Calculation method for fuel mass flow regulation range of gas cannon at different altitudes

Abstract

The invention relates to a method for calculating the fuel mass flow adjusting range of gas guns at different altitudes. The method comprises the steps that air parameters at the current altitude are calculated; calculating the combustible limit of the gas mixture; calculating the air mass flow output by an air compressor of the gas gun at the current altitude and the fuel mass flow required by the air compressor to output the mixed combustible gas with a certain fuel concentration; and substituting into the previous step to obtain the fuel mass flow regulation range of the gas gun at the current altitude. The method has the advantages that the altitude-atmospheric parameter-combustible limit-fuel flow four-dimensional correlation model is established, and the altitude of the fuel mass flow adjusting range is calculated in a self-adaptive mode in combination with the working characteristics of a gas gun air compressor; the optimal fuel supply quantity at different altitudes is dynamically deduced, it is ensured that the fuel concentration is always within the threshold value for normal work, and the problems that work is unstable and even work cannot be achieved due to reduction of the oxygen density in the plateau / mountain environment can be thoroughly solved.

Description

Technical Field

[0001] This invention belongs to the field of adjustment technology for gas cannons under different altitudes, and particularly relates to a method for calculating the adjustment range of fuel mass flow rate of gas cannons at different altitudes. Background Technology

[0002] my country has a vast distribution of plateaus and mountains, accounting for approximately 60% of the country's total area. Among these, plateaus with an altitude above 1000m account for about 58% of the total land area; those above 2000m account for about 33%; and those above 3000m account for about 26%. Changes in altitude cause changes in air temperature, pressure, and density. These changes directly affect the output of the gas cannon's air compressor: as the initial system pressure decreases, the internal system pressure also decreases, the intermolecular spacing becomes more dispersed, reducing the probability of collisions. This makes the initial combustion reaction and subsequent combustion more difficult, thus continuously narrowing the range of the gas's flammability limits.

[0003] With changes in altitude, the volume fraction and mass fraction of oxygen in the air remain essentially constant (21% by volume). However, because atmospheric pressure decreases with increasing altitude, both air density and air pressure decrease simultaneously, resulting in a corresponding decrease in the mass of oxygen per unit volume. In high-altitude areas, due to the higher altitude and lower air pressure, the air density and atmospheric oxygen content are significantly lower than in plains areas, and low-pressure hypoxia will have a significant impact on gas detonation. However, existing gas cannons used for gas detonation have the following shortcomings when dealing with different altitude environments:

[0004] (1) On the one hand, some gas cannons did not fully consider altitude factors in their design and lacked an adaptive adjustment mechanism for different altitudes. This caused their performance to be greatly reduced when used in non-standard altitude environments, and they could not meet actual needs.

[0005] (2) On the other hand, although some gas cannons have been tested to set adjustable parameters, the setting of these parameters is particularly dependent on the experience and judgment of the operators, and there is still a lack of scientific and accurate adjustment rules calculation methods. Operators have difficulty accurately grasping how to adjust the gas supply, air intake and ignition timing of the gas cannon at different altitudes, resulting in poor adjustment effect and even potential safety hazards due to misoperation.

[0006] Therefore, in order to enable the gas cannon to work stably and efficiently in different altitude environments, it is particularly important to design a method that can accurately calculate the adjustment law of the gas cannon at different altitudes. Summary of the Invention

[0007] The purpose of this invention is to fill the gap in the existing technology for calculating the fuel regulation law of gas cannons at different altitudes, and to provide a calculation method for the fuel mass flow rate regulation range of gas cannons at different altitudes.

[0008] The calculation method for the fuel mass flow rate adjustment range of this gas-fired gun at different altitudes includes the following steps:

[0009] Step 1: Changes in altitude will cause changes in air temperature, pressure, density, etc. Changes in air parameters will directly affect the output of the gas cannon air compressor. Based on the current altitude, obtain the current air parameters.

