[AR] Re: CopSub HEAT2X static test - first bulletin
- From: Paul Mueller <paul.mueller.iii@xxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Thu, 21 Aug 2014 12:57:20 -0600
If you don't seal the injector, seems like you'd have to have one heckuva
hydrotesting pump to maintain the pressure and flow rate. I suppose they
could have tried a full-flow test with water in the propellant tanks
instead of lox and alcohol, but it's always a question of how much time and
expense do you put into testing (and drying out your hardware after the
test!). Hindsight's always 20-20.
I wish them well--they have a very exciting program.
Paul M
On Thu, Aug 21, 2014 at 10:06 AM, Henrik Schultz <henrik@xxxxxx> wrote:
>
> It sounds like this is a regen cooled engine and the pressure in the
>> cooling
>> passages caused the chamber to collapse inward. It's the differential
>> pressure between the cooling passages and chamber that causes this so in
>> order for a hydro test to catch this you would have to seal the injector
>> somehow. A normal hydro test where you plug the nozzle wouldn't catch it.
>> It's a hard test to do and they are not the first group this has happened
>> to.
>>
> Why seal the injector? The pressure will build up on the backside of the
> injector regardless (key point for good atomization). Yeah, you may lose a
> bit of pressure through the cooling channels until you reach the injector,
> but OTOH having ambient pressure in the chamber/nozzle vs. your operating
> pressure, will only increase the pressure differential. The nozzle and
> cooling jacket must obviously be designed to withstand any transients
> during engine start-up (like water hammering effect), as well as softening
> from the pre-heat stage. Do we have any design info? This is an open-source
> project they claim ...
>
> /Henrik
>
>
>
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