A four-cylinder petrol engine has a swept volume of 2000 cm3, and the clearance volume in each cylinder is 60 cm3. Calculate the air standard cycle efficiency. If the introduction conditions are 1 bar and 24 ?C, and the maximum cycle temperature is 1400 ?C, calculate the mean effective pressure based on the air standard cycle.

ANSWERS(59.1%; 5.30 bar)

In a dual-combustion cycle, the maximum temperature is 2000 ?C and the maximum pressure is 70 bar. Calculate the cycle efficiency and the mean effective pressure when the pressure and temperature at the start of compression are 1 bar and 17 ?C, respectively. The compression ratio is 18/1.

ANSWERS(63.7%; 10.54 bar)

The engine of problem 10 is supplied with a mixture of gas and air in the proportion of 1 to 7 by volume. The estimated volumetric efficiency is 85 % and the Qnet,p of the gas is 38.6 MJ/m3. Calculate the brake thermal efficiency of the engine.

ANSWER (27.4 %)

The upper end of a vertical steel wire 4mm diameter and 2,5 m long is held securely. The other end is fixed central to a steel cylinder, 80 mm diameter and of density 7,8 Mg/m3, arranged with its axis vertically. Determine the length of the cylinder to give 0,6 torsional vibration per second.

Describe the Rockwell hardness test. Include information on the indenter type, loading conditions and quantities measured.

Describe how an Izod impact test of a polymer specimen is performed. What does the test measure?

estimate the microstructural properties (ferrite, pealite, bainite. martensite) from CCT tables. Estimated cooling time of 2900 seconds with vickers hardness value of 286

A 10-kg block A is released from rest 2 m above the 5-kg plate P, which can slide freely along the smooth vertical guides BC and DE. Determine the velocity of the block and plate just after impact. The coefficient of restitution between the block and the plate is e = 0.75. Also, find the maximum compression of the spring due to impact.The spring has an unstretched length of 600 mm

The spring with the 5 kg plate are stationary before impact at 450mm. The 600mm unstretch length of the spring is without the 5 kg plate.

Describe how Aluminium can corrode or degradein Aircraft Fuselage.

And methods for avoid degradation in Aircraft Fuselage.

Describe how Aluminium can corrode or degradein Aircraft Fuselage.

And methods for avoid degradation in Aircraft Fuselage.

1. Rocket motor cases may be fabricated as thin walled tubes from:

a) Low alloy steel of proof stress 1200 MPa and G_C = 24 kJ/m measured in sheet of an appropriate thickness, or

b) Maraging steel of proof stress 1800 MPa and G_C = 24 kJ/m

In a particular application the design code specifies that the design stress is StressY/1.5 where Y

is the proof stress. Calculate the minimum defect size

required to give brittle fracture in service for the two materials. Comment

on your result. You may take Young’s modulus to be 200 GPa in both cases.

2)If the fracture stress of a large sheet of

maraging

steel containing a central

crack of length 40 mm is 480 MPa, calculate the fracture stress of a similar

sheet containing a crack of length 100 mm.

Q] What are the advantages and disadvantages of acceptance sampling over 100% inspection? Under what conditions should acceptance sampling be preferred over 100% inspection?

Subject - Materials Management

3. One mole of air is compressed isothermally at 300K from one atmosphere to fifteen atmospheres.  
a) Calculate the amount of work required in the compression.
b) How much heat must be added or removed from the gas to maintain its temperature at 300K.  
c) Does the enthalpy of the gas change? If so, how much?
d) Does the entropy of the gas change? If so, how much?  
DATA: You may assume that air is an ideal gas with a constant volume heat capacity of 5/2R