Thesis Photos

I just thought I'd show you some of what I've been up to lately. Before we could do the jet pulsation tests, we needed some good steady-flow tests to demonstrate that we had a system that could accurately detect jet modulation photographically, and that our steady-state jets were smooth enough for easy comparison. Mike Massee from XCOR helped me take the following set of pictures:


This was with one of my abrasive flow machined nozzles (flow machined by Extrude Hone Corporation), using the slower strobe (pulse duration 250 microseconds).

This was the same nozzle, but with the much faster Strobotac (0.5 microsecond flash duration).


And this is the same nozzle flowing glycerin, using the Strobotac strobe. Amazing what a ~650x increase in kinematic viscosity can do eh? It's hard to believe, but the glycerin jet in this photo is going somewhere between 30-35 meters per second!

For comparison, here are two pictures of a new nozzle that wasn't abrasive flow machined:



Notice that in spite of the fact that the second nozzle was much rougher with the water flow, that both of them were perfectly smooth for the glycerin flow. This is good because it means that for experimentation and verifying the pulsation characteristics, you can demonstrate the concept using a more viscous fluid first, then once you have the concept figured out, you can go back and do all the fancy manufacturing processes to your nozzles to make them flow smoother. It also shows that our photographic test rig is totally up to the task.

Unfortunately...I broke my last set of piezoelectric crystals yesterday trying to fit them onto our latest nozzle. I don't know if I'll be able to get a new set in time for my thesis defense. So for now, I'm scrambling to finish getting my paper approved for defense without being able to perform the key validation experiment...

...Anyhow, back to work...