BHEL Model Questions 3

1.      Which is not present in CI engines?
Ans. carburettor.

2.      What will happen if one cylinder receives more amount of fuel spray from injectors than other injectors?

3.      Purpose of draft tube in hydraulic turbines?
Ans: The purpose of a draft tube is to convert some of the kinetic energy of the flow from the runner (the rotating part of the turbine) into pressure energy and thereby increase the efficiency of the hydro power turbine.

4.      What is the effect of reheater in the gas turbine?

5.      Ans: The advantage of reheater is significantly increased thrust; the
disadvantage is it has very high fuel consumption and inefficiency.

6.      Problems involving with friction coefficient.

7.      Factor of safety = Yield stress/Working stress.

8.      Which is the example of non parallel power transmission (Universal coupling)?

9.      For perpendicular shafts worm gear is used?

10.  A planet gear with 25 teeth is meshed with a sun gear of 100 teeth. Both are connected using an arm. How many rotations are needed for planet gear to complete one rotation around the sun gear?

11.  What is equivalent spring constant for spring in parallel?

12.  Some questions were asked related to boundary layer and vortex flow.

13.  Five questions were asked in PERT, Process planning, Product planning, Break even analysis.

14.  How tungsten and sintered composite materials are machined?
Ans: (Electro Discharge Machining, EDM)

15.  First law of thermodynamics?

Ans: (Q=W+dE)

BHEL Model Questions 2

1.      What percentage of carbon is present in pig iron?
Ans. 4.5 to 6%.

2.      Water is available at 10m height. What is the pressure available?
Ans: Pressure=Density*g*Height;
p=1000*9.81*10;
p=98100N/m2.

3.      What will happen if the speed of the centrifugal pump doubles?

4.      The unit eV is widely used in_____
Ans. Nuclear and atomic physics.

5.      What will happen to the resistance, when the diameter of the conductor is doubled?

6.      The power consumed by a electrical device is 1000W at 250V, What is the resistance in the device?
Ans. Power= Voltage*current,
        Current=Power/Voltage,
        Current,I=1000/250=4 amps.
        V=IR,
        Therefore R=250/4=62.5 ohms.

7.      Why DC current is not used in transformer?

8.      On what principle the sonar/ radar work?

9.      Bending moment diagram for the UDL is in what shape?

10.  Function of the distributor in petrol vehicles?
Ans. Spark timing.

BHEL Model Questions 1

1.      Unit of Entropy (J/kg K or kJ/kg K)?

2.      A mass of 100kg is falling from a height of 1 m and penetrates the sand into for 1 m. What is the resistance force given by sand?

3.      Ratio of specific heats of air? (1.41)

4.      A body weighs 3 kg in air. If it is submerged in a liquid, it weighs 2.5 kg. What is the specific gravity of the liquid?

5.      Two cars travel in same direction at 40 km/hr. at a regular distance. A car comes in an opposite direction in 60km/hr. It meets each car in a gap of 8 seconds. What is the distance between them?

6.      A simple problem involving in hoops stress. For sphere: M= [3/2]*p*V* [density of pressure vessel material/Maximum working stress it can tolerate] For Thin walled pressure walls: Hoops stress or stress in the radial direction =p*r/2t?

7.      A problem in force calculation in a body moving in an inclined surface?

8.      Composition of bronze?
Ans. Copper+zinc.

9.      Composition of stainless steel?
Ans. iron+chromium+nickel+carbon.

10.  CI is manufactured in which process?
Ans. Cupola process