Numerical Simulation of Unsteady Conjugate Heat Transfer of Electrothermal Deicing Process

Zuodong Mu,Guiping Lin,Xueqin Bu,Xiaobin Shen,Ying Zhou

doi:10.1155/2018/5362541

Zuodong Mu, Guiping Lin + Show 3 more

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https://doi.org/10.1155/2018/5362541

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Abstract

A novel 3-D unsteady model of in-flight electrothermal deicing process is presented in this paper to simulate the conjugate mass and heat transfer phenomena of water film runback, phase change, and solid heat conduction. Mathematical models of water film runback and phase change are established and solved by means of a loosely coupled method. At the current time step, solid heat conduction, water film runback, and phase change are iteratively solved until the heat boundary condition reaches convergence, then the temperature distribution and ice shape at the moment are obtained, and the calculation of the next time step begins subsequently. A deicing process is numerically simulated using the present model following an icing tunnel experiment, and the results match well with those in the literatures, which validate the present model. Then, an in-flight deicing process is numerically studied to analyze the effect of heating sequence.

Highlights

The water droplet in clouds may remain in a liquid state even if the temperature is below freezing point due to the surface tension and a lack of condensation nucleus
This paper focuses on the conjugate heat transfer mechanism of the in-flight electrothermal deicing
During the solution of the above unsteady conjugate heat transfer model, the water film runback and phase transition are coupled with the solid heat conduction, due to the fact that the solution of the solid heat conduction provides the interface heat flux which is needed in the water film energy balance equation; on the other hand, the boundary condition of the solid heat conduction is provided by the solution of the film runback and phase transition

Summary

Introduction

The water droplet in clouds may remain in a liquid state even if the temperature is below freezing point due to the surface tension and a lack of condensation nucleus. Supercooled water droplet would solidify when impinging on windward surfaces of aircraft, which would cause the deterioration in the aerodynamic performance due to the change of aerodynamic configuration [1]. In view of the serious threats that ice accretion would impose on flight safety, ice protection methods must be applied to prevent or control the ice accretion. Hot air antiicing method is widely applied in commercial jets. The bleed air from engine compressor impinges on the structure to heat the surface, so that the water evaporates or stays in a liquid state rather than freezes. The jet flow would cause excessive temperature at the impingement point, which may damage the composite materials that are widely used in a modern aircraft [3] or even the aluminum skin. The ice protection system of B-787 [4], which is based on the electrothermal method, serves as an example

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