Method for determining oxygen carrying performance of oxygen cylinder of oxygen supplementation subsystem of aircraft propulsion system

Abstract

The invention belongs to the technical field of aircraft propulsion system oxygen supplementation subsystem design, and particularly relates to an aircraft propulsion system oxygen supplementation subsystem oxygen cylinder oxygen carrying performance determination method which comprises the steps that 1, the oxygen demand mass m1 of engine air starting is calculated; 2, calculating the mass m2 of residual unavailable oxygen in the oxygen cylinder; 3, calculating the total mass m of oxygen required to be filled into the oxygen bottle according to the formula m = m1 + m2; 4, calculating the volume of the oxygen bottle needing to be filled under different environment temperatures and corresponding highest and lowest filling pressures; and step 5, comparing the volume of the oxygen bottle needing to be filled under different environment temperatures and corresponding highest and lowest filling pressures with the volume of the oxygen bottle, and determining whether the performance of the oxygen bottle carrying the oxygen can meet the requirement or not.

Description

Technical Field

[0001] This application belongs to the technical field of oxygen replenishment subsystem design for aircraft propulsion systems, specifically relating to a method for determining the oxygen-carrying performance of an oxygen cylinder in an oxygen replenishment subsystem of an aircraft propulsion system. Background Technology

[0002] The oxygen supply subsystem in the aircraft propulsion system is used to supply oxygen to the main combustion chamber of the engine after the engine stops in the air, providing oxygen for the engine to start in the air, expanding the boundaries of the engine's in-flight start, and ensuring the reliability of the engine's windmill / inertial start.

[0003] The oxygen replenishment subsystem mainly consists of oxygen cylinders, oxygen switches, oxygen pressure regulators, and oxygen replenishment pipelines. The oxygen replenishment subsystem is precisely designed to minimize its weight while still fulfilling its functions. Among these, accurately calculating whether the oxygen cylinders in the oxygen replenishment subsystem can carry enough oxygen to meet the engine restart requirements after an in-flight shutdown is a crucial aspect.

[0004] Currently, most methods use the ideal gas law and formula derivation to calculate whether the oxygen cylinder in the oxygen supply subsystem can carry enough oxygen to meet the engine's restart requirements after an in-flight shutdown. In addition, the amount of unusable oxygen remaining in the oxygen cylinder is usually ignored. This not only makes the calculation process cumbersome, but also results in low efficiency and often inaccurate results. Designing an oxygen supply subsystem in this way can easily lead to serious consequences such as insufficient oxygen supply to the engine, unsuccessful in-flight restarts, and excessive weight.

[0005] This application is made in view of the aforementioned technical deficiencies. Summary of the Invention

[0006] The purpose of this application is to provide a method for determining the oxygen-carrying performance of an oxygen cylinder in an oxygen replenishment subsystem of an aircraft propulsion system, so as to overcome or mitigate at least one of the known technical defects.

[0007] The technical solution of this application is:

[0008] A method for determining the oxygen-carrying capacity of an oxygen cylinder in an oxygen replenishment subsystem of an aircraft propulsion system includes:

[0009] Step 1: Calculate the oxygen demand m1 for air starting of the engine;

[0010] Step 2: Calculate the remaining unusable oxygen mass m2 in the oxygen cylinder;

[0011]

[0012] in,

[0013] M is the molar mass of oxygen;

[0014] V m0 The molar volume of the oxygen cylinder at the operating temperature and pressure.

[0015] V0 is the volume of the oxygen cylinder;

[0016] Step 3: Calculate the total mass of oxygen needed to fill the oxygen cylinder, m = m1 + m2;

[0017] Step 4: Calculate the volume of oxygen required to fill the oxygen cylinder under different ambient temperatures and their corresponding highest and lowest filling pressures;

[0018]

[0019]

[0020]

[0021] in,

[0022] V h The volume of oxygen required to fill the oxygen cylinder at the ambient temperature and the corresponding maximum filling pressure.

