A method, device, equipment and medium for over-temperature control of a ramjet integrated ramjet engine

Abstract

This application discloses a method, apparatus, equipment, and medium for overheat control of an integrated ramjet engine, relating to the field of ramjet engine control technology. The method acquires the difference between the fuel temperature at the cooling channel outlet and the fuel temperature at the cooling channel inlet, the fuel specific heat capacity, and the fuel mass flow rate. Based on these factors, the heat absorbed by the cooling channel is calculated. The cooling channel outlet fuel temperature is estimated based on the current fuel equivalence ratio, flight Mach number, and flight altitude. When the estimated cooling channel outlet fuel temperature reaches the fuel temperature threshold corresponding to a warning level, the increment of the fuel equivalence ratio is determined based on the heat absorbed by the cooling channel and the warning level. The fuel flow rate of the ramjet engine and the flight status of the aircraft are controlled based on the increment of the fuel equivalence ratio. This method can accurately control the overheating of a ramjet engine.

Description

Technical Field

[0001] This application relates to the field of ramjet engine control technology, and in particular to a method, apparatus, equipment and medium for over-temperature control of an integrated ramjet engine. Background Technology

[0002] Hypersonic vehicles use ramjet engines as their power source. During high-speed cruise, the combustion chamber is subjected to extreme aerodynamic and thermal loads. As the flight Mach number continues to increase, the total temperature of the airflow after compression through the inlet rises sharply. In addition, the combustion of fuel in the combustion chamber releases a large amount of chemical heat. The superposition of these two heat sources makes the thermal environment of the combustion chamber walls extremely harsh. The wall temperature can easily exceed the material's tolerance limit, seriously threatening the integrity of the engine structure and flight safety.

[0003] Existing overheat control strategies typically rely on threshold-triggered control based on the absolute values ​​of wall temperature or oil temperature. This means that when the temperature reaches or exceeds a preset threshold, the fuel flow is increased to enhance cooling. However, this control method does not quantitatively assess the actual heat absorbed by the cooling channels, leading to an inaccurate judgment of the current cooling margin. The adjustment range of the fuel flow often depends on empirical settings, making it difficult to achieve effective temperature control.

[0004] However, the existing solutions mentioned above have the problem of inaccurate control when controlling the overheating of ramjet engines. Summary of the Invention

[0005] This application provides a method, apparatus, equipment, and medium for over-temperature control of an integrated ramjet engine, which can accurately control the over-temperature of the ramjet engine.

[0006] To achieve the above objectives, this application adopts the following technical solution: In a first aspect, this application provides a method for over-temperature control of an integrated ramjet engine, comprising: The difference between the fuel temperature at the outlet of the cooling passage and the fuel temperature at the inlet of the cooling passage, the fuel specific heat capacity, and the fuel mass flow rate of the ramjet engine are obtained. The amount of heat absorbed by the cooling channel is obtained based on the difference between the fuel temperature at the outlet and the inlet of the cooling channel, the specific heat capacity of the fuel, and the fuel mass flow rate. Based on the current fuel equivalence ratio of the ramjet engine, the current flight Mach number of the aircraft, and the current flight altitude of the aircraft, estimate the fuel temperature at the outlet of the cooling channel. When the estimated fuel temperature at the cooling channel outlet reaches the fuel temperature threshold corresponding to the warning level, the increment of the fuel equivalence ratio is determined based on the heat absorbed by the cooling channel and the warning level. The fuel flow rate of the ramjet engine and the flight status of the aircraft are controlled based on the increment of the fuel equivalence ratio.

[0007] Optionally, controlling the fuel flow rate of the ramjet engine and the flight state of the aircraft based on the increment of the fuel equivalence ratio includes: The fuel flow rate increment is obtained based on the increment of the fuel equivalence ratio. Increase the fuel flow rate of the ramjet engine according to the fuel flow rate increment; The thrust increment of the ramjet engine is obtained based on the increase in the fuel equivalence ratio and the current thrust; the flight angle of attack and flight Mach number of the aircraft are adjusted based on the thrust increment.

[0008] Optionally, the warning levels include Level 1, Level 2, and Level 3 warnings, and the warning levels are determined in the following ways: The warning level is determined based on the measured wall temperature of the combustion chamber wall of the ramjet engine and the fuel temperature at the outlet of the cooling channel of the ramjet engine. A Level 1 warning is triggered when the fuel temperature at the cooling passage outlet reaches the first oil temperature threshold, or when the measured wall temperature reaches the first wall temperature threshold. When the fuel temperature at the cooling passage outlet reaches the second oil temperature threshold, or when the measured wall temperature reaches the second wall temperature threshold, a level 2 warning is triggered. A level 3 warning is triggered when the fuel temperature at the cooling channel outlet reaches the third oil temperature threshold, or when the measured wall temperature reaches the third wall temperature threshold. Among them, the first oil temperature threshold, the second oil temperature threshold and the third oil temperature threshold increase in sequence, the first wall temperature threshold, the second wall temperature threshold and the third wall temperature threshold increase in sequence, and the severity of overheating of the first-level warning, the second-level warning and the third-level warning increases in sequence.

[0009] Optionally, determining the increment of the fuel equivalence ratio based on the heat absorbed by the cooling channel and the warning level includes: Based on the aforementioned warning level, determine the target increment of cooling capacity; The target heat absorption is obtained based on the heat absorbed by the cooling channel and the target increment of the cooling capacity; The required fuel mass flow rate is obtained based on the difference between the fuel temperature at the outlet of the cooling passage and the fuel temperature at the inlet of the cooling passage, the specific heat capacity of the fuel, and the target heat absorption. The increment of the fuel equivalence ratio is obtained based on the current fuel mass flow rate and the required fuel mass flow rate.

[0010] Optionally, adjusting the aircraft's angle of attack and Mach number based on the thrust increment includes: The decrease in angle of attack is obtained based on the thrust increment. The angle of attack of the aircraft is reduced according to the reduction in angle of attack. The change in the flight Mach number of the aircraft is obtained based on the reduced angle of attack. Based on the change in flight Mach number, determine whether the flight Mach number of the aircraft is within the allowable window; When the flight Mach number exceeds the upper limit of the allowable window, the flight Mach number of the aircraft is reduced.

