A box-enclosed fan is pushing air downwards through a 1 m diameter blade span area. The whole system weighs 20 N and doe

[answerhappygod]

A box-enclosed fan is pushing air downwards through a 1 m diameter blade span area. The whole system weighs 20 N and does not rotate. In order for the system to hover mid-air (i.e. stay stationary in the air), determine the following:
Consider g = 9.81 m/s?, and pair = 1.25 kg/m3
-What are the valid assumptions ?
-What is the air exit velocity required? -What is the volumetric flow rate needed? Hint: The inlet air speed is very small due to sucking stationary air from the surrounding.
If the system is to accelerate upwards at constant value of 20 m/s?,
determine the following: Consider g = 9.81 m/s2, and pair = 1.25 kg/m3
What is the new air exit velocity needed? What is the increase in the air exit velocity?
Hint 1: The inlet air speed is very small due to sucking stationary air from the surrounding
། ། ། ། ། ། ། ། །