Sciencemadness Discussion Board

Combustion cycling.

KonkreteRocketry - 1-3-2013 at 12:37

Since rockets use Liquid H2 and Liquid O2 as a propellant, it will burn and make mostly H2O, so, wont the H2O thermally decompose back to H2 and O since the most water decompose at 3000, and the chamber temperature is around 4000, so wont the water decompose to H2 and O, and due to the heat and Ignite again, to form H2O, and the cycle continues until its been expelled out of the nozzle ? Does this happen ?

elementcollector1 - 1-3-2013 at 12:46

The initial reaction pushes most of the reactants out the nozzle before they have a chance to split again, I'd imagine.

KonkreteRocketry - 1-3-2013 at 13:06

Quote: Originally posted by elementcollector1  
The initial reaction pushes most of the reactants out the nozzle before they have a chance to split again, I'd imagine.


Maybe, but what if we burned a H2, O2 in a closed chamber assuming heat wont be transfered out of the chamber, will it be there, combusting forever ? lol

Trotsky - 1-3-2013 at 16:35

LOL

The energy needed to split H2O back apart is more than is produced by joining them, so you'd rapidly run out of energy.

This is entirely undesirable.

You don't need to save your water molecules for later use.

gregxy - 1-3-2013 at 16:47

If the heat cannot escape the temperature will rise until
the rate of the forward reaction equals the rate of the
reverse reaction. At this point no net energy is produced
and so the temperature stops rising and the system is in
steady state.

Morgan - 1-3-2013 at 17:54

3,560 m/s
http://en.wikipedia.org/wiki/Space_Shuttle_Main_Engine