Electro-impulse De-icing System Research Articles

Numerical Analysis of the Wing Leading Edge Electro-Impulse De-Icing Process Based on Cohesive Zone Model

Aircraft icing has historically been a critical cause of airplane crashes. The electro-impulse de-icing system has a wide range of applications in aircraft de-icing due to its lightweight design, low energy consumption, high efficiency, and other advantages. However, there has been little study into accurate wing electric-impulse de-icing simulation methods and the parameters impacting de-icing efficacy. Based on the damage mechanics principle and considering the influence mechanisms of interface debonding and ice fracture on ice shedding, this paper establishes a more accurate numerical model of wing electric-impulse de-icing using the Cohesive Zone Model (CZM). It simulates the process of electric-impulse de-icing at the leading edge of the NACA 0012 wing. The numerical results are compared to the experimental results, revealing that the constructed wing electro-impulse de-icing numerical model is superior. Lastly, the effects of varying ice–skin interface shear adhesion strengths, doubler loading positions, and impulse sequences on de-icing effectiveness were studied. The de-icing rate is a quantitative description of the electro-impulse’s de-icing action, defined in the numerical model as the ratio of cohesive element deletions to the total elements at the ice–skin interface. The findings reveal that varying shear adhesion strengths at the ice–skin interface significantly impact the de-icing effect. The de-icing rate steadily falls with increasing shear adhesion strength, from 66% to 56%. When two, four, and seven impulses were applied to doubler two, the de-icing rates were 59%, 71%, and 71%, respectively, significantly increasing the de-icing efficiency compared to when impulses were applied to doubler one. Doubler one and two impulse responses are overlaid differently depending on the impulse sequences, resulting in varying de-icing rates. When the impulse sequence is 20 ms, the superposition results are optimal, and the de-icing rate reaches 100%. These studies can guide the development and implementation of a wing electric-impulse de-icing system.

Ice detection and tracking by the infrared thermography based on the electro-impulse de-icing system

An infrared thermography method was proposed, which exploited the electro-impulse de-icing system as electromagnetic excitation to detect ice shape and track ice motion. The coupling physical fields of circuit, electromagnetic, stress and heat were expounded theoretically and numerical simulated to verify the feasibility of the measurement. With the use of image processing for ice samples of different system parameters and shapes, the original ice edge was obtained at discharge voltages of 100–200 V. As the residual icing state discussed at discharge voltages of 350–450 V, the trajectory of fragmented ice was tracked by interframe difference and centroid method, and de-icing effect was evaluated by the ratio of the Euclidean distance of the fragmented ice centroids as well. The proposed method presents a novel research insight into integrating ice detection and anti/de-icing technology of aircrafts. It can also be referenced for infrared thermography detection and fragmented ice tracking via heat sources.

Research on the dual-channel electro-impulse de-icing system of aircrafts

The electro-impulse de-icing system (EIDI) is a mechanical de-icing system that guarantees the safe flight of the aircraft under icing weather conditions. It owns many merits such as high reliability and low energy consumption. To solve the problem of the small de-icing area under single-channel, a dual-channel EIDI system model is proposed. The electro-magnetic field and de-icing results of the dual-channel EIDI system are investigated. Comparisons of de-icing results between simulations and experiments on the flat aluminum plate are also made. Furthermore, the de-icing research is carried out with a real wing structure by varying the excitation time and magnitude of impulse load. Simulation results of the electro-magnetic field show that the maximum of the density of electro-magnetic force always appears at the midpoint of the inner and outer radius of coils. The excitation of the two coils is independent and can be decoupled. The de-icing results illustrate that the de-icing rate increases with the striking intervals and impulse load. The load multiple (LM) should be selected between 1.5 and 3 for the dual-channel EIDI system for energy optimization. In addition, it is advisable to distribute the impulse loads with the largest possible difference on both sides when the LM is 1–3.

