DAYANANDA SAGAR COLLEGE OF ENGINEERING

DEPARTMENT OF AERONAUTICAL ENGINEERING

IV Semester : 2015 , ReTest

Applied Thermodynamics

Sub Code10ME43 Max Marks: 50

Duration: 1.5 Hrs Date: 21/05/2015

PART A

1 Define the following: a) Enthalpy of formation b) Heat of Reaction c) Calorific Value d)

Adiabatic Flame temperature e) Stoichiometric air-fuel ratio 10

2 The following observations were recorded in a test of 1 hour duration on a single cylinder

4-stroke oil engine.

Bore = 220mm, Stroke-300mm, Fuel used-4 Kgs, Calorific value- 42 MJ/Kg, Shaft

speed- 300 rpm, number of explosions per minute 148. MEP-5 bar, Load on brake drum-60Kgs.Spring balance reading 30 N, diameter of brake drum-1.4m, quantity of cooling water circulated-500Kgs, Increase in temperature of cooling water-20C, Air fuel ratio-16, Exhaust temperature-410C,specific heat of gases-1.1 KJ/KgK, ambient air temperature-30C. Determine IP,BP,Mechanical Efficiency,Brake thermal Efficiency,Specific fuel consumption, Draw heat balance sheet in KJ/min

10

3 Derive the expression for efficiency and MEP of a Diesel cycle stating the assumptions

and with suitable notations. 10

4 Two stage compressor delivering air at 15 bar has a clearance volume of 6% of the swept

volume of LP cylinder, at the start of the compression. The condition of the air at start of

compression is 30 deg C and 0.98 bar. The intercooler pressure is 4 bar. Compression and

expansion follows the polytropic law PV1.3

= Const. Assume perfect intercooling.

Determine i) volumetric efficiency referred to ambient condition ii) work required per

Kg of air delivered iii) isothermal efficiency of compression

10

5 An air refrigerator system operating on Bell Coleman cycle takes in air from cold room at

268 K and compresses it from 1 bar to 5.5 bar the index of compression being 1.25. The

compressed air is cooled to 300 K. the ambient temperature is 20C. Air expands in

expander where the index of expansion is 1.35. Calculate: COP, ii) Quantity of air

circulated per minute for production of 1500 kg of ice per day at 0C from water at

20C.iii) Capacity of the plant

10

6 Discuss the methods of improving thermal efficiency of a gas turbine cycle with neat

sketches 10