What could be the most efficient fan blade design? There are three main factors for a good fan: one is speed at which air is circulated; second,the volume of air it can circulate; and the third is providing maximum work for minimum power. Combining these three which would be the most efficient fan blade design.

$\begingroup$ I'm sure that there was no design goal other than keeping small fingers out of the blades. I demonstrated the overall safety of the cover-less fan by stopping it without damage (or any real pain, even) with my own fingers. It also moves more air than it did with the cage in place. Cheap fans are cheap. $\endgroup$ –

$\begingroup$ @qftme - there is a fan in base and then a series of angled holes in the ring shaped part that blow the air toward you. The clever part is that this high speed air drags more room air through the loop in the middle so gives you much more flow than the small hidden fan alone $\endgroup$ –

Sep 18, 2022 · A perfect fan, with no losses due to air resistance and friction in bearings and with perfect electrical conductors and a 100% efficient electric motor, could indeed run forever. You could use a battery to power the motor, the motor drives the fan, and the kinetic energy of the fan recharges the battery via a generator.

Dec 2, 2020 · Most answers about how spinning devices create suction often mention how air moves from high pressure to low pressure. The spinning fan creates low pressure and thus we have air moves from freestream (high pressure) toward the fan (low pressure). My question is: How is the low pressure created?

From the class notes from this Mechanical Engineering course about noise and its perception at Penn State, it looks like, all else being equal, there is a log-linear relationship between the rotational speed of a fan and the noise level (expressed in decibels): $$ \Delta N ~\sim~ 50 \, \Delta \log_{10}{\left[\text{rpm}\right]} $$

Dec 30, 2024 · I want to understand in depth how sweating cools down the body. When we sweat the body is cooled down by evaporative cooling; however, there seems to be a few different scenarios/mechanisms that are

$\begingroup$ The Landau level is the filling factor, both terms are employed to say the same thing. Now, for the factor 4 : in graphene, there are two types of degeneracy : there is the two equivalent sub-lattices degeneracy (usually referred to …

The design of windmills is such that they rotate to face the wind and have sails or blades that will absorb the impulse of the wind into rotation. They will always do that, and will turn in the designed clockwise or anticlockwise direction, so there is no way the air flow will force them to rotate against the design, imo. $\endgroup$

That implied the fan was in a window or such so that inside air would be on one side and outside air on the other. The more the fan is inside the room, the less effective it will be. Just moving air around inside the room does nothing to cool it. In fact, the extra power from the fan actually heats the room, although very slightly.