High speed image of potato cannon impinging a cement block

Shown at real time, then 16x slower, then 128x slower

Trebuchet throwing flaming projectile

High speed camera

This is my new tool. It is a high speed point and shoot Casio Exilim 1000. It can record up to a frame rate of 1000 frames per second. Here's a video showing its capabilities. I shot compressed air into a Pyrex dish of water. The video shows first at real time, then 4x slower, then 16x slower, then 64x slower. Enjoy.

Comparison of jet stove to other stoves

I wanted to compare the performance of the jet stove to a simple alcohol stove and to a propane/butane stove.  I heated 2 cups of water from room temperature up to boiling.  I used a thermocouple for the temperature measurements and recorded the temperature every 30 seconds.  I used a small pot without a lid.

Simple alcohol stove and propane/butane stove

Jet alcohol stove

The jet alcohol stove does much worse than the other stoves as far as time to boil (it actually didn't reach a full boil before it ran out of fuel).  One way to improve this would be to move the flames closer to the pot, ie. make the stand shorter.  The temperature drops rapidly as you move away from the flame.

Shadowgraphs of jet stove

 To really be able to analyze some of the qualitative differences between the stoves, I needed a way to visualize what is happening with the flames and heat released.  Shadowgraphs provide a way to do this because you are able to see the influence of the heat by visualizing the refraction of light through density gradients.  This is similar to when you see "heat waves" coming off a car on a hot day.  Here are some preliminary shadowgraphs of the jet stove that was shown in my last post.  I need to make a few changes to improve the contrast of the videos.

In case you are interested in how I did this, I used a projector as my light source and a white cloth as a screen.  I put the stove between the projector and the screen.  What looks like the top of the stove is actually the shadow of the top of the stove.

Jet Stove

This is my latest alcohol stove.  I slightly modified the design from my last one.  You will note the clean look of the stove because the seam is now on the bottom.  I will have data soon to go with this.