Experimental Study of Heat Transfer from Impinging Jet with Upstream and Downstream Crossflow

摘要

Numerous geometrical and flow parameters can affect the heat transfer in the impinging jet cooling methods. In this study, a configuration close to a real case of vane cooling was adopted. It consists of a main crossflow flowing into an injection hole of diameter D perpendicular to the main flow through a thin plate of thickness t equal to D and the Reynolds number of the injection is fixed to 23,000. A secondary crossflow with a Reynolds number of 1000 is fixed between the exit of the jet and the impingement region, to simulate the flow stream evacuation from the leading edge to the trailing edge of the vane. This geometry is very different from a jet issued from a long pipe as described in many previous studies. The flow field of the jet in the present case has a three-dimensional behavior due to its complex geometry. High levels of turbulence at the exit of the nozzle are observed with Particle Image Velocimetry measurements. The fields of the reference temperature and convective heat transfer coefficient on the impingement surface are calculated from infrared thermography measurements. The results show a significant drop of the heat transfer in such geometry.