0504 DNSによるノズル回転制御下における衝突噴流の流動・伝熱特性

Abstract

In order to develop a new heat transfer procedure of impinging jet, we conduct a DNS (direct numerical simulation) of controlled impinging jet. As a proposed procedure, a nozzle is rotated around a given axis normal to the impinging wall. Prom view of instantaneous velocity magnitude and instantaneous vortex structures, it is found that jet circumferentially rotates depend on the rotating frequency in the free jet region, and that the jet diffuses largely compared to the case of the uncontrolled jet. In order to estimate the heat transfer performance, the local Nusselt number distribution is calculated. For the controlled case, the heat transfer performance around the impinging position markedly decreases compared to the uncontrolled case, however it is found that a homogeneous heat transfer appears around the impinging position under a specific frequency of rotation and a rotating radius.