衝突噴流熱伝達に及ぼすタブの影響  [in Japanese] Effect of Tabs On Impinging Heat Transfer  [in Japanese]

The present work experimentally investigates the effect of vortex generators, in the form of small tabs projecting normally into the flow at the nozzle exit, on the flow and heat transfer characteristics of an axisymmetric impinging air jet at the subcritical Reynolds number range, with this comes the expectation of the large eddy structure variation and the possibility of the active control. Local heat transfer and static pressure were measured on the target plate for a round air jet issuing from a circular nozzle with rectangular tabs whose numbers and lengths changed at the constant nozzle-to-plate gap (L/d=8) and jet Reynolds number (Re=34000). The main results are the following:When two tabs were set at the exit of the circular nozzle, C_<pw> and Nu profiles flatten in the direction of the tab setting. In the case of three tabs, however, among both C_<pw> and Nu profiles a concentric profiles is expressed, as well as in one without the tab.