# JNTU previous question papers- B-Tech I Sem ,Thermal science – November 2008

JNTU previous question papers

JNTU II B.Tech I Semester Regular Examinations, November 2008

THERMAL SCIENCE

SET-2

1. (a) What are different forms of work energy? Explain each briefly.

(b) Write a note on Quasi static process.

2. (a) What do you understand by the ideal gas temperature scale?

(b) A closed system undergoes a thermodynamic cycle consisting of four separate

and distinct process. The heat and work transferred in each process are as tabulated below:

Process                   Heat transfer in KJ/min           Work transfer in KJ/min

1-2                                      20,000                                        0

2-3                                     -10,000                                    30,000

3-4                                           0                                        20,000

4-1                                      15,000                                   -25,000

Show that the data is consistent with the first law of thermodynamics. Also

evaluates the net work output in KW and the changes in internal energy?

3. (a) Define the COP of a refrigerator. How is the COP of a heat pump related to the COP of refrigerator?

(b) Prove that violation of the Kelvin-Planck statement leads to violation of the clausius statement of the second law of thermodynamics.

4. (a) Determine the ideal efficiency of the diesel engine having a cylinder with bore

250 mm, stroke 375 mm and a clearance volume of 1500CC, with fuel cut-off occurring at 5% of the stroke. Assume ?=1.4 for air.

(b) A diesel engine is working with a compression ratio of 15 and expansion ratio

of 10. Calculate the air-standard efficiency of the cycle. Assume ? = 1.4.

5. (a) Write the differences between refrigerator and heat pump? Derive the COP for both of them?

(b) The capacity of refrigerator is 280 tons. Determine the quantity of ice produced at 00 C with in 24 hours when water is supplied at a temperature of 200C.

6. (a) What is the importance of octane number in rating the quality of S.I. engine fuel? Explain.

(b) What are different chemical structures in petrol? Which one is advantages for better Combustion.

7. (a) Draw the schematic diagram of a Simple carburetor and explain its functionality with different conditions.

(b) What are different types of nozzles used in C.I. Engine fuel injector and explain

its working.

8. (a) Draw the schematic diagram of regenerative gas turbine unit. Explain it’s

working along with p-V and T-s diagrams.

(b) Derive the thermal efficiency of gas turbine unit with inter cooling.