Icing detection and evaluation of the electro-impulse de-icing system based on infrared images processing

The aircraft icing poses a significant hazard to aircraft safety and it is important to remove the ice in time. The electro-impulse de-icing (EIDI) system is a mechanical de-icing method, which prevents ice accumulation on that part of the aircraft where ice is more likely to form. Since its discovery research on the theory and application of the EIDI system continued to progress. In this paper, the formation of ice is detected using infrared thermography of the heat signal generated on the aircraft skin surface. Ice accretion specimen are produced to explore the effects of seven critical parameters. The performance of the EIDI system is evaluated using the infrared thermal wave test. The infrared thermography sequence of the ice accretion specimen is acquired by the infrared camera during de-icing operation. The ice detection of the EIDI system employs a method that achieves the original icing detection and icing damage detection based on infrared image processing, including principal component analysis (PCA) and Canny edge detection. The measurement of the original icing on center and radius is achieved by the three-point method, which may be further employed to evaluate the icing manufacturing error. An icing damage detection method is also designed and applied. An index based on the infrared thermal image processing results is introduced to evaluate the performance of the EIDI system under different experimental conditions. The quantitative behaviour of de-icing performance in terms of seven important parameters involved in manufacturing the ice has been verified and discussed. The results show that PCA and Canny edge detection may be effectively exploited to implement ice shape detection and, in turn, to improve the design of the EIDI system.

Design Research and Experimental Verification of the Electro-Impulse De-Icing System for Wind Turbine Blades in the Xuefeng Mountain Natural Icing Station

Functioned by mechanical vibration, the electro-impulse de-icing (EIDI) system has been widely utilized in various industrial applications. With a focus on the minimum energy consumption, a new design of the EIDI system is proposed in this paper. To study the performance of this new design, a square aluminum plate representing the Turbine blades is tested. This plate is 420 mm in side-length, 1.5 mm in thickness and covered with a 1 mm thick ice layer. Within this paper, a novel method based on optimization theory is proposed to calculate the desired electric circuit parameters for the de-icing system to be able to remove the 1 mm thick ice layer effectively (96.8% removal rate). The actual EIDI system is then built with the desired circuit parameters calculated from the proposed method, and its performance on de-icing has been tested within the Xuefeng Mountain natural icing station. The tested results achieved a removal percentage of only around 84.3%, which is caused by defects from manufacturing. To further investigate this, a 3D impulse coil-aluminum plate model is built in MAXWELL reflecting the manufacturing defects, and the simulated results are consistent with the 84.3% ice removal rate from experiments on Xuefeng Mountain experiment station. This verified the accuracy of this proposed prediction method. This unique prediction method opened a new floor for the research area of electro-impulse de-icing system and its application.

Experimental Study of Hybrid Deicing System

The hybrid deicing system combines the traditional electrothermal deicing system with the electro impulse deicing system. Firstly, the prototype design of the ice wind tunnel hybrid deicing system is carried out, and the electrothermal deicing system and the electro impulse deicing system are integrated in the airfoil model. Then, through the laboratory plate deicing experiment to study the deicing effect of different heating and excitation combinations, explore the work control law of the hybrid deicing system, and finally verify the effect of the hybrid deicing system through the ice wind tunnel test. The plate panel test found that with the increase of the surface temperature of the skin, there is a minimum binding force between the ice and the skin. In the ice wind tunnel deicing experiment, the prototype of the hybrid deicing system shows a good deicing effect with less energy consumption.

Modelling electro-impulse de-icing process in leading edge structure and impact fatigue life prediction of rivet holes in critical areas

The de-icing of a wing leading edge using an electro-impulse method benefits from its very low energy requirement and high efficiency. The high-frequency mechanical vibration activated by an electromagnetic pulse coil linked to an impulse circuit fractures the ice accumulating on the leading edge, and the ice is removed very rapidly when flying. An improved de-icing criterion based transient dynamics method is employed to accurately simulate the electro-impulse de-icing (EIDI) process. To reduce computational expenses in modelling all the rivet joints, a simplified model of leading edge structure ignoring all rivets is established using tie-constraints to identify high-stress areas or critical areas of leading edge structure during the EIDI process. Afterwards, a local detailed model of leading edge structure modelling rivets, rivet holes and their surfaces in critical areas, is set up to accurately describe the impact response and stress configuration of leading edge structure during the EIDI process. According to the EIDI local detailed model for leading edge structure, the fatigue life of critical rivet holes is predicted based on the local maximum stresses. Consequently, the endurance strength of the leading edge structure is estimated and a safe assembling scheme of the EIDI system is suggested.

