Wet APCP burn rate experiment

[thunderocketeer]

Guys, I have mixed a batch of APCP propellant today and performed a burn test of one grain (solid grain without a core) while it was wet (I mean the HTPB hadn't been set yet). I have observed almost instantenious burn of this grain, like half a second! Is that normal or it is a first symptom that there might be something wrong with the components composition?

 

[dhbarr]

Some things burn faster or slower when wet or dry, under higher or lower pressure.

Obviously we're not going to discuss formulas on the open forum, but as a cautionary tale: I am aware of at least one sugar motor formula which is orders of magnitude more reactive before it sets.

 

[patelldp]

If it's wet and is able to deform, burning surface area can increase as Pc increases and the propellant deforms.

 

[ECayemberg]

Guys, I have mixed a batch of APCP propellant today and performed a burn test of one grain (solid grain without a core) while it was wet (I mean the HTPB hadn't been set yet). I have observed almost instantenious burn of this grain, like half a second! Is that normal or it is a first symptom that there might be something wrong with the components composition?

No idea why anyone would perform this test other than out of sheer curiosity....

Aside from that, as others have said there are lots of variables here. BUT, at atmospheric pressure, no, I would not expect an end burner grain to be consumed that quickly.

Did someone mention the EX forum yet?

 

[patelldp]

out of shear curiosity....

Real missed opportunity there, Eric.