Icing detection system for aircraft, icing detection method and aircraft

Abstract

The present invention relates to an icing detection system for an aircraft, comprising: a first detector arranged in a first region of a nose of the aircraft and symmetrically arranged on both sides of the nose with respect to a symmetry plane of the aircraft; the second detectors are arranged in a second area of the nose of the aircraft and symmetrically arranged on the two sides of the nose with respect to the symmetry plane of the aircraft, and the second area is located on the rear side of the first area in the heading direction of the aircraft; and the icing signal processing device integrates the icing signals fed back by the first detector and the second detector, and judges whether the aircraft encounters a conventional icing condition or a supercooled large-water-drop icing condition. The icing detection system can detect and discriminate the overcooled large water drop icing condition existing in the flight environment where the aircraft is located, is high in reliability, can reduce misjudgment, and is suitable for various working conditions of the aircraft. In addition, the invention also relates to an icing detection method and an aircraft.

Description

Technical Field

[0001] This invention relates to an icing detection system for aircraft. Furthermore, this invention also relates to an icing detection method and an aircraft. Background Technology

[0002] Supercooled large droplets (SLDs) are a special type of hazardous icing phenomenon in nature. This icing condition was first observed in an American Eagle Airlines crash in the 1990s. While the aircraft was idling, ridge-like icing (ice ridges) formed on the upper wing surface, behind the wing's icing protection zone and in front of the ailerons, causing the aircraft to roll uninstructed and crash. The investigation revealed that the icing conditions in this accident exceeded the normal range for icing weather; the diameter of the supercooled droplets was significantly larger than that of supercooled droplets in conventional icing conditions. These large-diameter supercooled droplets are called supercooled large droplets (SLDs).

[0003] According to airworthiness regulations, supercooled large water droplet icing conditions include micro-freezing rain and freezing rain conditions. Compared to conventional water droplet icing conditions, supercooled large water droplet conditions can lead to more complex icing phenomena on aircraft surfaces and more serious safety impacts. Due to their relatively large size and mass, supercooled large water droplets have greater inertia and are less susceptible to being affected by airflow and deviating from their original trajectory. Compared to conventional small water droplets, large droplets have a larger impact range and icing area on the aircraft surface. For example, behind the icing protection zone on the upper wing leading edge, supercooled large water droplets can form ridge-like icing through direct impact freezing of the wing surface and subsequent freezing of liquid water, severely disrupting the aerodynamic design of the upper wing surface and significantly impacting the aircraft's aerodynamic performance and handling characteristics.

[0004] The primary challenge in protecting against icing from supercooled large water droplets lies in detecting these unique icing conditions and differentiating them from those of conventional small water droplets. Current aircraft icing detection systems can detect icing conditions, but they cannot differentiate between conventional icing conditions and those caused by supercooled large water droplets. Although the problem of supercooled large water droplet icing has been studied for many years, a mature, reliable, and practically applicable method for detecting it has yet to be developed. Existing supercooled large water droplet detection technologies primarily focus on the level of supercooled large water droplet icing detectors, proposing technologies for icing detectors capable of detecting supercooled large water droplet conditions.

[0005] For example, in the invention patent CN112550723, submitted by Huazhong University of Science and Technology on December 25, 2020, entitled "A Supercooled Large Water Droplet Icing Probe and Detector," a supercooled large water droplet icing detector was proposed. This detector is mainly composed of an aluminum alloy column formed by a front shuttle, a groove, and a rear shuttle, exhibiting a structure that is pointed at the front and rear and concave in the middle. The detector is externally mounted on an aircraft. A fiber optic icing sensor (referred to as the "front sensor") is mounted on each of the left and right side walls of the front shuttle to detect conventional icing; a fiber optic icing sensor (referred to as the "rear sensor") is mounted on each of the left and right side walls of the rear shuttle to detect supercooled large water droplet icing. The groove is frosted to increase the frictional resistance when supercooled large water droplets flow through, thereby improving the freezing coefficient of the supercooled large water droplets.