Numerical simulation and validation of electro-impulse de-icing on a leading edge structure

The Electro Impulse De-Icing (EIDI) system offers an energy-efficient way of mechanically de-icing aircraft. Structural deformations induced by electromagnetic fields remove the accreted ice, and during this failure process different phenomena can be observed. A complex pattern of multiple cracks arises inside the ice layer, whereas in the ice-structure interface delaminations occur. This paper presents a numerical approach to model the combined failure process and compares it to experimental results. Cohesive zones are chosen to describe the complex fracture processes inside the ice layer while an interfacial shear stress criterion is used to determine the ice detachment from the structure. The numerical model is applied to a leading edge structure and the simulations are validated by comparison with experimental studies performed under realistic icing conditions in an icing wind tunnel. The results of several consecutive de-icing impulses show that the dynamic structural behavior and de-icing process can be approximated very well by the simulations. Furthermore, different approaches to model the complex accreted ice shape are proposed and the results are compared to each other.

Studies on the Electro-Impulse De-Icing System of Aircraft

In order to solve the accidents caused by aircraft icing, electro-impulse de-icing technology was studied through numerical simulation and experimental verification. In addition, this paper analyzed in detail the influence of the number, placement arrangement, and starting time of pulse coils on the de-icing effect, which plays a guidance role in the design and installation of the subsequent electro-impulse de-icing system. In an artificial climate chamber, the new de-icing criteria were obtained by tensile test, and the platform for the electro-impulse de-icing system was built. Replacing the skin with an aluminum plate, an electro-impulse de-icing system with a single coil was used. A three-dimensional skin-ice layer model was established by using Solidworks software. The finite element method was adapted. Through comparison between the de-icing prediction results and the test results in the natural environment, it was proven that the calculation process of de-icing prediction was correct, which laid a theoretical foundation for the selection of the number, placement arrangement, and starting time of the pulse coils. Finally, in this paper, by choosing the leading edge of NACA0012 wing as the research object, the influence of the number, placement arrangement, and starting time of pulse coils on the de-icing effect was analyzed. The results show that to get a better de-icing effect, the electro-impulse de-icing system with two impulse coils should be selected. The two coils were installed in the central position of the top and bottom surfaces of the leading edge, respectively. In addition, one of the impulse coils started working 1200 μs later than the other one.

On measuring key parameters of an electro-impulse deicing system

The peak current and vibration peak acceleration are two important parameters in the electroimpulse deicing system. Available data on two parameters are sparse. An experimental setup to measure the peak current and vibration peak acceleration in the electroimpulse deicing system is presented. The measurement is performed in the icing wind tunnel. Rogowski coil’s principle on pulsed current measurement is applied in the electroimpulse deicing discharge current circuit. It is found that calculated results agree with the measured trend. A piezoelectric vibration acceleration sensor is adopted to measure the vibration peak acceleration. Test results show that when the peak current varies linearly, the vibration peak acceleration increases with the increase of discharge voltages and its variation is approximately linear. The experimental results in the electroimpulse deicing system demonstrate that the proposed measuring method is accurate and reliable.

Simulation and validation of slat de-icing by an electromechanical system

The Electro-Impulse De-Icing system is an alternative process of de-icing wing slat structures made of carbon fiber reinforced plastics or aluminum. It is especially qualified for no-bleed systems that are used in modern and future aircraft. Due to the time-dependent interactions between the induced magnetic field and the structural deformation it can be necessary to couple these physical fields in analyses. This paper presents a three-dimensional simulation as well as experiments of flat plates. The simulation is characterized by electrical and structural finite element calculations, which are two-way coupled in each time step. The current progress is based on real tests which are executed at a special test rig. A coil, which is connected to an impulse generator, is used to induce magnetic forces. Flat plates of aluminum or carbon fiber reinforced plastics (with an additional aluminum doubler) were tested at room temperature and deformation results were used to validate numerical simulations. Further research deals with the simulation of the de-icing process itself with a stress criterion for ice adhesion. Therefore, the test rig is mounted in a cooling chamber. The ice layer is produced by spraying cooled water through a nozzle with a droplet size of supercooled large droplets (SLD). The deformation progress with and without ice is analyzed at different impulse forces and ice thicknesses. The coupled finite element analysis gives the opportunity to simulate the process of de-icing in situ to the time-dependent loading of the plate by magnetic forces. Furthermore, the complex dynamic behavior of the structure can be simulated with excellent agreement to real tests.

