Ways to Move Air

The reasons they make noise are:

1 motor is a low cost brush type with a short life and is linked to 60 hz = high rpm.

2 small diameter airways that require higher velocity for the same mass flow.

To make it quiet use a synchronous motor and a larger diameter fan type blade.

you can even make a rim driven motor vis pulses as they do with small cooling fans.

Just costs a little more.

Common hair dryers are noisy because they are made of the cheapest possible parts

Yes, and most of the noise seems to be primarily at multiples of mains frequency, rather than the whistle or randomish noise we might expect. Does this indicate that the motor is dominant, or is it just that the fan is coupled to mains frequency?

I am of the opinion that your group must first determine how much water is to be evaporated from how much hair in how much time. Only then can you arrive at a viable method of heating and moving air at a rate to accomplish the desired result.

A turbine or fan is an obvious candidate.

A cordless hair drier is described by Dr. A. J. Organ in a technical book, "Air Engines." Powered by a Stirling engine running on butane cartridges. The engine drives the fan which induces an air stream to cool the engine, and heat the air simultaneously. Since patent considerations caused abandonment of the half completed prototype no db ratings are available.

If this is an acoustics course you might want to consider noise cancellation techniques as an alternate method of noise reduction.

You heat up the head and waft away the steam with a small hand fan.

Alternatively, if this is unacceptable, and if noise is the basic problem, then use something like a computer cooling fan(s) - they are very quiet - and quite cheap nowadays.

Your also need a supply of air that has a Relative Humidity (RH) below that of the hair. That is quite easy to start with because the hair is soaking wet, but you then need progressively dryer air as the hair dries out.

As you are (probably) using a source of ambient air for the purpose, you will find it becomes 'wetter' due to the hair drying out. This is self defeating.

You then need to lower the RH of the air. This can be done by heat (hot air can hold more moisture than cold air.

You are then back to the traditional hair dryer - but with a quiet fan.

This is really an idea I had for a one handed (hot air) paint stripper rather than a hair dryer but I think it might help. Move the noisy, and, heavy part of the machine away from the part that does the work. Wear the fan part like a satchel hanging on a strap and have a flexible hose with wires along the outside to the small lightweight heating element/nozzle at the handheld end.

In addition to what Aurizon said about hair dryer design and motor type, consider this. Noise involves a source, a receiver and a pathway. The most effective noise reduction techniques involve reducing noise at the source. Motor and fan design choices are in this category. Fan blade natural frequencies and harmonics need to be considered because fans "flutter", especially high speed fans. The next most effective noise reduction technique is to eliminate the noise pathways. A well designed shroud and rubber isolation gasket falls into this category. So do ear muffs and ear plugs, but they are the "trivial" solutions to this problem and are as such not acceptable.

Nikola Tesla made patents and claims upon an invention of his called the Bladeless turbine, for which he claimed a 10 times increase in efficiency over bladed turbines.

Its a fascinating concept, and is the ongoing subject of interest of the Tesla Engine Builders Association.

http://freeenergynews.com/Directory/Devices/TeslaTurbine/index.html

It might be worth a look.

Chris

10x more efficient than bladed turbines? Either the bladed turbines of the time were even more inefficient than I remember, or Tesla didn't understand thermodynamics. I took a quick look on one web site, and that claimed an expected efficiency BTU to mechanical efficiency of 98% - which would require a peak temperature in the cycle of 15000-degrees C. I believe that modern turbines are limited by a combination of the temperature handling of practical materials and thermodynamic considerations to about 70% efficiency - but in practice there are additional losses. The advantage of the turbine over the internal combustion engine is that the only material whose temperature changes through the cycle is the gas.

It could be possible to get much higher efficiency - either by bypassing the thermal stage (e.g. fuel cells - nowhere near that point yet), or by a combination of improved gas flows and finding materials that allow much greater temperature ratios. If you know somewhere (on any Tesla site) that shows HOW Tesla's bladeless turbine can achieve the improved peak temperature and/or the reduced loss requirement, that would be really worth seeing.

BTW I see this as a diversion relative to moving air -as that doesn't have the thermodynamic issues involved with verting heat to mechanical energy.

http://en.wikipedia.org/wiki/Tesla_turbine

http://www.teslaengine.org/main.html

A remote exhaust fan with the needed ducting to each hair drier would stop the use of the fans in the existing driers. The moving of this air completely out of the area would help with any humidity build up and reduce odor from hair treatments. More detailed information would be needed to make any further recommendations. The amount of air needed to moved from each drier would be needed to size an exhaust fan.

