Optimisation of a Nacelle Electro-Thermal Ice Protection System for Icing Wind Tunnel Testing

Abstract Aircraft are equipped with ice protection systems (IPS), to avoid, delay or remove ice accretion. Two widely used technologies are the thermo-pneumatic IPS and the electro-thermal IPS (ETIPS). Thermo-pneumatic IPS requires air extraction from the engine negatively affecting its performances. Moreover, in the context of green aviation, aircraft manufacturers are moving towards hybrid or fully electric aircraft requiring all electric on-board systems. In this work, an ETIPS has been designed and optimised to replace the nacelle pneumatic-thermal system. The aim is to minimise the power consumption while assuring limited or null ice formation and that the surface temperature remains between acceptable bounds to avoid material degradation. The design parameters were the length and heat flux of each heater. Runback ice formations and surface temperature were assessed by means of the in-house developed PoliMIce framework. The optimisation was performed using a genetic algorithm, and the constraints were handled through a linear penalty method. The optimal configuration required 33% less power with respect to the previously installed thermo-pneumatic IPS. Furthermore, engine performance is not affected in the case of the ETIPS. This energy saving resulted in an estimated reduction of specific fuel consumption of 3%, when operating the IPS in anti-icing mode

Robust Optimization of a Thermal Anti-Ice Protection System in Uncertain Cloud Conditions

International audience This paper presents a framework for the robust optimization of the heat flux distribution for an anti-ice electrothermal ice protection system under uncertain conditions. The considered uncertainty regards a lack of knowledge concerning the characteristics of the cloud, i.e., the liquid water content and the median volume diameter of water droplets, and the accuracy of measuring devices, i.e., the static temperature probe. Uncertain parameters are modeled as random variables, and two sets of bounds are investigated. A forward uncertainty propagation analysis is carried out using a Monte Carlo approach exploiting a surrogate models. The optimization framework relies on a gradient-free algorithm (mesh adaptive direct search), and two different objective functions are considered, namely, the 95 quantile of the freezing mass rate and the statistical frequency of the fully evaporative operating regime. The framework is applied to a reference test case, revealing a potential to improve the heat flux distribution of the baseline design. A new heat flux distribution is proposed, and it presents a more efficient use of the thermal power, increasing flight safety even at nonnominal environmental conditions. </jats:p

Numerical simulation of a thermal Ice Protection System including state-of-the-art liquid film model

In this work, a numerical model for the operation of an electro-thermal Ice Protection Systems (IPS) for an airfoil is presented. The present model solves the energy conservation laws and includes a boundary layer model to compute the relevant aerodynamic quantities based on previous works. Additionally, the computation of aerodynamic and water impingement properties is performed by means of open-source and in-house developed software. A state-of-the-art liquid film model based on lubrication theory has been deployed as an alternative to an element-wise mass balance. A simple ice formulation for the prediction of the formation of runback ice has been included. Moreover, a robust evaporation model based on the heat and mass transfer analogy is deployed. Finally, an interpolation scheme for the element-wise enthalpy variation is presented. The results obtained are in good agreement with the experimental data from the open literature for a range of different test cases including different operating modes, environmental and flight conditions