[0011] Optionally, the current thrust is obtained in the following way: The current thrust of the ramjet engine is obtained based on the dynamic pressure of the aircraft under its current flight condition, the reference area of ​​the ramjet engine, and the thrust coefficient of the ramjet engine.

[0012] Optionally, determining the target increment of cooling capacity based on the warning level includes: When a Level 1 warning is triggered, the first target increment of cooling capacity is obtained; When a level 2 warning is triggered, the second target increment of cooling capacity is obtained; When a Level 3 warning is triggered, the third target increment of cooling capacity is obtained; The first target increment, the second target increment, and the third target increment increase sequentially.

[0013] Secondly, this application provides a device for over-temperature control of an integrated ramjet engine, comprising: The acquisition module is used to acquire the difference between the fuel temperature at the outlet of the cooling passage and the fuel temperature at the inlet of the cooling passage of the ramjet engine, the fuel specific heat capacity, and the fuel mass flow rate. The processing module is used to obtain the heat absorbed by the cooling channel based on the difference between the fuel temperature at the cooling channel outlet and the fuel temperature at the cooling channel inlet, the fuel specific heat capacity, and the fuel mass flow rate; to estimate the fuel temperature at the cooling channel outlet based on the current fuel equivalence ratio of the ramjet engine, the current flight Mach number of the aircraft, and the current flight altitude of the aircraft; and to determine the increment of the fuel equivalence ratio based on the heat absorbed by the cooling channel and the warning level when the estimated fuel temperature at the cooling channel outlet reaches the oil temperature threshold corresponding to the warning level. The control module is used to control the fuel flow rate of the ramjet engine and the flight status of the aircraft based on the increment of the fuel equivalence ratio.

[0014] Thirdly, this application provides a computing device, including a memory and a processor; The memory stores one or more computer programs, the one or more computer programs including instructions; when the instructions are executed by the processor, the computing device performs the method as described in any one of the first aspects.

[0015] Fourthly, this application provides a computer-readable storage medium for storing a computer program for performing the method as described in any one of the first aspects.

[0016] As can be seen from the above technical solution, this application has at least the following beneficial effects: This application calculates the heat absorbed by the cooling channel by using the difference between the fuel temperature at the cooling channel outlet and the fuel temperature at the cooling channel inlet, the fuel specific heat capacity, and the fuel mass flow rate. Then, it determines the increment of the fuel equivalence ratio by combining the heat absorbed by the cooling channel with the warning level. This adjusts the fuel flow of the ramjet engine and simultaneously controls the flight status of the aircraft. It can quantify the heat dissipation by relying on the heat absorbed by the cooling channel, replacing the method of adjusting the fuel flow based solely on temperature thresholds and experience. This reduces the deviation in the fuel flow adjustment range. At the same time, it uses the aircraft's flight status adjustment to offset the thrust change caused by the increase in fuel flow, reducing the situation where the aircraft's flight parameters exceed the engine's operating range. Matching different warning levels with corresponding fuel equivalence ratio increments can also adapt to different levels of high-temperature combustion chamber conditions, reducing the situation where the temperature continues to exceed the limit.

[0017] Furthermore, this application uses measured wall temperature and cooling channel outlet fuel temperature to classify three progressively increasing warning levels. It matches progressively increasing cooling capacity targets to different warning levels, calculates the target heat absorption based on the heat absorbed by the cooling channel, and then back-calculates the required fuel mass flow rate. It compares the current fuel mass flow rate to obtain the fuel equivalence ratio increment, converts the fuel equivalence ratio increment to the fuel flow rate increment, and then calculates the thrust increment based on the current thrust obtained from dynamic pressure, reference area, and thrust coefficient. Based on the thrust increment, it calculates the angle of attack reduction and lowers the flight angle of attack. Finally, it calculates the Mach number change based on the adjusted angle of attack, determines whether the Mach number is within the allowable window, and lowers the Mach number if it exceeds the upper limit. The entire process relies on the heat absorbed by the cooling channel for quantitative calculation, replacing the method of directly adjusting fuel flow rate based solely on temperature thresholds. This reduces the deviation in fuel flow rate adjustment and offsets the thrust increment caused by increased fuel flow rate by simultaneously adjusting the flight angle of attack and flight Mach number, reducing situations where aircraft flight parameters exceed the engine operating range. The graded matching cooling capacity target increment can also correspond to different overheating severity conditions, reducing situations where combustion chamber temperature continuously exceeds limits.

[0018] It should be understood that the descriptions of technical features, technical solutions, beneficial effects, or similar language in this application do not imply that all features and advantages can be achieved in any single embodiment. Rather, it is understood that the description of a feature or beneficial effect means that a specific technical feature, technical solution, or beneficial effect is included in at least one embodiment. Therefore, the descriptions of technical features, technical solutions, or beneficial effects in this specification do not necessarily refer to the same embodiment. Furthermore, the technical features, technical solutions, and beneficial effects described in this embodiment can be combined in any suitable manner. Those skilled in the art will understand that embodiments can be implemented without one or more specific technical features, technical solutions, or beneficial effects of a particular embodiment. In other embodiments, additional technical features and beneficial effects may be identified in specific embodiments that do not embody all embodiments. Attached Figure Description

[0019] Figure 1 A schematic diagram illustrating an application scenario provided in an embodiment of this application; Figure 2 A flowchart illustrating a method for over-temperature control of an integrated ramjet engine provided in this application embodiment; Figure 3 A schematic diagram of an integrated ramjet engine over-temperature control device provided in an embodiment of this application; Figure 4 This is a schematic diagram of a computing device provided in an embodiment of this application. Detailed Implementation

[0020] The terms "first," "second," and "third," etc., used in this application specification and accompanying drawings are used to distinguish different objects, not to limit a specific order.

[0021] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0022] Current ramjet engine overheat control relies solely on adjusting fuel flow based on wall temperature and oil temperature thresholds. It fails to calculate the heat absorbed by the cooling channels, making it impossible to quantify the actual heat dissipation capacity of the cooling channels. The fuel flow adjustment range is set based on human experience, resulting in poor numerical matching and a tendency for excessive or insufficient fuel supply. Simply increasing fuel flow alters engine thrust without simultaneously adjusting the aircraft's angle of attack and Mach number. Thrust changes can cause the aircraft's Mach number to deviate from the permissible window. Furthermore, the lack of graded warning levels prevents the matching of fuel adjustment amounts to the actual severity of combustion chamber overheating. These multiple factors combined lead to unstable control performance during ramjet engine overheating, causing combustion chamber wall temperatures to consistently exceed material tolerance limits, impacting engine structural integrity and flight safety.

