I don’t know how to deal with your questions. Not enough education I guess.
My thinking is that the chemical equilibrium programs are based on minimization
of Gibbs free energy. How does one derive a heat of formation value for an
alloy of a small amount of lithium mixed with a large amount of aluminum?
Furthermore, how does one anticipate the mechanisms involved in combustion of
that alloy? I guess what I am trying to figure out is how a program based on
chemical oxidation/reduction reactions can predict a performance increase
caused by the method an intimate mixture of two metals reacts. I read what I
could find on the research of Alitec and they used a chemical equilibrium
program in their research. I find it amazing that a program can predict a
performance increase caused by different boiling points of two metals. I am
doing a poor job of communicating my thoughts so will quit here. I need a face
to face with a professor who can answer my questions.
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On May 3, 2022, at 13:11, Ben Brockert <wikkit@xxxxxxxxx> wrote:
Wouldn't that show up as variation of c* efficiency? The models assume the
chemicals are fully involved, if a significant amount of propellants are
going out the nozzle unreacted then there would be a performance shortfall
between the real motor and the model.
Does non-lithiated HTPB run at 85% c* typical?
Do lithiated rocket programs take into account that lithiated propulsion
engineers will be less worried about performance numbers?
On Tue, May 3, 2022 at 6:28 PM Barry Jolly <1bcjolly@xxxxxxxxxxxxx> wrote:
Question: Do computer programs such as Micropep and NASA’s CET85 have the
ability to predict improvements in parameters, such as Isp, due to changes
in combustion phenomena? From my understanding of Alitec’s explanation,
their propellants increased performance is due to a difference in boiling
temperature of lithium as compared to aluminum in alloy form causing an
explosion of the alloy into nano-type particles which burn very close to the
surface of the propellant. Such explanation appears to me to be based on
burning characteristics of the propellant rather than differences between
enthalpies of propellant reactants and exhaust products.
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