Method for evaluating external fuel supply amount of given distance of refueling aircraft

Abstract

The invention belongs to the technical field of aircraft performance calculation, and particularly relates to an external fuel supply quantity evaluation method for a given distance of a refueling aircraft. The method comprises the following steps: step 1, constructing a total weight data model of a refueling aircraft according to statistical data of aircrafts of the same kind; 2, constructing a flight performance model of each flight stage of the refueling aircraft according to the total weight data model; 3, a calculation model of the refueling distance and the external fuel supply amount is built according to the flight performance model; and 4, according to the calculation model of the refueling distance and the external oil supply amount, calculating the external oil supply amount of a given distance, and checking a calculation result. According to the method, a mathematical relationship between key design parameters and core capability indexes of the refueling aircraft is established through an overall weight model, a mission profile and a flight performance model of the refueling aircraft, and the mathematical relationship is used for evaluating an external fuel supply quantity result under a given refueling distance condition. The method grasps the key design parameters of the task performance evaluation of the refueling aircraft, and is visual and clear, and the calculation process is convenient.

Description

Technical Field

[0001] The present application belongs to the technical field of aircraft performance calculation, and in particular relates to a method for evaluating the external fuel supply amount of a refueling aircraft at a given distance. Background Art

[0002] A refueling aircraft is an aircraft that can provide fuel to other aircraft in the air. Refueling aircraft are often developed based on mature transport aircraft. Refueling equipment is installed on the fuselage and wings of the aircraft. Refueling is provided to aircraft performing missions through physical connection, allowing the refueled aircraft to expand the coverage of its strike capability and increase the duration of monitoring the battlefield. The world's major military powers have invested huge resources in the development or purchase of various refueling aircraft to maintain and improve their air capabilities and respond to various future threats.

[0003] The advanced refueling aircraft currently equipped in the world include Il-78, A330MRTT and KC-46A, etc. These aircraft are equipped with their own air forces on the one hand, and exported to other countries on the other hand. At present, most of the aerial refueling aircraft in the world are developed and produced by the United States, Russia and the European Union. The usual operation mode of refueling aircraft is to fly according to the designed route, meet with the refueling aircraft in the designated aerial refueling area and provide fuel, and return to the designated airport for landing after completing the mission. Extract core capability indicators based on the operation mode of refueling aircraft.

[0004] The core capability indicator of a refueling aircraft is the amount of fuel delivered at a given distance, and the calculation requirements are similar to the mission performance calculation of an aircraft. Therefore, the calculation and research of the core capability of a refueling aircraft can be promoted through aircraft performance evaluation.

[0005] Factors that affect the aircraft mission performance include: aerodynamic characteristics, power characteristics, overall weight parameters, mission profile, etc. In aircraft research institutions, these data belong to different disciplines, and finally the flight performance professionals will sort, summarize and calculate them to obtain the external fuel supply for a given distance at each evaluation stage.

[0006] At present, there are deficiencies in the rapid assessment of the core capabilities of refueling aircraft by aircraft designers. First, the traditional refueling aircraft mission performance assessment requires the coordination of multiple disciplines, and the calculation cycle is often very long; second, the traditional refueling aircraft mission performance assessment involves a large amount of data, and it is difficult for aircraft designers to simplify the research object; finally, the traditional refueling aircraft mission performance assessment often requires the mastery of specialized software, which increases the burden on aircraft designers. Therefore, it is very important to develop an intuitive, clear, and convenient method for evaluating the external fuel supply of a refueling aircraft at a given distance.

[0007] Therefore, it is desired to have a technical solution to overcome or at least alleviate at least one of the above-mentioned defects of the prior art. Summary of the invention

[0008] The purpose of the present application is to provide a method for estimating the external fuel supply amount of a refueling aircraft at a given distance, so as to solve at least one problem existing in the prior art.

[0009] The technical solution of this application is:

[0010] A method for evaluating the external fuel supply amount of a refueling aircraft at a given distance, comprising:

[0011] Step 1: Construct a total weight data model of the refueled aircraft based on statistical data of similar aircraft;

[0012] Step 2: constructing a flight performance model of the refueling aircraft at each flight stage according to the overall weight data model;

[0013] Step 3: constructing a calculation model for refueling distance and external fuel supply amount according to the flight performance model;

[0014] Step 4: Calculate the external fuel supply amount for a given distance based on the calculation model of the refueling distance and the external fuel supply amount, and check the calculation result.

[0015] In at least one embodiment of the present application, in step 1, constructing a total weight data model of a refueling aircraft based on statistical data of similar aircraft includes:

[0016] The overall weight data model of the refueling aircraft includes:

[0017] Take-off weight:

[0018] W0=W oe +W fuel +W pl

[0019] Where W0 is the takeoff weight, W oe is the empty weight, W fuel is the fuel weight during the flight, W pl The external oil supply;

[0020] The functional relationship between empty weight and takeoff weight is:

[0021] lgW oe =(lgW0-A) / B

[0022] Among them, A and B are the relationship parameters between empty weight and takeoff weight;

[0023] The total fuel weight is:

[0024] W all =W0-W oe

[0025] Among them, Wall is the total fuel weight;

[0026] The external fuel supply is determined according to the mission requirements of the refueling aircraft. The fuel weight during the route flight is:

[0027] W fuel =W all -W pl

[0028] Taking takeoff weight as the independent variable, the relationship parameters A and B are determined based on the statistical data of similar aircraft.

