This is a mystery - the paper says
In Figure 8.. the written explanation of motor heat is not correct..IMHO.
There is no mystery in Figure 8
I have asked Jed to adjust the caption
It should be waste heat from the blower.. rather than waste heat from the motor
if one defines blower waste heat as due to the blower blades heating of the air.
The actual kinetic energy pushing the flow forward amounts to only Pk= 0.15W out of the total 5W
Assuming electric motor efficiency 93%/87%
Power input 5W
Motor waste heat total= 0.35/0.65
Motor waste heat to outside = 0.1??
Pk =Power Mass flowratex Vsquared/2 (0.016x1.178kg/m3x4squared/2 =0.15W)
Blower “turbulent” waste heat to fan air = 4.5/4.2W
Motor waste to fan air=0.25/0.55W
Total Thermal heat in fan air-??
Mass Flowrate x Cv x delta T (0.016x1.178kg/m3x717.8 x 0.35=4.75W)