A hybrid scaling method for icing wind tunnel and validation

The scaling on test condition is an essential technique for icing wind tunnel tests to achieve conditions exceeded the capability of the wind tunnel facility. In order to overcome the shortages of usual scaling methods, a hybrid scaling method is presented. This method analyzes the scaling parameters and correlations of test conditions under constraints of scaling law. The hybrid method is partitioned into a two-stage procedure to coincide the principle scaling parameter, namely the inertia parameter and stagnant freezing factor respectively. And four modes are derived corresponding to different sets of target scaling parameters. The feature of mode 1 is the capability of coinciding all scaling parameters including three heat balance parameters which is not usually meet simultaneously. Mode 2 and mode 3 are considered as improved ONERA method and Ruff method respectively, in which the sequence of solving scaling equations are modified while the target parameters to meet are kept. Mode 4 applied Olsen method in the second stage procedure unchanged. Such method was tested by numerical simulation and wind tunnel tests with satisfying agreement of the resultant ice shape, and therefore the validity and practicality are proven.