Method for determining voyage of hypersonic cruise aircraft by considering effective weight

Abstract

The invention relates to a voyage determination method of a hypersonic cruise aircraft considering effective weight, which comprises the following steps of: 1, calculating an effective weight correction coefficient of the aircraft, wherein V is a flight speed, g is a gravitational acceleration and r is an earth radius; 2, the fuel weight fraction of the aircraft in the cruising flight process is calculated, Wfuel is the fuel weight, and Wininitial is the initial weight of the aircraft in the cruising stage; 3, calculating a natural logarithmic item after the effective weight of the aircraft is corrected; 4, calculating a cruise flight range of the aircraft, wherein Isp is specific impulse of the aircraft, L is lift force of the aircraft, and D is resistance of the aircraft.

Description

Technical Field

[0001] This application belongs to the technical field of hypersonic cruise vehicle range determination, specifically relating to a method for determining the range of a hypersonic cruise vehicle that takes into account its effective weight. Background Technology

[0002] Hypersonic cruise vehicles refer to aircraft with flight speeds exceeding Mach 5, and they hold significant research value and application prospects in the aerospace field. Accurately determining the cruise range of hypersonic vehicles is crucial for their design and performance analysis.

[0003] High-speed flight makes the effect of centrifugal force on the effective weight of an aircraft extremely significant. At low speeds, centrifugal force is relatively small, and its impact on the aircraft's weight is almost negligible. However, when an aircraft enters hypersonic flight, centrifugal force increases dramatically, significantly reducing the aircraft's effective weight. This weight change is not insignificant; it has a profound impact on the aircraft's flight performance, altering aerodynamic parameters such as lift and drag.

[0004] During hypersonic flight, parameters such as the lift-to-drag ratio and fuel weight fraction of the aircraft change dynamically. Unlike the relatively stable parameters in low-speed flight, the complexity of hypersonic flight means that these parameters are constantly changing. For example, as fuel is consumed, the weight of the aircraft gradually decreases, and the lift-to-drag ratio changes accordingly. This dynamic change increases the difficulty of calculating the cruise range of hypersonic aircraft.

[0005] Currently, the cruise range of aircraft is usually calculated based on the weight-range relationship model, which is well applicable to low-speed aircraft. However, it often ignores the influence of centrifugal force on the effective weight of the aircraft and adopts a simplified constant lift-to-drag ratio assumption. For hypersonic aircraft, the calculation results deviate significantly from the actual flight conditions, making it difficult to provide effective guidance for the design and performance analysis of hypersonic aircraft.

[0006] In view of the aforementioned technical deficiencies, this application is hereby filed. Summary of the Invention

[0007] The purpose of this application is to provide a method for determining the range of a hypersonic cruise vehicle that takes into account its effective weight. This novel method enables accurate calculation of the range of a hypersonic cruise vehicle, thereby accurately assessing its actual capabilities under complex flight conditions and providing effective guidance for the design and performance analysis of hypersonic vehicles.

[0008] The technical solution of this application is:

[0009] A method for determining the range of a hypersonic cruise vehicle considering its effective weight includes:

[0010] Step 1: Calculate the aircraft's effective weight correction factor: Where V is the flight speed, g is the gravitational acceleration, and r is the Earth's radius;

[0011] Step 2: Calculate the fuel weight fraction of the aircraft during cruise flight:

[0012]

[0013] Among them, W fuel W is the weight of fuel. initial This is the initial weight of the aircraft during the cruise phase;

[0014] Step 3: Calculate the natural logarithm of the aircraft's effective weight after correction.

[0015] Step 4: Calculate the aircraft's cruising range R:

[0016]

[0017] Where Isp is the specific impulse of the aircraft, L is the lift of the aircraft, and D is the drag of the aircraft.

[0018] According to at least one embodiment of this application, in the above-described method for determining the range of a hypersonic cruise vehicle considering effective weight, the gravitational acceleration g is taken as 9.81 m / s².

[0019] According to at least one embodiment of this application, in the above-described method for determining the range of a hypersonic cruise vehicle considering effective weight, the Earth's radius is taken as 6,371,000 m.

[0020] According to at least one embodiment of this application, in the above-described method for determining the range of a hypersonic cruise vehicle considering effective weight, in step three, the natural logarithm term after correction for the effective weight of the vehicle is calculated using Taylor expansion.

[0021] According to at least one embodiment of this application, in the above-described method for determining the range of a hypersonic cruise vehicle considering effective weight, in step three, the natural logarithm term after correction for the effective weight of the vehicle is calculated using Taylor expansion. Specifically:

[0022] Attached Figure Description

[0023] Figure 1This is a schematic diagram of the cruising flight trajectory of the aircraft provided in the embodiments of this application;

[0024] Figure 2 This is a schematic diagram of the method for determining the range of a hypersonic cruise vehicle considering effective weight, provided in the embodiments of this application.