[0023] In view of this, embodiments of this application provide a method for over-temperature control of an integrated ramjet engine, which can be executed by a processing device.

[0024] Existing ramjet engine overheat control relies solely on adjusting fuel flow rate to meet temperature thresholds, lacking quantitative calculations of the heat absorbed by the cooling channels. Fuel flow rate adjustments are based on experience, resulting in inconsistent performance. Furthermore, simply increasing fuel flow alters engine thrust without simultaneously adjusting the aircraft's flight status. This application first calculates the heat absorbed by the cooling channels using the fuel temperature difference between the cooling channel inlet and outlet, fuel specific heat capacity, and fuel mass flow rate, quantifying the existing heat dissipation level. Then, it determines the increment of the fuel equivalence ratio based on the warning level, thereby adjusting the engine fuel flow rate while simultaneously controlling the aircraft's flight status. This offsets the thrust changes caused by increased fuel flow, adapts to different levels of high-temperature combustion chamber conditions, and mitigates situations where wall temperatures exceed material tolerance limits.

[0025] To make the technical solution of this application clearer and easier to understand, the application scenarios of the technical solution of this application are described below with reference to the accompanying drawings. Figure 1 As shown in the figure, this figure is a schematic diagram of an application scenario provided by an embodiment of this application.

[0026] In this application scenario, a data transmission link is established between the ramjet engine 101 and the processing equipment (e.g., the onboard control computer 102). The processing equipment first obtains from the ramjet engine 101 the difference between the fuel temperature at the cooling channel outlet and the fuel temperature at the cooling channel inlet, the fuel specific heat capacity, and the fuel mass flow rate. Based on the difference between the fuel temperature at the cooling channel outlet and the fuel temperature at the cooling channel inlet, the fuel specific heat capacity, and the fuel mass flow rate, the processing equipment calculates the heat absorbed by the cooling channel. When an over-temperature warning is triggered, the processing equipment calculates and determines the increment of the fuel equivalence ratio based on the heat absorbed by the cooling channel and the warning level. Based on the increment of the fuel equivalence ratio, the processing equipment issues a fuel flow rate adjustment command to the ramjet engine 101 and a flight status adjustment command to the aircraft actuators, simultaneously completing the coordinated control of the ramjet engine fuel flow rate and the aircraft flight status.

[0027] To make the technical solution of this application clearer and easier to understand, the following application scenarios will be used to describe a method for over-temperature control of an integrated ramjet engine provided by an embodiment of this application. For example... Figure 2 As shown, this figure is a flowchart of a method for overheat control of an integrated ramjet engine according to an embodiment of this application. In this embodiment, the method includes: S201, The processing equipment obtains the difference between the fuel temperature at the outlet of the cooling channel and the fuel temperature at the inlet of the cooling channel of the ramjet engine, the fuel specific heat capacity, and the fuel mass flow rate.

[0028] The inlet fuel temperature of the cooling passage is the temperature value collected when fuel flows into the cooling passage of the ramjet engine; the outlet fuel temperature of the cooling passage is the temperature value collected when fuel flows out of the cooling passage of the ramjet engine; the difference between the outlet fuel temperature and the inlet fuel temperature is the temperature difference generated before and after the fuel flows through the cooling passage; the specific heat capacity of fuel is the amount of heat absorbed by a unit mass of fuel to increase its temperature by a unit, which is a fixed physical property parameter; the fuel mass flow rate is the mass of fuel flowing into the cooling passage per unit time.

[0029] The processing equipment reads the inlet and outlet fuel temperatures of the cooling passage from the ramjet engine sensors, calculates the difference between the two sets of temperature values, and simultaneously retrieves the internally stored fuel specific heat capacity and collects real-time fuel mass flow rate. This process summarizes and obtains three types of data, ultimately yielding three complete sets of calculated parameters: the inlet and outlet fuel temperature difference of the cooling passage, the fuel specific heat capacity, and the fuel mass flow rate. This combination of parameters can be used to calculate the amount of heat carried away by the fuel as it flows through the cooling passage, reflecting the total amount of heat exchanged by the fuel within the cooling passage.

[0030] S202. The processing equipment obtains the heat absorbed by the cooling channel based on the difference between the fuel temperature at the outlet of the cooling channel and the fuel temperature at the inlet of the cooling channel, the specific heat capacity of the fuel, and the mass flow rate of the fuel.

[0031] The heat absorbed by the cooling passage is the total heat transferred from the combustion chamber wall to the fuel in the cooling passage per unit time.

[0032] The processing equipment retrieves three sets of data previously acquired: the temperature difference between the inlet and outlet of the cooling channel, the specific heat capacity of the fuel, and the mass flow rate of the fuel. It then simultaneously substitutes these three sets of data into the heat conversion formula to complete the mathematical calculation. This operation ultimately calculates the heat absorbed by the cooling channel, which reflects the amount of heat carried away from the combustion chamber wall by the fuel under the current operating conditions.

[0033] The formula for calculating the heat absorbed by the cooling channel is:

[0034] in, This indicates the amount of heat absorbed by the cooling channels. Indicates fuel mass flow rate, Indicates the specific heat capacity of fuel. Indicates the fuel temperature at the cooling channel outlet. This indicates the fuel temperature at the inlet of the cooling passage. This indicates the difference between the fuel temperature at the cooling passage outlet and the fuel temperature at the cooling passage inlet.

[0035] S203. The processing equipment estimates the fuel temperature at the cooling channel outlet based on the current fuel equivalence ratio of the ramjet engine, the current flight Mach number of the aircraft, and the current flight altitude of the aircraft.

