A fan is a powered machine used to create a flow of air. A fan consists of a rotating arrangement of vanes or blades, which act on the air. The rotating assembly of blades and hub is known as an impeller, rotor, or runner. Usually, it is contained within some form of housing, or case. This may direct the airflow, or increase safety by preventing objects from contacting the fan blades. Most fans are powered by electric motors, but other sources of power may be used, including hydraulic motors, handcranks, and internal combustion engines.
Mechanically, a fan can be any revolving vane, or vanes used for producing currents of air. Fans produce air flows with high volume and low pressure (although higher than ambient pressure), as opposed to compressors which produce high pressures at a comparatively low volume. A fan blade will often rotate when exposed to an air-fluid stream, and devices that take advantage of this, such as anemometers and wind turbines, often have designs similar to that of a fan.
Typical applications include climate control and personal thermal comfort (e.g., an electric table or floor fan), vehicle engine cooling systems (e.g., in front of a radiator), machinery cooling systems (e.g., inside computers and audio power amplifiers), ventilation, fume extraction, winnowing (e.g., separating chaff of cereal grains), removing dust (e.g. sucking as in a vacuum cleaner), drying (usually in combination with a heat source) and providing draft for a fire.
While fans are often used to cool people, they do not cool air (electric fans may warm it slightly due to the warming of their motors), but work by evaporative cooling of sweat and increased heat convection into the surrounding air, due to the airflow from the fans. Thus, fans may become ineffective at cooling the body if the surrounding air is near body temperature and contains high humidity. A fan blade is generally made of wood, plastic, or metal.
Fans have several applications in the industries. Some fans directly cool the machine and process, and may be indirectly used for cooling in the case of industrial heat exchangers.
These are critical machines and responsible for operating the entire plant, which may shut down without the proper fan. In mine and tunnel, it also used as safety equipment.
Hi, I wanted to create my own computer fan control and bought a 100ohm potentiometer.
I have hooked the pot as shown in the picture except that it is in the yellow wire (+12V) and not the red one (+5V) , black is ground.
The fan will start at full speed and doesn't change one bit if I...
Homework Statement
A ceiling fan is turning at a rate of 100 revolutions per minute. A spiders is clinging to a blade of the fan. If the spider experiences a centripetal acceleration greater than 0.3g, it will lose its grip on the blad and be flung off. How far from the centre of the fan can...
An electric ceiling fan with blades of diameter 0.720 m is rotating about a fixed axis with an initial angular velocity of 0.240 rev/s. The angular acceleration is 0.899 rev/s^2.
C- What is the tangential speed of a point on the tip of the blade at time t = 0.201 s?
D- What is the magnitude of...
hello,
I am supposed to give a short (20-30 mins) lecture to some very smart 2nd year math majors, and i thought about finding an intersting physics topic.
my first idea was special relativity, or more specificly deriving E=MC^2 from einsteins assumptions about light's behevior, but in the...
I have a tiny fan installed in the lid of my aquarium (it's actually a CPU fan). It moves air from the air space over the water surface below the light. It's purpose is several-fold:
1] supply oxygen to the air-water interface, remove CO2
2] remove excess moisture
3] remove waste heat due to...
Right now (1600 IST, 3 march) I am sitting on my chair. When I look at the fan at a specific angle (about 75 deg) I can see a blue colour at one edge of the wings and yellow colour at the opposite edge of the same wing.
In my room there is one source of natural light and one white artificial...
Hello. I need an explanation for a strange phenomenon ... I use a fan (PC type) powered by mains (220 V / 50 Hz in my country). At a distance of about 3', I get a sin EM field (sure it is not by mains cords) at a stable frequency of 200 Hz synchronized on main frequency. Even during power on...
Introductory Narrative:
This is a story game where the posters of the thread will think up creative responses to the threats posed by the antagonists in the story. The succeeding chapters will be provided and act as an expansion pack for the game, just like an online RPG. When the poster...
I am building a Cigar Humidor, and need to have a fan control to operate 18 3.5"Computer Fans simotaniously as well as controll there speed. Here are some specs on the fans...
Rated Voltage: 10.8~13.2VDC
Starting Voltage: 7VDC
Rated Current: 0.16A
Power Input: 1.92W
I have found...
Is there an equation with which I can estimate the flow rate a fan will generate at a set diameter, speed and angle of the blades? Assume that this is a simple box fan that you would put in your window.
I'm assuming that you would have to determine the axial speed of the air given the angle...