[0025] Figure 3 This is a comparative diagram showing the range of a hypersonic vehicle during its cruise flight phase, considering both effective weight and non-effective weight, according to an embodiment of this application.

[0026] Figure 4 This is a schematic diagram showing the relative range error of a supersonic aircraft during cruise flight, considering and not considering effective weight, as the cruise flight Mach number changes.

[0027] To better illustrate this embodiment, some content in the accompanying drawings may be omitted, enlarged, or reduced. They are for illustrative purposes only and should not be construed as limiting the scope of this application. Detailed Implementation

[0028] To make the technical solution and advantages of this application clearer, the technical solution of this application will be described in a clearer and more complete manner below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of this application, and are only used to explain this application, not to limit this application. It should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, and other related parts can be referred to the general design.

[0029] Furthermore, unless otherwise defined, the technical or scientific terms used in this application description shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The word "comprising" as used in this application description indicates that the concept preceding the word encompasses the concepts listed following the word and their equivalents, without excluding other related concepts.

[0030] Symbol explanation:

[0031] R represents the cruising flight distance, measured in meters (m).

[0032] L is the lift of the aircraft, which is used to overcome the weight of the aircraft, and its unit is N;

[0033] D represents the lift of the aircraft, which is the force acting on the aircraft in the opposite direction of its motion during flight, and its unit is N;

[0034] Isp is specific impulse, measured in seconds (s).

[0035] T represents the thrust of the aircraft, which is the force that propels the aircraft forward, and its unit is N;

[0036] V is the flight speed, which reflects the distance the aircraft travels per unit time, and is measured in m / s.

[0037] g is the acceleration due to gravity, which is the acceleration caused by the Earth's gravitational pull on an object, and its unit is m / s². 2 ;

[0038] r is the Earth's radius, in meters (m).

[0039] W represents the weight of the aircraft, measured in N.

[0040] m is the mass of the aircraft, measured in kg.

[0041] h represents the flight altitude, in units of 1000 degrees Celsius.

[0042] The subscript "fuel" indicates the type of fuel used by the aircraft during the cruise phase.

[0043] The subscript "initial" indicates the initial state of the aircraft during the cruise flight phase;

[0044] The subscript final indicates the state of the aircraft at the end of its cruise flight phase;

[0045] The subscript "effective" indicates the effective state of the aircraft during the cruise flight phase.

[0046] The aircraft's cruise flight path, such as Figure 1 As shown, during the cruise of an aircraft, the conservation of energy is a fundamental physical law. Its total energy consists of potential energy and kinetic energy, and the rate of change of total energy equals the net thrust power. The rate of change of total energy can be expressed as:

[0047]

[0048] in, The kinetic energy of an aircraft depends on its mass and speed.

[0049] Mgh represents the gravitational potential energy of an aircraft, which is related to the aircraft's mass, gravitational acceleration, and altitude.

[0050] (TD)·V represents the net thrust power of the aircraft, that is, the work done by the resultant force of thrust T and drag D per unit time.

[0051] Comparing the rate of change of total energy with the net thrust power, when lift equals gravity, the expression for the rate of change of total energy can be simplified as follows:

[0052]

[0053] For low-speed aircraft, it is generally assumed that lift and drag are equal, and that speed and specific energy are considered constants, from which the Bregate range formula can be derived:

[0054]

[0055] For hypersonic vehicles, their flight speed is sufficient to make the centrifugal effect significant, and the effective weight of a hypersonic vehicle can be corrected to:

[0056]

[0057] With speed and lift-to-drag ratio remaining constant, the range of a hypersonic vehicle can be expressed as:

[0058]

[0059] because:

[0060] W final =W initial -W fuel …………(6)

[0061] Substituting formula (6) into formula (5), we get:

[0062]

[0063] Transforming the right side of equation (7), we have:

[0064]

[0065] Assume the fuel weight coefficient for the cruise phase of a hypersonic vehicle. The natural logarithm term after correction for effective weight is:

[0066]

[0067] According to the Taylor series expansion formula, we have:

[0068]

[0069] Based on engineering experience, taking the first four items, then:

[0070]

[0071] Substituting formula (11) into formula (9), we get:

[0072]

[0073] Right now:

[0074]

[0075] Substituting formula (13) into formula (8), we get:

[0076]

[0077]

[0078] Right now:

[0079]

[0080] Based on the above, this application provides a method for determining the range of a hypersonic cruise vehicle that considers its effective weight, such as... Figure 2 As shown.