[0010] Step 2: Based on the calculation results of air parameters, as the altitude increases, the air density and air pressure decrease simultaneously. As the initial pressure decreases, the internal pressure also decreases, and the spacing between molecules becomes more dispersed, reducing the probability of collisions. The initial reaction and the progress of combustion become more difficult, and the range of the gas flammability limit is thus continuously narrowing; calculate the flammability limit of the gas mixture.

[0011] Step 3: When altitude conditions change, the rated volumetric flow rate of the air compressor remains basically unchanged; calculate the air mass flow rate output by the air compressor of the gas cannon at the current altitude, and the fuel mass flow rate required for the air compressor to output a certain fuel concentration of mixed combustible gas.

[0012] Step 4: Substitute the flammability limit of the gas mixture and the fuel concentration in the gas mixture calculated in Step 2 into Step 3 to obtain the adjustment range of the gas cannon fuel mass flow rate at the current altitude.

[0013] Preferably, in step 1, the air parameters include air temperature, air pressure, and air density. The specific method for calculating the air parameters at the corresponding altitude is as follows:

[0014] Calculate the air temperature corresponding to the current altitude h. :

[0015] (1)

[0016] Calculate the air pressure corresponding to the current altitude h. :

[0017] (2)

[0018] In the above formula: This represents the theoretical exponent coefficient of the International Standard Air Density formula. The value ranges from 4.96 to 6.85; This indicates the air pressure under standard conditions. The air temperature under standard conditions is represented by a value of 288.15 K; substituting equation (1) into equation (2), the air pressure is... The formula for how altitude h changes is as follows:

[0019] (3)

[0020] Calculate the air density at the current altitude. :

[0021] (4)

[0022] In the above formula, This represents the air density under standard conditions, and its value is 1.225 kg / m³. 3 , This represents the theoretical exponent coefficient of the International Standard Air Density formula. The value ranges from 3.96 to 5.85.

[0023] As a preferred option The value is 5.25588. The value is 4.25588.

[0024] Preferably, step 2 specifically includes the following steps:

[0025] Based on the air pressure corresponding to the previous altitude h The upper limit volume fraction of flammability of pure propane gas in air was obtained by fitting. :

[0026] (5)

[0027] Based on the air pressure corresponding to the previous altitude h The lower flammability limit volume fraction of pure propane gas in air was obtained by fitting the data. :

[0028] (6)

[0029] Based on the air pressure corresponding to the previous altitude h The upper limit volume fraction of flammability of pure butane gas in air was obtained by fitting. :

[0030] (7)

[0031] Based on the air pressure corresponding to the previous altitude h The lower flammability limit volume fraction of pure butane gas in air was obtained by fitting. :

[0032] (8)

[0033] Using the Le Chatelier formula, calculate the flammability limits of a flammable gas mixture without inert gases in air at a given temperature and pressure:

[0034] (9)

[0035] In the above formula, L represents the flammability limit of the combustible gas mixture without inert gases in air, i represents the number of pure combustible gases in the mixture, n represents the total number of pure combustible gases in the mixture, and P i This indicates the relative volume percentage of each pure combustible gas in a mixed combustible gas. This represents the flammability limit of the i-th pure flammable gas in the air within a mixed flammable gas mixture;

[0036] Let x be the volume fraction of propane in liquefied petroleum gas (LPG). Then the flammability limit of LPG is:

[0037] (10)

[0038] In the above formula, This represents the flammability limit in air of liquefied petroleum gas (LPG) containing x volume fraction of propane, excluding inert gases. This indicates the flammability limit of pure propane gas in air. This indicates the flammability limit of pure butane gas in air;

[0039] Then, the lower flammability limit volume fraction of liquefied petroleum gas (LPG) with a propane volume fraction of x is:

[0040] (11)

[0041] In the above formula, x represents the volume fraction of propane in liquefied petroleum gas (LPG). This represents the lower flammability limit (LCL) of liquefied petroleum gas (LPG) in air, containing x volume fraction of propane and excluding inert gases. This indicates the lower flammability limit (V / V) of pure propane gas in air. This indicates the lower flammability limit (V / V) of pure butane gas in air.

