Question

a) Explain the difference between black and grey surfaces in terms of radiative heat transfer. [4 marks] b) Write the radiosity and irradiation equations for two grey surfaces transferring heat by radiation. [6 marks] c) Two surfaces make up an enclosure where surface 1 is flat and has area A1, temperature T1 and emissivity ?1. Surface 2 is black and has temperature T2. Show that the net power transfer rate in W/m² at surface 1 is given by ?1?(T1? – T2?) . [10 marks] d) Estimate the net radiative heat transfer between an ice rink of 20 m diameter and a hemispherical dome of the same diameter enclosing it. The temperature of the inner surface of the dome is 20 °C higher than the ice temperature of 270 K. Both surfaces are considered black. The Stephan-Boltzmann constant is 5.67x10?? W/m² K?. [5 marks]

          a) Explain the difference between black and grey surfaces in terms of radiative heat transfer.

[4 marks]

b) Write the radiosity and irradiation equations for two grey surfaces transferring heat by radiation.

[6 marks]

c) Two surfaces make up an enclosure where surface 1 is flat and has area A1, temperature T1 and emissivity ?1. Surface 2 is black and has temperature T2. Show that the net power transfer rate in W/m² at surface 1 is given by ?1?(T1? – T2?)
.

[10 marks]

d) Estimate the net radiative heat transfer between an ice rink of 20 m diameter and a hemispherical dome of the same diameter enclosing it. The temperature of the inner surface of the dome is 20 °C higher than the ice temperature of 270 K. Both surfaces are considered black. The Stephan-Boltzmann constant is 5.67x10?? W/m² K?.

[5 marks]

a) Explain the difference between black and grey surfaces in terms of radiative heat transfer.

[4 marks]

b) Write the radiosity and irradiation equations for two grey surfaces transferring heat by radiation.

[6 marks]

c) Two surfaces make up an enclosure where surface 1 is flat and has area A1, temperature T1 and emissivity ?1. Surface 2 is black and has temperature T2. Show that the net power transfer rate in W/m² at surface 1 is given by ?1?(T1? – T2?)
.

[10 marks]

d) Estimate the net radiative heat transfer between an ice rink of 20 m diameter and a hemispherical dome of the same diameter enclosing it. The temperature of the inner surface of the dome is 20 °C higher than the ice temperature of 270 K. Both surfaces are considered black. The Stephan-Boltzmann constant is 5.67x10?? W/m² K?.

[5 marks]

Added by Jonathon B.

Question

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