De-icing Operations Research Articles

Temporal and Spatial Thermal Performance of A Ground Heat Exchanger in Response to Bridge Solar Recharging and Deicing Operations: A Pilot Full-Scale Study

A full-scale mock-up geothermal bridge was built in Texas, USA, to evaluate the field performance of a novel external geothermal bridge de-icing system. The geothermal bridge system comprises a single U-loop ground heat exchanger (GHE) 131 m deep, a geothermal heat pump, four circulation pumps, and hydronic heating loops attached to the bridge deck. A comprehensive monitoring system was implemented to monitor the spatial ground temperature response. The geothermal bridge system was operated and monitored for solar collector and bridge de-icing operations totaling 99 days between August 2019 and April 2020. An average heat injection of 5.7 W/m was observed during the solar collector operation. Based on the defined control volume, approximately 48.9–380.8 kWh of energy, corresponding to 3.7-28.5% of the total injected energy, was available at the end of the solar-collector operation. Moreover, test results showed that 31.7-39.4% of stored thermal energy was preserved for utilization in the first winter de-icing test. The radius of the influence zone of the GHE operation was found to be 3.45 m. The outcome of the field experimental studies and further data collection performed over a year of operations showed that the heat injection into the soil by bridge solar collector was 54% more effective than heat extraction from the ground during the several de-icing tests performed from 2019 to 2020. 

Bi-Level Optimization for De-Icing Position Allocation and Unmanned De-Icing Vehicle Fleet Routing Problem.

Aircraft icing due to severe cold and local factors increases the risk of flight delays and safety issues. Therefore, this study focuses on optimizing de-icing allocation and adapting to dynamic flight schedules at medium to large airports. Moreover, it aims to establish a centralized de-icing methodology employing unmanned de-icing vehicles to achieve the dual objectives of minimizing flight delay times and enhancing airport de-icing efficiency. To achieve these goals, a mixed-integer bi-level programming model is formulated, where the upper-level planning guides the allocation of de-icing positions and the lower-level planning addresses the collaborative scheduling of the multiple unmanned de-icing vehicles. In addition, a two-stage algorithm is introduced, encompassing a Mixed Variable Neighborhood Search Genetic Algorithm (MVNS-GA) as well as a Multi-Strategy Enhanced Heuristic Greedy Algorithm (MSEH-GA). Both algorithms are rigorously assessed through horizontal comparisons. This demonstrates the effectiveness and competitiveness of these algorithms. Finally, a model simulation is conducted at a major northwestern hub airport in China, providing empirical evidence of the proposed approach's efficiency. The results show that research offers a practical solution for optimizing the use of multiple unmanned de-icing vehicles in aircraft de-icing tasks at medium to large airports. Therefore, delays are mitigated, and de-icing operations are improved.

Improvement in electrical characteristics by surface modification of multi-wall carbon nanotube based buckypaper for de-icing application

Icing hazards often cause severe mobility concerns, safety risks, and even accidents in modern industries. Various ice mitigation strategies have been employed. Electro-thermal heating approach is a popular measure for ice protection, in which heat is generated electrically by internal components and then transferred to the outer surface for anti-icing and de-icing operation. Given the increasing usage of composites in aircraft structures, self-heating fibre reinforced polymer composite has been studied as an ice protection solution for the new generation aircraft. The present work focuses on improving electrical characteristics of carbon nanotube (CNT) based buckypaper (via surface functionalization) and the heating performance with an ice-phobic resin. The results indicated that surface functionalization of multi-wall carbon nanotubes (MWCNTs) was effective in obtaining MWCNT buckypaper (CNP) with improved electrical conductivity. The de-icing test confirmed the electro-thermal heating performance of the CNP based composite in a climate chamber at −20°C. The utilisation of surface modified MWCNTs in self-heating composites could be a promising strategy for maintaining lightweight and efficiency for electro-thermal systems to mitigate icing hazards.

Robust and quantitative characterization of aircraft icing with mode and frequency selective ultrasonic guided wave

The aircraft flight safety and efficiency are largely affected by the aircraft icing, whose characterization is of great significance to guiding the de-icing operation. This study targets a robust and quantitative characterization of icing with ultrasonic guided wave (UGW) of selective frequency-mode pair. Firstly, the frequency domain finite element (FDFE) model is developed to quantitatively analyze the reflection, transmission, and mode conversion of UGW with icing aluminum plate of different lengths and thickness, in order to pick the UGW with appropriate frequency-mode pair sensitive to icing. With the candidate UGW frequency-mode pair, the time domain finite element (TDFE) analysis is further performed to validate the effectiveness of FDFE and to optimize the pulse duration cycle for icing detection. Finally, based on the performed FDFE and TDFE analysis, experimental icing characterization is carried out with the UGW of the selected frequency-mode pair. Results show that the selected UGW at (1239 kHz, mode A1) with ice (0.5 mm thick) has achieved a high detection sensitivity based on the time-of-flight and good robustness against the random error, showing the great potential for the application of UGW to aircraft icing characterization.

