Numerical Study of Entrainment Mixing of Two Gases

A computational fluid dynamics (CFD) study of entrainment mixing of two gases was carried out in which an upstream duct feeds a gas into a downstream duct of larger diameter. The annular gap between the ducts is open to a second gas causing both gases to come into contact. Lateral velocity gradients between the two gas streams create viscous forces resulting in the faster moving gas entraining the slower gas into the downstream duct where mixing and enthalpy transfer takes place.

When the two gases are at different temperatures, this technique also serves as a dilution heater or cooler. The focus of the paper will be to understand the fundamental heat transfer and fluid flow phenomena that arise and the key parameters that control heat transfer and mixing.