### FORMAT OF I A TEST QUESTION PAPER (CIE) | BASIC THERMAL ENGG. | I/II SEM| DIPLOMA

 Test/Date and Time Semester/year Course/Course Code Max Marks Ex: I test/6 th weak of sem 10-11 Am I/II SEM BASIC THERMAL ENGG. 20 Year: Course code:15ME42T Name of Course coordinator :                                                                                             Units:   CO’s: Question no Question MARKS CL CO PO 1 2 3 4

Note: Internal choice may be given in each CO at the same cognitive level (CL).

 MODEL QUESTION PAPER (CIE)

 Test/Date and Time Semester/year Course/Course Code Max Marks Ex: I test/6 th weak of sem 10-11 Am IVSEM BASIC THERMAL ENGG. 20 Year: 2016-17 Course code:15ME42T Name of Course coordinator :                                                                                             Units:1,2 Co: 1,2   Note:  Answer all questions Question no Question MARKS CL CO PO 1 Differentiate between intensive and extensive properties of a system. Give three examples for each. 04 U 1 1,2, 3,6, 10 2 A volume of 0.5 m3 of gas at a pressure of 10 bar and 200oC is expanded in a cylinder to 1.2 m3 at constant pressure. Determine the amount of work done by the gas and the increase in internal energy. Assume Cp = 1.005 kJ/kg K and Cv = 0.712 kJ/kg K. OR A closed system undergoes a change in process in which 5 kJ of heat energy is supplied to the system. Determine the change in internal energy under the following conditions. i)            1 kJ of work is done on the system. ii)          1.25 kJ of work is done by the system. 06 A 1 1,2, 3,4, 6,10 3 Derive an expression for work done during polytrophic process. 04 U 2 1,2, 3,4, 6,10 4 One kg of gas expands reversibly and adiabatically. Its temperature during the process falls from 515K to 390K, while the volume is doubled. The gas does 92 kJ of work in this process Calculate: The value Cp and Cv OR   A gas has a molecular mass of 26.7. The gas is compressed through a ratio of 12 according to the law PV1.25 = C, from initial conditions of 0.9 bar and 333 K. Assuming specific heat at constant volume Cv = 0.79 kJ/kg K. Calculate per kg of mass, work done and heat flow across the cylinder walls. Gas constant and ratio of specific heat. 06 A 2 1,2, 3,4, 6,10

MODEL QUESTION PAPER

IV- Semester Diploma Examination

Course Title: BASIC THERMAL ENGINEERING

Time: 3 Hours]                                                                                            [Max                                                                                          Marks:                                                                                               100

Note: Answer any SIX from PartA and any SEVEN from Part B

PART-A            6x5=30 marks

1.                 Define the terms: (i) system (ii) boundary and (iii) surroundings.

2.                 A closed system received a heat transfer of 120  kJ and delivers a work transfer of  150 kJ. Determine the change of internal energy.

3.                 Derive expression for work done in constant temperature process with PV diagram.

4.                 A volume of 0.5 m3 of gas at a pressure of 10 bar and 200oC is expanded in a cylinder to 1.2 m3 at constant pressure. Determine the amount of work done by the gas and the increase in internal energy. Assume Cp = 1.005 kJ/kg K and Cv = 0.712 kJ/kg K.

5.                 List the assumptions made in thermodynamic air standard cycle.

6            Define IC engine and give the classification of IC engines.

7.                 Explain following terms:

a)  Volumetric efficiency b) Mechanical efficiency

8.                 State and derive Fourier’s law of heat conduction.

9.                 State the applications and limitations of gas turbine.

PART-B

1.          a. Differentiate between intensive and extensive properties of a system. Give three examples for each.                                                                    04

b. A cold storage is to be maintained at -5o while surroundings are at 35oC. The leakage from the surroundings into the cold storage is estimated to be 29 kW. The actual C.O.P. of the refrigeration plant is one - third of an ideal plant working between the same temperatures. Determine the power required to drive the plant.                                                                            06

2.          a) Prove that Cp-Cv=R 04

a)   A piston - cylinder containing air expands at a constant pressure of 150 KPa from a temperature of 285 K to a temperature of 550 K. The mass of air is 0.05 kg. Determine the heat transfer, work transfer and change in internal energy during the process Cp =

1.01 kJ/kg K and Cv = 0.72 kJ/kg K.                                                                                     06

3.          a) List the thermodynamic processes on gases. 04

b)A piston cylinder containing air expands at a constant pressure of 150 kpa from a temperature of 285 K to a temperature of 550 K. The mass of air is 0.05 kg. Determine the heat transfer, work transfer and the change in internal energy during the process. Take Cp = 1 kJ/kg K, R = 0.287 kJ/kg K.                                                                    06

4.          a. Derive an expression for work done during polytrophic process. 04

b.  A gas of mass 0.56 kg is expanded adiabatically from a pressure at 8 bar to 1 bar adiabatically. Initial temperature of the gas is 200oC. Determine the work done and change in internal energy. Take Cp = 1 kJ/kg K and Cv = 0.714 kJ/kg K.                                                                    06

5.       Explain with the help of P-V and T-S diagrams working of Otto cycle and derive an expression for the air standard efficiency of it. 10

6.            A certain quantity of air at a pressure of 1 bar and temperature 70oC is compressed reversibly and adiabatically until the pressure is 7 bar in an Otto cycle engine. 460 kJ of heat per kg of air is now added at constant volume.

Determine:

i) Compression ratio of the engine.    ii)Temperature at the end of compression. iii)Temperature at the end of heat addition.Take for air, CP = 1 kJ/kg K and

Cv = 0.707 kJ/kg .                                                                                       10

7.          a)    Compare petrol and diesel engines. 04

b) A heat engine has a piston diameter of 150 mm, length of stroke 400 mm and mean effective pressure 5.5 bar. The engine makes 120 explosions per minute. Determine the mechanical efficiency of the engine, if the engine BP is 5 kW.                                                                    06

8.           The following data refers to a four stroke diesel engine, speed 300 rpm cylinder diameter 200 mm, stroke 300 mm, effective brake load 500 kg,                                                circumference of the brake drum 400 mm, mean effective pressure 6 bar. Diesel oil consumption 0.1 litres/min, specific gravity of diesel 0.78, calorific value of oil = 43900 kJ/kg.

Determine : i)  Brake power         ii)  Indicated power         iii) Frictional power                                                                                        10

9.                 a) Define : (i) Conduction (ii) Radiation.                                                                                   03

b) Heat is conducted through a wall of room made of composite plate with a conduction of 134 W/mK and 60 W/mK and thickness 36 mm and 42 mm respectively. The temperature at the outer face is 96 0C and 8 0C. Determine the temperature at the interface of the two materials.                                                                    07

10.              a) Explain closed cycle gas turbine with schematic diagram.                                                                                   06

b) State the applications and limitations of gas turbine                                                                                   04