An Experimental Investigation on the Convective Heat Transfer Process over an Ice Roughened Airfoil

Abstract

The initial ice roughness formed in icing process could essentially affect the local field flow, water collection and transport, heat transfer and ice accretion process. Assessing the impact of realistic roughness features on the initial ice accretion and heat transfer process is critical to improve the accuracy of ice accretion prediction. In this study, a NACA 23012 airfoil with realistic ice roughness is modeled to investigate the effect of realistic roughness on the transient initial ice accretion and heat transfer process. Icing experiments are performed in the ISU Icing Research Wind Tunnel (ISU-IRWT). A high speed videography is used to visualize the icing process including droplet collection, ice formation, water runback, and the evolution of the accreted ice. An infrared thermometry combined with thermocouple measurements is applied to map the temperature distribution over the ice accreting airfoil surfaces. The temperature measurement provides insight into the initial droplet collection distribution and the heat transfer process during icing process. The effect of the realistic ice roughness on the droplet collection distribution and heat transfer enhancement are elucidated.