**BOARD DIPLOMA EXAMINATIONS (C-14)**

**DEE – THIRD SEMESTER EXAMINATIONS**

**GENERAL MECHANICAL ENGINEERING**

**Time: 3 Hours Total marks: 80**

** PART-A 10X3=30**

** **

*Instructions:**1) Answer*

**all**questions.*2) Each question carries*

**three**marks.*3) Answer should be brief and straight to the point and shall not exceed*

**five***Simple sentences*

- List out the types of loads and describe any two loads with neat sketches?
- Define the terms stress & strain & its units?
- What is shaft? State its functions.
- Define polar moment of Inertia?
- State any 8 components of an IC engine and mention their functions?
- Define BDC, TDC & stroke length?
- State the principle of water tube boiler?
- Write the applications of steam turbine?
- Name different properties of lubricants?
- What are the advantages of centrifugal pump over the other pumps?

**PART-B **5X10=50

*Instructions:**1) Answer any*

**five**questions.*2) Each question carries*

**ten**marks.*3) Answer should be comprehensive and criterion for valuation is the content*

*but not the length of the answer.*

- Explain stress-Strain diagram for a ductile material indicating the salient points
- A bar of varying section is loaded as shown in fig determine the total elongation. If E= 2x10
N/mm^{5}^{2}

13.Design a suitable diameter of a solid shaft to transmit 110KW of power at 240 rpm , if the allowable stress is not to exceed 70 N/mm

^{2}and twist not to exceed 1

^{0}in a length of 3m . Take G=0.8 x 10

^{5}N/mm

^{2}

14.Explain with the help of line sketch the working principle of four stroke diesel engine?15.Describe the working of a simple carburetor with a neat sketch?

16.Describe the working of Babcock and Wilcox boiler with a neat sketch?

17.Differentiate between impulse turbine & reaction turbine?

18.Draw a simple sketch showing the installation & working of a centrifugal pump indicating various components & hydraulic heads?

**BOARD DIPLOMA EXAMINATIONS (C-14)**

**DME – THIRD SEMISTER EXAMINATIONS**

**GENERAL MECHANICAL ENGINEERING**

**Time: 3Hours Total marks: 80**** **

** PART-A 10 X 3=30**

*Instructions:**1) Answer*

**all**questions.*2) Each question carries*

**three**marks.*3) Answer should be brief and straight to the point and shall not exceed*

**five***Simple sentences*

- Define lateral strain & poisson’s ratio?
- Define the hook’s law & proportional limit?
- Define the torsion? Which stress is induced in shaft, when it is subjected to twisting moment?
- A solid shaft is to transmit350 KW of power at 110 rpm if the maximum shear stress is induced must not exceed 80N/mm
^{2}; find the diameter of the shaft? - What is an internal combustion engine?
- List out any six parts of an IC engine?
- Name different types of boiler mountings?
- Write the application of steam turbines?
- Write about priming of centrifugal pumps?
- Name different properties of lubricants?

**PART-B**5X10=50

*Instructions:**1) Answer any*

**five**questions.*2) Each question carries*

**ten**marks.*3) Answer should be comprehensive and criterion for valuation is the content*

*but not the length of the answer.*

- A bar of 30 mm dia is subjected to a pull of 60KN. The measured extension over a gauge length of 200 mm is 0.09 mm and change in dia is 0.0039 mm. Find the Poisson's ratio and the values of the three moduli.
- A bar of varying section is loaded as shown in fig determine the total elongation. If E= 2x10
N/mm^{5}^{2}

- A hollow shaft is required to transmit 400kw at 240 rpm. The maximum torque is 20% greater than the mean. The permissible shear stress is 60 N/mm
^{2}. The twist in a length of 4m is not to exceed 15^{0}. The ratio between inner and outer diameter is 2/3, calculate inner and outer diameters of the shaft. Take G = 80KN/mm^{2}. - Explain working principle of 2 stroke petrol engine with neat sketch?
- a) Compare two stroke engines with four stroke engines?
- b) Compare Compression ignition engine with Spark ignition engine?
- Explain the working of Benson boiler with a neat sketch?
- With a neat sketch explain the working of impulse turbine?
- Explain the working and constructional details of a centrifugal pump with a neat sketch.