Author Topic: Calculating Water Injection and placement  (Read 65137 times)

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Offline 1212FBGS

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Re: Calculating Water Injection and placement
« Reply #15 on: July 09, 2007, 12:07:02 PM »
a draw through turbo set up or injecting anything before the turbo will absolutely wear the turbo impellers and bearings out faster.
kent

Offline Dynoroom

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Re: Calculating Water Injection and placement
« Reply #16 on: July 09, 2007, 01:22:13 PM »
I've run draw-thru turbo systems for over 20 years on boats & cars. Never have I seen any noticeable compressor erosion & certainly never a bearing failure due to this type of layout. Any time I've had to replace a compressor wheel it's been due to FOD not to fuel or water. Maybe others have run less oil pressure and more water or something. Just what I've seen.
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Offline hotrod

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Re: Calculating Water Injection and placement
« Reply #17 on: July 09, 2007, 09:25:03 PM »
In my experience it depends on the droplet size and location of injection.

Ideally you want a spray as fine as a fog but that is difficult to achieve without high pressure injection.

Pre-compressor injection is used in the industrial world routinely to improve the efficiency of turbine compressors.

It takes very little water to improve the compressor efficiency max of 3% of air mass by weight is the max that gives you any efficiency gain on the compressor itself although your engine may want a bit more.

On my system I did some injection efficiency-compressor and got a small amount of impeller erosion.
On investigation what appears to have been happening is the spray was wetting the inside wall of the intake duct under certain conditions and then beads of liquid water were running down the tube into the spinning impeller as all the erosion was concentrated on the very tips of the impellers, and you could see the liquid path on the surface of the compressor inlet due to oil build up from the PCV system.

The WWII fighter planes injected both the gasoline and the ADI fluid (water injection) directly into the eye of the centrifugal compressor. I know of one person that has done a similar setup with the nozzle located very close to the compressor shaft nut and spraying directly on the end of the shaft. The nut spinning at 100,000 rpm beats the water jet into a micro fine spray moving radially out toward the compressor impellers, and has shown no signs of compressor erosion according to his accounts.

NACA designed a injection impeller that did about the same by drilling very small holes in the impeller hub pointed out toward the impellers and supplied the water to the impeller hub.

In my next setup I will take measures to prevent wall wetting, and have some trip points to re-suspend any water that runs down the intake.

The erosion I mentioned on my compressor impeller had no measurable impact on the compressors performance, and took months of daily driving to occur.

You might find this forum thread interesting reading regarding pre-compressor injection.

http://www.aquamist.co.uk/phpBB2/viewtopic.php?t=267


Larry

Offline Sumner

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Re: Calculating Water Injection and placement
« Reply #18 on: July 10, 2007, 12:22:11 AM »
In my experience it depends on the droplet size and location of injection.....................................You might find this forum thread interesting reading regarding pre-compressor injection.

http://www.aquamist.co.uk/phpBB2/viewtopic.php?t=267


Larry

Great thread and you did a good job of explaining what is going on.  I think I even understood most of it  8-) .  I saved it for future reference.  Thanks,

Sum

Offline bvillercr

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Re: Calculating Water Injection and placement
« Reply #19 on: July 11, 2007, 01:39:53 AM »
Here is our water injection system.





Nosle pointing directly into the compressor.



Injector nosle with an enderly jet.



our little water tank.  Do you recognize the colored markings?  If we put methanol in it it would put us in a fuel class.  We put sealed bottle water into the tank in front of the inspectors and they seal it.



This aluminum cover is used because we blew the top off of the plastic twist lid under boost.



« Last Edit: July 11, 2007, 01:58:18 AM by bvillercr »

Offline JackD

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Re: Calculating Water Injection and placement
« Reply #20 on: July 11, 2007, 04:54:17 AM »
Manifold pressure supplies and regulates the water volume.
 What a concept !
Reduce the size of the filler to a screw in pipe plug and your troubles with that are over. :wink:
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Offline SnowTech

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Re: Calculating Water Injection and placement
« Reply #21 on: July 11, 2007, 02:11:12 PM »
Manifold pressure supplies and regulates the water volume.
 What a concept !
Reduce the size of the filler to a screw in pipe plug and your troubles with that are over. :wink:

Jack, I think you would be disappointed to see what kind of atomization you get using manifold pressure to pressure your injection system.  There is a Ford-specific water/methanol injection system available that uses this type of operation.  With low boost pressures, the fluid simple dribbles into the intake providing zero benefit.  Proper atomization is the key to success as it gives the most surface area for cooling and equal distribution.

