Aircraft in-flight icing is a major safety issue for civil aviation, having already caused
hundreds of accidents and incidents related to aerodynamic degradation due to post takeoff ice
accretion.
Airplane makers have to protect the airframe critical surfaces against ice build up in order
to ensure continued safe flight. Ice protection is typically performed by mechanical, chemical, or
thermal systems. One of the most traditional and still used techniques is the one known as hot-air
anti-icing, which heats the interior of the affected surfaces with an array of small hot-air jets
generated by a piccolo tube. In some cases, the thermal energy provided by hot-air ice protection
systems is high enough to fully evaporate the impinging supercooled droplets (fully evaporative
systems), while in other cases, it is only sufficient to maintain most of the protected region free
of ice (running wet systems). In the latter case, runback ice formations are often observed
downstream of the wing leading edge depending on hot-air, icing, and flight conditions.
The design process of hot-air anti-icing systems is traditionally based on icing wind
tunnel experiments, which can be very costly. The experimental effort can be significantly
reduced with the use of accurate three-dimensional computational fluid dynamic (CFD)
simulation tools. Nevertheless, such type of simulation requires extensive CPU time for
exploring all the design variables. This thesis deals with the development of an efficient hot-air
anti-icing system simulation tool that can reduce the computational time to identify the critical
design parameters by at least two orders of magnitude, as compared to 3-d CFD tools, therefore
narrowing down the use of more sophisticated tools to just a small subset of the entire design
space.
The hot-air anti-icing simulation tool is based on a combination of available CFD software and a thermodynamic model developed in the present work. The computation of the
external flow properties is performed with FLUENT (in a 2-d domain) by assuming an isothermal condition to the airfoil external wall. The internal skin heat transfer is computed with
the use of local Nusselt number correlations developed through calibrations with CFD data. The
internal and external flow properties on the airfoil skin are provided as inputs to a steady state
thermodynamic model, which is composed of a 2-d heat diffusion model and a 1-d uniform film
model for the runback water flow.
The performance of the numerical tool was tested against 3-d CFD simulation and
experimental data obtained for a wing equipped with a representative piccolo tube anti-icing
system. The results demonstrate that the simplifications do not affect significantly the fidelity of
the predictions, suggesting that the numerical tool can be used to support parametric and
optimization studies during the development of hot-air anti-icing systems. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Aerospace Engineering.
| Identifer | oai:union.ndltd.org:WICHITA/oai:soar.wichita.edu:10057/3479 |
| Date | 08 1900 |
| Creators | Hoffmann-Domingos, Rodrigo |
| Contributors | Papadakis, Michael |
| Publisher | Wichita State University |
| Source Sets | Wichita State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
| Format | xiii, 110 p. |
| Rights | Copyright Rodrigo Hoffmann- Domingos, 2010. All rights reserved |
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