I wonder if there is a mathematical formula to calculate the flow rate of a fan if following parameter are known
Fan effective diameters
Blade Angle ( Pitch )
Number of Blades
Speed ( RPM )
Power Consumption
Pressure at inlet of the fan
Regards
Bernoulli"s Principal would a fan matter?
If you have air moving through a 3' tube connected to a 1' tube with a taperd connection. Than the pressure in the 3' tube would be greater than the 1' tube due to the speed in the 1' tube being higher than the 3' tube, correct?
Then if you put a...
My friends (all A&P Aircraft mechanics) say I'm nuts. A co-worker and I attended a Honneywell TFE731 jet engine maintenance school. During the class the instructor asked this question, "which side of the front fan on a TFE731 engine has the highest pressure?" His answer was the front. (we are...
Homework Statement
Can the addition of a second set of fan blades, below the first set and on the same axis, improve the lift force created? What is the theory associated with this phenomena?
Homework Equations
none, practical application in lab setting.
The Attempt at a Solution...
What follows will be a very practical question for the winter months.
I'm a senior math major who appreciates efficiency. And saving money, I like that too. As it turns out, the heater in my apartment eats money like there's no tomorrow, so it generally tends to be left off for obvious...
I looked, but didn't see any post on this topic. This is in regards to the selection process for fans/blowers in ventilation systems, which I am still new to.
From AC/Hr and the room volume we know the required CFM we need to supply to the space, and we can determine the size of ducts and FPM...
We are trying to improve the efficiency of a fan for an engineering project. However, we first need to figure out what the efficiency of the fan is now.
Since we know how many watts the fans motor is using at each setting, we figured we could just find how much power is in the air the fan is...
I have a question regarding the relationship between airflow restriction and fan power. If the pressure drop across an airflow restrictor (filter bank, heat exchanger coils, etc.) is known by measuring with a magnehelic differential pressure gage and that dP changes (filter replacement/removal...
if a fan with a battery is placed in space outside Earth and if it is switched on...
then what will happen?
will the fan go ahead, behind or will it remain at the same position?
A ceiling fan consists of a small cylindrical disk with 5 thin rods coming from the center. The disk has mass md = 2.9 kg and radius R = 0.26 m. The rods each have mass mr = 1.4 kg and length L = 0.8 m.
When the fan is turned on, it takes t = 3 s and a total of 15 revolutions to accelerate up...
Is the only reason air moving over your body caused by a fan or breeze feels cool because of increased evaporation of moisture from your skin? Or does it blow air being warmed by your skin away from your body to be replaced with relatively cooler air?
Also, does air movement also produce...
Hey guys, I'm a college student looking to build a miniature RC plane based off this picture here: [PLAIN]http://www.kruxor.com/wp-content/uploads/2010/07/SC2_Banshee_Art.jpg
As you can see, the thrust needed to lift and mobilize the plane is provided by the two fans on the sides (does this...
What I'm tring to do is connect FAN 2 Wiring (673 DKBLU 2nd picture top diagram) to
The Auto pole of the AUTO/ON/OFF switch so I can manually activate the FAN if needed.
I'm a little confused since in the 2nd pic, I don't see a Negative side to the coil on the relay.
Can/will this work?
I would like to power a duct booster fan (which I believe uses little energy) using solar panels. The store website says the fan runs at .35 Amps.
The solar panel would get direct sunlight for about 3 hours a day and indirect sunlight the rest of the day. I would like the fan to run at least...
I am working on a project where we are using ducted fans and just recently we were testing to effect of some bellmouth inlets we made for the ducts. At full throttle the thrust for the fans with no bellmouth inlet was approximately 8.8 lbs and with the inlet the thrust was approximately 10.5...
I am having a discussion with a co-worker. He doesn't believe that the curvature of a fan blade has any effect on efficiency. That one simple has to reverse the direction off rotation to get full flow in either direction. I know this isn't the case but am having a difficult time explaining and...
Hi all, I am wondering that we should choose fast or slow function of electric Fan in hot weather, which function will spend much more of energy?, can someone give me an explanation :D Forgive me if the questions is silly
First I thought of posting this on the random thoughts thread, but I need an answer to this bugging question.
Why the hell a microwave (the cooking device) makes that fanlike noise? While an infrared device (electric heater), visible light device (a flashlight), x-ray machine do not make any...
Rotation of a Fan - Unsolved
Homework Statement
A ceiling fan with 85cm diameter blades is turning at 66 rpm. Suppose the fan coasts to a stop 26 s after being turned off.
What is the speed of the tip of a blade 10 sec after the fan is turned off?