Synergistic effect of hybrid fillers on electro-thermal behavior of nanocomposite for active de-icing application

Since a range of composites are more extensively applied in modern industrial fields, de-icing strategies for their surfaces are urgently demanded. In the present study, the physically modified carbon nanotubes (CNT@X) and pristine graphene nanoplates (GNPs) were selected as the conductive reinforcing nanofillers, and the thermosetting epoxy acted as the polymer matrix to prepare conductive CNT@X-GNPs/EP nanocomposite. Subsequently, the electro-thermal behaviors of as-prepared nanocomposite correlated with active de-icing operation were characterized and investigated. Moreover, the synergistic effect of hybrid particles on the construction of conductive network and the electro-thermal energy on the epoxy matrix were also confirmed. Lastly, the difficult degree of de-icing operation with the CNT@X-GNPs/EP nanocomposite was considered, which placed stress on eliminating the ice accumulation by reducing its icing adhesion strength.

A novel full-scale external geothermal heating system for bridge deck de-icing

The utilization of geothermal energy for melting snow and ice on bridge decks has been shown to be effective. However, the existing geothermal heating systems work through hydronic loops embedded inside the bridge deck and therefore are only applicable to new bridges. A new external geothermal heating design for bridge de-icing has been explored in concept and tests in the laboratory, showing great implementation potential. This study presents the design and implementation procedure of a novel external geothermal heating system on a full-scale bridge deck for de-icing operations in field conditions for its first time. It tests and analyzes the system’s heating performance and the bridge deck’s thermal response under several winter events. The details and information pertaining to the design and construction of the hydronic loops, a ground loop heat exchanger (GLHE) monitoring system, are presented and can be pivotal for the designers of similar projects. The test results showed that the system was successful in de-icing the bridge deck and maintaining the bridge deck surface temperature above freezing in the event with a minimum ambient temperature of −6.2 °C. The de-icing system requires about 7–8 h of pre-heating to reach its maximum performance; however, less time is required during mild events. Moreover, this research investigated the performance of the system, and the experimental results showed an average system coefficient of performance (COP) of approximately 4.6 and a heating efficiency of about 55%.

A Proposition for Combining Rough Sets, Fuzzy Logic and FRAM to Address Methodological Challenges in Safety Management: A Discussion Paper

In recent years, the focus in safety management has shifted from failure-based analysis towards a more systemic perspective, redefining a successful or failed performance as a complex and emergent event rather than as a conclusion of singular errors or root causes. This paradigm shift has also necessitated the introduction of innovative tools capable of capturing the complex and dynamic nature of modern sociotechnical systems. In our research, we argued at previous stages for adopting a more systemic and human-centric perspective to evaluate the context of aircraft de-icing operations. The Functional Resonance Analysis Method (FRAM) was applied in the first stage for this purpose. Consequently, fuzzy logic was combined with FRAM in the second stage to provide a quantified representation of performance variability. Fuzzy logic was used as a quantification tool suitable for computing with natural language. Several limitations were found in the data collection and rule generation process for the first prototype. In the third phase, the model was further improved by integrating rough sets as a data-mining tool to generate and reduce the size of the rule base and classify outcomes. In this paper, we reflect on the three stages of the project and discuss in a qualitative manner the challenges and limitations faced in the development and application of the models. A summary of the advantages and disadvantages of the three models as experienced in our case are presented at the end. The objective is to present an outlook for future studies to address methodological limitations in the study of complex sociotechnical systems.