[0023] ρ h The density of oxygen at the ambient temperature of the oxygen cylinder and its corresponding maximum filling pressure;

[0024] p h This refers to the maximum filling pressure corresponding to the ambient temperature of the oxygen cylinder.

[0025] 'a' is a phenomenological parameter that measures the intermolecular attraction of oxygen molecules;

[0026] b is the volume contained within the oxygen molecule itself;

[0027] V mh This represents the molar volume of oxygen at ambient temperature and its corresponding maximum filling pressure.

[0028] R is the ideal gas constant;

[0029] T1 is the ambient temperature of the oxygen cylinder;

[0030]

[0031]

[0032]

[0033] in,

[0034] V l The volume of oxygen required to fill the oxygen cylinder at the ambient temperature and the corresponding minimum filling pressure.

[0035] ρ lThe density of oxygen at the ambient temperature of the oxygen cylinder and its corresponding minimum filling pressure;

[0036] p l This refers to the minimum filling pressure corresponding to the ambient temperature of the oxygen cylinder.

[0037] V ml This represents the molar volume of oxygen at ambient temperature and its corresponding minimum filling pressure.

[0038] Step 5: Compare the volume of oxygen required to fill the oxygen cylinder under different ambient temperatures and corresponding highest and lowest filling pressures with the volume of the oxygen cylinder to determine whether the oxygen cylinder's oxygen-carrying performance can meet the requirements.

[0039] According to at least one embodiment of this application, in the above-described method for determining the oxygen-carrying performance of the oxygen cylinder in the oxygen replenishment subsystem of an aircraft propulsion system, in step one, m1 = v × t × n;

[0040] in,

[0041] v represents the mass rate of oxygen replenishment required for engine air start-up.

[0042] t represents the oxygen replenishment time for each engine start-up in the air;

[0043] n represents the number of times the engine needs to be started and replenished with oxygen during air traffic control.

[0044] According to at least one embodiment of this application, in the above-described method for determining the oxygen-carrying performance of the oxygen cylinder in the oxygen replenishment subsystem of an aircraft propulsion system, in step two,

[0045] in,

[0046] p0 represents the minimum pressure at the oxygen cylinder inlet when the oxygen supply subsystem is operating normally.

[0047] T0 is the working temperature of the oxygen cylinder.

[0048] According to at least one embodiment of this application, in the above-described method for determining the oxygen-carrying performance of the oxygen cylinder in the oxygen replenishment subsystem of the aircraft propulsion system, the normal operating p0 of the oxygen replenishment subsystem is 2 MPa.

[0049] The oxygen cylinder operating temperature T0 is taken as the lowest operating temperature.

[0050] According to at least one embodiment of this application, in the above-described method for determining the oxygen-carrying performance of the oxygen cylinder in the oxygen replenishment subsystem of an aircraft propulsion system, the phenomenological parameter 'a', which measures the intermolecular attraction of oxygen molecules, is taken as 0.138m. 6 ·Pa·mol -2 ;

[0051] The volume b contained within the oxygen molecule itself is taken as 3.18 × 10⁻⁶.-5 m 3 ·mol -1 ;

[0052] The ideal gas constant R is taken as 8.314 Pa·m. 3 ·mol -1 ·K -1 .

[0053] This application has at least the following beneficial technical effects:

[0054] This paper provides a method for determining the oxygen-carrying performance of an oxygen cylinder in an oxygen replenishment subsystem of an aircraft propulsion system. Considering the remaining unusable oxygen in the cylinder, the method calculates the oxygen-carrying performance using the van der Waals equation of state for real gases. This method can efficiently and accurately determine whether the oxygen-carrying performance of the cylinder meets the requirements, providing effective guidance for the design of the oxygen replenishment subsystem and avoiding serious consequences such as insufficient engine oxygen supply, unsuccessful in-flight start-up, and excessive weight. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of a method for determining the oxygen-carrying capacity of an oxygen cylinder in an oxygen replenishment subsystem of an aircraft propulsion system, provided in an embodiment of this application.

