The Research of Correlationship and Critical Ice Shape Acquisition in CIRA-IWT Icing Wind Tunnel

Abstract

AbstractIcing wind tunnel is a mature way to obtain ice shape, and the SAE has conducted ice shape correlation work in the icing wind tunnels as IRT, BRAIT, COX, Goodrich, etc. On the basis of this, the NACA0012 standard model was adopted to implement series ice shapes test in CIRA-IWT, meanwhile, the ice shape was also calculated by CFD for comparison, then the icing parameters sensitivity was analysed. All this work confirmed the correlationship of CIRA-IWT with other icing wind tunnel around the world and was the basis of the following critical ice shape research. According to the FAR25 App.C, the 45 min holding ice shape acquired under continuous cloud icing condition can result in the most severe aerodynamic degradation of aircraft, which called the critical ice shape. A method based on the total water collection (TWC) was proposed to determine the critical icing parameters such as velocity, altitude, temperature, LWC and MVD. Furthermore, the method was verified in CIRA-IWT by observing the ice shedding at the end of 45 min duration and by the comparison of ice shape calculated by CFD. Finally, the critical ice shape prediction method based on the combination of CFD and icing wind tunnel test was the future research direction of this paper.KeywordsCritical ice shapeMean volume diameter (MVD)Liquid water content (LWC)Total water content (TWC)Ice shedding