💥The Basic 👉Engine👈 questions which are normally asked in Interview.

Q1. What is IC Engine and EC engine?

  Ans. In External combustion engine combustion is occurred outside the cylinder Ex. Steam Engine and In Internal combustion Engine Combustion occurred inside the cylinder Ex. Petrol Engine.

Q2. What is two stroke and four stroke engine?

Ans. In two stroke engine The working cycle completes in two stroke of the piston 1. Compression stroke 2. Power stroke

In four stroke engine the working cycle completes in four stroke of the piston 1.suction stroke 2. Compression stroke 3. Power stroke  4. Exhaust stroke.

Q3. What is low, medium, and high speed engine?

Ans. low<350rpm

Medium<350-1000   

  High>1000

Petrol engine always works on high speed greater than diesel engine.

Q4. Explain petrol engine and diesel engine?

Ans. In petrol engine Fuel and air mixture gets inside the cylinder and ignite by the spark plug and In Diesel engine natural air compressed by  the piston and fuel inject by the fuel injector.

Q5.Parts of the engine?

Ans. Some important parts of the engine:

a.      Cylinder block

b.      Cylinder head

c.      Piston

d.      Crank shaft

e.      Cam shaft

f.       Connecting rod etc

Q6. What

 is crank shaft and cam shaft?

Ans. Crank shaft convert reciprocating motion of the piston into rotary motion And Cam shaft regulate intake and exhaust valve.

Q7. What is piston?

Ans. Piston is mechanical part of the Engine which moves inside the cylinder and complete the strokes.

Q8. How connecting rod working?

Ans. Connect rod is connected with the piston and with the crank shaft, It transfer the reciprocating motion of  the piston to the crank shaft.

Q9. What is stroke length?

Ans. The distance between the TDC to BDC.

Q10. What is swept (Vs) and clearance volume (Vc)?

Ans. Displaced volume by the piston is called swept volume and volume of the space above the piston when it is at TDC is called clearance volume.

Q11. What is compression ratio?

Ans. Ratio of the compression volume before the stroke and after the stroke is called compression ration

                             CR= (Vs+Vc)/Vc

Q12. Tell me the working the piston rings.

Ans. There are  only two types of rings are used in Engine-Oil rings for lubricating of piston

Compression rings for providing air tight seal to prevent leakage of the burnt gases into the lower portion.

Q13. How to find piston speed?

Ans. Distance traveled by the piston per minute in cylinder is called piston speed.

Ps=2*L*N m/min

L=stroke length

N=engine speed

Q14. What is the compression ratio in petrol and Diesel engine?

Ans. In petrol engine it drives 5:1-10:1

 In diesel engine it drives 14:1-22:1

Q1. What is carbonation?

Ans. The process of preparing a combustible fuel-air mixture outside engine cylinder in SI engine is known as carbonation.

Q1. What is carburetor?

Ans.Carburetor is  a part of the Petrol & Gasoline engine,Which mix air and fuel in specific ratio.it can be burned in the combustion chamber.

Q17. What is fuel pump?

Ans.Fuel pump is Mechanical device using suction or pressure to raise  or move liquid, compress gases or force air into inflatable objects such as tires.

Q17. What is chocking?

Ans. In chocking, the fuel rate increase in carburetor for instant starting or better result.

Q18. Why cooling is important for engines?

Ans. Because after power stroke the temperature starts increasing so engine is cooled by water jacket or air fins otherwise some engine parts will damaged.

Q19. Lubrication system of IC Engine?

Ans. There are lots of moving & reciprocating parts work in engine so it's done for lubricating & save  the parts from wear & tear.

Q19. What is Auto Ignition?

Ans. When the fuel spontaneously ignites in a normal atmosphere without an external source of ignition is called auto ignition.

Q20. What is Surface ignition?

Ans. The ignition of a flame in the combustion chamber of the engine by any hot surface other than the spark discharge is called surface ignition.

Q21. What is Ignition delay?

Ans. The time travel between the fuel injection and it’s ignition is called ignition delay.

There  can be divided into two types
 1) Physical delay
 2) chemical delay

Ignition delay depends on fuel quality.

Q22. What is rapid combustion?

Ans. Rapid combustion  is a form of combustion in which large amount of heat is released,

Ex. Combustion during knocking time, Combustion of natural or LPG gas.

Q23. What is After burning? 

    Ans. After the combustion process some unburned fuel particles remains in combustion chamber and when compression stroke ends then combustion begins before the fuel injection or with fuel injection too, this process is called after burning.