Homework Equations...
I remember once observing a thread in a discussion forum by someone trying to build a backpack helicopter. Various people warned him about sprung-weight-vs-unsprung-weight, hazards of stability and flight control, etc.
But ever since reading about James Dyson's bladeless fan and the...
I am curious as to how a portable fan works. I took one apart and here are some pictures of the motor:
https://docs.google.com/leaf?id=0B9FkpE8S_7W0NTEwOGZlYzUtMzhkNS00ZmU4LWE5ODItN2Q5NWViNDNmOGMz&hl=en&invite=CIrB408"...
I am trying to figure out how to get cool air. Say, if I have a fan and ice cubes. Should the ice cubes be in front of the fan(air blowing at them) or back of the fan (fan sucking).
When I did it, I couldn't feel the difference.
Hey all,
I am working on a 0-40V variable power supply right now, and while the power supply is working I am wondering if it is in danger of overheating. I am using a LM317 with a 0-5k potentiometer between adjust and ground, and a 165ohm resistor between output and adjust. Input is regulated...
1. The blades of a ceiling fan have a radius of 0.318 m and are rotating about a fixed axis with an angular velocity of +1.48 rad/s. When the switch on the fan is turned to a higher speed, the blades acquire an angular acceleration of +2.22 rad/s2. After 0.394 s have elapsed since the switch was...
Ok i have the following problem, I have a fan connected to the nozzle, i am given the nozzle area and the volumetric flow rate generated by the fan. How can i find the velocity of the air at different distances from the tip of the nozzle?
any help is greatly appreciated
Hi friends,
My air conditioner is a split one (it has 2 parts: one inside the house and the other outside). It has 4 modes of operation: cool, fan, and 2 other modes.
My question is that what does the machine really do in the fan mode? I wonder whether it just serves as a normal fan...
Hi, my name is Steve..
I am working on a ducted fan. I want to simulate it in Fluent in order to optimize my design. I know that sliding mesh technique and multiple reference frame method will be used but I am having problems in Gambit.
I do not know how to model it in Gambit. I have made...
We have adapted a 60W A/C Fan Motor, 1500 RPM to run two spindles one at 6000 RPM and the other at 500 RPM using pulley & belt. On continuous use the motor heats up excessively and a few fail.
Load is winding of threads from a Cone to a bobbin.
I need a few suggestion
i) Can rewinding...
I built the unit linked below several years ago. I wanted to rebuild it to utilize a electrostatic filter and bag filter. Right now I just run 2 filters (11 merv) before the fans and 1 filter (11 merv) after the fans. I know things like design, filters, etc all work into the calculations of...
Here's a question that I thought up while shooting darts through a five-bladed ceiling fan. I'm lazy, so I'll use symbols for the constants in the equation.
Say I have a five-bladed fan of radius R, with a blade width W, spinning at angular velocity V. I shoot a dart of length L through the...
hi,
I am an electronic engineer student and I am doing a study on control systems that can be used to control a ball's height in a vertical wind tunnel.
I have a problem in calculating the fans needed (as in size and number of blades) and the amount of cfm that the fans need to produce...
for the following SC cube, find the miller indexes for the planes:
FAN
KFA
HAN
http://lh6.ggpht.com/_H4Iz7SmBrbk/SvhiU8OeicI/AAAAAAAAB8M/o8QPR2ht2gA/Capture.JPG
what i leared to do was find the points that the plane intercepts the x,y,z axis, i chose axes such that x+ is pointing...
I am not talking about superstrings, but the idea of supersymmetry itself.
Let me say what annoys me. I will put aside the advantages of it satisfying Coleman-Mandula theorem or solving the instabilities of the Higgs field, lorentz invariance or any other consistency that it satisfies in...
Let's say we have a rectangular surface or something. How about a piece of plywood. If we were to blow air say using a fan at the top of the wood and keep the air "calm" at the bottom, would it create lift?
I know it's not practical but in theory should there be a slight lift?
I am looking at fan curves here at work and I stumbled upon this one. Its for an 80mm diameter tube axial fan.
What's up with the Flowrate vs RPM curve (the dashed line)?
In the flowrate interval between 12 - 23 CFM there are instances of the same RPM for different flowrates.
That...
Dyson, the same guy who invented the bagless vacuum cleaners, has now come out with a bladeless fan:
http://www.time.com/time/health/article/0,8599,1931455,00.html
That makes me wonder - could similar principles be used to come up with a bladeless wind turbine? Some environmentalists are...