NUMERICAL INVESTIGATION OF JET-OBSTRUCTIONS TO AID IN ENHANCING SURFACE HEAT TRANSFER FROM AN IMPINGING 2D HOT-AIR JET

Aircraft icing is a serious concern for the aviation community since it adversely affects flight performance. There has always been a continuous effort to improve aircraft anti-icing systems. One such system is the hot-air anti-icing systems, which uses hot-air from the engine compressor bleed to heat critical aircraft surfaces. In this system hot-air is impinged on the inner side of critical aircraft surfaces which are susceptible to ice formation on the outer side. The heat transfer due to jet impingement prevents formation of ice and its accumulation. Numerous experimental and numerical studies have been performed to increase the efficiency of the hot-air jet based anti-icing systems. Most of the investigations have focused on either orifice design or the impingement region of target surface geometry. Since this surface heat transfer drops off sharply past the impingement region, investigators have studied the use of multiple jets to enhance surface heat transfer over a larger area. However, use of multiple jets is a further strain on engine resources. One way to conserve engine resources is to use single jet in conjunction with various mechanisms to enhance heat transfer over a large area. Hence, the study focuses on the heat transfer over a larger area using single jet and various mechanisms which can enhance heat transfer outside the impinging region. Most of these mechanisms increase the turbulence in the flow resulting in enhanced heat transfer. In this regards, several types of obstacles such as multiple triangles, cylinder, wedge and vortex generators were investigated. The commercial CFD code, FLUENT, was used for numerical simulation of the above models. Insight gained from this study will help understand ways or mechanisms to enhance surface heat transfer as applied in aircraft anti-icing system.