Q24. What is Knocking?

Ans.During Ignition delay some small drops of fuel remains in combustion chamber and when the fuel is injected (IC  fuel drops  and injected) then fuel and air mixture burned very fast.In this process high noise or vibration generate due to high pressure is called knocking.

Q25. What is fuel injection pump?

Ans.The main function of the fuel injection pump is to provide high pressurized fuel to injector by HP line.

Q26. How fuel filter work?

Ans.The main function of the fuel filter is to filter the fuel by removing all extremely small particles and transfer it to the fuel injection pump.

Q27. How fuel injector work?

Ans.The fuel injector,inject the high pressurized fuel in cylinder after compression stroke.

Q28. What is cetane number?

Ans.Cetane number is used to specify the ignition quality of diesel fuel,generally CN value vary 48-50.

Lower CN number= longer combustion delay

Higher CN number = Earlier ignition.

Q39. What is flash point?

Ans. It is the lowest temperature of the fuel at which the vapor of that liquid will ignite, if given an ignition source.

Petrol or gasoline=43 degree Celsius

Diesel= 52-96 degree.

Coming soon

💥The Basic 👉Thermodynamics👈 questions which are normally asked in Interview.

Q1.What is ‘Thermodynamics’?

Ans. Thermodynamics is a branch of science that deals with heat and temperature, and their   relation to energy,work,radiation, and properties of the matter.👍

Q2.What is Zeroth Law of Thermodynamics?

      Ans. If two systems are in thermodynamic equilibrium with third system, the original systems are in thermal equilibrium with each other.👍

Q3.What is First Law of Thermodynamics?

     Ans. Energy neither be generated nor destroyed, but it can be Change from one form to another form with the interaction of heat, work and internal energy.👍

Q4.What is Second Law of Thermodynamics?

      Ans. The whole of the heat energy can not be converted into work and part of energy therefore must be rejected to the surroundings.👍

Q.5What is Third Law of Thermodynamics?

    Ans. Entropy of any substance is zero on Zero absolute temperature.👍

Q.6 What is Enthalpy?

    Ans.Enthalpy is the sum of the internal energy of a system and the product of the pressure and the volume of the system.The change in enthalpy is the change in internal energy and  work done.👍

Q7,What is Ideal gas?

     Ans. The Gas which has no inter molecular forces and no molecular size is called ideal gas.An ideal gas never collides with other gas molecules because they are infinitely small.👍

                                       PV=nRT

Q8.What is Adiabatic process?

     Ans. An adiabatic process is a thermodynamic process in which there is no heat transfer

     into or out of a system.👍

Q9.What is acceleration?

    Ans. Rate of change of velocity is called acceleration.👍

Q10.What is Energy?

   Ans. The capacity of doing any work is called energy.👍

Q12.What is Entropy?

    Ans. Entropy is a measure of disorder or randomness of a system. An ordered system has low entropy. A disordered system has high entropy.👍

Q13.How many process are in Carnot cycle?

   Ans. 2-Adiabatic process,2- Isothermal process👍

Q14. What is  latent heat?

     Ans. The quantity of heat absorbed or released by a substance undergoing a change of state (temperature)  is called latent heat. It is represented by L or h_fg.👍

L.H of steam on atmospheric pressure is 2248.31 kJ/kg.

Q15.What is sensible heat?

      Ans. This is related to change in temperature to the body or system,where the system

      absorbs or release certain quantity of heat and changes the temperature of the system.👍

Q16.What is boiler?

    Ans. The main function of boiler is to heat water to generate steam.👍

Q17. Classification of boiler?

    Ans. There are two general  types of boilers; fire tube boilers and water tube boilers.

    Boilers are also classified as “high pressure boiler” and “low pressure boiler” and

    more.👍

Q18. What is economizer?

   Ans.  Economizer a device that  capture the waste heat from the boiler waste gases and

   transfer it to the boiler feed water.👍

Q19.What are boiler mountings and accessories ?

     Ans. Boiler mountings and accessories are used to increase safety and efficiency.

     Ex. Economizer, safety valve, fusible plug.👍

20.What is pressure gauge?

    Ans. Pressure gauge is used to measure and display pressure in an integral unit like 1bar or 1.3bar.👍

21.What is the use of fusible plug in boilers?

     Ans. It is fitting used in steam boilers to enhance the safety during  operations.It’s working depends upon the water level in boiler shell.👍

22.What is steam turbine?