Ice Detection on Aircraft Surface Using Machine Learning Approaches Based on Hyperspectral and Multispectral Images

Aircraft ground de-icing operations play a critical role in flight safety. However, to handle the aircraft de-icing, a considerable quantity of de-icing fluids is commonly employed. Moreover, some pre-flight inspections are carried out with engines running; thus, a large amount of fuel is wasted, and CO2 is emitted. This implies substantial economic and environmental impacts. In this context, the European project (reference call: MANUNET III 2018, project code: MNET18/ICT-3438) called SEI (Spectral Evidence of Ice) aims to provide innovative tools to identify the ice on aircraft and improve the efficiency of the de-icing process. The project includes the design of a low-cost UAV (uncrewed aerial vehicle) platform and the development of a quasi-real-time ice detection methodology to ensure a faster and semi-automatic activity with a reduction of applied operating time and de-icing fluids. The purpose of this work, developed within the activities of the project, is defining and testing the most suitable sensor using a radiometric approach and machine learning algorithms. The adopted methodology consists of classifying ice through spectral imagery collected by two different sensors: multispectral and hyperspectral camera. Since the UAV prototype is under construction, the experimental analysis was performed with a simulation dataset acquired on the ground. The comparison among the two approaches, and their related algorithms (random forest and support vector machine) for image processing, was presented: practical results show that it is possible to identify the ice in both cases. Nonetheless, the hyperspectral camera guarantees a more reliable solution reaching a higher level of accuracy of classified iced surfaces.

Low-Voltage Icing Protection Film for Automotive and Aeronautical Industries.

High-performance heater films are here proposed. They manifest great applicative potentiality in the de-icing technology of aircraft and motor vehicles. The films are suitable to be integrated into composite structures for the de/anti-icing function, which can be activated if the need arises. The heating is based on the joule effect of the current flowing through the electrically conductive films. Voltage and current parameters have been set based on the generators’ capacities on-board an aircraft and a car, as well as on the energy consumption during the operating conditions and the autonomy in the time. Green processes have been employed through all preparative steps of the films, which are composed of expanded graphite (60% wt/wt) and polyvinyl alcohol (PVA) (40% wt/wt). The results reveal a very significant influence of the aspect ratio of the filler on the heating and de-icing performance and suggest how to enhance the de-icing efficiency saving energy and adapting the current on-board aircraft/car generators for de-icing operations.

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.

An experimental study on a hot-air-based anti-/de-icing system for aero-engine inlet guide vanes

In the present study, a comprehensive experimental study was conducted to quantify the dynamic ice accretion process on aero-engine inlet guide vanes (IGVs) and to characterize a hot-air-based anti-/de-icing system in order to optimize the design paradigms to reduce the requirements of the bleed air for IGV icing protection, thereby, minimizing the performance penalties to the aero-engines. A hollowed IGV model embedded with U-shaped hot-air flowing conduit was designed/manufactured and mounted inside an Icing Research Tunnel for the experimental study. During the experiments, while a high-speed imaging system was used to record the dynamic ice accretion or anti-/de-icing process over the surface of the IGV model for the test cases without and with turning on the hot-air supply system, the corresponding surface temperature distributions on the IGV model were also measured quantitatively by using a row of embedded thermocouples. The unsteady heat transfer process over the surface of the IGV model was analyzed quantitatively, revealing that the convective heat transfer would dissipate over 85% of the thermal energy provided by the hot-air stream for the anti-/de-icing operation. A comprehensive parametric study was also conducted to evaluate the effects of the operation parameters of the hot-air-based system on its performance for IGV icing protection. It was demonstrated clearly that, with proper operation parameter settings (i.e., the temperature of the hot-air stream being greater than 30 °C and its flow rate is higher than 4.0 g/s), the hot-air-based system was able to effectively prevent ice formation/accretion over the entire IGV surface. The quantitative measurement results would not only be very helpful to elucidate the underlying physics of the important microphysical processes pertinent to IGV icing phenomena, but also can be used as valued database to validate/verify theoretical modeling and numerical simulations for the development of effective and robust anti-/de-icing systems to protect IGVs from harsh icing environment.

Energy saving strategy for the development of icephobic coatings and surfaces

Aircraft are frequently exposed to cold environments and ice accumulation on aircraft surface may lead to catastrophic accidents. An effective solution of ice protection is a critical requirement in the aerospace industry. For the research and development of icephobic coatings, the current coating design target mainly focuses on lowering the ice adhesion strength between the ice and the surface. However, as a passive ice protection approach, the use of icephobic coating often has to be combined with an active ice protection solution (e.g. electro-thermal heating, hot air bleeding, and vibration, etc.), especially for the in-flight application where the reliability of ice protection must be ensured. Therefore, ice adhesion strength is no longer the sole criterion to evaluate the icephobic performance of a coating or a surface. It is a need to establish a more practical strategy for the design of icephobic coatings and surface. In this work, an energy saving strategy is proposed to assess the de-icing performance of the icephobic coating and surface when active heating is involved. The energy consumed for the de-icing operation assisted by the ice gravity is used as the key criterion for the overall performance of icephobic coating and surface. Successful validation has been achieved for evaluating the de-icing performance of selected coatings and surfaces, which demonstrates an alternative strategy for the design and practical application of icephobic coatings and surfaces in ice protection.