[0042] The upper limit of the flammability volume fraction of liquefied petroleum gas (LPG) with a propane volume fraction of x is:

[0043] (12)

[0044] In the above formula, x represents the volume fraction of propane in liquefied petroleum gas (LPG). This represents the upper limit of the flammability volume fraction of liquefied petroleum gas (LPG) in air, containing x volume fraction of propane and excluding inert gases. This indicates the upper limit of the flammability (volume fraction) of pure propane gas in air. This indicates the upper limit of the flammability volume fraction of pure butane gas in air.

[0045] As a preferred option, in formulas (5) to (8) The value range is 0.05 MPa to 0.1 MPa.

[0046] Preferably, step 3 specifically includes the following steps:

[0047] The air mass flow rate output by the air compressor of the gas cannon at the current altitude is calculated using the conversion formula between volumetric flow rate and mass flow rate in formula (13). :

[0048] (13)

[0049] In the above formula, Indicates the mass flow rate of air. Indicates air density, Indicates the volumetric flow rate of air;

[0050] (14)

[0051] In the above formula, Q0 represents the rated volumetric flow rate of the air compressor; This indicates the air density under standard conditions; 'b' represents the air temperature under standard conditions; 'b' represents the theoretical exponent coefficient of the international standard atmospheric density formula. The value ranges from 3.96 to 5.85;

[0052] Based on the above equation (14), the fuel mass flow rate required for the air compressor to output a certain fuel concentration of mixed combustible gas at the current altitude is calculated in the following equation (15). :

[0053] (15)

[0054] In the above formula: This indicates the volume fraction of fuel in a mixed combustible gas. The value of is less than 1; This indicates the molar mass of a combustible gas.

[0055] Preferably, step 4 specifically includes the following steps:

[0056] The upper limit volume fraction of flammable propane gas in air obtained from formulas (5) and (6) Lower flammability limit (volume fraction) of pure propane gas in air The upper limit volume fraction of flammability of pure butane gas in air obtained by formulas (7) and (8) Lower flammability limit (volume fraction) of pure butane gas in air Substituting all values ​​into formula (15), we obtain the adjustment range of liquefied petroleum gas gun fuel mass flow rate at the current altitude:

[0057] The lower limit of the mass flow rate of liquefied petroleum gas (LPG) gun fuel at the current altitude is: :

[0058] (16)

[0059] In the above formula: This represents the lower flammability limit (LCL) of liquefied petroleum gas (LPG) in air, containing a volume fraction of propane (x) and excluding inert gases. Q0 represents the molar mass of liquefied petroleum gas containing x volume fraction of propane and excluding inert gases; Q0 represents the rated volumetric flow rate of the air compressor. This indicates the air density under standard conditions; The air temperature is indicated under standard conditions; h represents the altitude. The theoretical exponent coefficient representing the international standard atmospheric density formula;

[0060] The upper limit of the mass flow rate of liquefied petroleum gas (LPG) gun fuel at the current altitude is :

[0061] (17)

[0062] In the above formula, This represents the upper limit of the flammability volume fraction of liquefied petroleum gas (LPG) in air, where the volume fraction of propane is x and the LPG itself does not contain any inert gases.

[0063] The beneficial effects of this invention are:

[0064] This invention establishes a four-dimensional correlation model of altitude, atmospheric parameters, flammability limit, and fuel flow rate. Combined with the working characteristics of the gas cannon air compressor, it realizes for the first time the altitude-adaptive calculation of the fuel mass flow rate adjustment range. This invention can dynamically derive the optimal fuel supply at different altitudes, ensuring that the fuel concentration is always within the threshold for normal operation. It can completely solve the problem of unstable operation or even inability to operate due to the decrease in oxygen density in plateau / mountain environments.