     Ans. A steam turbine is a prime mover in which the potential energy of the steam is

     transformed into kinetic energy and later transformed into mechanical energy of rotation of the turbine shaft.👍

23.What are impulse or reaction turbine?

      Ans. Nozzles  are used in impulse turbine and not used in reaction turbine.👍

24.Degree of reaction?

     Ans. It’s ratio of change in pressure energy inside turbine to the change of total energy

     turbine.👍

25.What is bleeding in steam turbines?

     Ans.  Bleeding is process in which some part of steam is taken off of certain sections of a turbine that is used for heating and sealing purpose.👍

26.What is governing in turbine?

     Ans. It is used to run the  and turbine at high speed or at low speed or at constant speed can be maintain by the governing is called governor of turbine.👍

27.What is atmospheric pressure or barometric pressure?

     Ans.The pressure exerted by the atmosphere is called atmospheric pressure .👍

28.What is steam condenser?

    Ans. Steam condenser is a mechanical device which converts the low pressure exhaust

    steam from the turbine into water.👍

29.What are the types of condensers?

    Ans. The three main types of condenser used;👍

           a)     Air cooled

           b)     Water cooled

           c)      evaporative

30.What is the main use cooling tower?

     Ans. A cooling tower is heat rejection device, which extracts waste heat to the atmosphere through the cooling of a water stream to a lower temperature.👍

31.What is gas turbine?

     Ans. Gas turbine is a combustion engine that can convert natural gas or other liquids fuel to mechanical energy.👍

32.What is generator?

     Ans. A generator is a mechanical device that converts mechanical or chemical energy into electrical energy.👍

34.what is compressor?

     Ans. A compressor is a pump used to increase the low pressure of air to a greater pressure.

                                                                                       Or

A compressure is a mechanical device that increase the pressure of a gas by reducing its volume.👍

35.What is jet propulsion?

     Ans. Jet propulsion means the propulsion or movement of the bodies such as ships,

     aircrafts, rocket etc with the help of jet. It works on newton’s third law.👍

36.What is heat exchanger?

     Ans. A heat exchanger is a device used to transfer heat between two or more fluids.👍

37.What is moderator in nuclear power plant.

     Ans. moderator are used to decrease neutron speed in reactor Ex. Graphite and He.👍

38.What is the different between fission and fusion?

     Ans. In a fission  reaction, a heavy nucleus is split into smaller nucleus, other particles and other radiation or

      In fission reaction, two or more light atomic nucleus fuse to form a single heavier

      nucleus.👍

40.What is refrigeration and air conditioning?

      Ans. Air conditioning  is the process of removing heat and moisture from the interior of an occupied space.👍

41.Which  gas is used in refrigerator?

Ans. HFC 134 Tetrafluroethane.

Note☝ If there is any mistake occurred please comment I'll fix that immediately🙅

🙌The Basic hydraulics questions which are normally asked in Interview.

Q 1. What is Cohesion?

Ans.  The force of attraction between molecules of the same substances is called Cohesion

Ex. Water drops.

Q2. What is adhesion?

Ans. The force of attraction between molecules of the Different substances is called Adhesion

Ex. Water & Glass.

Q3. What is Viscosity?***

Ans.  Viscosity is property of the fluid which oppose the relative motion between the two surfaces of the  fluid that are moving at different. 

Q4. What is Surface Tension?*

Ans. Surface tension is property of the surfaces to shrink into the minimum surfaces area possible.

Q 5. What is Pascal’s Law?

Ans. According to Pascal’s law if any force is applied on an enclosed fluid then the force will act equally on every point of the fluid.

Ex. Hydraulic Jack.

Q 6.  What is density?

Ans. The ratio of Mass & Volume of any substance is called Density and it’s unit is kg/m3

Q  7 . Which instruments are used to measure viscosity of the fluids?

Ans.  Viscometer or viscosimeter is used to measure viscosity of the fluids.

Q 8.  Where pascal’s law is used in Hydraulics.

Ans. In hydraulic jack, hydraulic brakes, hydraulic pump.

Q9.  What is the center of gravity from base of Triangle, Rectangle,circle?

Ans. X=h/2, x=h/3, x=h/2  

Q10. What is ‘Buoyancy’?

Ans. Buoyancy is an upward force Applied by a fluid that opposes the weight of an immersed object.

Q11 What is Buoyancy force?

Ans.  The force that works on a immersed body is always equal to the displaced fluid by the object is called buoyancy force.

