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Eric November 12, 2003 10:11

Pre-heating combustion air
 
Hi,

I want to investigate the effect of pre-heating the combustion air to a burner. I'm doing this by simulating a system with an inlet velocity , calculated from a known mass flow rate, for stiochiometric conditions and then simulating the same system for stoichiometric conditions with the pre-heated combustion air.

If the air is pre-heated there is a density change that in turn causes an increase in velocity if the mass flow rate must remain the same, I'm sure this correct??

So how do you tell the difference between the effect the preheat has on the flow and the effect the increased velocity has on the flow?????

Or can the velocity be kept constant?? Please help really stuck!!

Regards,

Eric

T. Pallidum November 12, 2003 13:20

Re: Pre-heating combustion air
 
It depends on what you are trying to accomplish. With a computational study, you can make whatever you want constant. You get to pick whether you want mass flow rate or velocity or some other parameter to be constant. It's strictly your choice, and it will be influenced by your research goals.

Eric November 12, 2003 14:54

Re: Pre-heating combustion air
 
Hi T.,

I want to investigate the effect the preheated air has on a flow with stoichiometric conditions. However to keep the stoichiometric condition, i have to increase the velocity, is this correct?

This increase in velocity naturally has an effect on the flow so how do i determine the effect the of the preheating without the velocity effect on the flow?????

Thanks

Eric

T. Pallidum November 12, 2003 17:35

Re: Pre-heating combustion air
 
"I want to investigate the effect the preheated air has on a flow with stoichiometric conditions. However to keep the stoichiometric condition, i have to increase the velocity, is this correct?"

If you want to keep the fuel flow rate the same, that is correct.

"This increase in velocity naturally has an effect on the flow so how do i determine the effect the of the preheating without the velocity effect on the flow?????"

You can't separate the two. The system is constrained such that if you change one thing, you have to change something else at the same time. If you want to hold the heating power of the flame, pressure, and stoichometry the same, then you have to vary the inflow velocity of the combustion air.


Eric November 13, 2003 04:19

Re: Pre-heating combustion air
 
Thanks

Do you know of any papers online that have simulated preheated combustion air using FLUENT. I'd like to read up on it properly before i try it. I'd especially like to read up on how to uderstand the results produced by the simulation.

Thanks

Eric


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