[0036] Specifically, the processing equipment reads three sets of operating parameters in real time: the current fuel equivalence ratio of the ramjet engine, the current Mach number of the aircraft, and the flight altitude. Using these three sets of parameters as an index, the equipment queries a pre-calibrated data table stored in the ground test database. This data table records the steady-state values ​​of the fuel temperature at the cooling channel outlet under different combinations of fuel equivalence ratios, Mach numbers, and flight altitudes. The equipment then searches the data table for the data point closest to the current values ​​of the three sets of operating parameters and reads the corresponding fuel temperature at the cooling channel outlet as the estimated temperature for 5 to 10 seconds later.

[0037] S204. When the estimated fuel temperature at the cooling channel outlet reaches the fuel temperature threshold corresponding to the warning level, the increment of the fuel equivalence ratio is determined based on the heat absorbed by the cooling channel and the warning level.

[0038] The warning level is divided into levels based on the measured wall temperature of the combustion chamber wall and the fuel temperature at the cooling channel outlet. The higher the level, the more severe the overheating of the combustion chamber. The increase in fuel equivalence ratio is the difference between the current fuel mass flow rate and the fuel mass flow rate required for temperature control, which is used to reflect the extent to which the fuel supply needs to be increased.

[0039] The warning levels include Level 1, Level 2, and Level 3, and the warning levels are determined in the following ways: The processing equipment determines the warning level based on the measured wall temperature of the ramjet engine combustion chamber wall and the fuel temperature at the cooling channel outlet of the ramjet engine. A Level 1 warning is triggered when the fuel temperature at the cooling channel outlet reaches the first oil temperature threshold, or when the measured wall temperature reaches the first wall temperature threshold. A Level 2 warning is triggered when the fuel temperature at the cooling channel outlet reaches the second oil temperature threshold, or when the measured wall temperature reaches the second wall temperature threshold. A Level 3 warning is triggered when the fuel temperature at the cooling channel outlet reaches the third oil temperature threshold, or when the measured wall temperature reaches the third wall temperature threshold. The first, second, and third oil temperature thresholds increase sequentially, as do the first, second, and third wall temperature thresholds, and the severity of overheating in the Level 1, Level 2, and Level 3 warnings increases sequentially.

[0040] The measured wall temperature is the real-time temperature value of the combustion chamber wall of the ramjet engine collected by the sensor; the first oil temperature threshold, the second oil temperature threshold, and the third oil temperature threshold are three sets of successively increasing temperature boundary values ​​used to classify the overheating levels corresponding to the fuel temperature, for example, the corresponding values ​​are 720K, 770K, and 800K respectively; the first wall temperature threshold, the second wall temperature threshold, and the third wall temperature threshold are three sets of successively increasing temperature boundary values ​​used to classify the overheating levels corresponding to the combustion chamber wall temperature, for example, the corresponding values ​​are 1000K, 1080K, and 1150K respectively; the first-level warning, the second-level warning, and the third-level warning are three types of indicators representing the overheating situation of the combustion chamber, and the severity of the overheating corresponding to the three types of warnings increases progressively.

[0041] The processing equipment continuously acquires two sets of real-time data: the measured wall temperature of the combustion chamber wall and the fuel temperature at the cooling channel outlet. It compares the fuel temperature at the cooling channel outlet with three sets of oil temperature thresholds: 720K, 770K, and 800K. At the same time, it compares the measured wall temperature with three sets of wall temperature thresholds: 1000K, 1080K, and 1150K. As long as either the oil temperature or the wall temperature reaches the corresponding threshold, a corresponding warning indicator is matched. This operation ultimately outputs one of the following warning levels: Level 1, Level 2, or Level 3. The output warning level reflects the current heat load of the combustion chamber and the degree of overheating risk.

[0042]

[0043] in, Indicates the warning level; This represents a Level 1 warning. This represents a Level II warning. This represents a Level 3 warning; Indicates the fuel temperature at the outlet of the cooling channel; This represents the measured wall temperature of the combustion chamber wall; ∨ represents a logical OR relation. Indicates the first oil temperature threshold. Indicates the first wall temperature threshold. Indicates the second oil temperature threshold. This indicates the second wall temperature threshold. Indicates the third oil temperature threshold. This indicates the third wall temperature threshold.

[0044] The processing equipment compares the estimated fuel temperature at the cooling channel outlet with the oil temperature threshold corresponding to the warning level. It should be noted that the oil temperature threshold refers to one of three thresholds: the first, second, and third. The specific threshold chosen depends on the currently triggered warning level: if no warning level is triggered, the first threshold is used; if a level one warning is triggered, the second threshold is used; and if a level two warning is triggered, the third threshold is used. In other words, the target threshold is the next lower threshold after the current warning level. If the estimated temperature reaches this threshold, it is determined that the next lower warning level needs to be triggered in advance, and cooling operations should be performed.

[0045] For example, if no warning has been triggered, the processing device will compare the estimated temperature with 720K; if a Level 1 warning has been triggered, the processing device will compare the estimated temperature with 770K; if a Level 2 warning has been triggered, the processing device will compare the estimated temperature with 800K.

[0046] When the estimated temperature reaches or exceeds the threshold, the processing equipment determines that a cooling operation needs to be performed in advance and initiates the calculation process for the fuel equivalence ratio increment.

[0047] In some embodiments, the processing device determines a target increment of cooling capacity based on the warning level; The target increment of cooling capacity is the additional heat dissipation capacity that the current cooling system needs to increase. It is divided into three groups: the first target increment, the second target increment, and the third target increment, with the values ​​increasing sequentially.

[0048] Specifically, when a Level 1 warning is triggered, the first target increment of cooling capacity is obtained; when a Level 2 warning is triggered, the second target increment of cooling capacity is obtained; and when a Level 3 warning is triggered, the third target increment of cooling capacity is obtained. The first, second, and third target increments increase sequentially.

[0049] The processing device reads the current completed warning level, matches the corresponding heat dissipation supplement value with the preset correspondence, and retrieves the first target increment when a level 1 warning is identified, the second target increment when a level 2 warning is identified, and the third target increment when a level 3 warning is identified. The entire operation outputs the target increment of cooling capacity corresponding to the level. This value can reflect the amount of heat dissipation that the cooling system needs to supplement under the current operating conditions.

[0050]

[0051] in, This represents the target increment of cooling capacity. Indicates the increment of the first target. This indicates the increment of the second objective. This represents the increment of the third objective. .

