Janardan Rai Nagar Rajasthan Vidyapeeth 2007 Diploma Mechanical Engineering THERMAL ENGINEERING - Question Paper
JRN Rajasthan Vidyapeeth University
DIPLOMA
SEMESTER - 4
THERMAL ENGINEERING
Model Question paper
DSA10 - THERMAL ENGINEERING
Time : 3 hrs Maximum marks : 75
Instruction:
1. Question paper is divided into Group A, Group B and Group C
2. Each Group is 25 Marks
3. Figure to the right in bracket indicates marks.
4. Good Handwriting is expected
5. Assume suitable data if necessary.
Group A (25 Marks)
Answer any three questions (Question 1 is compulsory)
Q.1. Show that Isochoric (constant volume) process on p-v and T-S chart and explain it (05)
Q.2. What is Tidal power. Are there any chances of this power, to be successfully used in our country? (10)
Q.3. Write down energy equation from first low of thermodynamics applied to
i. Closed System
ii. Stead flow System (10)
Q.4. One kg of air at initial condition of 3 bar and 1770c expands adiabatically with out friction to a final condition of 1.2 bar.calculate change of internal energy and external work done during expansion (10)
Q.5: (a) What are the various Boiler Mountings and Accessories? (10)
(b) Explain the working of Economiser and Superheated?
Group B (25 Marks)
Answer any three questions (Questions 6 is compulsory)
Q.6. Three kg of gas at 60oC is heated at constant volume so that pressure of gas is doubled. Find i) final temperature ii) the change in internal energy iii) the change in enthalpy, Take Y = 1.27 for the gas and C = 1.005 kJ/ Kg-K (05)
Q.7. A single stage, single acting air compressor has the cylinder diameter 15cm, stroke 20 cm and rpm 600 . Estimate the quantity of free air handled per second, if the volumetric efficiency is 85%. Te compressor takes in air at 1 bar absolute, and compresses it to 7 bar absolute. Estimate the poser required to drive the compressor if isothermal efficiency with respect to brake power is 60%. (10)
Q.8. Derive the relation for heat transfer through composite wall (10)
Q.9: A single stage reciprocating air compressor has bore 300 mm and stroke 400 mm is required to compress air from 1 bar to 5 bar. Find the power required to drive the compressor while running at 200 rpm. When the index of compression of air is 1 (isothermal), 1.4 (adiabatic) and 1.35 (polytropic). (10)
Q.10: Discuss the following boiler mountings and boiler accessories. (10)
a) pressure gauge
b) blow of cock
c) feed check valve
d) superheater
Group C (25 Marks)
All Questions are Compulsory.
Q.11 Fill in the blanks ( each question carry 2 marks)
1. Dryness fraction x = ________
2. Enthalpy of a wet steam h = _________
3. A process in which no heat transfer takes place is called _________
4. The process of heating feed water is known as ________
5. The velocity compounded turbine is known as _________
Q.12 Multiple choices Question (Each question carries 2 marks)
(1) 1 kw = ________________.
1) 10 watts
2) 100 watts
3) 1000 watts
4) 10000 watts
(2) In motorcycle cooling system used is
1) Water cooling
2) Air cooling
3) Thermosyphone cooling
4) Any of above we can use
(3) The system in which, there is no mass transfer takes place between the system & surrounding is known as, ___________________.
1) Isolated system
2) Closed system
3) Open system
4) Interactive system
(4) The properties which are independent on the mass is known as ________________.
1) Extensive property
2) Intensive property
3) Thermodynamics property
4) None of these
(5) Which of the following is a water tube boiler
1) Cornish boiler
2) Locomotive boiler
3) Benson boiler
4) Cochron boiler
Q.13 True or false (each question carry 1 marks).
(1) Fusible plug is fitted in the crown of the furnace.
(2) Staem stop valve is used to regulate the flow of steam from boiler to main steam pipe.
(3) Economizer consist of a no. of vertical & horizontal tubes.
(4) Economizer increases the life of boiler by reducing the temperature difference between different parts.
(5) SAE is the rating for lubricating oil.
***********
| Earning: Approval pending. |
