Anti-icing hot air jet heat transfer augmentation employing inner channels

• Published in: Advances in mechanical engineering 2021-12, Vol.13 (12)
• Main Authors: Saeed, Farooq, Ahmed, Kamran Z, Owes, Amro OE, Paraschivoiu, Ion
• Format: Article
• Language: English
• Subjects: Air jets; Aircraft; Aircraft icing; Angles (geometry); Commercial aircraft; Deicing; Empirical analysis; Flight safety; Flow characteristics; Fluid flow; Heat transfer; Jet nozzles; Leading edges; Mathematical models; Parameters; Reynolds number; Transport aircraft; Weather; Wings (aircraft)
• ISSN: 1687-8132; 1687-8140
• DOI: 10.1177/16878140211066212

Many approaches exist today that employ hot-air from aircraft compressor bleed for anti-icing critical aircraft surfaces. This paper introduces and numerically analyzes the novel application of an inner or etched channel to augment heat transfer from a hot-air jet impinging on a curved surface representing the inner surface of an aircraft wing’s leading edge or slat. The study shows that proper positioning, geometry, and flow characteristics of a channel along the inner surface of the leading edge can significantly enhance heat transfer, boost the anti-icing system performance, and greatly enhance flight safety during critical icing weather conditions. Commercially available CFD software, ANSYS Fluent is used to model and analyze the effect of different geometric and flow parameters typical of those found in small to medium category commercial transport aircraft to help determine the optimum arrangement. These parameters include: (1) jet nozzle height-to-slot diameter ratios from 4 to 8, (2) channel width-to-slot diameter ratios from 0.4 to 1.8, and (3) inner-channel inlet location angles from 10° to 60°. Each configuration resulting from a combination of the above parameters was simulated at Reynolds numbers based on jet-slot diameter of 30,000, 60,000, and 90,000. Empirical relations based on available experimental data are used to validate the results. The main findings of the study reveal that the jet height-to-slot diameter ratio of 6, inner channel height-to-slot diameter ratios of 1.8, and inner-channel inlet angular locations of 10° combination resulted in the highest heat transfer at all Reynolds number as well as higher at increased Reynold numbers. Graphical abstract Description of figures: (a) RAE 2822 airfoil with a modified leading edge to incorporate, (b) a typical wing leading slat, (c) internal layout of the piccolo tube inside a typical edge slat (Courtesy of Bombardier Aerospace), (d) numerical simulation of heat transfer from the hot-air jet from a piccolo tube impinging on the inner surface of the slat, and (e) numerical model with etched channel (novel idea) for enhanced heat transfer being investigated in current study.