Answer:
a) The exit temperature is 39.25°C
b) The highest component surface is 132.22°C
c) The average temperature for air equal to 35°C is a good assumption because the air temperature at the inlet will increase due to the result in the heat gain produced by the duct and whose surface is exposed to a flow of hot.
Explanation:
a) The properties of the air at 35°C:
p = density = 1.145 kg/m³
v = 1.655x10⁻⁵m²/s
k = 0.02625 W/m°C
Pr = 0.7268
cp = 1007 J/kg°C
a) The mass flow rate of air is equal to:
The exit temperature is:
°C
b) The mean fluid velocity is:
The hydraulic diameter is:
The Reynold´s number is:
Assuming fully developed turbulent flow, the Nusselt number is:
The highest component surface temperature is:
°C