[0029] In at least one embodiment of the present application, in step 2, constructing a flight performance model of each flight phase of the refueling aircraft according to the overall weight data model includes:

[0030] According to the mission profile of the refueling aircraft, the flight phase is divided into take-off phase, climb phase, outbound cruise phase, aerial refueling phase, return cruise phase, descent phase, landing phase, and taxi phase;

[0031] Determine the initial and final weights of the take-off, climb, descent, landing and taxi segments;

[0032] Calculate the horizontal distance of the climb and descent segments based on the specific range concept.

[0033] In at least one embodiment of the present application, determining the initial weight and final weight of the take-off segment, the climb segment, the descent segment, the landing segment, and the taxi segment includes:

[0034] The final landing weight is:

[0035] W7=W oe +0.1W fuel

[0036] The initial weight and final weight of the take-off phase, climb phase, descent phase, landing phase, and taxi phase are:

[0037]

[0038] Among them, W0 is the initial weight of the take-off segment, W1 is the final weight of the take-off segment and the initial weight of the climb segment, W2 is the final weight of the climb segment and the initial weight of the outbound cruise segment, W3 is the final weight of the outbound cruise segment and the initial weight of the aerial refueling segment, W4 is the final weight of the aerial refueling segment and the initial weight of the return cruise segment, W5 is the final weight of the return cruise segment and the initial weight of the descent segment, W6 is the final weight of the descent segment and the initial weight of the landing segment, W7 is the final weight of the landing segment and the initial weight of the taxiing segment, and W8 is the final weight of the taxiing segment.

[0039] In at least one embodiment of the present application, the horizontal distances of the climbing segment and the descending segment are calculated based on the concept of specific range, including:

[0040] The specific range of the climb and descent segments is obtained as follows:

[0041] SR Climb =0.7SR Cruise

[0042] SR Decline =2SR Cruise

[0043] Among them, SR Climb is the specific range of the climb segment, SR Decline is the specific range of the descent segment, SR Cruise is the specific range of the cruise segment;

[0044] Calculate the horizontal distance of the climbing section and the descending section as:

[0045] L Climb =SR Climb ×(W1-W2)

[0046] L Decline =SR Decline ×(W5-W6)

[0047] Among them, L Climb is the horizontal distance of the climbing section, L Decline is the horizontal distance of the descending segment.

[0048] In at least one embodiment of the present application, in step 3, constructing a calculation model of refueling distance and external fuel supply amount according to the flight performance model includes:

[0049] Given the initial value W of the final weight W3 of the cruise segment, 3,初值 , calculate the distance of the outbound cruise segment according to the Bregate range formula;

[0050] The refueling distance is calculated based on the horizontal distance of the climb phase and the distance of the cruise phase;

[0051] The distance of the return cruise segment is calculated based on the horizontal distance of the descent segment and the refueling distance;

[0052] The external fuel supply is calculated based on the distance of the return cruise segment.

[0053] In at least one embodiment of the present application, the initial value W of the final weight W3 of the given cruise segment is 3,初值 , calculate the distance of the cruise segment according to the Bregate range formula, including:

[0054] The Bregate range formula is:

[0055]

[0056] Among them, L Cruise is the distance of the cruise segment, V cruise is the cruising speed, K is the cruising lift-to-drag ratio, S fc is the cruising fuel consumption rate, cr is the maximum cruising factor, and k is the correction coefficient;

[0057] The initial value W of the final weight W3 of the cruise segment is given 3,初值 As W 终了 , calculate the distance L of the cruise segment Cruise1 .

[0058] In at least one embodiment of the present application, the refueling distance is calculated according to the horizontal distance of the climbing segment and the distance of the cruise segment, including:

[0059] L=L Cruise1 +L Climb

[0060] Wherein, L is the refueling distance.

[0061] In at least one embodiment of the present application, calculating the distance of the return cruise segment according to the horizontal distance of the descent segment and the refueling distance includes:

[0062] L Cruise2 =LL Decline

[0063] Among them, L Cruise2 is the distance of the return cruise segment.

[0064] In at least one embodiment of the present application, the amount of external fuel supply is calculated according to the distance of the return cruise segment, including:

[0065] The final weight W4 of the aerial refueling segment is calculated based on the distance of the return cruise segment:

[0066]

[0067] Waiting for the weight after confluence W 31 for:

[0068]

[0069] Fuel consumption weight after waiting for merging W rr1 for:

[0070]

[0071] Fuel consumption weight during aerial refueling operation W rr2 for:

[0072]

[0073] The fuel consumption weight of the whole aerial refueling process is W rr for:

[0074] W rr =W rr1 +W rr2

[0075] External oil supply W pl 'for:

[0076] W' pl =W3-W4-W rr

[0077] Among them, m is the average flight weight during the aerial refueling operation, T1 is the waiting time for rendezvous, and T2 is the time for the aerial refueling operation.

