Nozzle sizing /Flow rate

[spindrift]

In a diesel application I've heard that flow rate can vary significantly. What is the most appropriate method for determining water flow rate? Should nozzles be specced according to fuel delivery rate or boost level, or both?

[Richard L]

ideally, the water flowrate should match the air mass. Fuel flow rate is also possible but not as accurate.

[spindrift]

My 6.5L turbo diesel flows a little over 400 CFM. What nozzle size would provide an appropriate water flow rate at maximum load? Since I have a tough time with metric conversions I would appreciate knowing the nozzle water flow rate in either oz/min. or GPH.

[Richard L]

My 6.5L turbo diesel flows a little over 400 CFM. What nozzle size would provide an appropriate water flow rate at maximum load? Since I have a tough time with metric conversions I would appreciate knowing the nozzle water flow rate in either oz/min. or GPH.

1. 1 cu ft per minute = 0.028cu m per minute
2. 400 cu ft = 11.2cu m per minute
3. 1 cu m of air weights 1Kg at 25C
4. so 400 cu ft per minute is 11.2Kg per minute.

1mm nozzle flow 330cc/min (aquamist pump) or 11.6 oz/min

[spindrift]

I'm looking at fine spray atomizing nozzles. These nozzles are available in brass, 303 stainless steel and 316 stainless steel. There is a wide range in cost among the three materials. Is a specific nozzle material recommended over another?

How important is water particle size? Depending upon the quality and number of nozzles used, you can achieve a relatively wide margin in particle size as measured in microns.

[Richard L]

Any nozzle material will do as long as it is compatible with the water you use.

Drop size should vary between 30-80 micron - too small droplet will displace air space after evaporation. Too big will cause distribution problems.

[masterp2]

Richard,

Are you saying here that you don't promote 100% saturation, with some of the water going to the cylinder as liquid?

[Richard L]

I missed this post sorry.

100% saturation is normally achieved in winter and rarely in hot Summer, so for a system that will inject water proportional to the degree of saturation under all boost, summer, winter and differebt load is not going to be easy.

I have no strong view on 100% saturation - metering the water against the fuel flow is pretty accurate.

Water is a very powerful coolant, I am only concern with a system that cannot determine where the 100% saturation point is, over watering might loose power instead of gaining. It is silly to use a good portion of power produced by the engine just to turn the water into steam and to come out of the exhaust pipe.

[masterp2]

Spindrift

Your diesel is an airpump with fuel metered in for power. For charge cooling, the rate of air is going to be the dominant factor in how much water can be metabolized, so MAF or boost would be good metering dependents (inputs).

[Prometeus]

We in Italy have developed sys. related to the turbo pressure...

[miata_rp]

Hello to Everyone,

Hi Richard, I recently viewed this post regarding the approach to use in sizing a nozzle for turbodiesel applications.
Am I correct in understanding your computation which implies 3% of mass air flow is a good starting point? i recently
installed a water injection system using aquamist nozzles and pump on a Toyota 2.4 turbodiesel with .8 bar(12 psi boost).


11.2 kg/min=395 oz./min; a 1 mm nozzle flows 11.6 oz/min; 11.6/395 oz min ==3% of mass air flow

"spindrift wrote:
My 6.5L turbo diesel flows a little over 400 CFM. What nozzle size would provide an appropriate water flow rate at maximum load? Since I have a tough time with metric conversions I would appreciate knowing the nozzle water flow rate in either oz/min. or GPH."

Richard L:

1. 1 cu ft per minute = 0.028cu m per minute
2. 400 cu ft = 11.2cu m per minute
3. 1 cu m of air weights 1Kg at 25C
4. so 400 cu ft per minute is 11.2Kg per minute.

1mm nozzle flow 330cc/min (aquamist pump) or 11.6 oz/min

[Bikenuts]

Hello to Everyone,

Hi Richard, I recently viewed this post regarding the approach to use in sizing a nozzle for turbodiesel applications.
Am I correct in understanding your computation which implies 3% of mass air flow is a good starting point? i recently
installed a water injection system using aquamist nozzles and pump on a Toyota 2.4 turbodiesel with .8 bar(12 psi boost).


11.2 kg/min=395 oz./min; a 1 mm nozzle flows 11.6 oz/min; 11.6/395 oz min ==3% of mass air flow

"spindrift wrote:
My 6.5L turbo diesel flows a little over 400 CFM. What nozzle size would provide an appropriate water flow rate at maximum load? Since I have a tough time with metric conversions I would appreciate knowing the nozzle water flow rate in either oz/min. or GPH."

Richard L:

1. 1 cu ft per minute = 0.028cu m per minute
2. 400 cu ft = 11.2cu m per minute
3. 1 cu m of air weights 1Kg at 25C
4. so 400 cu ft per minute is 11.2Kg per minute.

1mm nozzle flow 330cc/min (aquamist pump) or 11.6 oz/min

If my Maths is right 330cc/min = 4.4 GPH.
For refrence I'm using 5GPH in a 3Liter Toyota turbo diesel (12psi no cooler; 130bhp stock 170bhp with LPG)
Results are good - a real kick when I turn on the water and EGT down about 50C.