[0006] In a patent application titled "Supercooled Large Water Droplet Detector" filed on November 23, 2023, by inventors from the Shanghai Aircraft Design and Research Institute, with publication number CN117585166, a supercooled large water droplet detector is proposed, comprising a detector base and a detection structure. The detection structure is used to detect supercooled water droplets in airflow and identify the icing conditions of supercooled large water droplets in icing weather. The outer layer of the detection structure is a temperature sensor layer, the middle layer is an electrically heated film layer, and the inner layer is a structural substrate. The electrically heated film layer provides heating energy through an electric heating circuit to maintain a uniform temperature on the surface of the detection structure. The temperature sensor layer has multiple temperature sensors, and a controller is installed in the structural substrate. The controller determines the impact range of the supercooled water droplet by observing the temperature changes at multiple different locations caused by the impact of the supercooled water droplet on the detection structure, and determines whether the impacting water droplet is a supercooled large water droplet by judging the impact range.

[0007] An invention patent titled "An Icing Detector," filed on September 10, 2019, by inventors from the Shanghai Aircraft Design and Research Institute, with publication number CN110606209, proposes an icing detector comprising multiple detection units, a protection unit, and a processor, mounted on the leading edge surface of a slat. Each detection unit can detect the icing thickness at its location, ensuring the aircraft can detect supercooled large water droplets. The detection units, arranged on the leading edge slats, can detect icing conditions at locations that have the most direct impact on flight.

[0008] Based on existing aircraft icing detection technology, this invention proposes a technical solution for an icing detection system capable of detecting supercooled large water droplets. This technical solution can overcome one or more shortcomings of the existing technology. Summary of the Invention

[0009] The purpose of this invention is to provide an icing detection system for aircraft, which, through system integration design, forms a supercooled large water droplet icing detection system.

[0010] Because small and large water droplets have different physical properties (mass, inertia), the actual impact characteristics and impact range of small and large water droplets on the aircraft during flight will also be significantly different.

[0011] Figure 1 The diagram illustrates the trajectories of small and large water droplets impacting the leading edge of an aircraft wing. It schematically shows the impact ranges L1 and L2 of the small and large water droplets at the leading edge of the wing when they are impacted by the small and large water droplets, respectively.

[0012] As shown in the figure, due to the different physical properties (mass, inertia) of small and large water droplets, when small water droplets are in the flow, those near the upper and lower edges of the airfoil's leading edge are affected by the airflow and will not collide with the airfoil's leading edge. Instead, they deviate from their original path and bypass the airfoil's leading edge. Large water droplets, due to their greater mass and inertia, are less affected by the airflow during their motion relative to the aircraft, thus their trajectories are less likely to deviate. Therefore, the impact range L2 of the large water droplet is significantly larger than the impact range L1 of the small water droplet.

[0013] Therefore, the inventors envisioned that if icing detectors were placed outside the small water droplet impact area and within the large water droplet impact area, the icing conditions of large water droplets could be detected, and the icing conditions of regular water droplets and large water droplets could be distinguished. Based on this inventive concept, the inventors further studied its specific deployment method on an aircraft.

[0014] If icing detectors are placed on the leading edge of the wing, to ensure the smoothness of the wing's aerodynamic design, only flush-mounted icing detectors (mainly flat-film and fiber-optic icing detectors) that do not disrupt the airfoil can be installed. Furthermore, because icing on the aircraft wing surface is not limited to a single airfoil section but occurs in three-dimensional space along the spanwise direction of the entire wing's windward surface, multiple flush-mounted icing detectors are needed to achieve the desired icing detection function, both along the spanwise direction (from wing root to wingtip) and the chordwise direction (from the leading edge to the trailing edge within the airfoil section). This approach has the following drawbacks: First, considering the working principle of flush-mounted detectors, those installed on the windward side of the wing are easily contaminated by non-icing particles such as sand and insects during flight, causing false alarms even under non-icing conditions. Second, within a wing section, the impact range of supercooled large water droplets and ordinary water droplets varies with the angle of attack (aircraft pitch attitude change) during flight. It's difficult to find a fixed area on the upper and lower wing surfaces, making it challenging to ensure that while ordinary water droplets cannot impact this area, large water droplets can. Therefore, determining the detector's installation position along the chord of the wing is difficult. Third, the aerodynamic design of each section of the full-span wing considers aerodynamic twisting requirements. From the wing root to the wingtip, the airfoil shape, size, and torsional characteristics differ, resulting in significant variations in the impact range of supercooled water droplets across different sections. This makes it difficult to implement a spanwise placement of the detector. Fourth, deploying multiple detectors along the chord and span of the wing results in receiving multiple detection signals during flight. Processing these signals to determine if the aircraft has encountered icing and the type of icing conditions involves highly complex logic, increasing the complexity of the detection system and reducing its reliability. Fifth, the internal space of the aircraft wing is limited. Various pipelines and fuel tanks need to be installed within the complex truss structure, and anti-icing cavities are also required on the leading edge of the wing in civil aircraft. There is little space available to install multiple flush-mounted icing detectors and their wiring.

[0015] In conclusion, installing icing detectors on aircraft wings to detect icing (including icing of supercooled large water droplets) presents significant difficulties, making it challenging to realize the aforementioned inventive concept. Similar problems exist when installing icing detectors on the tail section and nacelle lip.

[0016] To overcome the above-mentioned difficulties and achieve effective detection of icing conditions of supercooled large water droplets, the inventors of this application propose an icing detection system for aircraft.

[0017] In a first aspect, the present invention provides an icing detection system for detecting icing conditions of supercooled large water droplets. The icing detection system may include: a first detector, disposed in a first region of the nose of an aircraft; preferably, two first detectors are provided and symmetrically arranged on both sides of the nose of the aircraft to improve detection reliability and increase system redundancy; a second detector, disposed in a second region of the nose of the aircraft; preferably, two second detectors are provided and symmetrically arranged on both sides of the nose of the aircraft to improve detection reliability and increase system redundancy, wherein the second region is located behind the first region along the heading direction of the aircraft; and an icing signal processing device, which integrates the icing signals fed back from the first and second detectors to determine whether the aircraft is encountering conventional icing conditions or supercooled large water droplet icing conditions.

[0018] This invention employs a magnetostrictive icing detector to achieve the integrated design of the proposed icing detection system. The magnetostrictive icing detector is a mature icing detector used in the aviation field. This type of detector is typically mounted on the nose of an aircraft and includes a cylindrical extended probe and a mounting base. The cylindrical probe extends beyond the skin of the aircraft's nose. Supercooled water droplets in the clouds impact the probe, freezing and increasing its mass. This alters the probe's normal operating vibration frequency, triggering an icing alarm signal. This detector's working principle avoids the inherent shortcomings of flush-mounted detectors, resulting in higher reliability.

[0019] According to the above aspects of the present invention, preferably, one of the first detector and the second detector may be a magnetostrictive icing detector, and more preferably, both the first detector and the second detector are magnetostrictive icing detectors.

[0020] The mounting position of the magnetostrictive icing detector on the nose of the aircraft can depend on the following parameters: the aircraft's flight envelope constraints (including flight altitude, speed, etc.); the icing weather envelope constraints (including ambient temperature, water droplet size, etc.); and the pressure distribution characteristics of the nose surface. By identifying these key parameters, the inventors were able to calculate and analyze the mounting position of the magnetostrictive icing detector on the nose for different aircraft models, ensuring the feasibility of the solution.

[0021] In order to coordinate the processing of the working signals of each icing detector, the icing detection system proposed in this invention includes an icing signal processing device. The icing signal processing device integrates the working signals from the first detector and the second detector, uses preset icing judgment logic to determine whether the aircraft has encountered icing conditions and the type of icing conditions encountered (normal icing conditions or supercooled large water droplet icing conditions), and issues alarm information on specific icing conditions to the aircraft crew.

[0022] The preset icing judgment logic includes: when only the first detector detects icing and issues an icing signal, it is determined that the aircraft has encountered the normal icing condition of small water droplets; when both the first and second detectors detect icing and issue dual icing signals, it is determined that the aircraft has encountered the icing condition of supercooled large water droplets; when only the second detector issues an icing signal, it is determined to be a false alarm.

[0023] Thus, the icing detection system proposed in this invention, by installing a first and second detector on the nose of the aircraft and combining them with an icing signal processing device, can detect and identify supercooled large water droplet icing conditions in the aircraft's flight environment. It boasts high reliability, reduces false alarms, and is applicable to various aircraft operating conditions. Furthermore, this icing detection system, installed on the forward fuselage, facilitates placement, installation, and subsequent maintenance and replacement, further enhancing its practicality. Once implemented, the system can be directly installed and applied to aircraft, enabling rapid deployment of the icing detection system.

[0024] A second aspect of the present invention provides a method for detecting icing on an aircraft. The method includes: feedback from a first detector and a second detector in the icing detection system according to the first aspect of the present invention regarding whether icing has been detected; and determining, via an icing signal processing device, whether the aircraft has encountered icing conditions and the type of icing conditions encountered through a preset icing condition judgment logic.

[0025] A third aspect of the invention relates to an aircraft that may be equipped with an icing detection system according to the first aspect.

[0026] Therefore, the icing detection system for aircraft of the present invention can meet the requirements for detecting and identifying icing conditions of supercooled large water droplets, overcome the shortcomings of the prior art, and achieve the intended purpose. Attached Figure Description

[0027] To further describe the icing detection system for aircraft of the present invention clearly, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments, in which: Figure 1 The diagram shows the trajectories of small and large water droplets impacting the leading edge of an aircraft airfoil. Figure 2 This is a schematic diagram showing the arrangement positions of the first and second detectors at the nose of the aircraft in a non-limiting embodiment of the present invention; and Figure 3 This is a schematic diagram of the icing judgment logic of the icing signal processing device in a non-limiting embodiment of the present invention.

[0028] The above figures are for illustrative purposes only and are not drawn to scale.

[0029] List of reference numerals in the accompanying drawings and embodiments: 1000 - Aircraft, including: 100 – Icing detection systems for aircraft, including: 10 – First detector; 10A – Zone 1; 20 – Second detector; 20A – Second Zone; 30 – Icing signal processing device; Y – heading direction; L1 – The impact range of the small water droplet; L2 – Impact range of a large water droplet. Detailed Implementation

[0030] It should be understood that, unless explicitly stated otherwise, the invention may employ various alternative orientations and sequences of steps. It should also be understood that the specific apparatus shown in the drawings and described in the specification are merely exemplary embodiments of the inventive concept disclosed and defined herein. Therefore, unless expressly stated otherwise, the specific orientations, directions, or other features involved in the various disclosed embodiments should not be considered limiting.

[0031] Figure 2 This is a schematic diagram of the arrangement position of the icing detection system 100 for an aircraft on the aircraft 1000 in a non-limiting embodiment of the present invention; Figure 2 It is a view taken along the span of the aircraft.

[0032] As shown in the figure, as a non-limiting embodiment of the present invention, the icing detection system 100 mainly includes: a first detector 10, a second detector 20, and an icing signal processing device 30, etc.

[0033] The first detector 10 is arranged in a first region 10A of the aircraft nose. In a preferred embodiment, two first detectors 10 may be provided, symmetrically arranged on both sides of the nose in the first region 10A. Similarly, two second detectors 20 are arranged in a second region 20A of the aircraft nose, symmetrically arranged on both sides of the nose in the second region 20A. The second region 20A is located behind the first region 10A along the aircraft's heading direction Y. Considering the advantages and disadvantages of different types of icing detectors (aligned detectors and magnetostrictive detectors) in practical applications on aircraft, the icing detection system 100 for aircraft of the present invention uses a magnetostrictive icing detector. The magnetostrictive icing detector includes a cylindrical probe and a mounting base (preferably with a streamlined design). The cylindrical probe is mounted on the base and extends outwards beyond the skin at the aircraft nose. Specifically, at least one of the first detector 10 and the second detector 20 is a magnetostrictive icing detector. Preferably, both the first detector 10 and the second detector 20 are magnetostrictive icing detectors.

[0034] As a non-limiting embodiment, the mounting position of the magnetostrictive icing detector used in this invention on the nose depends on the following parameters: the aircraft's flight envelope constraints (including flight altitude, speed, etc.); the icing weather envelope constraints (including ambient temperature, water droplet size, etc.); and the pressure distribution characteristics on the nose surface, etc.

[0035] For small water droplets, due to their small mass, they can only collide with the first detector 10 (installed in the first area 10A). Behind the first area 10A, the small water droplets are affected by the airflow on the fuselage surface, and their trajectory deviates outward from the fuselage, preventing them from colliding with the second detector 20 (installed in the second area 20A). However, large water droplets, due to their large mass, are less affected by airflow and can collide with both the first detector and the second detector 20 simultaneously. The combination of icing signals from different detectors is then used to determine whether the aircraft encountered conventional icing conditions or supercooled large water droplet icing conditions.

[0036] like Figure 2As shown, the icing detection system 100 also includes an icing signal processing device 30, which is connected to the first detector 10 and the second detector 20. The icing signal processing device 30 integrates signals from the first detector 10 and the second detector 20, uses preset icing judgment logic to determine the icing conditions encountered by the aircraft (conventional icing conditions or supercooled large water droplet icing conditions), and issues alarms and displays specific icing condition information to the aircraft crew. Alternatively, the icing detection system 100 does not require a separate icing signal processing device 30; instead, the predetermined icing condition judgment logic is integrated into the aircraft's avionics system.

[0037] Figure 3 This is a schematic diagram of the icing determination logic of a non-limiting embodiment of the present invention.

[0038] When only the first detector 10 (either one or both of the two first detectors on both sides of the nose) detects icing, the first detector 10 that detects icing sends an icing signal, while the second detector 20 does not send an icing signal, it can be determined that the aircraft has encountered the normal icing conditions of small water droplets.

[0039] When the first detector 10 (any one or both of the two first detectors on both sides of the nose) and the second detector 20 (any one or both of the two second detectors on both sides of the nose) detect icing, the first detector 10 and the second detector 20 that detect icing send out icing signals, it can be determined that the aircraft has encountered supercooled large water droplet icing conditions.

[0040] If only the second detector 20 (any one or both of the two second detectors on both sides of the nose) sends an icing signal, while the first detector 10 does not send an icing signal, it can be determined to be a false alarm.

[0041] In a non-limiting embodiment of the present invention, during flight, the icing signal processing device 30 receives only signals from four detectors. By combining these four signals, it can determine whether the aircraft has encountered icing and the type of icing conditions, without needing to access the aircraft's atmospheric data or other information. Thus, the working logic design of the icing detection system 100 for determining icing conditions is relatively simple and feasible. Furthermore, the four detectors used in this invention are all located on the forward fuselage of the aircraft, where there is sufficient internal and external space to meet installation requirements, facilitating implementation on the aircraft.

[0042] In a non-limiting embodiment of the present invention, the icing detection method for an aircraft includes: determining whether icing is detected by the first detector 10 and the second detector 20 in the icing detection system 100; and determining, via the icing signal processing device 30, whether the aircraft has encountered icing conditions and the type of icing conditions encountered through a preset icing condition judgment logic, and issuing alarm and display information on specific icing conditions to the aircraft crew.

[0043] The terms “nose section”, “spanning direction”, and “first”, “second” used herein to indicate orientation or direction are merely to enable those skilled in the art to better understand the concept of the invention as illustrated in the preferred embodiments, and are not intended to limit the invention. Unless otherwise stated, all orders, orientations, or directions are used only to distinguish one element / component / structure from another, and unless otherwise stated, do not indicate any particular order, sequence of operations, direction, or orientation.

[0044] As used herein, unless otherwise specified, the terms “approximately” and “about” are interpreted as indicating a value or range of values ​​plus or minus five percent, or a deviation of the shape and / or position from the value by plus or minus five percent.

[0045] While the icing detection system for aircraft of the present invention has been described above with reference to preferred embodiments, those skilled in the art should recognize that the above examples are merely illustrative and should not be construed as limiting the invention. Therefore, various modifications and variations can be made to the invention within the spirit and scope of the claims, and all such modifications and variations will fall within the scope claimed by the claims.

Claims

1. An icing detection system (100) for aircraft, comprising: The first detector (10) is arranged in a first region (10A) of the nose of the aircraft and is arranged symmetrically on both sides of the nose about the symmetrical plane of the aircraft; as well as The second detector (20) is arranged in the second region (20A) of the nose of the aircraft and is arranged symmetrically on both sides of the nose about the aircraft, wherein the second region (20A) is located behind the first region (10A) along the heading direction (Y) of the aircraft. as well as Icing signal processing device (30): The icing signal processing device integrates the icing signals fed back by the first detector (10) and the second detector (20) to determine whether the aircraft is encountering conventional icing conditions or supercooled large water droplet icing conditions.

2. The icing detection system (100) according to claim 1, characterized in that, At least one of the first detector (10) and the second detector (20) includes a magnetostrictive icing detector.

3. The icing detection system (100) according to claim 2, characterized in that, The magnetostrictive icing detector includes a cylindrical extended probe and a mounting base, with the extended probe extending outside the skin at the nose of the aircraft.

4. The icing detection system (100) according to claim 2, characterized in that, The mounting position of the magnetostrictive icing detector on the head depends on the following parameters: Aircraft flight envelope constraints; Icing weather envelope constraints; and Pressure distribution characteristics on the surface of the machine head.

5. The icing detection system (100) according to claim 1, characterized in that, Two of the first detectors (10) are provided and are arranged symmetrically on both sides of the nose of the aircraft with respect to the symmetry of the aircraft.

6. The icing detection system (100) according to claim 1, characterized in that, Two second detectors (20) are provided and are arranged symmetrically on both sides of the nose of the aircraft with respect to the symmetry of the aircraft.

7. The icing detection system (100) according to claim 1, characterized in that, The icing signal processing device (30) integrates the icing signals from the first detector (10) and the second detector (20), uses preset icing condition judgment logic to determine whether the aircraft has encountered icing and the type of icing condition encountered, and sends alarm information on the specific icing condition to the aircraft crew.

8. The icing detection system (100) according to claim 7, characterized in that, The preset icing condition judgment logic includes: When only the first detector (10) detects icing, it is determined that the aircraft encountered the normal icing conditions of small water droplets; When both the first detector (10) and the second detector (20) detect icing, it is determined that the aircraft has encountered supercooled large water droplet icing conditions; When only the second detector (20) sends an icing signal, it is determined to be a false alarm.

9. A method for detecting icing in an aircraft, the icing detection method comprising: In the icing detection system (100) according to any one of claims 1-8, the first detector (10) and the second detector (20) provide feedback on whether icing is detected; and the icing signal processing device (30) determines whether the aircraft has encountered icing conditions and the type of icing conditions encountered.

10. An aircraft (1000) equipped with an icing detection system (100) according to any one of claims 1-8.

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