[0065] This invention quantifies the compression effect of altitude changes on the explosion limit of LPG mixtures. It can reduce the prediction error of flammability limits to an acceptable range for engineering purposes, thus ensuring safe operation. By integrating atmospheric parameters, compressor flow characteristics, and fuel properties, this invention can directly output the mass flow rate adjustment range, enabling precise matching of altitude, fuel quantity, and target performance (balancing fuel consumption minimization and launch effect optimization to reduce consumption). This ensures stable combustion pressure of the gas cannon at different altitudes and effectively suppresses the risk of deflagration in the low-pressure environment of high-altitude areas.

[0066] This invention allows for flexible configuration of propane volume fraction, adapting to different LPG compositions and significantly expanding the application boundaries of gas cannons in special scenarios such as high-altitude mining areas and border defense. It improves the performance of gas cannons in complex environments, broadens their application range, and provides more reliable protection for safe production and operations in related fields. Attached Figure Description

[0067] Figure 1 This is a flowchart illustrating the calculation method for the fuel mass flow rate adjustment range of a gas-fired cannon at different altitudes, according to an embodiment of the present invention. Detailed Implementation

[0068] The present invention will be further described below with reference to embodiments. The description of the embodiments below is only for the purpose of helping to understand the present invention. It should be noted that those skilled in the art can make several modifications to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0069] As one example, such as Figure 1 As shown, the calculation method for the adjustment range of fuel mass flow rate of this gas-fired gun at different altitudes for liquefied petroleum gas (LPG) includes the following steps:

[0070] Step 1: Changes in altitude will cause changes in air temperature, pressure, density, etc. These changes in air parameters directly affect the output of the gas cannon's air compressor. Based on the current altitude, the current air parameters are obtained; these air parameters include air temperature, air pressure, and air density. The specific method for calculating the air parameters at the corresponding altitude is as follows:

[0071] Calculate the air temperature corresponding to the current altitude h. :

[0072] (1)

[0073] Calculate the air pressure corresponding to the current altitude h. :

[0074] (2)

[0075] In the above formula: This represents the theoretical exponent coefficient of the International Standard Air Density formula. The value is 5.25588; This indicates the air pressure under standard conditions. The air temperature under standard conditions is represented by a value of 288.15 K; substituting equation (1) into equation (2), the air pressure is... The formula for how altitude h changes is as follows:

[0076] (3)

[0077] Calculate the air density at the current altitude. :

[0078] (4)

[0079] In the above formula, This represents the air density under standard conditions, and its value is 1.225 kg / m³. 3 , This represents the theoretical exponent coefficient of the International Standard Air Density formula. The value is 4.25588.

[0080] Step 2: Based on the calculation results of air parameters, as the altitude increases, the air density and air pressure decrease simultaneously. As the initial pressure decreases, the internal pressure also decreases, and the spacing between molecules becomes more dispersed, reducing the probability of collisions. The initial reaction and the progress of combustion become more difficult, and the range of the gas flammability limit is thus continuously narrowing; calculate the flammability limit of the gas mixture.

[0081] Based on the air pressure corresponding to the previous altitude h The upper limit volume fraction of flammability of pure propane gas in air was obtained by fitting. ( The value is 0.05 MPa).

[0082] (5)

[0083] Based on the air pressure corresponding to the previous altitude h The lower flammability limit volume fraction of pure propane gas in air was obtained by fitting the data. ( The value is 0.05 MPa).

[0084] (6)

[0085] Based on the air pressure corresponding to the previous altitude h The upper limit volume fraction of flammability of pure butane gas in air was obtained by fitting. ( The value is 0.05 MPa).

[0086] (7)

[0087] Based on the air pressure corresponding to the previous altitude h The lower flammability limit volume fraction of pure butane gas in air was obtained by fitting. ( The value is 0.05 MPa).

