Numerical investigation of thermal and mechanical equilibrium characteristics of ice crystal in large icing wind tunnel

In order to understand the thermal and mechanical equilibrium characteristics of ice crystal in large icing wind tunnel，a numerical approach based upon the Eulerian method coupling movement and heat and mass transfer of ice crystal was developed to simulate the process of movement and heat transfer of ice crystal in the typical configuration of China Aerodynamics Research and Development Center icing wind tunnel.The effects of particle shape and bulk density were examined from three aspects of sink and contraction，momentum equilibrium and thermal equilibrium.Results showed that the particle shape and bulk density had no significant effects on the thermal and mechanical equilibrium characteristics of small size ice crystals.Decreased particle sphericity and bulk density could restrain the sink and contraction of large size ice crystals，thereby increasing the ice crystal cloud size at the exit of configuration.The decrease in particle sphericity and bulk density could increase the particle modified drag coefficient and modified Nusselt number，and then enhance particle momentum and thermal followability，thereby facilitating large size ice particles approaching the momentum equilibrium and thermal equilibrium states at the exit.Under typical computational conditions with large size ice crystal，the velocity and temperature differences of spherical particle at the exit of configuration were about 21 m/s and 8.6 ℃，while those of plate-shaped particle with low bulk density reduced to about 1 m/s and 5.8 ℃，respectively.