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SysCrusher · 02-06-2003, 08:22 PM

Hey I see your pic now. That's exactly the idea I had just without my tapered base which i'm wondeing if the taper base helps any. The only thing I would change is move that nozzle closer to the base. What happens is that the surounding water that the jet is passing through effects the volocity of the jet stream which slows it down and lowers the pressure against the base making the stagnation area smaller. Plus the water that just hit the base is now heated up and will tend to swirl up and back into the jet stream and recyclng that warm water. Closer to the base and that will be avoided. Also make the nozzle so that it's flat at the tip. That will keep old water from getting into the stagnation area and help keep the volocity up after it hits the base. Plus it helps guide it across the base. That was my first mistake on my first block.

Doing a submerged jet inpingement in a water block is different. My first time I looked at as a water jet hitting a plate and forgetting it was submerged. If you could look at the jet impingement magnified you would see small vortexes(sp?) being created right at the surface of fast moving water the impingment creates. The water surrounding it effects it greatly. After the jet hits the base it thins or eliminates the boundary layer and spreads out with high velocity. Called the stagnation area. This fast or higher velocity water will actually create a vortex of heated water from the water sorrounding the jet impingement that will help heat the new cooler water hitting the base. We don't need that. So it's best to keep the nozzle close to the base, make the tip of the base flat or the same shape as the base so that it covers the area just above the stagnation area. This will make sure that the impingement is not effected by any old heated water and it's velocity won't be effected by surrounding water.

The idea is to keep all stagnate water away from the impingement.

I'd put a jet impingement block done right on par with performance to a micro-channel block any day. Mixing the two just right might be even better.

02-06-2003, 08:22 PM	#28
SysCrusher Cooling Savant Join Date: Dec 2002 Location: Florida Posts: 256	Hey I see your pic now. That's exactly the idea I had just without my tapered base which i'm wondeing if the taper base helps any. The only thing I would change is move that nozzle closer to the base. What happens is that the surounding water that the jet is passing through effects the volocity of the jet stream which slows it down and lowers the pressure against the base making the stagnation area smaller. Plus the water that just hit the base is now heated up and will tend to swirl up and back into the jet stream and recyclng that warm water. Closer to the base and that will be avoided. Also make the nozzle so that it's flat at the tip. That will keep old water from getting into the stagnation area and help keep the volocity up after it hits the base. Plus it helps guide it across the base. That was my first mistake on my first block. Doing a submerged jet inpingement in a water block is different. My first time I looked at as a water jet hitting a plate and forgetting it was submerged. If you could look at the jet impingement magnified you would see small vortexes(sp?) being created right at the surface of fast moving water the impingment creates. The water surrounding it effects it greatly. After the jet hits the base it thins or eliminates the boundary layer and spreads out with high velocity. Called the stagnation area. This fast or higher velocity water will actually create a vortex of heated water from the water sorrounding the jet impingement that will help heat the new cooler water hitting the base. We don't need that. So it's best to keep the nozzle close to the base, make the tip of the base flat or the same shape as the base so that it covers the area just above the stagnation area. This will make sure that the impingement is not effected by any old heated water and it's velocity won't be effected by surrounding water. The idea is to keep all stagnate water away from the impingement. I'd put a jet impingement block done right on par with performance to a micro-channel block any day. Mixing the two just right might be even better. Last edited by SysCrusher; 02-06-2003 at 08:28 PM.