For drying and styling of hair, current process uses heat and air flow. Air flow is contaminated by "noisy" motors and fans.

You will still need your heat source.

You mentioned "pneumatics" as an idea.

I would expand on that idea. If you have available a small diameter (Guess around 3mm inside diameter) compressed air source blowing through your large tube (40mm inside diameter) and heat coils, with proper aim of the compressed air, there will be a "venturi" effect created that will draw in substantial quantities of additional air through the heating coils. The only noise then would be that from the imperfections in the air path.

The "up" side of this is that the handpiece would weigh much less. (No motor or fan blades, no large chamber necessary for the fan and so on.) With no rotating motor there would also be no "torque" to work against to "aim" the dryer handpiece. (Spinning motor and fan are like a small gyro.) This could also conceivably run "air only" as well.

The "down" side to this is your dryer would need two leads. One for power and the other as the air source) The "switch" would become more complex, needing to control air flow and heater power simultaneously. You would also need a source of compressed air like a small compressor.

SAFETY note: Compressed air source would need to be well isolated from coming in contact with the person.

An "out there" extension of this would be using small compressed gas cylinders (like soda syphone bulbs) as the source of the gas. I don't know if there would be enough charge in one to do a complete style. You would still need electrical lead to power the heater.

There's another idea that's on a differnt direction. I'll send that separately

Me again.

You mentioned also "like the diaphram and lungs do".

This ones maybe a bit over the top, but when I saw that I imagined a set of bagpipes that the stylist would operate. If they had a spring inside, they would "self inflate" when left alone and then the stylist could squash them to cause air flow.

I imagine that to be unsuitable since the movement necessary would detract from the focus of styling the customer's hair.

This idea might kick off someone else though with something more practical.

Have fun with the science project.

First off this thread has been dormant for over a year so I doubt anything we post will be of any use to SrProjectCCA.

Nonetheless, if you were to go down the pneumatic path then it would definitely be worth looking at a device called a vortex tube. The physics behind a vortex tube is still open for debate but regardless of why they do work and can be used to supply hot and cold air.

Basically they work by taking a stream of compressed air (marked as red Input) into a vortex chamber (bright blue) that directs the air along a cylindrical chamber towards the control valve (bright green). A percentage is allowed to escape (dark red) that is hotter than the input air while the rest is directed back along the cylindrical tube where it forms a smaller vortex inside the primary vortex. The air that escapes from the other end (dark blue) is cooler than the input air.

The difference in temperatures between the hot and cold ends can then be varied by adjusting the control valve. You can also cascade vortex tubes together and produce cryogenic type temperatures at the cold end and similarly warm air at the hot end. The great thing about vortex tubes is there lack of moving parts. The only moving part is the control valve and if you are operating it to produce a constant temperature and flow it only needs to be set once.

I have never used them myself but they have been around for some time and from the reports I have read they can be a cheap and extremely reliable way of supplying cooled or heated air.

I don't know how noisy they are but if you have access to a supply of compressed air they could be an easy way to produce hot air without a fan or heating element.

It's clearly useful in environments where there is already a supply of compressed air for other reasons. It also behaves (to an extent) as a heat pump; but I'm not knowledgeable enough on the subject to know how the kinetic energy lost to the cold air compares with the thermal gain. (Anyone know more about this?)
Another possible issue (again this may be a red herring) - my observation of Mr Dyson's cleaners suggests that it could be difficult to create a quiet vortex.

Vortex tubes are handy, but low in efficiency, and are mostly used for small portable uses. Those haz-mat suits and clean room bunny suits are often connected to compressed dried air to serve to cool the person and make the suit a positive flow situation. In many cases the air is also exhausted through another tube to avoid dumping suit air into the clean environment. Such tethered suits are used for local tasks and have enough air in them to disconnect and walk out through the airlock. Often the suits carry compressed air tanks for breathing and cooling and thus have short endurance.

There are many variations on this method. A search will find them

http://www.google.com/search?hl=en&safe=off&q=%22vortex+tube%22+%2B%22air+supply%22&btnG=Search

http://www.google.com/search?hl=en&safe=off&q=%22vortex+tube%22+%2B%22clean+room%22&btnG=Search