Heating at different zones on the airfoil: Experimental study on boundary layer flow and convection heat transfer scaling

Abstract

For future wing layouts and delicate laminar-wing aircraft with full-surface anti-/de-icing requirements, electric heating technology offers the advantages of flexible heating positions, high thermal efficiency and environmental friendliness. However, in addition to achieving good protection, advanced anti-de-icing technology must also take into account the requirements of efficient aerodynamic design. To investigate the effects of different heating zones on heat transfer efficiency and flow pattern within the boundary layer of wing, 15 heating zones based on bus temperature control were constructed on the leading edge and upper surface of the NACA2412 standard airfoil model, and a wind tunnel test framework was built for the study of electro-thermal convection. This is because accurate quantification of the heat transfer efficiency and precise identification of the flow effects in the boundary layer, which are crucial for effective thermal management and satisfying aerodynamic design. Within the airfoil boundary layer, test results from four typical flow characterization zones were selected for elucidation, and the spatial distribution of velocity and temperature induced by each heating zone were quantitatively characterized. Subsequently, the convective heat transfer efficiency in each heat affected zone was demonstrated using convective heat resistance. The results show that: abrupt changes in the flow state of the boundary layer can have a significant truncation effect on the temperature distribution of the flow field, leading to significant differences in the heat diffusion and heat transfer efficiency in the influence aera; moderate heating before the boundary layer burst can effectively delay the end position of the transition; and the temperature boundary layer conditions show a bimodal peak after localized heating in the airfoil. The experimental data elucidate the effects of heating at different zones on the airfoil boundary, and this work contributes to non-isothermal flow field simulation and anti-deicing design.