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
Answer:
The heat loss rate through one of the windows made of polycarbonate is 252W. If the window is made of aerogel, the heat loss rate is 16.8W. If the window is made of soda-lime glass, the heat loss rate is 1190.4W.
The cost associated with the heat loss through the windows for an 8-hour flight is:
For aerogel windows: $17.472 (most efficient)
For polycarbonate windows: $262.08
For soda-lime glass windows: $1,238.016 (least efficient)
Explanation:
To calculate the heat loss rate through the window, we can use a model of heat transmission by conduction throw flat wall. Using unidimensional Fourier law:

In this case:

If we replace the data provided by the problem we get the heat loss rate through one of the windows of each material (we only have to change the thermal conductivities).
To obtain the thermal conductivity of the soda-lime glass we use the graphic attached to this answer (In this case for soda-lime glass k₃₀₀=0.992w/m·K).
To calculate the cost associated with the heat loss through the windows for an 8-hour flight we use this formula (using the heat loss rate calculated in each case):

Answer:B
Explanation:
Given
For motor A
Characteristic life(r)=4100 hr
MTTF=4650 hrs
shape factor(B )=0.8
For motor B
Characteristic life(r)=336 hr
MTTF=300 hr
Shape Factor (B)=3
Reliability for 100 hours



For B


B is better for 100 hours
(b)For 750 hours


So here B is more Reliable.
Answer:
E=52000Hp.h
E=38724920Wh
E=1.028x10^11 ftlb
Explanation:
To solve this problem you must multiply the engine power by the time factor expressed in h / year, to find this value you must perform the conventional unit conversion procedure.
Finally, when you have the result Hp h / year you convert it to Ftlb and Wh

E=52000Hp.h

E=38724920Wh

E=1.028x10^11 ftlb