[0088] (8)

[0089] Using the Le Chatelier formula, calculate the flammability limits of a flammable gas mixture without inert gases in air at a given temperature and pressure:

[0090] (9)

[0091] In the above formula, L represents the flammability limit of the mixed combustible gas without inert gas in air, i represents the number of pure combustible gases in the mixed combustible gas, n represents the total number of pure combustible gases in the mixed combustible gas, and P i This indicates the relative volume percentage of each pure combustible gas in the mixed combustible gas. This indicates the flammability limit of the i-th pure flammable gas in the mixed flammable gas in air;

[0092] Let x be the volume fraction of propane in liquefied petroleum gas (LPG). Then the flammability limit of LPG is:

[0093] (10)

[0094] In the above formula, This represents the flammability limit in air of liquefied petroleum gas (LPG) containing x volume fraction of propane, excluding inert gases. This indicates the flammability limit of pure propane gas in air. This indicates the flammability limit of pure butane gas in air;

[0095] The lower flammability limit volume fraction of the liquefied petroleum gas (LPG) in which propane has a volume fraction of x is:

[0096] (11)

[0097] In the above formula, x represents the volume fraction of propane in liquefied petroleum gas (LPG). This represents the lower flammability limit (LCL) of the liquefied petroleum gas (LPG) containing x volume fraction of propane in air, excluding inert gases. This indicates the lower flammability limit (V / V) of pure propane gas in air. This indicates the lower flammability limit (V / V) of pure butane gas in air.

[0098] The upper limit of the flammability volume fraction of the liquefied petroleum gas (LPG) in which propane has a volume fraction of x is:

[0099] (12)

[0100] In the above formula, x represents the volume fraction of propane in liquefied petroleum gas (LPG). This represents the upper limit of the flammability volume fraction of the liquefied petroleum gas (LPG) in air, which contains no inert gases and has a propane volume fraction of x. This indicates the upper limit of the flammability (volume fraction) of pure propane gas in air. This indicates the upper limit of the flammability volume fraction of pure butane gas in air;

[0101] Step 3: When altitude conditions change, the rated volumetric flow rate of the air compressor remains basically unchanged; calculate the air mass flow rate output by the air compressor of the gas cannon at the current altitude, and the fuel mass flow rate required for the air compressor to output a certain fuel concentration of mixed combustible gas.

[0102] The air mass flow rate output by the air compressor of the gas cannon at the current altitude is calculated using the conversion formula between volumetric flow rate and mass flow rate in formula (13). :

[0103] (13)

[0104] In the above formula, Indicates the mass flow rate of air. Indicates air density, Indicates the volumetric flow rate of air;

[0105] (14)

[0106] In the above formula, Q0 represents the rated volumetric flow rate of the air compressor; This indicates the air density under standard conditions; 'b' represents the air temperature under standard conditions; 'b' represents the theoretical exponent coefficient of the international standard atmospheric density formula. The value ranges from 3.96 to 5.85;

[0107] Based on the above equation (14), the fuel mass flow rate required for the air compressor to output a certain fuel concentration of mixed combustible gas at the current altitude is calculated in the following equation (15). :

[0108] (15)

[0109] In the above formula: This indicates the volume fraction of fuel in a mixed combustible gas. The value of is less than 1; Indicates the molar mass of a combustible gas;

[0110] Step 4: Substitute the flammability limit of the gas mixture calculated in Step 2 and the fuel concentration in the gas mixture into Step 3 to obtain the fuel mass flow rate adjustment range of the gas cannon at the current altitude.

