A theoretical sensitivity study of wet thermal anti-icing

A theoretical study has been conducted of the influences of changes in the physical parameters of an icing condition on the heat addition rate required to keep the stagnation line of a cylinder ice-free (anti-ice). The governing equations of energy and mass transport for the stagnation region of a cylinder are presented. A parametric analysis was conducted to determine the relationships between required surface anti-icing heating rate and the physical parameters of the process. A sensitivity analysis was conducted to determine the rate of change in the anti-icing heating rate with respect to the physical parameters. The physical parameters considered were the static air pressure, static air temperature, liquid water content, mass median droplet diameter, and airspeed. The analyses were conducted for three cylinder diameters, 0.25, 2.0, and 6. inches.

The analyses demonstrated the relationship of the required anti-icing heating rate and the sensitivity of the heating rate to the governing parameters. The influences of static pressure changes were found to be relatively insignificant. The static temperature was found to be the most influential governing parameter on required anti-icing heating rate. The influences of the liquid water content, droplet diameter, and airspeed on anti-icing heating rate were found to depend strongly on the particular icing conditions established.