[0078] In at least one embodiment of the present application, step three further includes: calculating the external oil supply amount W pl 'The difference from the target external fuel supply is used as the weight iteration method:

[0079] W 3,初值 =W 3,初值 +(W pl -W pl ') / 2

[0080] Through several iterative calculations, the target external oil supply volume W is obtained. pl Accurate refueling distance under certain conditions.

[0081] In at least one embodiment of the present application, step three further includes: calculating a set of target external fuel supply amounts W pl The refueling distance results under the following conditions were obtained. The refueling distance was taken as the independent variable and the external fuel supply amount was taken as the dependent variable. The linear relationship between the refueling distance and the external fuel supply amount was fitted.

[0082] In at least one embodiment of the present application, in step 4, the external fuel supply amount for a given distance is calculated according to the calculation model of the refueling distance and the external fuel supply amount, and the calculation result is checked, including:

[0083] Substitute the given refueling distance into the fitted linear relationship to calculate the external fuel supply amount corresponding to the refueling distance;

[0084] Substituting the external fuel supply amount into the calculation model of the refueling distance and the external fuel supply amount to calculate the refueling distance;

[0085] Check if there is a difference between the given refueling distance and the calculated refueling distance.

[0086] The invention has at least the following beneficial technical effects:

[0087] The method for evaluating the external fuel supply of a refueling aircraft at a given distance in this application builds a set of mathematical relationships between key design parameters and core capability indicators of the refueling aircraft through the overall weight model, mission profile, and flight performance model of the refueling aircraft, which is used to evaluate the external fuel supply results under given refueling distance conditions. This method focuses on the key design parameters for evaluating the mission performance of the refueling aircraft, and the method is intuitive, clear, and the calculation process is convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] Figure 1 It is a schematic diagram of a refueling aircraft model and mission performance calculation results according to one embodiment of the present application;

[0089] Figure 2 It is a calculation formula and iterative calculation result diagram of a refueling task performance model according to one embodiment of the present application;

[0090] Figure 3 It is a fitted line graph of the parameter relationship between the refueling distance and the external fuel supply amount of a refueling aircraft according to one embodiment of the present application. DETAILED DESCRIPTION

[0091] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the embodiment of this application will be described in more detail below in conjunction with the drawings in the embodiment of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of this application, not all of them. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain this application, and should not be construed as limitations on this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The embodiments of this application are described in detail below in conjunction with the drawings.

[0092] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present application.

[0093] The following is combined with Figures 1 to 3 This application is described in further detail.

[0094] The present application provides a method for evaluating the external fuel supply amount of a refueling aircraft at a given distance, comprising the following steps:

[0095] Step 1: Construct a total weight data model of the refueled aircraft based on statistical data of similar aircraft;

[0096] Step 2: construct a flight performance model of the refueling aircraft at each flight stage based on the overall weight data model;

[0097] Step 3: Construct a calculation model for refueling distance and external fuel supply amount based on the flight performance model;

[0098] Step 4: Calculate the external fuel supply volume for a given distance based on the calculation model of the refueling distance and the external fuel supply volume, and check the calculation results.

[0099] The method for evaluating the external fuel supply of a refueling aircraft at a given distance in the present application comprises, in step 1, building a total weight data model of the refueling aircraft in combination with statistical data of similar aircraft. Weight data affects the flight performance of the aircraft, including takeoff weight W0, aircraft empty weight W oe , the relevant fuel weight W during the route flight fuel , the external fuel supply of the refueling aircraft W pl , the total fuel weight of the refueled aircraft is W all The weight statistics involved include parameters A and B. These parameters are determined by Figure 2 The calculation method in achieves the goal of configuring the overall weight model.

[0100] In the method for evaluating the external fuel supply of a refueling aircraft at a given distance of the present application, in step 2, a flight performance model of each flight phase is constructed according to the mission profile of the refueling aircraft. The high-high-high mission profile of the refueling aircraft is divided into 8 mission segments, and the weight ratios of the take-off segment, climb segment, descent segment, landing segment and taxi segment are given with reference to statistical results, and the starting and ending weight results of multiple mission segments are calculated. The performance results of cruise and aerial refueling are calculated based on the Bregate range / flight time formula, and the horizontal distances of the climb segment and the descent segment are calculated based on the concept of relative range.

[0101] In the method for evaluating the external fuel supply of a refueling aircraft at a given distance of the present application, in step 3, a mathematical relationship between the refueling distance and the external fuel supply is constructed according to the influence law of the external fuel supply of the refueling aircraft. By setting the initial value W of the weight W3 3,初值 After completing the task performance calculation, the calculated external fuel supply volume W pl The difference between the target external fuel supply and the weight iteration method W 3,初值 =W 3,初值 +(W pl -W pl ') / 2, through several iterative calculations, obtain W plThe accurate refueling distance under the condition. Using a similar method, calculate the refueling distance results under a set of external fuel supply conditions. Take the refueling distance as the independent variable and the external fuel supply as the dependent variable to draw a line graph. There is an approximate linear relationship between the refueling distance and the external fuel supply, and fit the linear relationship.