[0052] Then, the processing equipment obtains the target heat absorption based on the heat absorbed by the cooling channel and the target increment of cooling capacity; it obtains the required fuel mass flow rate based on the difference between the fuel temperature at the cooling channel outlet and the fuel temperature at the cooling channel inlet, the fuel specific heat capacity, and the target heat absorption; and it obtains the increment of the fuel equivalence ratio based on the current fuel mass flow rate and the required fuel mass flow rate.

[0053] The target heat absorption is the total heat dissipation required by the cooling channel, which is obtained by adding the existing heat absorption to the target increase in cooling capacity.

[0054] The processing equipment retrieves the calculated heat absorbed by the cooling channel and the target increase in cooling capacity, adds the two sets of values ​​to calculate the target heat absorption, then retrieves the fuel temperature difference at the inlet and outlet of the cooling channel and the fuel specific heat capacity, and converts them into the required fuel mass flow rate based on the target heat absorption. Finally, the required fuel mass flow rate is subtracted from the current fuel mass flow rate to calculate the increase in the fuel equivalence ratio. This process calculates the target heat absorption, the required fuel mass flow rate, and the increase in the fuel equivalence ratio in sequence. The increase in the fuel equivalence ratio reflects how much the fuel supply needs to be increased under the current operating conditions.

[0055] Target heat absorption calculation formula:

[0056] in, Indicates the target heat absorption. This indicates the amount of heat absorbed by the cooling channels. This indicates the target increment of cooling capacity.

[0057] The formula for calculating the required fuel mass flow rate is:

[0058] in, This indicates the required fuel mass flow rate. This indicates the target heat absorption.

[0059] The formula for calculating the fuel equivalence ratio increment is:

[0060] in, Indicates the increase in fuel equivalence ratio. A fixed conversion factor representing the ratio of fuel mass flow rate to equivalence. This indicates the current fuel mass flow rate.

[0061] S205. The processing equipment controls the fuel flow of the ramjet engine and the flight status of the aircraft based on the increase in the fuel equivalence ratio.

[0062] The fuel flow rate of a ramjet engine is the mass of fuel delivered to the cooling channel and combustion chamber of the ramjet engine per unit time; the flight status of an aircraft refers to the adjustable flight parameters during the operation of the aircraft, including two types of parameters: angle of attack and Mach number.

[0063] The processing equipment reads the increment of the calculated fuel equivalence ratio, converts it into the fuel flow increment, and sends a command to the ramjet engine to increase the fuel flow. At the same time, it calculates the thrust change value based on the fuel equivalence ratio increment, and then generates an aircraft flight parameter adjustment command based on the thrust change value to change the flight state. This operation outputs a ramjet engine fuel flow adjustment command and an aircraft flight state adjustment command. The two sets of commands can correspond to and match the fuel supply and aircraft operating parameters that need to be changed under the current operating conditions.

[0064] In some embodiments, the processing device obtains the fuel flow rate increment based on the increment of the fuel equivalence ratio; and increases the fuel flow rate of the ramjet engine based on the fuel flow rate increment.

[0065] The processing equipment retrieves the increment of the calculated fuel equivalence ratio, substitutes it into the conversion relationship between the equivalence ratio and fuel flow rate to complete the numerical conversion, and obtains the fuel flow rate increment. Then, based on the fuel flow rate increment, it generates an adjustment signal and sends it to the fuel supply component of the ramjet engine to increase the fuel flow rate of the ramjet engine. This operation yields the fuel flow rate increment, which reflects the additional fuel mass that the fuel supply system needs to output per unit time.

[0066]

[0067] in, This indicates the increase in fuel flow.

[0068] In some embodiments, the processing device obtains the thrust increment of the ramjet engine based on the increment of the fuel equivalence ratio and the current thrust; and adjusts the flight angle of attack and flight Mach number of the aircraft based on the thrust increment.

[0069] Current thrust is the thrust output of the ramjet engine under real-time flight conditions; thrust increment is the change in engine output thrust after fuel supply adjustment; angle of attack is the angle between the aircraft fuselage axis and the oncoming airflow; flight Mach number is the ratio of the aircraft's flight speed to the local speed of sound, and is a flight state parameter of the aircraft.

[0070] The processing equipment first retrieves three sets of parameters corresponding to the real-time flight of the aircraft: dynamic pressure, ramjet engine reference area, and thrust coefficient. It then substitutes these parameters into the thrust conversion formula to calculate the current thrust of the ramjet engine. Next, it reads the increment of the fuel equivalence ratio that has already been solved and combines it with the current thrust value to calculate the thrust increment. Finally, it generates an adjustment command based on the thrust increment to change the aircraft's angle of attack and Mach number. This process calculates the current thrust and thrust increment of the ramjet engine in sequence. The thrust increment can reflect the change in engine thrust after the fuel supply is increased.

[0071] The current thrust is obtained in the following way: The processing equipment obtains the current thrust of the ramjet engine based on the dynamic pressure of the aircraft under its current flight conditions, the reference area of ​​the ramjet engine, and the thrust coefficient of the ramjet engine.

[0072] Dynamic pressure is the pressure value of airflow acting on the engine intake section, calculated from flight speed and air density; reference area is the reference flow cross-sectional area of ​​the ramjet engine intake, which is a fixed structural parameter; thrust coefficient is a dimensionless fixed parameter characterizing the engine's thrust output capability.

[0073] The expression for calculating the current thrust of a ramjet engine is:

[0074] in, This indicates the current thrust of the ramjet engine. Indicates the thrust coefficient. This indicates the dynamic pressure of the aircraft during its current flight state. This represents the reference area of ​​the ramjet engine.

[0075] It should be noted that the thrust coefficient of a ramjet engine is not a fixed constant; its value increases with the flight Mach number, angle of attack, and fuel equivalence ratio. Therefore, when the cooling system enhances cooling by increasing the fuel equivalence ratio, the thrust coefficient itself will also increase, further amplifying the thrust increment. Conversely, when the cooling system reduces the angle of attack to offset the thrust increment, the thrust coefficient will decrease as the angle of attack decreases, thus helping to mitigate the thrust increment.

[0076]

[0077] in, Indicates the thrust increment. This represents the conversion function for calculating the thrust increment based on the equivalence ratio increment and the current thrust.

