Setting particle parameters

Mark

Hi,

I am trying to determine the residence time of the hot gases in a steady state simulation of a furnace.

I'm not sure, but I think the way to do this is using 'particle tracking'. It was posted on this site last year by jinwook, that to use this method one should do the following:

"1). set particle size so that the particle should be small enough, e.g., 1.e-09 meter, and 2). density is similar or very low compared to the gas phase density".

Can anyone tell me how I set the particle size and density?

thanks,

Mark