Hydraulic Contamination, Testing Heat Exchangers, and more.

Evening',

I am a grad student working in a laboratory which does dynamic engine testing using a hydrostatic dynamometer. Currently, we have a contamination problem.

Our hydraulic fluid is milky. I don't have any pictures, but the closest comparison I could find was this. More specific pictures may become available if necessary or requested.

Our system holds around 200 gallons. We have yet to send a sample to a lab for accurate testing, but we are way over 50ppm, or even 300ppm. We think we might even have as high as 1%.

We're working on determining where the leak is coming from right now. Any guesses on where so much water (Or other contaminate) could come from now would be great.

We have 3 guesses right now on where it could be coming from.

1. Water-Oil Heat Exchangers (HX)
2. Condensation
3. Human stupidity.

HXes

We're currently in the process of investigating the HXs. There are two currently connected ones. The largest one is connected to the main reservoir. A second one is connected to a pump/motor which functions as a dynamometer.

In '11, the reservoir HX failed, and was quicklyreplaced. I cannot find any documentation yet to see if they did extensive testing on the pump/motor HX to determine if it was broken.

Currently we're doing "testing" on the pump/motor HX, mostly by filling each stage with clear or colored distilled water, and seeing if the other stage comes out as clear or colored. Results have been inconclusive, but these are extremely rudimentary.

Any advice on testing and reasons the HX failed would be appreciated. We believe one reason would be thermal shock. We are dumb enough to run the hydraulic fluid way up, and then reluctantly turn the coolant on.

Condensation

Condensation seems extremely unlikely. Quick HVACcalculations imply that if the entire reservoir was filled with 100% saturated air at 75°F, then dropped to 45°F (Approximate cooling temp), we would only have .08 pounds of water to account for. Even if the entire room was dropped from 50% to 30% relative humidity, we'd only end up with .8 pounds.

We don't think Condensation is a possibility.

Stupidity

Human stupidity seems to be the one thing that would be a catch all, but is also something we can't test.

My thoughts right now is that when the reservoir HXwas replaced two years ago, the cleaning job wasn't nearly what they thought it was. I imagine leaving 3 gallons behind somewhere in a 200 gallon system would not be that hard. I do not currently know what the cleaning procedure was when that HX was replaced.

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I'm mostly looking for experienced input on any of these things, especially the HX testing. Off the top of my head, pneumatic testing of the HX might be in order, and may be the easiest to do.

Some quick specs on the Pump/Motor HX: It's a U-type, shell and tube, rated to 250°F. Shell pressure (Hydraulic Oil) is rated to 500 PSI, tube pressure (Water) to 150. I don't have drawings or more advanced specs, yet. Working on getting that documentation.

Any and all advice will be appreciated. Thanks for your time.