[0056] To better illustrate this embodiment, some content in the accompanying drawings may be omitted, enlarged, or reduced. They are for illustrative purposes only and should not be construed as limiting the scope of this application. Detailed Implementation

[0057] To make the technical solution and advantages of this application clearer, the technical solution of this application will be described in a clearer and more complete manner below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of this application, and are only used to explain this application, not to limit this application. It should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, and other related parts can be referred to the general design.

[0058] Furthermore, unless otherwise defined, the technical or scientific terms used in this application description shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The word "comprising" as used in this application description indicates that the concept preceding the word encompasses the concepts listed following the word and their equivalents, without excluding other related concepts.

[0059] A method for determining the oxygen-carrying capacity of an oxygen cylinder in an oxygen replenishment subsystem of an aircraft propulsion system, such as... Figure 1 As shown.

[0060] Step 1: Calculate the oxygen demand m1 for air starting of the engine.

[0061] m1 = v × t × n;

[0062] in,

[0063] v represents the mass rate of oxygen replenishment required for engine air start-up.

[0064] t represents the oxygen replenishment time for each engine start-up in the air;

[0065] n represents the number of times the engine needs to be started and replenished with oxygen during air traffic control.

[0066] Step 2: Calculate the remaining unusable oxygen mass m2 in the oxygen cylinder.

[0067] When the oxygen cylinder inlet pressure drops to a certain level, the oxygen replenishment subsystem can no longer function properly, and at this point, the remaining oxygen in the cylinder is unusable.

[0068]

[0069] in,

[0070] M is the molar mass of oxygen;

[0071] V m0 The molar volume of the oxygen cylinder at the operating temperature and pressure.

[0072] V0 is the volume of the oxygen cylinder.

[0073] According to the van der Waals equation:

[0074] It can be transformed into:

[0075] p0V m0 3 -(p0b+RT)V m0 2 +aV m0 -ab = 0;

[0076] in,

[0077] p0 is the minimum pressure at the oxygen cylinder inlet when the oxygen supply subsystem is working normally; it can be taken as 2 MPa.

[0078] 'a' is a phenomenological parameter measuring the intermolecular attraction of oxygen molecules, which can be taken as 0.138m. 6 ·Pa·mol -2 ;

[0079] b is the volume contained within the oxygen molecule itself, which can be taken as 3.18 × 10⁻⁶. -5 m 3 ·mol -1 ;

[0080] R is the ideal gas constant, which can be taken as 8.314 Pa·m.3 ·mol -1 ·K -1 ;

[0081] T0 is the working temperature of the oxygen cylinder, and the lowest working temperature can be used.

[0082] Step 3: Calculate the total mass of oxygen needed to fill the oxygen cylinder, m = m1 + m2.

[0083] Step 4: Calculate the volume of oxygen required to fill the oxygen cylinder under different ambient temperatures and their corresponding highest and lowest filling pressures.

[0084]

[0085]

[0086]

[0087] in,

[0088] V h The volume of oxygen required to fill the oxygen cylinder at the ambient temperature and the corresponding maximum filling pressure.

[0089] ρ h The density of oxygen at the ambient temperature of the oxygen cylinder and its corresponding maximum filling pressure;

[0090] p h This refers to the maximum filling pressure corresponding to the ambient temperature of the oxygen cylinder.

[0091] V mh This represents the molar volume of oxygen at ambient temperature and its corresponding maximum filling pressure.

[0092] T1 is the ambient temperature of the oxygen cylinder.

[0093]

[0094]

[0095]

[0096] in,

[0097] V l The volume of oxygen required to fill the oxygen cylinder at the ambient temperature and the corresponding minimum filling pressure.

[0098] ρ l The density of oxygen at the ambient temperature of the oxygen cylinder and its corresponding minimum filling pressure;

[0099] p l This refers to the minimum filling pressure corresponding to the ambient temperature of the oxygen cylinder.

[0100] V ml This represents the molar volume of oxygen at ambient temperature and its corresponding minimum filling pressure.