[0102] In the method for evaluating the external fuel supply of a refueling aircraft at a given distance of the present application, in step 4, the above-mentioned calculation models are combined to build a set of mathematical relationships between the key design parameters and core capability indicators of the refueling aircraft. For the evaluation of the external fuel supply at a given distance, a linear relationship is used to infer the external fuel supply at a given distance and the calculation is checked. The given refueling distance is substituted into the fitted linear relationship to infer the external fuel supply for the distance. Repeat the above steps and calculate the external fuel supply result W pl Substitute it into the calculation process and calculate the refueling distance. Check the calculation results in this way. If there is a difference, increase the number of iterative calculations.

[0103] The method for evaluating the external fuel supply of a refueling aircraft at a given distance in the present application first constructs a total weight data model of the refueling aircraft in combination with statistical data of similar aircraft; then constructs a flight performance model of each flight phase according to the mission profile of the refueling aircraft; then constructs a mathematical relationship between the refueling distance and the external fuel supply according to the influence law of the external fuel supply of the refueling aircraft, and draws a line graph. Finally, these calculation models are combined to build a set of mathematical relationships between the key design parameters and core capability indicators of the refueling aircraft. In this way, the method for evaluating the external fuel supply of a refueling aircraft at a given distance is completed.

[0104] Specifically, the overall weight data model of the refueled aircraft is constructed by combining the statistical data of similar aircraft. The weight data affects the flight performance of the aircraft, among which the key data is the takeoff weight W0, which is composed as follows:

[0105] W0=W oe +W fuel +W pl (1)

[0106] Where: W oe W is the empty weight of the aircraft; fuel W is the fuel weight related to the flight route; pl is the loading weight. The loading of the refueling aircraft is fuel, so W is used. pl It expresses the amount of external fuel supplied to the refueled aircraft. The weight referred to in this article refers to mass, unit kg, the same below.

[0107] In aircraft evaluation, the empty weight W oe On the one hand, it is related to the takeoff weight W0, and on the other hand, it is related to the design and production level of the aircraft. For aircraft of the same type and similar level, W0 can be constructed through statistical data. oeThe functional relationship between and W0. The relationship for transport aircraft is as follows:

[0108] lgW oe =(lgW0-A) / B (2)

[0109] The aircraft evaluation literature provides the values ​​of parameters A and B in different situations. For example, the statistical data of civil aircraft that widely use composite materials is A = 0.09907 and B = 1.0411. In this way, using W0, A, and B as independent variables, W can be calculated. oe , W0 and W oe The difference is the total fuel weight of the refueled aircraft.

[0110] W all =W0-W oe (3)

[0111] For a mission performance evaluation of a refueling aircraft, it is necessary to set the external fuel supply volume W pl As a result, the relevant fuel weight W during the route flight fuel The calculation formula is as follows:

[0112] W fuel =W all -W pl (4)

[0113] The flight performance model of each flight phase is constructed according to the mission profile of the refueling aircraft. The refueling aircraft in this paper adopts a high-high-high mission profile, and the aircraft's outbound cruise and return cruise are both in the most efficient cruise flight mode. In the process of mission performance evaluation, the performance results are calculated using the ratio of the final weight to the initial weight of each mission segment. The weight ratio given by the reference statistical data is shown in Table 1.

[0114] Table 1

[0115]

[0116] The landing weight is W7. The reserve fuel weight in this embodiment is 10% of the route fuel weight. Then W7 = W oe +0.1W fuel .

[0117] The above formulas for W0 and W7 are given. Combined with the data in Table 1, the calculation formula for the initial weight of each task segment can be obtained as shown below:

[0118]

[0119] Load the cruise factor V of the refueling aircraft during the cruise flight process cruise K / S fc Value, where: V cruiseis the cruising speed, K is the cruising lift-to-drag ratio, S fc is the cruise fuel consumption rate. For an aircraft operating at a high-high-high profile, the cruise factor under different cruise weight conditions varies little. The maximum cruise factor under different weight conditions is called cr, and the cruise factors of other weights are expressed as k·cr, where k is the correction factor.

[0120] The specific range SR of an aircraft during cruising refers to the flight distance per unit weight of fuel consumed, and is calculated as follows:

[0121] SR Cruise =cr / m (6)

[0122] Refer to the specific range setting of cruise to set the specific range of climb and descent.

[0123] SR Climb =L Climb / W Climb (7)

[0124] The specific range of an aircraft during climbing and descending is positively correlated with the specific range during cruising.