[0111] The upper limit volume fraction of flammable propane gas in air obtained from formulas (5) and (6) Lower flammability limit (volume fraction) of pure propane gas in air The upper limit volume fraction of flammability of pure butane gas in air obtained by formulas (7) and (8) Lower flammability limit (volume fraction) of pure butane gas in air Substituting all values ​​into formula (15), we obtain the adjustment range of liquefied petroleum gas gun fuel mass flow rate at the current altitude:

[0112] The lower limit of the mass flow rate of liquefied petroleum gas (LPG) gun fuel at the current altitude is: :

[0113] (16)

[0114] In the above formula: This represents the lower flammability limit (LCL) of liquefied petroleum gas (LPG) in air, containing a volume fraction of propane (x) and excluding inert gases. Q0 represents the molar mass of liquefied petroleum gas containing x volume fraction of propane and excluding inert gases; Q0 represents the rated volumetric flow rate of the air compressor. This indicates the air density under standard conditions; The air temperature is indicated under standard conditions; h represents the altitude. The theoretical exponent coefficient representing the international standard atmospheric density formula;

[0115] The upper limit of the mass flow rate of liquefied petroleum gas (LPG) gun fuel at the current altitude is :

[0116] (17)

[0117] In the above formula, This represents the upper limit volume fraction of the flammable petroleum gas in air, which contains no inert gases and has a volume fraction of propane of x.

Claims

1. A method for calculating the adjustment range of fuel mass flow rate in a gas-fired gun at different altitudes, characterized in that, Includes the following steps: Step 1: Obtain the current air parameters based on the current altitude; Step 2: Calculate the flammability limits of the gas mixture; Step 3: Calculate the air mass flow rate output by the air compressor of the gas cannon at the current altitude, and the fuel mass flow rate required for the air compressor to output a certain fuel concentration of mixed combustible gas; Step 4: Substitute the flammability limit of the gas mixture calculated in Step 2 and the fuel concentration in the gas mixture into Step 3 to obtain the adjustment range of the gas cannon fuel mass flow rate at the current altitude.

2. The calculation method for the fuel mass flow rate adjustment range of a gas-fired gun at different altitudes according to claim 1, characterized in that, In step 1, the air parameters include air temperature, air pressure, and air density. The specific method for calculating the air parameters at the corresponding altitude is as follows: Calculate the air temperature corresponding to the current altitude h. : （1） Calculate the air pressure corresponding to the current altitude h. : （2） In the above formula: This represents the theoretical exponent coefficient of the International Standard Air Density formula. The value ranges from 4.96 to 6.85; This indicates the air pressure under standard conditions. This represents the air temperature under standard conditions; substituting equation (1) into equation (2), the air pressure... The formula for how altitude h changes is as follows: （3） Calculate the air density at the current altitude. : （4） In the above formula, This represents the air density under standard conditions. This represents the theoretical exponent coefficient of the International Standard Air Density formula. The value ranges from 3.96 to 5.

85.

3. The method for calculating the fuel mass flow rate adjustment range of a gas-fired gun at different altitudes according to claim 2, characterized in that: The value is 5.25588. The value is 4.25588.

4. The calculation method for the fuel mass flow rate adjustment range of a gas-fired gun at different altitudes according to claim 2, characterized in that, Step 2 specifically includes the following steps: Based on the air pressure corresponding to the previous altitude h The upper limit volume fraction of flammability of pure propane gas in air was obtained by fitting. : （5） Based on the air pressure corresponding to the previous altitude h The lower flammability limit volume fraction of pure propane gas in air was obtained by fitting the data. : （6） Based on the air pressure corresponding to the previous altitude h The upper limit volume fraction of flammability of pure butane gas in air was obtained by fitting. : （7） Based on the air pressure corresponding to the previous altitude h The lower flammability limit volume fraction of pure butane gas in air was obtained by fitting. : （8） Using the Le Chatelier formula, calculate the flammability limits of a flammable gas mixture without inert gases in air at a given temperature and pressure: （9） In the above formula, L represents the flammability limit of the mixed combustible gas without inert gas in air, i represents the number of pure combustible gases in the mixed combustible gas, n represents the total number of pure combustible gases in the mixed combustible gas, and P i This indicates the relative volume percentage of each pure combustible gas in the mixed combustible gas. This indicates the flammability limit of the i-th pure flammable gas in the mixed flammable gas in air; Let x be the volume fraction of propane in liquefied petroleum gas (LPG). Then the flammability limit of LPG is: （10） In the above formula, This represents the flammability limit in air of liquefied petroleum gas (LPG) containing x volume fraction of propane, excluding inert gases. This indicates the flammability limit of pure propane gas in air. This indicates the flammability limit of pure butane gas in air; Then the lower flammability limit volume fraction of the liquefied petroleum gas in which the volume fraction of propane is x is: （11） In the above formula, x represents the volume fraction of propane in liquefied petroleum gas. This represents the lower flammability limit (LCL) of the liquefied petroleum gas (LPG) containing x volume fraction of propane in air, excluding inert gases. This indicates the lower flammability limit (V / V) of pure propane gas in air. This indicates the lower flammability limit (V / V) of pure butane gas in air. The upper limit of the flammability volume fraction of the liquefied petroleum gas in which the volume fraction of propane is x is: （12） In the above formula, x represents the volume fraction of propane in liquefied petroleum gas. This represents the upper limit of the flammability volume fraction of the liquefied petroleum gas (LPG) in air, which contains no inert gases and has a propane volume fraction of x. This indicates the upper limit of the flammability (volume fraction) of pure propane gas in air. This indicates the upper limit of the flammability volume fraction of pure butane gas in air.

