Orifice Jet Control Using Sub-Flows Issuing from Circular and Non-Circular Openings

Nozzle shapes offer the possibility of a passive control technique to provide high mixing and heat transfer rates. Thus, a number of investigations have been carried out to elucidate the influence of nozzle configuration including noncircular orifices on the flow and heat transfer characteristics. This paper demonstrates the effects of sub-flows issuing from different shaped openings on main orifice air jet flow characteristics. Mean velocity measurements by a constant temperature hot-wire anemometer are carried out at a Reynolds number of Re = 2.2 × 104 to investigate the flow characteristics of orifice jets with sub-flows. The effects of the opening shape on the main orifice flow are also demonstrated by flow visualization. It is shown that the potential core lengths and mixing characteristics with ambient fluids of orifice jet flows can be controlled by the sub-flows.