[0125] generally:

[0126] SR Climb =0.7SR Cruise (8)

[0127] SR Decline =2SR Cruise (9)

[0128] Use equations (8) and (9) to calculate the horizontal distance of the climb and descent mission segments:

[0129] L Climb =SR Climb ×(W1-W2) (10)

[0130] L Decline =SR Decline ×(W5-W6) (11)

[0131] Initial weight W through the cruise segment 初始 , Final weight W 终了 , combined with the cruise factor, the cruise distance can be calculated using the Bregate range formula as follows:

[0132]

[0133] Give the initial value W of the cruise end weight W3 3,初值 , using the Bregate range formula to calculate the cruise segment is L Cruise1 , then the refueling distance L is as follows:

[0134] L=L1=L Cruise1 +L Climb (13)

[0135] Then the distance of the return cruise segment is:

[0136] L Cruise2 =LL Decline =L1-L Decline (14)

[0137] Calculate L Cruise2 Substitute the result into formula (12) to calculate W4:

[0138]

[0139] According to the influence of the external fuel supply of the refueling aircraft, the mathematical relationship between the refueling distance and the external fuel supply is constructed. The fuel consumption weight W of the entire aerial refueling process is calculated. rr The whole process of aerial refueling is divided into two parts: the waiting time before aerial refueling and the aerial refueling operation. The waiting time T1 has nothing to do with the external fuel supply, and the aerial refueling operation time T2 is linear with the external fuel supply.

[0140] The weight after waiting for confluence is W 31 , convert the Bregate flight time formula into the following:

[0141]

[0142] The fuel consumption weight after waiting for the rendezvous is W rr1 , the calculation is as follows:

[0143] W rr1 =W3-W 31 (17)

[0144] The weight of fuel consumed during aerial refueling is W rr2 , the calculation is as follows:

[0145]

[0146] Where m is the average flight weight during the aerial refueling operation, which is 0.5W 31 +0.5W4; T2 is the time of aerial refueling operation, T2=W pl / refueling rate; K is the lift-to-drag ratio during aerial refueling; S fc It is the fuel consumption rate during aerial refueling. Simplified processing, K and S fc The average parameters of the cruise process are adopted.

[0147] In this way, the fuel consumption weight W of the entire aerial refueling process is obtainedrr :

[0148] W rr =W rr1 +W rr2 (19)

[0149] The calculation is based on the initial value W 3,初值 The result of the external oil supply W pl ':

[0150] W' pl =W3-W4-W rr (20)

[0151] External oil supply W pl The value of ' is the same as when W pl The target values ​​of W are different. 3,初值 The value of is adjusted by iterative calculation, and the calculation method is as follows:

[0152] W 3,初值 =W 3,初值 +(W pl -W' pl ) / 2 (21)

[0153] Through several iterative calculations, the external oil supply volume W is obtained. pl Accurate refueling distance under certain conditions.

[0154] A similar method is used to calculate the refueling distance results under a set of external fuel supply conditions.

[0155] With the refueling distance as the independent variable and the external fuel supply as the dependent variable, a line graph is drawn. There is an approximate linear relationship between the refueling distance and the external fuel supply, and a linear relationship is fitted.

[0156] Combine the above calculation models to build a set of mathematical relationships between the key design parameters and core capability indicators of the refueling aircraft. For the evaluation of the external fuel supply for a given distance, use the linear relationship to deduce the external fuel supply for a given distance and check the calculation. Substitute the given refueling distance into the fitted linear relationship to deduce the external fuel supply for that distance. Repeat the above steps and calculate the external fuel supply result W pl Substitute it into the calculation process and calculate the refueling distance. Check the calculation results in this way. If there is a difference, increase the number of iterative calculations.

[0157] In one embodiment of the present application, the research object is a subsonic jet refueling aircraft. Taking the refueling aircraft as an example, a method for evaluating the external fuel supply amount of the refueling aircraft at a given distance is described in detail.

[0158] S1. Construct the functional relationship between the total weight data of the refueled aircraft and the independent variables. The independent variables include the takeoff weight W0, and the weight statistical data A and B. For example, W0 = 130000 kg, A = 0.09907, B = 1.0411. Use formula (2) to calculate W oe =65599kg. Using formula (3), the total fuel weight of the refueled aircraft is calculated to be 64401kg. The range of the external fuel supply of the refueled aircraft is set to 10000kg~40000kg. First, calculate W pl =40000kg, W fuel =24401kg. Figure 1 Upper left corner.

[0159] S2. Construct the functional relationship between the weight data and the independent variable at each stage of the refueling aircraft flight mission profile. The mission profile of the refueling aircraft is divided into 8 mission segments, and the starting weight of each mission segment is W. i-1 , the final weight is W i , see Table 1. Note that the ratio of the final weight to the initial weight of some mission segments does not change much, such as the take-off segment, climb segment, descent segment, landing segment and taxi segment. The statistical results are given as W i / W i-1 . Combined with W0=W oe +W fuel +W pl and W7=W oe +0.1W fuel The formula for W1, W2, W5, W6 and W8 is given in formula (5). The calculation results show that W1 = 128700 kg, W2 = 126126 kg, W5 = 69211 kg, W6 = 68588 kg, and W7 = 68039 kg. Figure 1 Central.