Coupled Numerical Simulation and Experimental Validation of the Electroimpulse De-Icing Process

The electroimpulse de-icing system is an alternative process of de-icing wing slat structures made of carbon-fiber-reinforced plastics or aluminum. Because of the interactions between the induced magnetic field and the structural deformation, it is necessary to couple these parts. This paper presents a three-dimensional simulation as well as experiments of flat plates made of aluminum or carbon-fiber-reinforced plastics. The simulation is characterized by electrical and structural finite element calculations, which are coupled in each time step. The current propagation is based on real tests that are executed at a special test rig. A coil, which is connected to an impulse generator, is used to induce magnetic forces. Flat plates of aluminum or carbon-fiber-reinforced plastics (with an additional aluminum doubler) were tested and deformation results were used to validate numerical simulations.

Deicing Excitation Simulation and Structural Dynamic Analysis of the Electro-Impulse Deicing System

A two-dimensional electromagnetic eddy current field analysis model of the experimental electro-impulse deicing system (EIDI) is developed. Additionally, a numerical post-processing method is proposed to calculate the deicing excitation exerting on the testing skin. Moreover, a three-dimensional dynamic analysis finite element model of the testing skin loaded the excitation is built for evaluating the response accelerations. Then, the calculated accelerations are compared with the experimental measured data to validate the correctness of the proposed methods. It is obtained that the results agree well, which indicates that it is feasible to use the method of post-processing pressure distribution for solving the deicing excitation and the method of structural dynamic finite element analyzing the testing skin for simulating dynamic response. The presented methods pave a way for ice failure analysis of the EIDI system.

Simulation of the Electroimpulse De-Icing Process of Aircraft Wings

The electroimpulse de-icing system of an aircraft wing leading edge is investigated through the development of a methodology for the numerical simulation of the electroimpulse de-icing process. The principle of electroimpulse de-icing is that the ice is removed due to the leading edge local mechanical vibration, which is induced by an electromagnetic pulse. The numerical simulation methodology is based on a nonlinear transient three-dimensional stress analysis of the ice-covered wing, combined to a de-icing criterion that takes into consideration the tensile and shear stresses at the ice-skin interface. The developed methodology is verified on de-icing experimental tests of an aluminum plate. Afterwards, the methodology is applied to the prediction of de-icing of an aircraft wing leading edge. The dominant process parameters are determined to be the coil number and position, the ice thickness and coverage, the radius of wing curvature, and the electroimpulsive load amplitude. A parametric study is performed to determine the influence of the process parameters on the system effectiveness, defined as the percentage of the de-iced surface over the total leading edge surface. From the results of the parametric study, the possibilities of reducing the weight and energy consumption of the electroimpulse de-icing system can arise.

Finite element studies of the electro impulse de-icing system

In this study, analytically determined impulsive forces of an electro impulse de-icing (EIDI) system are used as input to a finite element model to predict the dynamic response of an airfoil coated with impact ice. By making use of the basic mechanical properties of impact ice and the test results on the EIDI system, a comparison is made between finite element calculations and measured displacements on an airfoil section. Experimental data were provided in the form of time-dependent displacements along both the transverse and lateral directions of the leading edge of an airfoil section. A finite element model of the EIDI system using MSC Nastran was developed with plate elements representing the aluminum skin of the test section and the accreted impact ice. Weightless stiff beam elements provided the shear connection between the ice and aluminum elements. Force-time history was input through eight nodes at the coil location.