Development of multifunctional hybrid metal/carbon composite structures

The aim of this work is to design, manufacture and test a hybrid composite by embedding optimised copper or Shape Memory Alloy (SMA) wires within carbon fibre laminate for improved impact resistance, intrinsic strain sensing and impact detection capability, non-destructive testing and de-icing functionalities. It was demonstrated that with an appropriate optimisation of the wires a reduction of damaged area was experienced. It was shown that the hybrid network can work as a strain sensor by monitoring the variation of its electrical resistance under load and to identify the presence of a localised load such as an impact event. Then, non-destructive capability for assessing defects was shown where by applying an electrical current to the metal wires, heat was generated and distortion of the thermal field due to a damaged area was measured using a Step Heating Thermography (SHT) process, creating an image of the damage. De-icing operations was presented by exploiting the Joule effect where the local temperature increase was able to melt down an ice layer and hence avoid aerodynamic variation of aircraft surfaces. The results showed that the multifunctionality of this embedded smart material can improve the safety and reliability of aircraft structures and reduce maintenance costs.

A Proposal for a Predictive Performance Assessment Model in Complex Sociotechnical Systems Combining Fuzzy Logic and the Functional Resonance Analysis Method (FRAM)

Modern sociotechnical systems exhibit dynamic and complex behavior, which can be difficult to anticipate, model and evaluate. The perpetually evolving nature and the emergent properties of such systems require a continuous re-evaluation of adopted safety and risk analysis methods to comply with arising challenges and ensure successful performance. One of the interesting methods proposed in recent years is the Functional Resonance Analysis Method (FRAM). FRAM adopts a systemic perspective to model sociotechnical systems characterizing non-linear relationships and quality of outcome arising from performance variability and functional resonance. This paper aims to further improve the framework and expand the spectrum of features provided by FRAM through the integration of fuzzy logic. Fuzzy logic offers adequate mathematical tools capable of quantifying qualitative concepts and uncertain information applying comprehensible inference systems based on human judgement. An example of a possible application scenario is included through a simulation of aircraft on-ground deicing operations. The preliminary results of this project present an approach to generate numerical indicators for the quality of outputs, which can allow for a more comprehensible representation of potential performance variability. The presented model, however, requires further validation and optimization work to provide more representative and reliable results.

Groundwater resources in a Mediterranean mountainous region: environmental impact of road de-icing

Water from mountainous regions is a strategic natural resource. In Mediterranean mountainous regions, which, in many cases, correspond to protected areas, high-altitude roads are often the main threat to the sustainability of water resources. In these regions, the regular socioeconomic functioning requires frequent road de-icing operations which normally consist of spreading NaCl and other chemicals, such as CaCl2, in pavements. The main purpose of this research is to assess the environmental impact of road de-icing on groundwater resources in a Mediterranean mountainous region and to describe it by means of a hydrogeological conceptual model. The research focused in a cross-sectional sector located in Serra da Estrela (Central Portugal), where a hydrogeological inventory was carried out, followed by hydrogeochemical and hydrogeophysical studies. The results clearly identify different hydrogeochemical signatures in polluted (Cl–Na facies and higher EC) and unpolluted (HCO3–Na, Cl–Na, and very low EC). The relation of hydrogeochemistry and altitude is complex and depends on both natural processes (namely, water–rock interaction) and anthropic processes (de-icing operations). The hydrogeophysical survey systematically identified the presence of a pollution plume migrating downstream from roads.

An experimental study of icing control using DBD plasma actuator

Ice accretion on aircraft or wind turbine has been widely recognized as a big safety threat in the past decades. This study aims to develop a new approach for icing control using an AC-DBD plasma actuator. The experiments of icing control (i.e., anti-/de-icing) on a cylinder model were conducted in an icing wind tunnel with controlled wind speed (i.e., 15 m/s) and temperature (i.e., $$-10\,^{\circ }$$ C). A digital camera was used to record the dynamic processes of plasma anti-icing and de-icing whilst an infrared imaging system was utilized to map the surface temperature variations during the anti-/de-icing processes. It was found that the AC-DBD plasma actuator is very effective in both anti-icing and de-icing operations. While no ice formation was observed when the plasma actuator served as an anti-icing device, a complete removal of the ice layer with a thickness of 5 mm was achieved by activating the plasma actuator for $$\sim$$ 150 s. Such information demonstrated the feasibility of plasma anti-/de-icing, which could potentially provide more effective and safer icing mitigation strategies.