[0160] Construct the functional relationship between the flight capability and independent variables of each stage of the refueling aircraft flight mission profile. Calculate the maximum cruise factor of the refueling aircraft during the cruise flight process, giving, for example, V cruise =850km / h, K=18, S fc =0.65kg / kgf / h, then cr = 23538. Reference cruise process SR Cruise =cr / m, set the climb-to-range and descent-to-range, that is, the ratio of the horizontal flight distance to the fuel weight during the climb-to-descent process. The refueled aircraft needs to consume more fuel during the climb process, and the climb-to-range is less than the cruise-to-range. Calculate the ratio of the two. Climb =0.65SR Cruise The refueled aircraft consumes less fuel during the descent process, and the descent range is greater than the cruising range. The ratio of the two is calculated. Decline =1.30SRCruise .See Figure 1 Upper right corner.

[0161] Calculate the flight distance of the climb, descent and cruise phases of the refueled aircraft. The average weight of the climb phase is 127413kg, the fuel consumption of the climb phase is 2574kg and the specific range of the climb phase is 0.65SR Cruise , the horizontal distance of the climbing process is calculated to be (15300 / 127413×2574)309km. The horizontal distance of the descending process is calculated to be 277km in a similar way.

[0162] S3. Give the initial value W of the cruise end weight W3 3,初值 =0.95W2=119820kg, using the Bregate range formula to calculate the cruise segment is 1207km. The average flight weight of the cruise is 122973kg, and the cruise distance correction factor is 0.000001289×122973+0.8415=1. The total distance of the cruise is the sum of the climb distance and the cruise distance, 309+1207×1=1516km. The total distance of the return flight is the same as the total distance of the outbound flight, so the return cruise segment is 1516-277=1239km. The passenger aircraft calculates W by formula (15) 4,初值 =73230kg. Figure 1 Below.

[0163] Calculate the time and external fuel supply of the refueling aircraft in the air. The flight weight after waiting for rendezvous for 0.5 hours in the air is calculated by formula (16) to be 117676kg, the flight weight after 0.5 hours in the air is calculated by formula (18) to be 73230kg, and the flight weight after 0.5 hours in the air is calculated by formula (20) W pl '=W3-W4-W rr The result of calculating the external oil supply is 42722kg. pl The value of ' is the same as when W pl The target values ​​of W are different. 3,初值 The value of W is adjusted by iterative calculation. 3,初值 =W 3,初值 +(W pl -W pl ') / 2. Finally, W3=118158kg, W5=74325kg, and the total sailing distance is 1844km.

[0164] Calculate the total sailing distance under different external fuel supply conditions. Repeat step S3 and set the target external fuel supply amount W plThe values ​​are set to 30,000 kg, 20,000 kg and 10,000 kg respectively, and the total distances calculated are 2,963 km, 4,074 km and 5,177 km respectively. A line graph is drawn with the total distance as the independent variable and the external fuel supply as the dependent variable. See Figure 3 As can be seen from the figure, there is an approximate linear relationship between the total voyage distance and the external fuel supply, and a linear relationship is fitted.

[0165] S4. Use the linear relationship to calculate the external fuel supply for a given distance and check the calculation. Substitute the given refueling distance into the fitted linear relationship to calculate the external fuel supply for the distance. Repeat step S3 and calculate the external fuel supply result W pl Substitute it into the calculation process and calculate the total distance of the voyage. Check the calculation results in this way. If there is a difference, repeat step S3.

[0166] The parameters involved in this application are defined as follows:

[0167] W0——Takeoff weight of the refueled aircraft, kg;

[0168] W oe ——empty weight of the refueled aircraft, kg;

[0169] W fuel - the weight of fuel relevant to the route flight;

[0170] W pl ——Loading weight. If the load of a refueling aircraft is fuel, W is used. pl Indicates the external oil supply;

[0171] W all ——W fuel With W pl The sum of the total fuel weight of the refueled aircraft;

[0172] W rr ——Fuel consumption of the refueling aircraft during the aerial refueling and waiting for rendezvous, kg;

[0173] W rr1 ——Fuel consumption of the refueling aircraft during the aerial refueling and waiting for rendezvous, kg;

[0174] W rr2 ——Fuel consumption of the refueling aircraft during aerial refueling operations, kg;

[0175] A——About W oe A parameter related to W0;

[0176] B——About W oe A parameter related to W0;

[0177] Mission profile refers to the projection of the flight trajectory in the vertical plane during the entire process of the aircraft performing the flight mission.

[0178] Mission segment refers to the specific flight process within a period of time as required during the entire process of an aircraft performing a flight mission.