Nate

Offline SnowTech

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Re: Calculating Water Injection and placement
« Reply #22 on: July 11, 2007, 03:06:59 PM »
A competitor of ours released a water injection system specifically for diesels.  Their system uses Hilborn/Enderle mechanical fuel injection type nozzles.  We did some testing to see what kind of atomization these types of nozzles really produce.  Please see the following:

Low speed shot of competitors nozzle - notice the non-uniform spray pattern:



High speed shot of competitors nozzle - notice the poor atomization, streaming, and fan spray:



Here is the Snow Performance 375 ml/min nozzle doing what it does best:



Keep in mind that the competitors nozzle was tested at 150 psi of line pressure.  Line pressures below 60 psi will not create very favorable atomization.  This is the main reason why systems that use manifold pressure to pressurize the reservoir don't work very well.

Nate
« Last Edit: July 11, 2007, 03:12:54 PM by SnowTech »

Offline joea

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Re: Calculating Water Injection and placement
« Reply #23 on: July 11, 2007, 05:33:13 PM »
Nate I think you would be disappointed to see how
many records JackD (and others) broke using this method........

Joe

Offline JackD

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Re: Calculating Water Injection and placement
« Reply #24 on: July 11, 2007, 05:58:52 PM »
I have seen fluids sprayed at various delivery rates and with various pressures on injection systems and know how they work.
I should send some of my collection of pre-adomizer nozzles and some with replaceable inserts that replace the flair feature on the supply ends.
They are used for not only for cooling fluid but as the primary supply for fuel.
The system that is being sold does take some advantage of modern electronic controls is certainly good for many applications, however it has not reinvented the wheel that serves many others just fine for many years in the past and for the foreseeable future.
If you think you need it, you probably do.  :wink:
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Offline jl222

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Re: Calculating Water Injection and placement
« Reply #25 on: July 11, 2007, 06:10:19 PM »
A competitor of ours released a water injection system specifically for diesels.  Their system uses Hilborn/Enderle mechanical fuel injection type nozzles.  We did some testing to see what kind of atomization these types of nozzles really produce.  Please see the following:

Low speed shot of competitors nozzle - notice the non-uniform spray pattern:



High speed shot of competitors nozzle - notice the poor atomization, streaming, and fan spray:



Here is the Snow Performance 375 ml/min nozzle doing what it does best:



Keep in mind that the competitors nozzle was tested at 150 psi of line pressure.  Line pressures below 60 psi will not create very favorable atomization.  This is the main reason why systems that use manifold pressure to pressurize the reservoir don't work very well.

Nate

Looks good, what car or bike are you running it on.  What are your performance gains with and without?

Offline Speed Limit 1000

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Re: Calculating Water Injection and placement
« Reply #26 on: July 11, 2007, 10:49:51 PM »
Maybe the Webmaster can tell us how it works on the turbo 600 :-D
John Gowetski, red hat @ 221.183 MPH MSA Lakester, Bockscar #1000 60 ci normally aspirated w/N20

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Re: Calculating Water Injection and placement
« Reply #27 on: July 12, 2007, 08:29:16 AM »
Nate I think you would be disappointed to see how
many records JackD (and others) broke using this method........

Joe

Just because they had it on there doesn't mean it did anything worth while.

Offline JackD

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Re: Calculating Water Injection and placement
« Reply #28 on: July 12, 2007, 10:58:37 AM »
The people that depend on atomization of very large volumes of liquid fuel with no more than the pressure drop in a carburetor and appropriate manifolding will be very disappointed to hear it won't work.
Who dares tell them ?
Not Me, Ima gonna let you.
As I have said, it is probably a fine system that is useful in many situations but doesn't satisfy the needs for everybody.
It is like the reinvention of the wheel, the best you can hope for is to uniquely modify it for a particular market and then you have sell it. :wink:
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Offline SnowTech

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Re: Calculating Water Injection and placement
« Reply #29 on: July 12, 2007, 12:13:26 PM »
It is like the reinvention of the wheel, the best you can hope for is to uniquely modify it for a particular market and then you have sell it. :wink:

Well we're definitely not trying to reinvent the wheel but we sure can improve it and that's what we've done.  The idea and viability of water/methanol injection is nothing new just like the idea and viability of a gasoline powered internal combustion engine is nothing new either.  It's pretty obvious that in the last one hundred or so years there have been vast improvements in engine management systems.  The whole suck-squeeze-bang-push idea hasn't changed one bit but again, thanks to modern engine management advancements, the whole system has improved.  I'm sure even the most rudimentary water/methanol injection systems work but water/methanol is all we do here at Snow Performance and we've dedicated ourselves to provide the best that there is. 

Nate