Milk Jug Failure Modes
Posted: Mon Apr 10, 2017 7:01 pm
I was playing around with my hybrid, trying to fine tune the optimum mix pressure for my volumetric meter setup and I noticed I got three failure modes when using milk jug burst disks. My union is 1" and I was at 4X. For correct mixtures (at least according to my calcs) and slightly rich mixtures I got a burst like example #1. Sort of a linear tear and bulging of the surface subjected to the pressure. Note this was the loudest bang as well. For slightly lean mixtures I got #2, a nice circular opening with the center still attached like a door. And sometimes with any mix the disk would deform and slip out like #3.
Do any of you have experience with these and/or have any suggestions as to what these failure modes mean?
My guess is that #2 is optimum because of greater flow and indicates that the combustion was fastest because the shock caused a more brittle failure. # 1 looks more like a slower build up in pressure until the material undergoes ductile yielding and ruptures. #3 looks like I just didn't tighten the union enough.
Do any of you have experience with these and/or have any suggestions as to what these failure modes mean?
My guess is that #2 is optimum because of greater flow and indicates that the combustion was fastest because the shock caused a more brittle failure. # 1 looks more like a slower build up in pressure until the material undergoes ductile yielding and ruptures. #3 looks like I just didn't tighten the union enough.