Experimental study on the relation between thermophoresis and size of aerosol particles

In the field of temperature gradient, mass transfer is also induced by the temperature gradient. When a small particle is suspended in such a field, it will be driven to move toward a colder region. This phenomenon is called thermophoresis. The relation between the diameter of aerosol particles and thermophoresis effect is investigated by getting rid of the particle movement induced by the effects of natural convection and gravity. The particle velocities induced by the thermophoretic effect are measured changing the diameter of particles from 1 to 30 mu m. Results show that the thermophoretic effect depends on the particle diameter. The particle velocity becomes large as the particle diameter becomes small.