Thursday, November 15, 2018

Fill Drain how to make safe...

One way to fill a tank... (and how I've filled every rocket tank to date)
Is just put a removable fitting on the top of the tank and pour in the propellant.
Its real hard to make a system lighter than just a single AN cap.

This has several problems...
  • It does not scale, in a Otrag vehilce you might have 128+ tanks to fill.
  • On a biprop vehicle, once one of the propellants is loaded loading the other propellant becomes a hazard.
  • Its very difficult to precisely fill to exact levels.
  • It does not help you drain after an abort scenario.

    So I'd like to do remote fill and drain on the vehicle without adding a bunch of weight...
    Here is one possible scheme that can be done with a single tank penetration.










At the expense of wasign some propellant it ensures the system is filled to a precise level (the level of the bottom of the dip tube, and only requires one tank penetration.

It has the added advaltage that if you use the valve RV1 to vent the tank in an in flight abort, it does nto vent the all the propellant, only the pressurization gas.... With Lox its not an issue to dump propellant while in the air, with H2O2 dumping in the air can start a large area brush fire.








4 comments:

Ben Brockert said...

Ground abort, yes, mostly ullage gas will come out. In flight the liquid will not be settled at the bottom of the tank in most abort cases, so some liquid is still going to come out the vent.

Unknown said...

So the OTRAG design is modular. Can each tank be assembly line filled then attached?

Paul Breed said...

Don't want to handle prefilled tank, too hazardous....
Also tank is likely not strong enough un-presurized.

Ben, actually in an inflight abort all propellant is probably flung forward fairly quickly and the vent tube being in the half way center of the tank could really only ever have propellant in zero G, any other time only passing blobs of propellant..


Kate Berry said...
This comment has been removed by a blog administrator.