Q12 What is ‘Archimedes’s Principle?

Ans. When a object is dipped or floating in fluid then a lackness is felt in it’s weight this lackness is always equal to the displaced fluid by object.

Q13 What is Meta center?

Ans. Metacentre is the point about which all the parts of a body oscillate when an angular motion is applied on body.

                 GM= 1/V+GM

Q14 What is the Specific gravity of water?

Ans. 1.o

Q15 What is the specific density of water?

Ans. 13.6

Q16-   What is orifice  ?

 Ans.  Orifice is an opening made on the side & at the bottom of the tank throw which the liquid flows and  the water level Is always above the opening.

Q17-   What is notch?

Notch is an opening made on the side & at the bottom of the tank throw which the liquid flows and  the water level Is always above the crest.

Q18-   What are the Basic principles of Liquid flow.

Ans.   1- Principle of conservation of mass in flow.

           2- Principle of conservation of energy.

           3- Principle of conservation of momentum.

Q19- What are steady ?

Ans. A flow in which the velocity, pressure & density doesn’t change at the particular fixed point is called steady flow.

Q20- What is turbulent flow.

Ans. A flow in which the velocity of the fluid  varies at the particular point is called turbulent flow.

Q21- What is Reynolds Numbers.

Ans. Reynolds number is used to identify the flow pattern in different fluid flow situations.

R_N =    ᵨᵥd/µ

Q22- What is the formula of Discharge or Rate of flow.

                                                                             Q=V/t

Q23 - What is continuity equation.

Ans.    Q₁=Q₂=Q₃  

Q24 - What is Discharge.

Ans.   The quantity of fluid  releasing per second from any pipe, hole or channel is called Discharge.

Q26- What is Bernoulli’s Theorem?

Ans. When a liquid is influenced by the linear effect from one place to another place then  pressure energy , kinetic energy and  potential energy is fixed at each point of the path.

                                        H = Z + p/ρg + V2/2g  = constant

Q27- What is Venturi Meter?

Ans. Venturi meter is a mechanical device which is used to measure the rate of water flow at any point.

Q28- What is orifice Meter?

Ans. Orifice meter or orifice plate is also like venturi meter but it takes a little place than venture meter.

Q29- Which instrument is used to measure discharge flow in an open channel?

Ans. Pivot tube is used to measure discharge flow in open channel.

Q30. What is thermostat?

Ans. A  device that automatically activates when the temperature reaches a certain point.

Q31. What is the relation between C_d (Coefficient of Discharge) _,C_v (Coefficient of velocity) and C_c (coefficient of contraction).

Ans.                                                               C_d = C_cC_v

Q32. What is venture flume?

Ans. It is used to measure the rate of flow  in Streams or Channel.

Q33. What is formula to find head loss due to friction?

Ans.                    h _f = 4flV²/2gd         Where f = coefficient of friction.

Q33. What is Chezy’s Formula?

Ans. V = C√mi

   Where m = A / P , i= h_f/l

Q34. What is pump?

Ans. A pump is a device which is used to increase the pressure of the fluid.

Q34.  Tell us any five parts name of the centrifugal pump.

Ans.

1)     Suction pipe

2)     Eye

3)     Casing

4)     Impeller

5)     Delivery pipe

Q35. What kind of losses can be occurred in pump?

Ans.                 

1)     Hydraulic losses

2)     Volumetric losses

3)     Mechanical losses

Q36. What is Turbine.

Ans. Turbine is a machine that changes fluid energy into mechanical energy.

Q37. What  is the unit of surface tension?

Ans. Newton/meter or N/m.

Q38. What is the dimension of coefficient of viscosity?

Ans. ML^-1T^-1

Q39. What is the dimension of surface tension?

Ans. MLT^-2

Q40.What is the specific weight of water?

Ans. 1000kg/m³.

Q41. What is hydrometer?

Ans. it is used to measure specific gravity of fluids.

Q42. What is the unit of viscosity?

Ans. N/m² or Pascal & CGS unit is Poise.

Q43. What is ideal fluid?

Ans. An ideal fluid is that which has no viscosity, compressibility or surface tension and it is frictionless.

Q45. What is weir.

Ans. A structure, used to dam up a stream or river, over which the water flows, is called a weir. The main difference between notch and weir that weir is used to measure major discharge flow.

Q46. What is crest in Hydraulics.

Ans. The upper edge of notch & weir by which the water flows is called crest