A method for assessing the hazard level of aircraft icing during flight based on a scoring method

Abstract

The present invention discloses a method for assessing the icing hazard degree of an aircraft flight based on a scoring grade method, comprising the following steps: referring to the read real-time flight detection data and combining previous experience to provide a threshold library of the real-time icing temperature, cloud particle effective diameter and liquid water content of the aircraft flight; reading the real-time observed temperature, cloud particle effective diameter and liquid water content of the aircraft flight and matching them with the given threshold library to obtain an icing risk score of the temperature, cloud particle effective diameter and liquid water content at the time of the aircraft flight, and then obtaining a total score of the icing hazard degree at the time of the aircraft flight, and outputting an assessment result; the technical method of the present invention is theoretically applicable to all current mainstream human shadow aircraft flight safety warnings, applicable to real-time risk monitoring of artificial rainmaking or snowmaking aircraft operations, and can be extended to civil aviation flight safety detection.

Description

Technical Field

[0001] The present invention relates to the technical field of ice accretion risk assessment, and in particular to a method for assessing the hazard level of ice accretion during aircraft flight based on a scoring grading method. Background Art

[0002] The process of icing on an aircraft and the process in which supercooled water droplets in the clouds condense on its surface or water vapor condenses and gathers into ice when the aircraft passes through clouds during flight can seriously affect the flight safety of the aircraft, may reduce the stability and maneuverability of the aircraft, and cause failure of navigation instruments and radio communication equipment.

[0003] The main conditions that cause aircraft icing include the external temperature when the aircraft is flying, the content and size of supercooled water droplets in the cloud. Since the factors that cause aircraft icing are many and complex, there is currently no good way to monitor in real time whether icing will form during the flight of the aircraft when the aircraft passes through the cloud. In addition, my country's detection of aircraft icing conditions and analysis of flight data are not mature enough. Therefore, it is necessary to conduct an icing risk assessment based on the conditions during the aircraft process and to conduct a large amount of data analysis on the flight process of my country's aircraft in order to improve the real-time monitoring and understanding of my country's aircraft flight icing. Therefore, a method for assessing the hazard level of aircraft flight icing based on a rating level method and its application are needed. Summary of the invention

[0004] The object of the present invention is to provide a method for evaluating the hazard level of ice accumulation in aircraft flight based on a scoring method.

[0005] To achieve the above object, the present invention is implemented according to the following technical solutions:

[0006] A first aspect of the present invention provides a method for assessing the hazard level of aircraft flight icing based on a scoring method, comprising the following steps:

[0007] 1. A method for assessing the hazard level of aircraft flight icing based on a scoring method, characterized by comprising the following steps:

[0008] A reads parameters based on flight detection history data parameters, the parameters including temperature, true airspeed, effective diameter of particles in the cloud, liquid water content, median volume diameter MVD of water droplets, and time periods corresponding to the parameters;

[0009] B. The functional relationship between the water droplet collection rate and the median volume diameter MVD of the water droplet is constructed by the cubic fitting method, and the water droplet collection rate β is calculated;

[0010] C. Based on the empirical formula for calculating the liquid water content under different ice accretion intensities, the liquid water content under different ice accretion intensities in the selected time period is calculated by using the true air speed to obtain the liquid water content integral threshold value under different ice accretion intensities;

[0011] D. The threshold library is constructed by the integral threshold of temperature and effective diameter of cloud particles and the integral threshold of liquid water content, and the total integral threshold library is constructed;

[0012] E outputs the corresponding ice accumulation hazard degree score result and calculates the total score based on the read temperature, effective diameter of cloud particles and liquid water content data, and matches the above data with the threshold library at the same time, and outputs the evaluation result;

[0013] Furthermore, in step B, the method for obtaining the functional relationship between the water droplet collection rate and the water droplet median volume by cubic fitting comprises the following steps:

[0014] A cubic fitting curve is performed on the median volume diameter MVD of water droplets in the range of 10 μm to 30 μm to calculate the collection rate β in the range of 10 μm to 30 μm;

[0015] When the MVD is less than 10 μm, the water droplet collection rate is 0.53260, and when the MVD is greater than 30 μm, the water droplet collection rate is 0.80228;

[0016] A curve was fitted to determine the functional relationship between the droplet collection rate and the median volume diameter of the droplets.

