[erkampasha]

In combustion flow anaylsis or reaction flow analysis, reaction mechanism file required. I wonder that how those files are prepared. What is your strategy to determine reaction mechanism file.


Thank you.

[erkampasha]

Is there anybody who can help me?

[LuckyTran]

There isn't much strategy involved. If you are doing reacting flows, you are going to be using a very practical fuel/oxidizer combination. Whatever fuel/oxidizer combination you have, there is rarely more than 1 reaction mechanism that is even decent. And if you read a recent paper on that particular topic that is similar to what you are interested it where any detailed kinetic model is used, it usually falls right out. People don't exactly come up with new reaction mechanisms every day. That's the story if you're looking for a detailed (aka a good) kinetic model.

The caveat is that there are a ton of people that used reduced models. If you're in this category then good luck. There is no end to the number of surrogate models out there. It's uncountable in the mathematical sense.

[aerosayan]

Originally Posted by LuckyTran

There isn't much strategy involved. If you are doing reacting flows, you are going to be using a very practical fuel/oxidizer combination. Whatever fuel/oxidizer combination you have, there is rarely more than 1 reaction mechanism that is even decent. And if you read a recent paper on that particular topic that is similar to what you are interested it where any detailed kinetic model is used, it usually falls right out. People don't exactly come up with new reaction mechanisms every day. That's the story if you're looking for a detailed (aka a good) kinetic model.

The caveat is that there are a ton of people that used reduced models. If you're in this category then good luck. There is no end to the number of surrogate models out there. It's uncountable in the mathematical sense.

Can we do simulations with fuel and oxidizer combinations that aren't standard?


I see many papers use H2, CH4, O2 combinations mostly as they are in gaseous phase and don't require phase change models. In some papers I've read the use of refined Kerosene, O2 combinations.


What if I want to do a simulation with other fuels like hypergolic fuels or Ammonia + Red Fuming Nitric Acid?


How do we find the reaction rates for these mixtures?

[LuckyTran]

I can tell right away just from hearing these mixtures that these are all from rocketry. These are very common, very standard, and (from a chemist's point of view) very simple reactions.

Btw, in CFD-land nearly everybody uses the chemkin format (for historical reasons). You can google these combinations + chemkin + detailed mechanism and find a paper reference with all the reaction rates. You can make the chemkin file yourself. Or if you are lazy like me, you email the author and ask them for their chemkin file (which they've emailed to hundreds of researchers already).

For example, if you want H2/O2 at high pressure, you go straight to Michael Burke.

Again, if you want any reaction rate, you can get millions of hits. You can get single-step reaction rates from high school chemistry text books. You can find two-step, three-step skeletal mechanisms and so on. But if you want a detailed mechanism, there's not that many.