Heat transfer enhancement of impingement cooling by adopting circular-ribs or vortex generators in the wall jet region of a round impingement jet

Authors

Kenichiro Takeishi - Tokushima Bunri University
Robert Krewinkel - MAN Energy Solutions SE
Y. Oda - Kansai University
Yuichi Ichikawa - Mitsubishi Heavy Industries

Abstract

In the near future, when designing and using Double Wall Airfoils, which are will be manufactured by 3D printers, the positional relationship between the impingement cooling nozzle and the heat transfer enhancement ribs on the target plate naturally become more accurate. Taking these circumstances into account, an experimental study was conducted to enhance the heat transfer of the wall jet region of an impingement round jet cooling by installing circular ribs or vortex generators (VGs) in the impingement cooling wall jet region. The local heat transfer coefficient was measured using the naphthalene sublimation method, which utilizes the analogy between heat and mass transfer. As a result, it was clarified within the ranges of geometries and Reynolds-numbers at which experiments were conducted that it is possible to improve the averaged Nusselt number Nu up to 21% for circular ribs and up to 51% for VGs, respectively.