[0078] In some embodiments, the processing device obtains the angle-of-attack reduction based on the thrust increment; reduces the aircraft's angle of attack based on the angle-of-attack reduction; obtains the change in the aircraft's Mach number based on the reduced angle of attack; determines whether the aircraft's Mach number is within the allowable window based on the change in the Mach number; and reduces the aircraft's Mach number when the Mach number exceeds the upper limit of the allowable window.

[0079] The angle of attack reduction is the downward adjustment of the flight angle of attack required to offset the thrust increase; the reduced flight angle of attack is the new angle obtained by subtracting the angle of attack reduction from the original flight angle of attack; the flight Mach number change is the change in the flight Mach number of the aircraft after the angle of attack adjustment; the upper limit of the flight Mach number is the maximum Mach number that the aircraft can operate at within the allowed window.

[0080] The processing equipment reads the thrust increment value, compares it with the internally stored matching data table of thrust increment and angle of attack reduction, and reads the corresponding angle of attack reduction. It then subtracts the angle of attack reduction from the original angle of attack to obtain the reduced angle of attack. Next, it compares it with the internally stored data table of angle of attack and Mach number change to read the corresponding Mach number change. It adds the original Mach number and the Mach number change, and compares the sum with the upper limit of the Mach number allowable window. If the sum exceeds the upper limit, a control command is issued to reduce the aircraft's Mach number. This process sequentially outputs the angle of attack reduction, the reduced angle of attack, and the Mach number change. The Mach number change reflects the magnitude of the change in the aircraft's speed caused by the angle of attack modification.

[0081] In some embodiments, while reducing the angle of attack or the Mach number, the processing device also obtains an altitude adjustment amount based on the amount of the reduction in angle of attack or the change in Mach number; and adjusts the flight altitude of the aircraft based on the altitude adjustment amount.

[0082] Specifically, when a Level 2 warning is triggered, the processing equipment increases the fuel equivalence ratio by +0.05, simultaneously decreases the angle of attack by 0.5° to 1°, and adjusts the flight altitude by ±0.3km to maintain lift-weight balance at the new angle of attack. When a Level 3 warning is triggered, the processing equipment increases the fuel equivalence ratio by +0.10, simultaneously decreases the angle of attack by 2° to 4°, and allows the Mach number to drift within the permissible window (e.g., from Ma4.0 to Ma3.8), while simultaneously adjusting the flight altitude by ±0.5km to maintain lift-weight balance at the new angle of attack and Mach number.

[0083] The method also includes: The processing equipment acquires the fuel temperature at the cooling channel outlet once at preset intervals. When the fuel temperature at the cooling channel outlet drops N times consecutively and falls below the second fuel temperature threshold, and the current flight Mach number is within the allowable window, the fuel equivalence ratio, flight angle of attack, and flight Mach number will be adjusted back to their original values.

[0084] The processing equipment repeatedly collects the fuel temperature at the cooling channel outlet at fixed preset time intervals. After each collection, the temperature value is recorded and compared with the previous collection result. The number of collections in which the temperature drops consecutively is counted. When the fuel temperature collected for N consecutive times continues to drop and all fuel temperature values ​​are below 770K, and the current flight Mach number of the aircraft is read to be within the allowable window range, the stored original parameters before the modification are retrieved, and control commands are issued to restore the fuel equivalence ratio, flight angle of attack, and flight Mach number to their original values ​​before the modification. This operation continuously outputs the fuel temperature at the cooling channel outlet and the number of consecutive temperature drops collected in each round. The combination of the number of consecutive temperature drops and the fuel temperature value can indicate that the combustion chamber heat load has dropped back to the safe range.

[0085] This scheme periodically collects the fuel temperature at the cooling channel outlet. Once the fuel temperature continues to drop and the flight Mach number is within a safe range, it automatically restores the fuel equivalence ratio, flight angle of attack, and flight Mach number to their original values ​​before adjustment. It can remove the previous heat reduction intervention measures after the combustion chamber heat load decreases, restore the aircraft's original fuel supply ratio and flight status, avoid the thrust loss caused by long-term low fuel supply and reduced angle of attack, and allow the aircraft to return to its original flight conditions after the heat load returns to a safe level, thus balancing high-temperature protection of the combustion chamber and normal flight performance of the aircraft.

[0086] When the fuel temperature at the cooling channel outlet continuously exceeds 820K, the processing equipment performs a protective shutdown, stopping the fuel supply to the ramjet engine.

[0087] In each round of evaluation, the processing equipment monitors the real-time value of the fuel temperature at the cooling channel outlet. When the temperature continues to be higher than 820K, it is determined that all active cooling and flight status coordination adjustment measures have failed and the combustion chamber heat load is approaching the material tolerance limit. At this time, a shutdown command is immediately generated and sent to the fuel supply system of the ramjet engine to cut off the fuel supply, so that the ramjet engine stops working and avoids structural damage to the combustion chamber wall due to continuous overheating.

[0088] Based on the above description, this application has the following beneficial effects: This application calculates the heat absorbed by the cooling channel by using the temperature difference between the inlet and outlet of the cooling channel, the specific heat capacity of the fuel, and the mass flow rate of the fuel. This allows for the determination of the actual heat exchange value of the cooling channel. By combining the warning level with the increase in the fuel equivalence ratio, the fuel flow rate can be adjusted. This changes the operating mode of adjusting the fuel flow rate based solely on temperature thresholds and experience. At the same time, it simultaneously controls the flight status of the aircraft, which can offset the thrust changes caused by the increase in fuel flow rate and reduce the occurrence of aircraft operating parameters deviating from the normal range. Different warning levels correspond to different fuel equivalence ratio increases, which can adapt to different high-temperature conditions in the combustion chamber and reduce the frequency of wall temperatures continuously exceeding the material's tolerance limit.

[0089] The above text combined Figures 1 to 2 The method for over-temperature control of an integrated ramjet engine provided in this application embodiment has been described in detail. The apparatus and equipment provided in this application embodiment will be described below with reference to the accompanying drawings.

