Thread: Ramjet Rocket engine hybrid? View Single Post
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Ramjet Rocket engine hybrid?

Yeh i went ahead and did it now, and really wish i had not but its a great learning experiance though a very steep learning curve with alot of work even though i am trying to keep it as simple as possible.

I have one question, i never took chemistry (and for some reason we missed the thermodynamics section at my uni, shocking i know, had to learn it myself) I am trying to find out a very approximate pressure in my rocket combustion chamber given that I am using a O2 H2 mix for propellent/oxidizer combo. I have been trying to find the equations to use, would this one work for a rought estimate (I found it in a old book V was not defined but I assume volume):

P = (C/V) (R T/M)

Where:
P is max pressure, C is mass of propellent, V is volume (or rather my combustion chamber area I assume) R is universal gas constant, T is max temperature, M is average molecular weight.

or could i just use P = nRT/V where n is moles in this case? In equations like this is volume just the area that the gas can expand to, or for my purposes the combustion chamber).