Ethanol-Gox Torch Igniter

Version 1 Igniter

The first torch igniter that was designed and printed out of 316L Stainless steel was designed poorly and didn't function. Mix ratio, inlet pressure, and spark plug placement, among other things, resulted in a test campaign with very minimum results, including minimal valuable data collected. Finally, after six attempts at firing, I realized something was fundamentally wrong with the design and moved onto version 2.

Image: Torch igniter on the workbench, and torch igniter on the stand, Jan 12, 2021 , Torch igniter, Nov 23, 2021

Image: Test 1 of V1 Igniter March 15 2022

Version 2 Igniter

The version 2 igniter had some bizarre initial tests, with tests 1-3 resulting in a skewed plume shape. I believe it was caused by excessively higher oxygen inlet velocities making the net momentum smash against the side wall. The high inlet pressure was due to the flow being controlled by the solenoid, not the orifice on the igniter. The spark plug would also vaporize in its position, hence the green plume.

Image: Test 1 and 2 of V2 Igniter April 9, 2022

After replacing the oxygen solenoid to accommodate the higher oxygen mass flow, I saw some serious results. After adding some spacers to the spark plug and letting it melt essentially to a point where it wouldn't melt anymore, it stopped melting. Test 5 and on produced beautiful data and results with a chamber pressure of 92 psi holding steady I was thrilled with the consistency; however, there were more improvements to be made, so I continued to v3.

Image: Test 5, 7, and 10 of V2 Igniter April 19-23, 2022

Version 3 Igniter

V3 of the ethanol-Gox Torch igniter was by far the best iteration. It's highly reliable, super consistent, and reusable—the new spark-plug placement results in virtually no erosion of the plug. For example, one spark plug lasted 27 firings before I pushed it during a 10-second test firing. It then partially melted but wasn't short, so it was still technically usable. Its design also ensures the net propellant momentum direction is axial, resulting in more even combustion throughout the chamber.

Image: Family photo of igniters May 6 2022, Test 1, and 3 of V3 Igniter May 6-13, 2022

Image: Long duration Test 5 of V3 Igniter June 7, 2022

TLRD: Youtube Video compiling all the tests: