Airborne intelligent supercooled large water drop detection device and detection method

Abstract

The invention belongs to the technical field of anti-icing detection, and particularly relates to an airborne intelligent supercooled large water drop detection device and method, and the device comprises a body, a total static pressure sensor, a first optical fiber detector, and a second optical fiber detector. The body is a cylinder and is divided into two sections, and the diameter of the front section is smaller than that of the rear section; the front end surface of the body front section is connected with a hemispherical surface; a plurality of air inlet holes are formed in the hemispherical surface along the radial direction; the first optical fiber detector is located at the front section and close to the edge of the hemispherical surface; the second optical fiber detector is positioned on the front end surface of the body rear section; the total static pressure sensor is arranged below a transition area of the front section and the rear section; a pressure sensor is arranged in the body; a heating component is arranged at the front section of the body.

Description

Technical Field

[0001] The present invention belongs to the technical field of ice protection detection, and in particular relates to an airborne intelligent supercooled large water droplet detection device and a detection method. Background Art

[0002] Aircraft icing is one of the killers that seriously threaten flight safety. In severe cases, it can even lead to major accidents with aircraft destruction and loss of life. With the increasing air traffic, the relaxation of aircraft launch conditions and the change of global climate conditions, more complex new aircraft icing phenomena have emerged, that is, icing phenomena outside the icing envelope regulations that have been common for decades, namely supercooled large droplet (SLD) icing. Droplet diameters greater than 50 μm and reaching hundreds of μm are called supercooled large droplets.

[0003] Large water droplets and small water droplets have different movement characteristics. The larger the water droplets, the greater the possibility of hitting the aircraft wall. Small water droplets will deviate with the airflow, while large water droplets are less affected by the airflow than small water droplets, and are more likely to directly collide, resulting in a larger water droplet collision area, higher water droplet collection efficiency and freezing rate, resulting in a larger freezing area and greater harm.

[0004] Based on the SLD icing conditions, the FAA issued a Notice of Proposed Regulation Revision (NPRM) with the document number FAA-2010-0636 on June 29, 2010, namely, "Qualified Aircraft and Engine Settings for SLD, Mixed Phase, and Ice Crystal Icing Conditions". The NPRM proposed to add Appendix O "SLD Icing Conditions" to FAR-25 and Appendix D "Mixed Phase and Ice Crystal Icing Conditions" to FAR-33. The supercooled water droplets defined in Appendix O include freezing drizzle and freezing rain. Water droplets with a maximum particle size between 100 and 500 μm are called freezing drizzle, and the maximum particle size of freezing rain is greater than 500 μm.

[0005] EASA believes that SLD icing conditions must be verified for all aircraft. AMCE780 in the 4th Amendment to CS-E promulgated in 2015 clearly mentioned that for SLD icing conditions, experimental verification methods must be used, while for other icing conditions, a combination of testing, analysis, and usage experience can be accepted to demonstrate compliance.

[0006] Since the current aircraft anti-icing system cannot effectively detect the supercooled large water droplet icing situation, it is particularly important to develop an effective and reliable icing detector that can adapt to the characteristics of general aviation aircraft and predict and measure SLD in advance. Summary of the invention

[0007] The purpose of the present invention is to provide an onboard intelligent supercooled large water droplet detection device and detection method for the inability of the anti-icing system on the aircraft to effectively detect the supercooled large water droplet icing situation, and to achieve intelligent identification of large and small water droplets and icing conditions. In addition, an alarm signal can be generated to remind the crew to perform heating maintenance.

[0008] Technical Solution

[0009] An airborne intelligent supercooled large water droplet detection device comprises: a body, a total static pressure sensor, a first optical fiber detector and a second optical fiber detector;

[0010] The main body is a cylinder, which is divided into two sections, and the diameter of the front section is smaller than that of the rear section;

[0011] The front end surface of the front section of the body is connected to the hemispherical surface; the hemispherical surface is provided with a plurality of air inlet holes along the radial direction;

[0012] The first optical fiber detector is located at the front section and close to the edge of the hemispherical surface;

[0013] The second optical fiber detector is located at the front end surface of the rear section of the body;

[0014] The total static pressure sensor is arranged below the transition area between the front section and the rear section;

[0015] A pressure sensor is provided inside the body;

[0016] The front section of the main body is provided with a heating component.

[0017] Furthermore, a water outlet hole with a diameter of 0.6 mm is provided on the side wall of the front section of the main body. When small water droplets in the air enter the main body, the water droplets are depressurized and discharged to prevent the water droplets from clogging the air inlet hole.

[0018] Furthermore, by determining the difference between the first pressure data of the pressure sensor and the second pressure data of the total static pressure sensor, it is determined whether the air inlet is blocked and whether there are water droplets in the air.

[0019] Furthermore, the diameter of the rear section of the body is 5mm larger than that of the front section, mainly to identify small water droplets and SLD, forming multiple discontinuous ice areas. The trajectory of conventional small water droplets will be disturbed by the front section of the body, forming a shielding area at the rear, while SLD will collide with the front section of the body, break, overflow, etc., and will have a secondary impact at the rear section; if there are only conventional small water droplets, they will only appear at the front section of the body, collide and freeze, and if the rear section captures water droplets and freezes, then SLD must exist.

[0020] Furthermore, the transition area between the rear section and the front section of the main body is a concave arc, mainly to form a negative pressure vortex area. When the SLD collides with the front section of the main body, breaks, overflows, etc., a secondary collision will occur in the rear section to form multiple discontinuous ice areas, which are easy to capture the existence of SLD.

[0021] Furthermore, a camera is arranged above the rear section of the main body to observe at any time when water droplets or ice appear on the surface of the main body.

[0022] Furthermore, the total static pressure sensor is installed in the middle of the concave arc in the transition area. The base of the total static pressure sensor does not exceed the surface of the front section of the main body. It is mainly used to compare the pressure difference with the air inlet hole opened at the front edge of the main body to determine whether there is water droplet blockage or ice formation.

[0023] Furthermore, the air inlet hole has a diameter of 0.2 mm, which is mainly used for the exchange of airflow during flight in the air for pressure measurement.

[0024] An airborne intelligent supercooled large water droplet detection method, the steps are as follows:

[0025] Step 1: Collecting first pressure data from the pressure sensor;

[0026] Step 2: Compare the first pressure data with the second pressure data of the total static pressure sensor; when the first pressure data is 500Pa lower than the second pressure data, proceed to step 3, otherwise return to step 1;

[0027] Step 3: Determine whether there is a blockage by comparing the first pressure data with the second pressure data, and determine whether there is ice according to the detection of the first optical fiber detector; when the frequency signal of the optical fiber detector is inconsistent, turn on the front end heating component of the body, otherwise proceed to step 4;

[0028] Step 4: Use the second optical fiber detector to detect whether there are supercooled large water droplets. When the frequency signal of the optical fiber detector is inconsistent, it indicates the presence of supercooled large water droplets, sends an early warning, and returns to step 1; when the frequency signal of the optical fiber detector is consistent, there are no supercooled large water droplets but only small water droplets, and returns to step 1.

[0029] The technical effects of the present invention are:

[0030] (1) The probe of the traditional ice detector is small in size, which may easily lead to the measured ice intensity being too small or even failing. The SLD detection device provided by this patent can not only have the anti-icing function but also perform SLD prediction and ice intensity prediction; there is no need to additionally correct the effect of the sensor's own heating on the measurement;

[0031] (2) This patent uses a fiber optic detector for high-precision measurement, and the pressure detector uses the acquisition board 422 bus output circuit to compare pressure data. The second fiber optic detector connection circuit continuously measures the resistance value of the accumulated water, and calculates the current accumulated water content through data processing to determine the SLD situation, and generates an alarm signal to remind the crew.

[0032] (3) The intelligent SLD detection device provided in this patent can be promoted and applied in general aviation aircraft and bomb products. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the structure of the intelligent SLD detection device;

[0034] 1 is the air inlet, 2 is the optical fiber detector, 3 is the water outlet, and 4 is the total static pressure sensor;

[0035] Figure 2 It is a schematic diagram of the motion trajectory of a conventional water droplet and SLD;

[0036] 5 is a small water drop, 6 is SLD, and 7 is SLD after overflow;

[0037] Figure 3 It is a diagram of the software components;

[0038] Figure 4 It is the resistance measurement circuit diagram. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0040] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0041] In addition, the terms "installed", "set", "provided with", "connected", "connected", and "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0042] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0043] The SLD detection device solution provided by the present invention mainly realizes the SLD detection function by utilizing the boundary layer principle, the different trajectory deviations of the inertia of large and small water droplets, and the freezing area differentiation principle.

[0044] (1) Figure 1 As shown, the main body is a cylinder, which is divided into two sections, and the diameter of the front section is smaller than that of the rear section; the front end surface of the front section of the main body is designed as an arc-shaped hemispherical surface; and multiple air inlets are opened radially along the hemispherical surface, and the pressure sensor is connected inside to sense the pressure measurement in real time. A water outlet is set below the central vertical part, and when small water droplets in the air enter the main body, the pressure is released and discharged to prevent water droplet blockage. And a fiber optic sensor can be buried below the arc of the head near the edge of the hemispherical surface. Once ice occurs, the different conductivity and capacitance characteristics of ice can be sensed by the fiber optic sensor to measure the ice intensity, and heaters are set inside the detection device to prevent ice from freezing and making it impossible to measure the pressure difference.

[0045] (2) Figure 2 As shown, mainly for the impact characteristics of SLD, the transition area between the rear section of the body and the front section of the body is made into an inward concave arc to form a negative pressure vortex area. When the SLD collides with the front section of the body, breaks, overflows, etc., it will have a secondary impact in the rear section to form multiple discontinuous ice areas, which are easy to capture SLD. When conventional small water droplets and SLD move together, the small water droplets will separate the air flow at the front end of the body, and a shielding area will be formed behind the turbulence. If the SLD directly collides, if the pressure is abnormal, it means that blockage has occurred, and the water content in the atmosphere can be judged by the hole blockage range. The total static pressure sensor is also installed in the middle of the concave arc in the transition area. The base of the total static pressure sensor does not exceed the surface of the front section of the body. It is mainly used to compare the pressure difference with the air inlet opened at the front edge of the body to determine whether there is water droplet blockage or ice, and to detect whether to turn on the heating function inside the detection device. Pressure measurement can also be performed under the condition of no cloud, rain or ice, and the measured value is converted into an electrical signal and transmitted to the atmospheric data computer to complete the total static pressure measurement.

[0046] (3) The rear section of the body is designed to have a diameter 5 mm larger than that of the front section in order to form multiple discontinuous ice areas and fully capture SLD. Conventional small water droplets will only appear in the head impact, while the rear is a water drop shielding area and will not impact. The embedded fiber optic detector can not only detect the presence of SLD, but also detect the ice intensity through the ice condition at the rear, and the camera installed at the rear can take pictures of the ice condition.

[0047] (4) Intelligent feedback design

[0048] The first and second fiber optic sensors are installed at the front and rear of the detection device for circuit feedback design and intelligent recording to predict the presence of SLD in the atmosphere, generate alarm signals, and alert the crew.

[0049] Circuit diagram Figure 4 As shown, the resistance measurement circuit adopts a voltage divider type. Two high-precision test resistors R1 and R2 of 2MΩ are selected in series, and a +10V excitation voltage is applied in the circuit. In this way, the +10V excitation voltage is divided into two parts, one part is the voltage across R1, which is U1, and the other part is the voltage across R2, which is U2. In order to eliminate interference in the circuit, the voltage signal passes through a first-order low-pass filter circuit, and then an instrument amplifier AD620 (i.e., N1, N2) is selected for voltage acquisition. The selected AD620 instrument amplifier has high precision, low offset voltage and low offset drift characteristics, as well as low noise, low input bias current and low power consumption characteristics, which improves the acquisition accuracy and stability of the circuit; the output signal enters the input end of the operational amplifier after RC filtering. The device is used for impedance matching in the circuit to eliminate common-mode effects. The subsequent circuit only needs to measure the voltages U1 and U2 of the two parts respectively to solve the resistance value of the resistor to be measured.

[0050] An airborne intelligent supercooled large water droplet detection method, such as Figure 3 As shown, the steps are as follows:

[0051] Step 1: Collecting first pressure data from the pressure sensor;

[0052] Step 2: Compare the first pressure data with the second pressure data of the total static pressure sensor; when the first pressure data is 500Pa lower than the second pressure data, proceed to step 3, otherwise return to step 1;

[0053] Step 3: Determine whether there is a blockage by comparing the first pressure data with the second pressure data, and determine whether there is ice according to the detection of the first optical fiber detector; when the frequency signal of the optical fiber detector is inconsistent, turn on the front end heating component of the body, otherwise proceed to step 4;

[0054] Step 4: Use the second optical fiber detector to detect whether there are supercooled large water droplets. When the frequency signal of the optical fiber detector is inconsistent, it indicates the presence of supercooled large water droplets, sends an early warning, and returns to step 1; when the frequency signal of the optical fiber detector is consistent, there are no supercooled large water droplets but only small water droplets, and returns to step 1.

[0055] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An airborne intelligent supercooled large water droplet detection device, characterized in that: The device comprises: a body, a total static pressure sensor, a first optical fiber detector and a second optical fiber detector; The main body is a cylinder, which is divided into two sections, and the diameter of the front section is smaller than that of the rear section; The front end surface of the front section of the body is connected to the hemispherical surface; the hemispherical surface is provided with a plurality of air inlet holes along the radial direction; The first optical fiber detector is located at the front section and close to the edge of the hemispherical surface; The second optical fiber detector is located at the front end surface of the rear section of the body; The total static pressure sensor is arranged below the transition area between the front section and the rear section; A pressure sensor is provided inside the body; The front section of the main body is provided with a heating component.

2. The device according to claim 1, characterized in that: The front side wall of the main body is provided with a water outlet hole with a diameter of 0.6mm.

3. The device according to claim 2, characterized in that: Whether the air intake hole is blocked is determined by determining the difference between the first pressure data of the pressure sensor and the second pressure data of the total static pressure sensor.

4. The device according to claim 3, characterized in that: The diameter of the rear section of the body is 5 mm larger than the diameter of the front section of the body.

5. The device according to claim 1, characterized in that: The transition area between the rear section of the body and the front section of the body is in a concave arc shape.

6. The device according to claim 2, characterized in that: A camera is arranged above the rear section of the main body.

7. The device according to claim 6, characterized in that: The total static pressure sensor is installed in the middle of the concave arc in the transition area, and the base of the total static pressure sensor does not exceed the surface of the front section of the body.

8. The device according to claim 6, characterized in that: The diameter of the air inlet hole is 0.2mm.

9. An airborne intelligent supercooled large water droplet detection method, implemented based on the device of any of the preceding claims, characterized in that: Here are the steps: Step 1: Collecting first pressure data from the pressure sensor; Step 2: Compare the first pressure data with the second pressure data of the total static pressure sensor; when the first pressure data is 500Pa lower than the second pressure data, proceed to step 3, otherwise return to step 1; Step 3: determining whether there is a blockage by comparing the first pressure data with the second pressure data, and determining whether there is ice formation by detecting with the first optical fiber detector; When the frequency signal of the optical fiber detector is inconsistent, the front end heating component of the main body is turned on, otherwise, step 4 is entered; Step 4: Detect whether there are supercooled large water droplets by using the second optical fiber detector. When the optical fiber detector shows inconsistent frequency signals, it indicates that there are supercooled large water droplets, sends an early warning, and returns to step 1; When the frequency signals of the optical fiber detectors are consistent, there are no supercooled large water droplets but only small water droplets, and the process returns to step one.

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