[0090] like Figure 3 As shown in the figure, this is a schematic diagram of an integrated ramjet engine overheat control device provided in an embodiment of this application. The device includes: The acquisition module 301 is used to acquire the difference between the fuel temperature at the outlet of the cooling channel and the fuel temperature at the inlet of the cooling channel of the ramjet engine, the fuel specific heat capacity, and the fuel mass flow rate. The processing module 302 is used to obtain the heat absorbed by the cooling channel based on the difference between the fuel temperature at the cooling channel outlet and the fuel temperature at the cooling channel inlet, the fuel specific heat capacity, and the fuel mass flow rate; to estimate the fuel temperature at the cooling channel outlet based on the current fuel equivalence ratio of the ramjet engine, the current flight Mach number of the aircraft, and the current flight altitude of the aircraft; and to determine the increment of the fuel equivalence ratio based on the heat absorbed by the cooling channel and the warning level when the estimated fuel temperature at the cooling channel outlet reaches the oil temperature threshold corresponding to the warning level. The control module 303 is used to control the fuel flow rate of the ramjet engine and the flight status of the aircraft based on the increment of the fuel equivalence ratio.

[0091] Optionally, the control module 303 is specifically used to obtain the fuel flow increment based on the increment of the fuel equivalence ratio; Increase the fuel flow rate of the ramjet engine according to the fuel flow rate increment; The thrust increment of the ramjet engine is obtained based on the increase in the fuel equivalence ratio and the current thrust; the flight angle of attack and flight Mach number of the aircraft are adjusted based on the thrust increment.

[0092] Optionally, the processing module 302 is specifically used to determine the warning level based on the measured wall temperature of the combustion chamber wall of the ramjet engine and the fuel temperature at the cooling channel outlet of the ramjet engine. A Level 1 warning is triggered when the fuel temperature at the cooling passage outlet reaches the first oil temperature threshold, or when the measured wall temperature reaches the first wall temperature threshold. When the fuel temperature at the cooling passage outlet reaches the second oil temperature threshold, or when the measured wall temperature reaches the second wall temperature threshold, a level 2 warning is triggered. A level 3 warning is triggered when the fuel temperature at the cooling channel outlet reaches the third oil temperature threshold, or when the measured wall temperature reaches the third wall temperature threshold. Among them, the first oil temperature threshold, the second oil temperature threshold and the third oil temperature threshold increase in sequence, the first wall temperature threshold, the second wall temperature threshold and the third wall temperature threshold increase in sequence, and the severity of overheating of the first-level warning, the second-level warning and the third-level warning increases in sequence.

[0093] Optionally, the processing module 302 is specifically used to determine the target increment of cooling capacity based on the warning level; The target heat absorption is obtained based on the heat absorbed by the cooling channel and the target increment of the cooling capacity; The required fuel mass flow rate is obtained based on the difference between the fuel temperature at the outlet of the cooling passage and the fuel temperature at the inlet of the cooling passage, the specific heat capacity of the fuel, and the target heat absorption. The increment of the fuel equivalence ratio is obtained based on the current fuel mass flow rate and the required fuel mass flow rate.

[0094] Optionally, the control module 303 is specifically used to obtain the angle of attack reduction based on the thrust increment; The angle of attack of the aircraft is reduced according to the reduction in angle of attack. The change in the flight Mach number of the aircraft is obtained based on the reduced angle of attack. Based on the change in flight Mach number, determine whether the flight Mach number of the aircraft is within the allowable window; When the flight Mach number exceeds the upper limit of the allowable window, the flight Mach number of the aircraft is reduced.

[0095] Optionally, the processing module 302 is specifically used to obtain the current thrust of the ramjet engine based on the dynamic pressure of the aircraft under the current flight state, the reference area of ​​the ramjet engine, and the thrust coefficient of the ramjet engine.

[0096] Optionally, the processing module 302 is specifically used to obtain the first target increment of cooling capacity when a first-level warning is triggered; When a level 2 warning is triggered, the second target increment of cooling capacity is obtained; When a Level 3 warning is triggered, the third target increment of cooling capacity is obtained; The first target increment, the second target increment, and the third target increment increase sequentially.

[0097] The device for overheat control of an integrated ramjet engine according to the embodiments of this application can correspond to the execution of the method described in the embodiments of this application, and the other operations and / or functions of each module / unit of the device for overheat control of an integrated ramjet engine are respectively for implementing Figure 2 For the sake of brevity, the corresponding processes of each method in the illustrated embodiments will not be described in detail here.

[0098] This application also provides a computing device. For example... Figure 4 As shown in the figure, this is a schematic diagram of a computing device provided in an embodiment of this application. The computing device 400 includes a bus 401, a processor 402, a communication interface 403, and a memory 404. The processor 402, the memory 404, and the communication interface 403 communicate with each other via the bus 401.

[0099] Bus 401 can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of representation, Figure 4 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0100] Processor 402 can be any one or more of the following processors: central processing unit (CPU), graphics processing unit (GPU), microprocessor (MP), or digital signal processor (DSP).

[0101] Communication interface 403 is used for communication with external devices.

[0102] Memory 404 may include volatile memory, such as random access memory (RAM). Memory 404 may also include non-volatile memory, such as read-only memory (ROM), flash memory, hard disk drive (HDD), or solid state drive (SSD).

[0103] The memory 404 stores executable code, and the processor 402 executes the executable code to perform the aforementioned method for over-temperature control of the integrated ramjet engine.

[0104] Specifically, in achieving Figure 3 In the case of the illustrated embodiment, and Figure 3 When the modules or units of the integrated ramjet engine over-temperature control device described in the embodiment are implemented by software, the execution... Figure 3 The software or program code required for the functions of each module / unit can be partially or entirely stored in memory 404. Processor 402 executes the program code corresponding to each unit stored in memory 404 to execute the aforementioned method for over-temperature control of the integrated ramjet engine.

[0105] This application also provides a computer-readable storage medium. The computer-readable storage medium can be any available medium capable of being stored by a computing device, or a data storage device such as a data center containing one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state drive). The computer-readable storage medium includes instructions that instruct the computing device to execute the aforementioned method for controlling the over-temperature of an integrated ramjet engine.

[0106] This application also provides a computer program product comprising one or more computer instructions. When the computer instructions are loaded and executed on a computing device, all or part of the processes or functions described in this application are generated.

[0107] The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from one website, computer, or data center to another website, computer, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) means.