[0017] Furthermore, the liquid water content calculation formula is:

[0018]

[0019] Where L represents the liquid water content, dD is 0.635 cm, dT is 5 minutes, 15 minutes, 60 minutes, and 200 minutes, β is the droplet collection efficiency related to the aircraft airfoil, TAS is the true airspeed at this moment, and A is the proportional empirical constant of 0.00118.

[0020] Furthermore, the scoring criteria for forming a threshold library by integrating the integral threshold of temperature and effective diameter of particles in the cloud and the integral threshold of liquid water content and constructing a total integral threshold library are as follows:

[0021] ① For the temperature score, the primary condition for ice formation is that the ambient temperature is below 0℃. According to previous research results, the ambient temperature with a faster freezing rate is -4 to -10℃. Scores are given for different temperature ranges, ranging from 0 to 30. The detailed scores within the same temperature range are graded in stages according to the average temperature gradient, where 0℃ and above are scored as 0. When the temperature drops to -7℃, the maximum score is 30. When the temperature continues to drop to -45℃, the score drops to 0 again.

[0022] ② For the scoring of effective cloud particle diameter, the effective cloud particle diameters of different particle size segments are scored according to the envelope distribution in different ranges. The scoring range of effective cloud particle diameters is 0-30 points. The detailed scoring within the same cloud particle interval is staged according to the average gradient of cloud particles. The effective cloud particle diameter is less than 15μm and the score is 0. When the effective cloud particle diameter rises to 20μm, the score reaches the maximum value of 30. When the cloud particle diameter continues to rise to 50μm, the score drops to 0 again.

[0023] ③ For the score of liquid water content in the cloud, the liquid water threshold of the ice accumulation score is calculated according to the liquid water content of the current environment required for 5 minutes, 15 minutes, 60 minutes, and 200 minutes. The liquid water score range is 0-40. The detailed score within the same liquid water content range is scored in stages according to the average gradient of the liquid water content observation value. When the liquid water content is less than the threshold of 200 minutes, the score is 0. When the liquid water content increases to a threshold greater than or equal to 5 minutes, the score reaches a maximum value of 40.

[0024] ④Finally, the aircraft icing hazard score is the sum of the above three scores, with a score range of 0-100 points. When the temperature is greater than 0 or the liquid water content is less than the liquid water content of the current environment required for 200 minutes, the total score is 0.

[0025] Furthermore, the output scoring result evaluates the icing risk level of the aircraft during flight according to the severity as no icing, slight icing, mild icing, moderate icing and severe icing, where 0 represents no icing, scores between 0 and 22 represent slight icing, scores between 22 and 53 represent mild icing, scores between 53 and 78 represent moderate icing, and scores between 78 and 100 represent severe icing.

[0026] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects:

[0027] The technical method of the present invention is theoretically applicable to all current mainstream human shadow aircraft flight safety warnings, and is applicable to real-time risk monitoring of artificial rainmaking or snowmaking aircraft operations, and can be extended to civil aviation flight safety detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is an overall flow chart of a method for assessing the hazard level of aircraft flight icing based on a scoring method;

[0029] Figure 2 The functional relationship between the droplet collection rate and the median volume diameter of the droplets constructed from 13:15 to 13:38 on May 22, 2018;

[0030] Figure 3The temperature, effective diameter of cloud particles, and liquid water content factor scores change over time from 13:15 to 13:38 on May 22, 2018;

[0031] Figure 4 The temperature from 13:15 to 13:38 on May 22, 2018, the total score during the aircraft process, and the scores of three factors: the effective diameter of cloud particles and the liquid water content factor changed over time. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] like Figure 1 As shown, Example 1, a method for assessing the hazard level of aircraft flight icing based on a scoring grading method, was evaluated and applied to a flight data of the Xian MA60 rainmaking aircraft on May 22, 2018.

