# Pre-heating combustion air

 Register Blogs Members List Search Today's Posts Mark Forums Read

 November 12, 2003, 10:11 Pre-heating combustion air #1 Eric Guest   Posts: n/a 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

 November 12, 2003, 13:20 Re: Pre-heating combustion air #2 T. Pallidum Guest   Posts: n/a 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.

 November 12, 2003, 14:54 Re: Pre-heating combustion air #3 Eric Guest   Posts: n/a 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

 November 12, 2003, 17:35 Re: Pre-heating combustion air #4 T. Pallidum Guest   Posts: n/a "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.

 November 13, 2003, 04:19 Re: Pre-heating combustion air #5 Eric Guest   Posts: n/a 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