5. The method for calculating the fuel mass flow rate adjustment range of a gas-fired gun at different altitudes according to claim 4, characterized in that: In formulas (5) to (8) The value range is 0.05 MPa to 0.1 MPa.

6. The method for calculating the fuel mass flow rate adjustment range of a gas-fired gun at different altitudes according to claim 4, characterized in that, Step 3 specifically includes the following steps: The air mass flow rate output by the air compressor of the gas cannon at the current altitude is calculated using the conversion formula between volumetric flow rate and mass flow rate in formula (13). : （13） In the above formula, Indicates the mass flow rate of air. Indicates air density, Indicates the volumetric flow rate of air; （14） In the above formula, Q0 represents the rated volumetric flow rate of the air compressor; This indicates the air density under standard conditions; 'b' represents the air temperature under standard conditions; 'b' represents the theoretical exponent coefficient of the international standard atmospheric density formula. The value ranges from 3.96 to 5.85; Based on the above equation (14), the fuel mass flow rate required for the air compressor to output a certain fuel concentration of mixed combustible gas at the current altitude is calculated in the following equation (15). : （15） In the above formula: This indicates the volume fraction of fuel in a mixed combustible gas. The value of is less than 1; This indicates the molar mass of a combustible gas.

7. The method for calculating the fuel mass flow rate adjustment range of a gas-fired gun at different altitudes according to claim 6, characterized in that, Step 4 specifically includes the following steps: The upper limit volume fraction of flammable propane gas in air obtained from formulas (5) and (6) Lower flammability limit (volume fraction) of pure propane gas in air The upper limit volume fraction of flammability of pure butane gas in air obtained by formulas (7) and (8) Lower flammability limit (volume fraction) of pure butane gas in air Substituting all values ​​into formula (15), we obtain the adjustment range of liquefied petroleum gas gun fuel mass flow rate at the current altitude: The lower limit of the mass flow rate of liquefied petroleum gas (LPG) gun fuel at the current altitude is: : （16） In the above formula: This represents the lower flammability limit (LCL) of liquefied petroleum gas (LPG) in air, containing a volume fraction of propane (x) and excluding inert gases. Q0 represents the molar mass of liquefied petroleum gas containing x volume fraction of propane and excluding inert gases; Q0 represents the rated volumetric flow rate of the air compressor. This indicates the air density under standard conditions; The air temperature is indicated under standard conditions; h represents the altitude. The theoretical exponent coefficient representing the international standard atmospheric density formula; The upper limit of the mass flow rate of liquefied petroleum gas (LPG) gun fuel at the current altitude is : （17） In the above formula, This represents the upper limit volume fraction of the flammable petroleum gas in air, which contains no inert gases and has a volume fraction of propane of x.

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