[0034] Step 1. Select the data from 13:15 to 13:38 on May 22, 2018, and read the temperature, true airspeed, effective diameter of cloud particles, liquid water content factor, and median volume diameter of water droplets during this period. The meteorological element T and true airspeed TAS are from the aircraft detection data of AIMMS, while the effective diameter of cloud particles Rd, liquid water content factor Lobs, and median volume diameter MVD are from the aircraft detection data of CDP.

[0035] Step 2: Use the cubic fitting method to construct the functional relationship between the water droplet collection rate and the median volume diameter of the water droplets in this time period. When the median volume diameter of the water droplets is less than 10 μm, the water droplet collection rate is 0.53260 (and the maximum collection rate at 10 μm in Table 1). When the median volume diameter of the water droplets is greater than 30 μm, the water droplet collection rate is 0.80228 (and the maximum collection rate at 30 μm in Table 1). When the median volume diameter of the water droplets is between 10 μm and 30 μm, a cubic fitting curve is performed on these data according to Table 1 to calculate the water droplet collection rate in the range of 10 μm to 30 μm. The function of the water droplet collection rate and the median volume diameter of the water droplets in this time period is as follows: Figure 2 .

[0036] MVD Maximum collection rate 10μm 0.53260 16μm 0.68963 20μm 0.73788 30μm 0.80228

[0037] Table 1 Water droplet collection rate corresponding to MVD

[0038] Step 3: Substitute the water droplet collection rate obtained in step 2 and the true air speed read in step 1 into the formula in 4 and calculate the four thresholds of the liquid water content score in the ice accumulation score during this period and L5, L15, L60, and L200.

[0039] Calculate the liquid water content through relevant data:

[0040]

[0041] Where L is the liquid water content, dD is 0.635 cm (1 / 4 inch), dT is 5, 15, 60, 200 (minutes), β is the droplet collection efficiency related to the aircraft airfoil, TAS is the true airspeed at this moment, and A is the proportional empirical constant of 0.00118.

[0042] L5, L15, L60, and L200 are the liquid water content L when dT is 5, 15, 60, and 200 (minutes). Their physical meaning is the liquid water content in the current environment required for accumulating 0.635 cm (1 / 4 inch) thick ice in 5 minutes, 15 minutes, 60 minutes, and 200 minutes. L5, L15, L60, and L200 are calculated and constitute the liquid water content thresholds for the aircraft ice accretion score.

[0043] Step 4: Integrate and rate the temperature, effective diameter of cloud particles and observed liquid water content during the period from 13:15 to 13:38 on May 22, 2018, and draw three curves of integral changes over time ( Figure 3 ).

[0044] Step 5: Calculate the total score based on the scores of temperature, effective diameter of cloud particles and observed liquid water content, and draw the curves of the scores of the three variables and the total score over time, and analyze the change process of the scores ( Figure 4 ), and calculate the maximum, minimum, average and proportion of each level of the data in this time period.

[0045] After analysis, it was found that most of the flight process during this period (44.1%) was in a non-icing situation. In the case of icing, mild icing accounted for 31.3%. It is worth noting that severe icing scores (over 78) appeared in this period and accounted for 2.6%, with a maximum value of 89.7. Moderate icing also accounted for 20.0% of the intercepted flight period. In other time periods, slight icing accounted for 3.5% of the entire time period, and the average value of the entire time period was 26.5, which was slight icing. The aircraft's score had two peaks, which appeared at approximately 13:18-13:20 and approximately 13:25-13:28.

[0046] In the composition of the total score during this period, due to the liquid water content with a score of 0 (the observed content is less than L200) at 13:20-13:25 and 13:33 to 13:38, the total score during this period is basically 0. The increase in the two peaks is mainly caused by the increase in particle diameter and liquid water content in the cloud. The influence of temperature on ice accumulation is relatively stable throughout the process.