[0179] i——the number of the mission segment in the mission profile of the refueling aircraft;

[0180] W i-1 ——The initial weight of the refueling aircraft in the i-th mission segment, kg;

[0181] W i ——The final weight of the refueling aircraft at the i-th mission segment, kg;

[0182] W 初始 ——initial weight of the cruise mission segment, kg;

[0183] W 终了 ——end weight of the cruise mission segment, kg;

[0184] m——instantaneous flight weight, or average flight weight during a flight, kg;

[0185] V cruise - cruising speed;

[0186] K——mean value of cruise lift-to-drag ratio;

[0187] S fc ——Average cruising fuel consumption;

[0188] cr——mean value of cruise factor, calculated as V cruise K / S fc ;

[0189] SR - Specific Range, which refers to the flight distance per unit weight of fuel consumed by the aircraft;

[0190] SR Cruise ——Cruise specific range refers to the flight distance per unit weight of fuel consumed by the aircraft during the cruise, km / kg;

[0191] SR Climb ——Climb specific range refers to the flight distance per unit weight of fuel consumed by the aircraft during the climb, km / kg;

[0192] SR Decline ——Descent specific range refers to the flight distance per unit weight of fuel consumed by the aircraft during descent, km / kg;

[0193] L Cruise ——Cruise distance refers to the flight distance of the aircraft during the cruise, km;

[0194] L Cruise1 ——Departure cruise distance refers to the flight distance of the aircraft during the departure cruise, km;

[0195] L Cruise2 ——Return cruise distance refers to the flight distance of the aircraft during the return cruise, km;

[0196] L Climb ——Climb distance refers to the flight distance of the aircraft during the climb, km;

[0197] L Decline ——Descent distance refers to the flight distance of the aircraft during the descent, km;

[0198] L——Refueling distance, which refers to the flight distance from the deployment airport to the aerial refueling point, km;

[0199] L1——departure distance, which refers to the flight distance of the flight segment, km;

[0200] L2——Return distance, refers to the flight distance of the return leg, km;

[0201] T——the whole process of aerial refueling, the flight time of the refueling aircraft, h;

[0202] T1——Flight time for waiting for rendezvous before aerial refueling, regardless of external fuel supply, h;

[0203] T2 - flight time of aerial refueling operation, related to the amount of external fuel supplied, h.

[0204] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for evaluating the external fuel supply of a refueling aircraft at a given distance, characterized in that: include: Step 1: Construct a total weight data model of the refueled aircraft based on statistical data of similar aircraft; Step 2: constructing a flight performance model of the refueling aircraft at each flight stage according to the overall weight data model; Step 3: constructing a calculation model for refueling distance and external fuel supply amount according to the flight performance model; Step 4: Calculate the external fuel supply amount for a given distance based on the calculation model of the refueling distance and the external fuel supply amount, and check the calculation result.

2. The method for evaluating the external fuel supply amount of a refueling aircraft at a given distance according to claim 1, characterized in that: In step 1, the overall weight data model of the refueled aircraft is constructed based on the statistical data of similar aircraft, including: The overall weight data model of the refueling aircraft includes: Take-off weight: W0=W oe +W fuel +W pl Where W0 is the takeoff weight, W oe is the empty weight, W fuel is the fuel weight during the flight, W pl The external oil supply; The functional relationship between empty weight and takeoff weight is: lgW oe =(lgW0-A) / B Among them, A and B are the relationship parameters between empty weight and takeoff weight; The total fuel weight is: IN all =W0-W oe Among them, W all is the total fuel weight; The external fuel supply is determined according to the mission requirements of the refueling aircraft. The fuel weight during the route flight is: IN fuel =In all -IN pl Taking takeoff weight as the independent variable, the relationship parameters A and B are determined based on the statistical data of similar aircraft.

3. The method for evaluating the external fuel supply amount of a refueling aircraft at a given distance according to claim 2, characterized in that: In step 2, a flight performance model of each flight phase of the refueling aircraft is constructed according to the overall weight data model, including: According to the mission profile of the refueling aircraft, the flight phase is divided into take-off phase, climb phase, outbound cruise phase, aerial refueling phase, return cruise phase, descent phase, landing phase, and taxi phase; Determine the initial and final weights of the take-off, climb, descent, landing and taxi segments; Calculate the horizontal distance of the climb and descent segments based on the specific range concept.

4. The method for evaluating the external fuel supply amount of a refueling aircraft at a given distance according to claim 3, characterized in that: Determine the initial and final weights for takeoff, climb, descent, landing, and taxi, including: The final landing weight is: W7=W oe +0.1W fuel The initial weight and final weight of the take-off phase, climb phase, descent phase, landing phase, and taxi phase are: Among them, W0 is the initial weight of the take-off segment, W1 is the final weight of the take-off segment and the initial weight of the climb segment, W2 is the final weight of the climb segment and the initial weight of the outbound cruise segment, W3 is the final weight of the outbound cruise segment and the initial weight of the aerial refueling segment, W4 is the final weight of the aerial refueling segment and the initial weight of the return cruise segment, W5 is the final weight of the return cruise segment and the initial weight of the descent segment, W6 is the final weight of the descent segment and the initial weight of the landing segment, W7 is the final weight of the landing segment and the initial weight of the taxiing segment, and W8 is the final weight of the taxiing segment.