[0108] When the computer program product is executed by a computer, the computer performs any of the aforementioned methods for controlling the over-temperature of the integrated ramjet engine. The computer program product can be a software installation package; when any of the aforementioned methods for controlling the over-temperature of the integrated ramjet engine needs to be used, the computer program product can be downloaded and executed on the computer.

[0109] The descriptions of the processes or structures corresponding to the above figures each have their own emphasis. For parts of a process or structure that are not described in detail, please refer to the relevant descriptions of other processes or structures.

[0110] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be covered within the scope of protection of this application.

Claims

1. A method for over-temperature control of an integrated ramjet engine, characterized in that, The method includes: The difference between the fuel temperature at the outlet of the cooling passage and the fuel temperature at the inlet of the cooling passage, the fuel specific heat capacity, and the fuel mass flow rate of the ramjet engine are obtained. The amount of heat absorbed by the cooling channel is obtained based on the difference between the fuel temperature at the outlet and the inlet of the cooling channel, the specific heat capacity of the fuel, and the fuel mass flow rate. Based on the current fuel equivalence ratio of the ramjet engine, the current flight Mach number of the aircraft, and the current flight altitude of the aircraft, estimate the fuel temperature at the outlet of the cooling channel. When the estimated fuel temperature at the cooling channel outlet reaches the fuel temperature threshold corresponding to the warning level, the increment of the fuel equivalence ratio is determined based on the heat absorbed by the cooling channel and the warning level. The fuel flow rate of the ramjet engine and the flight status of the aircraft are controlled based on the increment of the fuel equivalence ratio.

2. The method according to claim 1, characterized in that, The control of the fuel flow rate of the ramjet engine and the flight state of the aircraft based on the increment of the fuel equivalence ratio includes: The fuel flow rate increment is obtained based on the increment of the fuel equivalence ratio. Increase the fuel flow rate of the ramjet engine according to the fuel flow rate increment; The thrust increment of the ramjet engine is obtained based on the increase in the fuel equivalence ratio and the current thrust; the flight angle of attack and flight Mach number of the aircraft are adjusted based on the thrust increment.

3. The method according to claim 1, characterized in that, The warning levels include Level 1, Level 2, and Level 3 warnings, and the warning levels are determined in the following ways: The warning level is determined based on the measured wall temperature of the combustion chamber wall of the ramjet engine and the fuel temperature at the outlet of the cooling channel of the ramjet engine. A Level 1 warning is triggered when the fuel temperature at the cooling passage outlet reaches the first oil temperature threshold, or when the measured wall temperature reaches the first wall temperature threshold. When the fuel temperature at the cooling passage outlet reaches the second oil temperature threshold, or when the measured wall temperature reaches the second wall temperature threshold, a level 2 warning is triggered. A level 3 warning is triggered when the fuel temperature at the cooling channel outlet reaches the third oil temperature threshold, or when the measured wall temperature reaches the third wall temperature threshold. Among them, the first oil temperature threshold, the second oil temperature threshold and the third oil temperature threshold increase sequentially, the first wall temperature threshold, the second wall temperature threshold and the third wall temperature threshold increase sequentially, and the overheating severity of the first warning, the second warning and the third warning increases sequentially.

4. The method according to claim 1, characterized in that, The step of determining the increment of the fuel equivalence ratio based on the heat absorbed by the cooling channel and the warning level includes: Based on the aforementioned warning level, determine the target increment of cooling capacity; The target heat absorption is obtained based on the heat absorbed by the cooling channel and the target increment of the cooling capacity; The required fuel mass flow rate is obtained based on the difference between the fuel temperature at the outlet of the cooling passage and the fuel temperature at the inlet of the cooling passage, the specific heat capacity of the fuel, and the target heat absorption. The increment of the fuel equivalence ratio is obtained based on the current fuel mass flow rate and the required fuel mass flow rate.

5. The method according to claim 1, characterized in that, The adjustment of the aircraft's angle of attack and Mach number based on the thrust increment includes: The decrease in angle of attack is obtained based on the thrust increment. The angle of attack of the aircraft is reduced according to the reduction in angle of attack. The change in the flight Mach number of the aircraft is obtained based on the reduced angle of attack. Based on the change in flight Mach number, determine whether the flight Mach number of the aircraft is within the allowable window; When the flight Mach number exceeds the upper limit of the allowable window, the flight Mach number of the aircraft is reduced.

6. The method according to claim 1, characterized in that, The current thrust is obtained in the following way: The current thrust of the ramjet engine is obtained based on the dynamic pressure of the aircraft under its current flight condition, the reference area of ​​the ramjet engine, and the thrust coefficient of the ramjet engine.

7. The method according to claim 4, characterized in that, The step of determining the target increment of cooling capacity based on the warning level includes: When a Level 1 warning is triggered, the first target increment of cooling capacity is obtained; When a level 2 warning is triggered, the second target increment of cooling capacity is obtained; When a Level 3 warning is triggered, the third target increment of cooling capacity is obtained; The first target increment, the second target increment, and the third target increment increase sequentially.

8. A device for over-temperature control of an integrated ramjet engine, characterized in that, The device includes: The acquisition module is used to acquire the difference between the fuel temperature at the outlet of the cooling passage and the fuel temperature at the inlet of the cooling passage of the ramjet engine, the fuel specific heat capacity, and the fuel mass flow rate. The processing module is used to obtain the heat absorbed by the cooling channel based on the difference between the fuel temperature at the cooling channel outlet and the fuel temperature at the cooling channel inlet, the fuel specific heat capacity, and the fuel mass flow rate; to estimate the fuel temperature at the cooling channel outlet based on the current fuel equivalence ratio of the ramjet engine, the current flight Mach number of the aircraft, and the current flight altitude of the aircraft; and to determine the increment of the fuel equivalence ratio based on the heat absorbed by the cooling channel and the warning level when the estimated fuel temperature at the cooling channel outlet reaches the oil temperature threshold corresponding to the warning level. The control module is used to control the fuel flow rate of the ramjet engine and the flight status of the aircraft based on the increment of the fuel equivalence ratio.

9. A computing device, characterized in that, Including memory and processor; The memory stores one or more computer programs, the one or more computer programs including instructions; when the instructions are executed by the processor, the computing device performs the method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium is used to store a computer program for performing the method as described in any one of claims 1 to 7.

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