[0081] Step 1: Calculate the aircraft's effective weight correction factor: Where V is the flight speed, g is the gravitational acceleration, and r is the Earth's radius.

[0082] The gravitational acceleration g is usually taken as 9.81 m / s^2, and the Earth's radius is usually taken as 6,371,000 m.

[0083] Step 2: Calculate the fuel weight fraction of the aircraft during cruise flight:

[0084]

[0085] Among them, W fuel W is the weight of fuel. initial This is the initial weight of the aircraft during the cruise phase.

[0086] Step 3: Calculate the natural logarithm of the aircraft's effective weight after correction.

[0087] Using Taylor expansion, calculate the natural logarithm of the aircraft's effective weight after correction:

[0088]

[0089] Step 4: Calculate the aircraft's cruising range R:

[0090]

[0091] Where Isp is the specific impulse of the aircraft, L is the lift of the aircraft, and D is the drag of the aircraft.

[0092] In a specific example, the flight conditions for a hypersonic cruise vehicle are: initial weight W initial =100000N, fuel weight W fuel =20000N, flight speed V=3000m / s, specific impulse Isp=1000s, lift-to-drag ratio L / D=5, Earth radius r=6371000m, gravitational acceleration g=9.81m / s^2.

[0093] The method for determining the range of a hypersonic cruise vehicle that takes into account effective weight, as disclosed in the above embodiments, is implemented as follows:

[0094] Step 1: Calculate the aircraft's effective weight correction factor:

[0095] Step 2: Calculate the fuel weight fraction of the aircraft during cruise flight.

[0096] Step 3: Calculate the natural logarithm of the aircraft's effective weight after correction.

[0097] Step 4: Calculate the aircraft's cruising range R:

[0098]

[0099]

[0100]

[0101] A comparison of the range of a hypersonic vehicle during its cruise phase, considering and not considering effective weight, such as... Figure 3 As shown, the relative error of the flight range changes with the Mach number of the cruise flight, such as... Figure 4 As shown, it can be seen that as the Mach number of cruise flight increases, the relative error of the range increment gradually increases, and the influence of effective weight must be taken into account during hypersonic cruise flight.

[0102] The above-described method for determining the range of a hypersonic cruise vehicle, which considers effective weight, incorporates effective weight, allowing the calculation results to more accurately reflect the actual dynamic characteristics of hypersonic flight. Considering that centrifugal force significantly affects the effective weight of the vehicle during hypersonic flight, a centrifugal force correction coefficient is introduced to accurately correct for the vehicle's actual weight. This enables calculations of key aerodynamic parameters such as lift and drag to more closely reflect actual force conditions, avoiding calculation errors caused by neglecting centrifugal force. The method of incorporating effective weight fundamentally solves the accuracy deficiencies of existing methods, providing a more reliable basis for the design and performance evaluation of hypersonic vehicles.

[0103] In hypersonic flight, the performance parameters of the aircraft are constantly changing, and existing calculation methods are difficult to adapt to this dynamic characteristic. This application combines variable lift-to-drag ratio and fuel weight fraction to accurately describe the changes in aircraft performance parameters. It enables precise calculation of the range performance of hypersonic cruise vehicles, accurately obtaining the range of hypersonic cruise vehicles under given conditions.

[0104] The technical solution of this application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. A method for determining the range of a hypersonic cruise vehicle considering effective weight, characterized in that, include: Step 1: Calculate the aircraft's effective weight correction factor: Where V is the flight speed, g is the gravitational acceleration, and r is the Earth's radius; Step 2: Calculate the fuel weight fraction of the aircraft during cruise flight: Among them, W fuel W is the weight of fuel. initial This is the initial weight of the aircraft during the cruise phase; Step 3: Calculate the natural logarithm of the aircraft's effective weight after correction. Step 4: Calculate the aircraft's cruising range R: Where Isp is the specific impulse of the aircraft, L is the lift of the aircraft, and D is the drag of the aircraft.

2. The method for determining the range of a hypersonic cruise vehicle considering effective weight according to claim 1, characterized in that, The gravitational acceleration g is taken as 9.81 m / s^2.

3. The method for determining the range of a hypersonic cruise vehicle considering effective weight according to claim 2, characterized in that, The Earth's radius is taken as 6,371,000 m.

4. The method for determining the range of a hypersonic cruise vehicle considering effective weight according to claim 3, characterized in that, In step three, the natural logarithm of the aircraft's effective weight is calculated using Taylor expansion.

5. The method for determining the range of a hypersonic cruise vehicle considering effective weight according to claim 4, characterized in that, In step three, the natural logarithm of the aircraft's effective weight is calculated using Taylor expansion. Specifically:

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