| The supercooled large droplet’s (SLD) diameter is bigger than50μm,which beyond the size of the droplet in the icing environment defined byFAR25Appendix C. It’s easy to appear abnormal icing when aircraftencountered with SLD icing environment, which would lead to shapechanging of airfoil, and lift force’s descending. This abnormal icingseriously affects the flight safety.Large size would cause dynamic effect of impacting splashing, so thispaper took this dynamic effect as starting point, and put forward aexperimental research method which considering both the dynamicparameters and icing parameters after viewing the problems of presentresearching. Based on the analyses of the experiment data, this papercame up with a collection efficiency distribution model which could beused to calculate the ice shape on the airfoil.Based on the measurement of experiments, this paper found that theSLD’s impacting icing could be divided into two stages. One is the SLD’simpacting-spreading stage, and the other is the supercooled water’sretraction-icing stage. This paper analyzed the supercooled and dynamicparameters’ effects to the impacting-icing process of SLD， andsummarized the effective laws of SLD’s supercooled and dynamic parameters. Based on these laws, this paper came up with a collectionefficiency distribution model which considered the SLD’s spreading andflow phenomenon. After importing this model in the airfoil icingsimulation, the simulation results were much better in compare with theexperiment results.This study has a certain improvement to the research of the mechanism ofSLD’s Impacting Icing and the simulation of airfoil icing. |
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