Numerical Investigation on the Effects of Vortex Generator Locations on Film Cooling Performance

Described in this paper is a numerical investigation on the concept for enhancing film cooling performance by placing vortex generator (VG) upstream the film hole. Six film cooling configurations with different VG locations are investigated, including the distances for VG upstream the film hole (Upstream Distances) of 20 mm, 25 mm, and 30 mm and the VG gaps of 0, 2 mm, 4 mm and 6 mm respectively. The effect of VG locations on film cooling performance were conducted. The film cooling performance is evaluated at the density of 0.97 with the blowing ratio of 1.0. Results obtained show that the twisted flow generated by upstream VG rotates in the opposite direction of kidney vortex, producing an adverse effect on kidney vortex. The enhanced adverse effect could dramatically improve the film cooling performance. Moreover, the intensity of twisted flow is greatly related to the VG locations. The film cooling performance improves with the increasing upstream distances. The film cooling performance improves first and then impairs with increasing VG gaps. In this case, the film cooling performance in the case with gap of 4 mm is superior to those in other cases.

Photogrammetric Investigation of the Flying Shape of Spinnakers in a Twisted Flow Wind Tunnel

This paper describes a method for the acquisition of the flying shape of spinnakers in a twisted flow wind tunnel. The method is based on photogrammetry. A set of digital cameras is used to obtain high resolution images of the spinnaker from different viewing angles. The images are post-processed using image-processing tools, pattern recognition methods and finally the photogrammetry algorithm. Results are shown comparing design versus flying shape of the spinnaker and the impact of wind velocity and wind twist on the flying shape. Finally some common rules for optimum spinnaker trimming are investigated and examined.