1. a)

b)

i)

ii)

A liquid cooled rocket nozzle is made from a metal with density 8050 kg⋅m-³ and

thermal conductivity 185 W-m-¹-K-1. The combustion gases in the nozzle are at

2950°C and the gas side heat transfer coefficient is 3x104 W-m-2-K-¹. The nozzle

wall is 3 mm thick. If the maximum allowable temperature of the material is 1100°C,

what must be the temperature of the cooled outer surface of the nozzle? As the

radius of the nozzle is much larger than the wall thickness, the problem may be

considered as a plane system.

[15 marks]

iii)

Consider an internal combustion engine for a vehicle that has been designed

to run on pure ethanol fuel.

Describe, with supporting explanation, what pollutants other than CO2 the

engine would produce when in operation.

[3 marks]

Outline briefly one technique that could be used to minimise the quantities of the

pollutants in your answer to i) that are released to the atmosphere.

[3 marks]

If the ethanol fuel is manufactured from corn, discuss briefly how the CO2

emissions from combustion in the engine and the fuel manufacturing process

(i.e. on a lifecycle basis) would compare with those from a diesel engine of

comparable power output and efficiency.

[4 marks]