抄録
Mixing/diffusion enhancement is one of the key technologies in various aspects, and is needed in chemical reactors, heat exchangers, burners/combustors, low-noise jet engines, air conditioners and so on. Jets are known to be useful for such mixing/diffusion enhancement. The authors research the jet from an asymmetrical two-dimensional nozzle, especially concerning the effect of the lip length of the nozzle. Experiments are conducted at a Reynolds number of 6000. The aspect ratio of the nozzle exit is fixed to 300. And, the lip length is 0,2.0h, 3.3h, 4.0h, 5.0h, 6.0h, 7.3h, 8.0h and 10h, where h denotes the height of the nozzle exit. The authors show mean-velocity and turbulence-intensity profiles at various downstream sections, in order to reveal fundamental characteristics of the jet. Furthermore, in the near downstream, the authors visualise the flow by glycol smoke so as to get quantitative information using a PIV technique, and perform the dominant-frequency measurements to reveal flow-instability characteristics.