Impact of Road De-icing on the Hydrogeochemistry of Groundwater from a Mountain Area (Serra da Estrela, Central Portugal)

The importance of Mountains for the world's water supply has been increasingly recognized. However, in many cases the existing roads require regular de-icing operations which may have a severe impact on the natural hydrogeochemical conditions of the local hydrological systems due to the regular use of substances such as sodium chloride and calcium chloride. The Serra da Estrela Mountain is a strategic area for the water resources management in Portugal because of its geological, geomorphological and climatic framework. This study was carried out in the highest part of the mountain, where road de-icing is frequent during winter. The hydrogeochemical characteristics of several springs, located downstream from roads between 1500 m a.s.l. and 1990 m a.s.l., present clear anthropic signatures which disturbs the quality of the local water resources.

Road salt application planning tool for winter de-icing operations

Road authorities, who are charged with the task of maintaining safe, driveable road conditions during severe winter storm events are coming under increasing pressure to protect salt vulnerable areas (SVAs). For the purpose of modelling urban winter hydrology, the temperature index method was modified to incorporate ploughing and salting considerations and was calibrated using winter field data from two sites in Southern Ontario and validated using data collected from a section of Highway 401 – Canada’s busiest highway. The modified temperature index model (MTIM) accurately predicted salt-induced melt (R2 = 0.98 and 0.99, RMSE = 19.9 and 282.4 m3, CRM = −0.003 and 0.006 for calibration and validation sites respectively), and showed a demonstrable ability to calculate the Bare Pavement Regain Time (BPRT). The BPRT is a key factor on road safety and the basis for many winter maintenance performance standards for different classes of highways. Optimizing salt application rate scenarios can be achieved using the MTIM with only two meteorological forecast inputs for the storm event – readily available on-line through the Road Weather Information System (RWIS) – and can serve as a simple yet effective tool for winter road maintenance practitioners seeking to optimize salt application rates for a given storm event in salt vulnerable areas.

Treatment performance of an aerated constructed wetland treating glycol from de-icing operations at a UK airport

Mayfield Farm Treatment System receives effluent collected from the Southern Catchment of Heathrow Airport, a total of 290ha. During winter operations, weather-related de-icing activity results in large shifts in the flow and concentrations of airport run-off. The biological treatment of spent de-icing fluids is challenging because it involves the treatment of a cold and nutrient-deficient wastewater of variable flow and strength. After a successful full scale trial to determine the efficacy of aerated wetlands, the entire treatment system was upgraded and optimized in 2010. It consisted of a primary reservoir, partial and complete mix zones, a balancing lagoon, and 12 aerated horizontal sub-surface flow (HSSF) treatment wetlands operating in parallel, with a total wetland area of 2.08ha. The original non-aerated HSSF wetland system, commissioned in 2001 had a design cBOD5 loading rate of 374kg/day at a flow rate of 40l/s (Revitt et al., 2001; Richter et al., 2003). The aerated HSSF wetlands now have a design cBOD5 loading rate of 2073kg/day at a maximum flow rate of 80l/s. Due to the weather conditions of the UK, the system is event-driven with highly variable flows and loads, with peak cBOD5 loadings of up to 12,188kg/day.The entire treatment system is now designed to remove 3500kg/day cBOD5 at a design flow of 40l/s. It has a combined capacity of >44,000m3 of wastewater with a retention time of approximately 21 days, depending on the pump flow rate which varies between 40 and 80l/s. Nutrient dosing points have been positioned at strategic points throughout the whole system to prevent nutrient deficiency becoming a limiting factor in the development of a stable and viable mass of bacteria necessary to achieve the design criteria.

Game Model Solution of Aircraft Deicing Operation Scheduling Based on Shapley Value

The aircraft deicing process is discussed to establish the airlines cooperative game model. The characteristic function and the core of the airlines coalition game model are analyzed, and then the solution of the model is proposed based on Shapley value. Finally, the result of the simulation shows that the cooperative game model motivates the cooperative action. The algorithm based on the Shapley value can meet both individual rationality and collectivity rationality. The results show the distribution is more reasonable and better.