[0047] The above contents are merely examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for assessing the hazard level of aircraft flight icing based on a scoring method, characterized in that The following steps are involved: A reads parameters based on flight detection history data parameters, the parameters including temperature, true airspeed, effective diameter of particles in the cloud, liquid water content, median volume diameter MVD of water droplets, and time periods corresponding to the parameters; B. The functional relationship between the water droplet collection rate β and the water droplet median volume diameter MVD is constructed by the cubic fitting method, and the water droplet collection rate β is calculated; C. Based on the empirical formula for calculating the liquid water content under different ice accretion intensities, the liquid water content under different ice accretion intensities in the selected time period is calculated by using the true air speed to obtain the liquid water content integral threshold value under different ice accretion intensities; D. The threshold library is constructed by the integral threshold of temperature and effective diameter of cloud particles and the integral threshold of liquid water content, and the total integral threshold library is constructed; E outputs the corresponding ice accumulation hazard degree score result and calculates the total score based on the read temperature, effective diameter of cloud particles and liquid water content data, and matches the above data with the threshold library at the same time, and outputs the evaluation result; In step B, the method for obtaining the functional relationship between the water droplet collection rate β and the water droplet median volume diameter MVD by cubic fitting comprises the following steps: A cubic fitting curve is performed on the median volume diameter MVD of water droplets in the range of 10 μm to 30 μm to calculate the water droplet collection rate β in the range of 10 μm to 30 μm; When the median volume diameter of the water droplet MVD is less than 10 μm, the water droplet collection rate β is 0.53260, and when the median volume diameter of the water droplet MVD is greater than 30 μm, the water droplet collection rate β is 0.80228; A curve is fitted to determine the functional relationship between the water droplet collection rate β and the median volume diameter MVD of the water droplets; The empirical calculation formula for the liquid water content is: Where L represents the liquid water content, dD is 0.635 cm, dT is 5 minutes, 15 minutes, 60 minutes, and 200 minutes, TAS is the vacuum speed at this moment, and A is the proportional empirical constant of 0.00118.

2. The method for assessing the hazard level of aircraft flight icing based on the scoring method according to claim 1, characterized in that: The scoring criteria for constructing a threshold library by using the integral threshold of temperature and cloud particle effective diameter and the integral threshold of liquid water content and constructing a total integral threshold library are as follows: ① For the temperature score, the primary condition for ice formation is that the ambient temperature is below 0℃. According to previous research results, the ambient temperature with a faster freezing rate is -4 to -10℃. Scores are given for different temperature ranges, ranging from 0 to 30. The detailed scores within the same temperature range are graded in stages according to the average temperature gradient, where 0℃ and above are scored as 0. When the temperature drops to -7℃, the maximum score is 30. When the temperature continues to drop to -45℃, the score drops to 0 again. ② For the scoring of effective cloud particle diameters, the effective cloud particle diameters of different particle size segments are scored according to the envelope distribution in different ranges. The scoring range of cloud particle effective diameters is 0-30 points. The detailed scoring within the same cloud particle interval is staged according to the average gradient of cloud particles. The effective cloud particle diameter is less than 15μm and the score is 0. When the effective cloud particle diameter rises to 20μm, the score reaches the maximum value of 30. When the cloud particle diameter continues to rise to 50μm, the score drops to 0 again. ③ For the score of liquid water content in the cloud, the liquid water threshold of the ice accumulation score is calculated according to the liquid water content of the current environment required for 5 minutes, 15 minutes, 60 minutes, and 200 minutes. The liquid water score range is 0-40. The detailed score within the same liquid water content range is scored in stages according to the average gradient of the liquid water content observation value. When the liquid water content is less than the threshold of 200 minutes, the score is 0. When the liquid water content increases to a threshold greater than or equal to 5 minutes, the score reaches a maximum value of 40. ④Finally, the aircraft icing hazard score is the sum of the above three scores, with a score range of 0-100 points. When the temperature is greater than 0 or the liquid water content is less than the liquid water content of the current environment required for 200 minutes, the total score is 0.

3. The method for assessing the hazard level of aircraft flight icing based on the scoring method according to claim 1, characterized in that: The output scoring results rate the ice accumulation risk level of the aircraft during flight according to the severity level as no icing, slight icing, mild icing, moderate icing and severe icing.

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