5. The method for evaluating the external fuel supply amount of a refueling aircraft at a given distance according to claim 4, characterized in that: Calculate the horizontal distance of the climb and descent segments based on the concept of specific range, including: The specific range of the climb and descent segments is obtained as follows: SR Climb =0.7SR Cruise SR Decline =2SR Cruise Among them, SR Climb is the specific range of the climb segment, SR Decline is the specific range of the descent segment, SR Cruise is the specific range of the cruise segment; Calculate the horizontal distance of the climbing section and the descending section as: L Climb =SR Climb ×(W1-W2) <h2 style=";text-align:left;direction:ltr">L<h2 style=";text-align:left;direction:ltr"> Decline <h2 style=";text-align:left;direction:ltr"> =SR<h2 style=";text-align:left;direction:ltr"> Decline <h2 style=";text-align:left;direction:ltr"> ×(W5-W6) Among them, L Climb is the horizontal distance of the climbing section, L Decline is the horizontal distance of the descending segment.

6. The method for evaluating the external fuel supply amount of a refueling aircraft at a given distance according to claim 5, characterized in that: In step 3, a calculation model for refueling distance and external fuel supply amount is constructed according to the flight performance model, including: Given the initial value W of the final weight W3 of the cruise segment, 3,初值 , calculate the distance of the outbound cruise segment according to the Bregate range formula; The refueling distance is calculated based on the horizontal distance of the climb phase and the distance of the cruise phase; The distance of the return cruise segment is calculated based on the horizontal distance of the descent segment and the refueling distance; The external fuel supply is calculated based on the distance of the return cruise segment.

7. The method for evaluating the external fuel supply amount of a refueling aircraft at a given distance according to claim 6, characterized in that: Given the initial value W of the final weight W3 of the cruise segment, 3,初值 , calculate the distance of the cruise segment according to the Bregate range formula, including: The Bregate range formula is: Among them, L Cruise is the distance of the cruise segment, V cruise is the cruising speed, K is the cruising lift-to-drag ratio, S fc is the cruising fuel consumption rate, cr is the maximum cruising factor, and k is the correction coefficient; The initial value W of the final weight W3 of the cruise segment is given 3,初值 As W 终了 , calculate the distance L of the cruise segment Cruise1 .

8. The method for evaluating the external fuel supply amount of a refueling aircraft at a given distance according to claim 7, characterized in that: The refueling distance is calculated based on the horizontal distance of the climb segment and the distance of the cruise segment, including: L=L Cruise1 +L Climb Wherein, L is the refueling distance.

9. The method for evaluating the external fuel supply amount of a refueling aircraft at a given distance according to claim 8, characterized in that: The distance of the return cruise segment is calculated based on the horizontal distance of the descent segment and the refueling distance, including: L Cruise2 =LL Decline Among them, L Cruise2 is the distance of the return cruise segment.

10. The method for evaluating the external fuel supply amount of a refueling aircraft at a given distance according to claim 9, characterized in that: The external fuel supply is calculated based on the distance of the return cruise segment, including: The final weight W4 of the aerial refueling segment is calculated based on the distance of the return cruise segment: Waiting for the weight after confluence W 31 for: Fuel consumption weight after waiting for merging W rr1 for: W rr1 =W3-W 31 Fuel consumption weight during aerial refueling operation W rr2 for: The fuel consumption weight of the whole aerial refueling process is W rr for: IN rr =In rr1 +W rr2 External oil supply W pl 'for: <h2 style=";text-align:left;direction:ltr">W'<h2 style=";text-align:left;direction:ltr"> pl <h2 style=";text-align:left;direction:ltr"> =W3-W4-W<h2 style=";text-align:left;direction:ltr"> rr Among them, m is the average flight weight during the aerial refueling operation, T1 is the waiting time for rendezvous, and T2 is the time for the aerial refueling operation.

11. The method for evaluating the external fuel supply amount of a refueling aircraft at a given distance according to claim 10, characterized in that: Step three also includes: calculating the external oil supply amount W pl 'The difference from the target external fuel supply is used as the weight iteration method: IN 3,初值 =In 3,初值 +(W pl -IN pl ') / 2 Through several iterative calculations, the target external oil supply volume W is obtained. pl Accurate refueling distance under certain conditions.

12. The method for evaluating the external fuel supply amount of a refueling aircraft at a given distance according to claim 11, characterized in that: Step three also includes: calculating a set of target external fuel supply volume W pl The refueling distance results under the following conditions were obtained. The refueling distance was taken as the independent variable and the external fuel supply amount was taken as the dependent variable. The linear relationship between the refueling distance and the external fuel supply amount was fitted.

13. The method for evaluating the external fuel supply amount of a refueling aircraft at a given distance according to claim 12, characterized in that: In step 4, the external fuel supply amount for a given distance is calculated based on the calculation model of the refueling distance and the external fuel supply amount, and the calculation result is checked, including: Substitute the given refueling distance into the fitted linear relationship to calculate the external fuel supply amount corresponding to the refueling distance; Substituting the external fuel supply amount into the calculation model of the refueling distance and the external fuel supply amount to calculate the refueling distance; Check if there is a difference between the given refueling distance and the calculated refueling distance.

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