I need a way to generate a small souce of smoke to use in a smal scale wind tunnel. The wind tunnel measures 24"x12"x5' and is made out of acrylic. Building the tunnel is done. Ideally the smoke could be delivered through a small 1/4" tube so it can be placed anywhere in the airflow over the model.

Thank you in advance for your help.

The most common practice is to heat either propylene glycol or white mineral oil to produce the smoke. There's a great description of how one student made a smoke generator from a post way back in 2002.

Good luck with your project.