WorksheetsEFPLab1 Energy Balance Digital Twin 1
Total questions: 12
Worksheet time: 16mins
Do you understand how this quiz works?
yes
no
not sure
What assumptions do we make to calculate the power of the cartridge heater?
channel is frictionless
channel (surface) has no heat loss
ideal gas
neglect kinetic energy
neglect heat input of fan
What is the power you calculated in Watts [W]?
Round your result reasonably and only type in the number.
The following measurement are taken with a fan voltage of 15 V (see also in the video):
ϑair,α = 26.2 °C
ϑair,ω = 35.6 °C
c = 2.82 m/s
How much heat does a human body approximately emit while sitting or standing (no activity)?
50 W
100 W
200 W
500 W
1000 W
what happens if the fan speed is being reduced?
heat flux increases
heat flux decreases
temperature difference increases
temperature difference decreases
nothing, only the volume flow changes
What is the power you calculated in Watts [W]?
Round your result reasonably and only type in the number.
The following measurement are taken with a fan voltage of 14 V (see also in the video):
ϑair,α = 26.6 °C
ϑair,ω = 36.4 °C
c = 2.79 m/s
What would happen if the fluid would be water instead of air?
nothing
lower temperature difference
bigger temperature difference
less heating power
What is the power you calculated in Watts [W]?
Round your result reasonably and only type in the number.
The following measurement are taken with a fan voltage of 12 V (see also in the video):
ϑair,α = 26.5 °C
ϑair,ω = 38.1 °C
c = 2.51 m/s
What would happen with the calculated heating power if we consider heat losses in the energy balance equation?
heating power would increase
heating power would decrease
nothing would happen
What is the power you calculated in Watts [W]?
Round your result reasonably and only type in the number.
The following measurement are taken with a fan voltage of 10 V (see also in the video):
ϑair,α = 26.9 °C
ϑair,ω = 40.7 °C
c = 2.04 m/s
Why do we not calculate the exact same heating power of the cartridge heater for different fan speeds?
why should we, there is no reason the heating power should be constant
measurement errors
different heat losses over time in reality
What is the power you calculated in Watts [W]?
Round your result reasonably and only type in the number.
The following measurement are taken with a fan voltage of 8.5 V (see also in the video):
ϑair,α = 26.6 °C
ϑair,ω = 43.2 °C
c = 1.73 m/s
