Shinan Chang

Aircraft Ice Accretion Prediction Using Neural Network and Wavelet Packet Transform

Purpose – The purpose of this paper is to present a new technique based on the combination of wavelet packet transform (WPT) and artificial neural networks (ANNs) for predicting the ice accretion on the surface of an airfoil. Design/methodology/approach – Wavelet packet decomposition is used to reduce the number of input vectors to ANN and to improve the training convergence. An ANN is developed with five variables (velocity, temperature, liquid water content, median volumetric diameter and exposure time) taken as input data and one dependent variable (the decomposed ice shape) given as the output. For the purpose of comparison, three different ANNs, back-propagation network (BP), radial basis function network (RBF) and generalized regression neural network (GRNN), are trained to simulate the wavelet packet coefficients as a function of the in-flight icing conditions. Findings – The predicted ice accretion shapes are compared with the corresponding results from previously published NASA experimentation, L...

Study on the Minimum Anti-Icing Energy Based on the Icing Limit State

This investigation presents a new approach for calculating the minimum aircraft anti-icing heat load based on an icing limit state in which all of the heat fluxes on the outer surface of the skin reach equilibrium without having additional heat supplied to the skin and there is no ice formation. Different from the conventional method where the surface temperature is assumed to be a constant value (for example, 4 or 20°C), this investigation uses a surface temperature distribution in the icing limit state to calculate the anti-icing heat load of the flight conditions, which avoids the randomness of the assumed temperature value and provides a theoretical reference for the aircraft anti-icing heat load calculation. A relevant calculation code is developed using the Visual Basic .NET language. This investigation calculates the minimum anti-icing heat load of a DFVLR R-4 airfoil in numerous cases and compares the results with those for which the surface temperatures are 10 and 20°C. The results indicate that ...

Experimental Study of the Dynamics of Water Film on an Aluminum Substrate under Wind Shear

This document is the Accepted Manuscript version of a paper presented at the 9th AIAA Atmospheric and Space Environments Conference, 5-9 June 2017, Denver, Colorado. Content in the UH Research Archive is made available for personal research, educational, and non-commercial purposes only. Unless otherwise stated, all content is protected by copyright, and in the absence of an open license, permissions for further re-use should be sought from the publisher, the author, or other copyright holder.

Transient characteristics of an electrothermal anti-icing process based on the improved messinger model

An unsteady numerical study on the electrothermal anti-icing process of an aeroengine rotating fairing was performed. The water droplets impingement was firstly simulated based on the Eulerian theory for two-phase flow. Then the calculation method of the convection heat transfer on the fairing surface was proposed and the corresponding code for anti-icing calculation was developed based on the improved Messinger model. The model and method were validated by comparing the present results with those obtained by FLUENT or FENSAP-ICE. System start-up characteristics and effects of rotation were investigated and different heating strategies were compared subsequently. The analysis indicates that rotation can enhance convection heat transfer on the fairing surface; icing and ice shedding phenomenon may appear during the system start-up stage and the response time of the system can be reduced by considering these phenomena; besides, the periodic anti-icing is more energy-efficient compared to the continuous heating when the heating power supply is the same, while when the same energy is consumed by the two patterns, the periodic system shows faster start-up response, but faces the greater risk of icing.