Squirrel By Balinju & Hara

[hara]

Does this mean that d + 2R2 < D (in the diagram)?

Also, what are the last two criteria L1 and l ? Can't see them.

Is this for liquids?

[bigben2k]

L1 refers to the straight extension of the nozzle. I, I believe, refers to the thickness of the nozzle material, and is irrelevant.

Yes, it's for liquids, but not necessarily a submerged jet.

The reference to B (Beta) is the proportion of the incoming tube, to the nozzle outlet.

d + 2 * r2 should be equal to D. d is the outlet diameter, and D is the inlet diameter. The drawing makes a reference to D3, but that includes the flange on the tube, where the nozzle is mounted.

[hara]

ok, I understand now. What nozzle size do you recommend?

[hara]

The 3/8" barbs we're using are 7mm internally

[Balinju]

when the exams are all over, i will try to design that with a cad so that i would be able to pass to the machinist cause now they now how to use their new 3axis mill

[jaydee]

What if the nozzel used a strait line as the angle instead of the gradual curve?

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.....l l

LOL looks nothing like what it does while typing in in the reply box.

[Balinju]

Originally posted by jaydee116
What if the nozzel used a strait line as the angle instead of the gradual curve?

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.....l l

LOL looks nothing like what it does while trying in in the reply box.

from what i managed to read, i think the curve makes less pressure drop

[jaydee]

Originally posted by Balinju
from what i managed to read, i think the curve makes less pressure drop

lol, I am at work so I can't post a drawing of what I mean. But i think you got my drift. I wonder how much difference it would make. Of course with the ball end mill and spiraling pass mentioned earlier it shouldn't be all that hard to make. I have not tried a pass where the Z axis moves yet. Not sure my mill even supports it.

[bigben2k]

Here are the specs, including a high B ratio.

[bigben2k]

Originally posted by hara
ok, I understand now. What nozzle size do you recommend?

It depends on a few things:
#1: how much pressure will you have available, for this waterblock, and at what flow rate?

#2: Are you going for a single nozzle, or multiple ones? (I have no comments on that, it's a design decision)

Once you have that, you can calculate the size of the opening you need. You'll then have a fully optimized nozzle

[trit187]

hey, I'm making my own block for a physics project but don't have alot of time, I was hoping I could get the design you did in cad format, and then make some of my own modifications, so I owuldn't be compleatly copying you :-) if you don't mind of course, you can e-mail me traviss_187@yahoo.com
Thanks alot

[hara]

I have no issues with borrowing some of our work, but always give credit where due. Cad file is in previous page.

[jaydee]

This is what I was refering to earlier:

[MadDogMe]

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use code /code in the [ ] [ ] thingies ...

[Balinju]

but ben, wouldn't a low beta value be better for a nozzle. and we are going for a single nozzle not multiple

[Balinju]

jaydee i think your nozzle would be something to consider also, but i would be prefere if for this project we did something with all the proofs to support our design. hope you understood. because there are too many things which we did not proof mathematically yet and that is going to be our job this summer before we fly

[hara]

This is the problem: the white water nozzle is 45mm^2

We know that the white water is a high pressure drop block.

A 7mm nozzle has an area of 38mm^2 (smaller than WW)
A 3/8" barb has an internal diameter of 7mm
Therefore nozzling is only needed if the jet will be smaller than 7mm.
But a 7mm nozzle is already smaller than that of WW's

With an average pump, i.e. an Eheim, I'd go with a single nozzle entrance, possibly around 1/4 inch (6.4 mm).

The hypotetical "pump" for the project would give the flow of a 1046 (estimate).

Suggestions?

[Cathar]

Originally posted by hara
This is the problem: the white water nozzle is 45mm^2

Remember, the WW's nozzle is 7/15's blocked off by the tops of the fins.

[hara]

Thanks, that completely got out of my mind. On squirrel, the only part blocked with a <6.52mm dia jet is the point of the cone.

[bigben2k]

Originally posted by Balinju
but ben, wouldn't a low beta value be better for a nozzle. and we are going for a single nozzle not multiple

No, I don't believe that B (Beta) makes any difference, it's just an added design parameter, to optimize the flow.

If you look at the two types of nozzles, they're actually very similar. R1 is smaller in the high-B design, because the diameter difference is smaller, i.e. the water flow isn't so much restricted by the nozzle. L1 is the same or smaller, again because the flow doesn't need to be straightened out as much.

If this nozzle spec is indeed for a water-to-air nozzle, the beveled angles would probably be radically different for a submerged jet. the 10 degree angle is the only one that's relevant (IMO) here, and given the much lower density of air, I would expect a submerged application to require an angle around 45 degrees, in the opposite direction, but I'm just guessing, I don't really know.

[hara]

What does ASME stand for. Why do you think that's the best way to make a jet?

Just asking cause I don't take anything for granted.

[bigben2k]

Originally posted by hara
What does ASME stand for. Why do you think that's the best way to make a jet?

Just asking cause I don't take anything for granted.

Good! Always question things, or otherwise confirm everything from two other independant sources.

ASME stands for "American Society of Mechanical Engineers". Their home is at www.asme.org , but you need to be registered to access most of their info.

As far as I've seen and read, this nozzle shape is optimal for the lowest pressure drop. As pressure is critical in our designs (and often neglected, I might add), I've opted to go this route.

I had a reference to efficiency ratios of various nozzle shapes (I'll post it, if I can find it again), and this shape is really optimal. I still have to clear up the whole "submerged" issue, but I believe that the basic shape would not change. Only the angle of the outlet should be affected.

[hara]

Thanks for you informative answer.

[Balinju]

this morning i can up with an equation (derived it myself, but probably there are a lot of persons who knows it) to calculate the pressure that a nozzle is producing.

Is there any method of how to calulate the velocity of water, not the flow, but the velocity at a certain point?

[Balinju]

ok i may cancel my question posted above. thankx to a suggestion of hara, i arrived to a point to say how velocity can be easily calculated Here you will find what i thought of. Anyone can correct my physics pls and point to me any mistakes or any comments??