Equivalent Pressure Washing Tests

[ddelaiarro]

I have a washdown spec for a unit we are designing. We need to be able to withstand a maximum of 85 gpm through a 5/8" nozzle at 75gpm. Now, I don't have access to equipment that can mimic that scenario.

What I'm wondering if can I use my average, run-of-the-mill, garden-variety pressure washer (rated at 2500psi) to mimic that test?

I'm looking at needing about 14gpm through that setup (based on calculations from http://books.google.com/books?id=_7...resnum=3&ved=0CCgQ6AEwAg#v=onepage&q&f=false").

Can someone help me justify that calculation? I'm at a loss here...

 

[Q_Goest]

Hi ddelaiarro, I'm not clear on what you're looking for. Do you want to verify the pressure drop of water through a nozzle? Or perhaps through a pipe? Or both? If so, what flow and what diameter pipe/nozzle? Please be as specific as possible.

 

[ddelaiarro]

What I'm really trying to do is figure out if there is a way to mimic a volumetric flow rate and pressure combination to another volumetric flow rate and pressure combination.

So, for instance, I can't create the ideal situation of 85psi and 75gpm, but I'm wondering if A) a solution at 2500psi and some VFR would be an equivalent 'experience' to our module and, if so, B) how do I calculate the correct pressure/VFR combination.

Basically, I want to simulate the environment of 85psi/75gpm with the equipment I have at my disposal (a household pressure washer capable of 2500psi) - I don't even know if that's possible. My gut tells me no, but I can't mathematically prove myself right or wrong.

 

[Q_Goest]

What are you trying to duplicate? The pressure drop through the system or the affect of aiming a high pressure water jet at something to remove material/dirt? If the former, it's easy enough to do the calculations on pressure drop through piping. You can find a manual that explains the basics https://www.physicsforums.com/showthread.php?t=179830". If you're trying to duplicate the affect of a high pressure water jet, then having a water jet with the same pressure going in is sufficient to get the same velocity. It may not be as effective simply because it doesn't cover the same area, but I'd think it should give you a very good idea of how effective a water jet having some given inlet pressure should work at removing material or debris. I don't think reducing the nozzle inlet pressure and comparing a high flow, low pressure nozzle to a low flow, high pressure nozzle is reasonable. The ability to remove debris is going to be a function of the impact velocity of the water which is only a function of nozzle inlet pressure.