Nozzle without straws

Hi,

Just wondered if anyone else has tried nozzles without straws? I started playing with nozzles last summer, read the patents, and experimented with different inlet designs, ordered samples of foam and then sheets of it for filters and lining my nozzle, and of course went the straws route trying a couple of different diameters and lengths. I think the sainsburys checkout staff here in the UK must have thought there was going to be one heck of a party! I had fine results over a decent distance. Out of curiosity I thought I'd try without straws, and to my surprise, the nozzle worked just as well, and a few layers of foam and gaps to let the turbulences cancel out seemed to be sufficient.

Hi Ioncube,

Interesting, but it doesn't surprise me that you can get 'laminar' flow from a single orifice (straw, essentially) - I've often wondered what all the extraneous straws are doing. Like you, I bought a few thousand straws, not from Sainsburys - being a mean Scotsman, I bought them from a Pub supplier. Lack of time has prevented me from getting anything built yet but as soon as I've finished the current three/four projects plus the day job, I intend getting stuck in. One of the first things to do if/when I have any success is to build the Epcot Centre in a 6 inch bowl.

Best of Luck

Ed

Any experts reading correct me if I'm wrong, but from reading a little about fluid dynamics, flow becomes laminar when a value called the Reynolds number (Re) is below a certain value. One parameter determining Re for flow in a pipe is the diameter of the pipe (higher D, higher Re), along with velocity and other factors. Flow within the straws is more likely to be laminar than the pipe, and if there's sufficient gap above the straws for the turbulences introduced when the flows combine to die out, the resultant flow should be substantially laminar too. A sine wave shaped cap to accelerate the velocity more gradually is also said to help, but I had no luck there. Quite a few of the patents in the area use tubes of some kind, but not all. I haven't fitted a lensed LED or fiber optic yet (had a cool fibre bundle made by universal-fibre-optics.com for the purpose but the PMMA solution in the forum here is cheaper and may be better for this application), but straws seem convenient to anchor a central light tube so I may reintroduce those.

Whatever you do, it's great fun building these and experimenting. Hope you get time this year to play.

The Oase laminar nozzle that sells professionally does not have straws (i think) .
Only mesh that filter the water into a laminar flow..

so yes it`s possible

liteglow wrote:The Oase laminar nozzle that sells professionally does not have straws (i think) .
Only mesh that filter the water into a laminar flow..

Right. I started by ordering samples of plastic mesh, reticulated foam and closed cell foam, then ordered a roll of mesh and some large sheets of foam once I'd got something that worked. Removing the straws allowed me to shorten the length of the jet. I use rings of closed cell foam as lining of the jet, with the reticulated and mesh at several stages. I tried to construct domed meshes as I'd read paper suggesting that it may improve the flow, but my efforts there made no difference there. Also tried metal mesh, but plastic seemed to offer advantages. Wondered if anyone has tried to construct a non-cylindrical jet. The ones deliberately irregularly shaped and with pockets of air in the corners and mounted on springs seemed interesting.

Where are you getting your mesh from?

John wrote:Where are you getting your mesh from?

Fujifilm Sericol UK

I think the product is one of the ones from this list.

http://www.fujifilmsericol.co.uk/ff/fabrics/products/proinfo.html

I'd looked online for likely suppliers of meshes, made some calls and got samples around A4 (US letter) size that were large enough to cut out 2 or 3 discs. When I found it worked, I ordered a roll of fairly fine mesh. It's tough and doesn't stretch.

I'd tried metal mesh cut from frying pan (skillet) splash guards but found that it collected limescale quickly whereas the plastic mesh didn't seem to.

For LED's, http://www.polymer-optics.co.uk have some very interesting lenses and PCB's, perhaps useful for jets but also for lighting in general, but samples from them never arrived despite them saying that they'd been sent several times by their distribution agent so I gave up on them. I'd offered to pay for items too, but they said that sending samples was easier, and their distributor outlets couldn't stock the particular parts I was interested in, so they were a dead loss. My company has moved address now so I may try again and hopefully have better luck.

The PMMA light guides described in forum seem ideal. I paid about £80 (probably around $140 at the time) for a large glass fibre bundle (around 2000 strands or so), which is nicely engineered and will probably work, but 3 guides rather than a single may be better as you don't need to use an RGB LED or other mechanism to combine the light first. I put some pics's on flickr at the time because the fibre manufacturer said that they'd not had good luck with using LED's. I tried an 80mw green laser and and LED (1W or maybe 3W), and it chucked out a fair bit of light as the pics show.

http://www.flickr.com/photos/26901008@N04/sets/72157606243699566/

Nick