[0101] Step 5: Compare the volume of oxygen required to fill the oxygen cylinder under different ambient temperatures and corresponding highest and lowest filling pressures with the volume of the oxygen cylinder to determine whether the oxygen cylinder's oxygen-carrying performance can meet the requirements.

[0102] If the volume of oxygen required to be filled into the oxygen cylinder at different ambient temperatures and their corresponding highest and lowest filling pressures is less than the volume of the oxygen cylinder, then the oxygen cylinder's oxygen-carrying capacity is deemed to meet the requirements; otherwise, the oxygen cylinder's oxygen-carrying capacity is deemed not to meet the requirements.

[0103] In one example, the oxygen replenishment rate required for an engine in-flight start is v = 5 g / s, the oxygen replenishment time for each in-flight start is t = 40 s, the number of in-flight start oxygen replenishment requests is n = 4, and the oxygen cylinder volume is V0 = 7 L. The maximum filling pressure of the oxygen cylinder under different ambient temperatures is shown in the table below: Ambient temperature (°C) -50 -40 -30 -20 -10 0 10 20 30 40 50 Maximum filling pressure (MPa) 10 11 12 13 14 15 16 17 18 19 20

[0104] The minimum filling pressure of oxygen cylinders under different ambient temperatures is shown in the table below: Ambient temperature (°C) -50 -40 -30 -20 -10 0 10 20 30 40 50 Minimum filling pressure (MPa) 9 10 11 12 13 14 15 16 17 18 19

[0105] The method for determining the oxygen-carrying performance of the oxygen cylinder in the oxygen replenishment subsystem of the aircraft propulsion system disclosed in the above embodiments is implemented as follows.

[0106] Step 1: Calculate the oxygen required for air starting of the engine, m1 = 0.80 kg.

[0107] Step 2: Calculate the remaining unusable oxygen mass m2 in the oxygen cylinder.

[0108] The oxygen cylinder's operating temperature T0 is taken as 293.15K, the oxygen replenishment subsystem is operating normally, and the minimum inlet pressure p0 of the oxygen cylinder is taken as 2MPa. Calculate the molar volume of the oxygen cylinder at its operating temperature and pressure. V m0 =1.194 L / mol, and then the remaining unusable oxygen mass m2 in the oxygen cylinder can be calculated as = The following table shows the remaining unusable oxygen mass (m2) in oxygen cylinders at different operating temperatures (T0) of 0.1876 kg:

[0109] Step 3: Calculate the total mass of oxygen needed to fill the oxygen cylinder, m = m1 + m2.

[0110] Step 4: Calculate the required oxygen volume for the oxygen cylinder under different ambient temperatures and their corresponding maximum filling pressures, as shown in the table below: Ambient temperature ℃ -50 -40 -30 -20 -10 0 10 20 30 40 50 Maximum filling pressure (MPa) 10 11 12 13 14 15 16 17 18 19 20 Oxygenated volume L 6.11 5.73 5.42 5.16 4.94 4.74 4.57 4.42 4.29 4.17 4.07

[0111] The required oxygen volume for filling oxygen cylinders under different ambient temperatures and their corresponding minimum filling pressures is calculated, as shown in the table below: Ambient temperature ℃ -50 -40 -30 -20 -10 0 10 20 30 40 50 Minimum filling pressure (MPa) 9 10 11 12 13 14 15 16 17 18 19 Oxygenated volume L 6.78 6.31 5.91 5.59 5.32 5.08 4.88 4.70 4.55 4.41 4.28

[0112] Furthermore, based on the difference between the volume of oxygen required to be filled into the oxygen cylinder at different ambient temperatures and their corresponding highest and lowest filling pressures, and the volume of the oxygen cylinder itself, the remaining air start-up time can be calculated in reverse, as shown in the table below: Ambient temperature ℃ -50 -40 -30 -20 -10 0 10 20 30 40 50 Maximum filling pressure (MPa) 10 11 12 13 14 15 16 17 18 19 20 Remaining in-flight start time s 30.81 46.02 59.94 72.73 84.52 95.43 105.55 114.97 123.75 131.97 139.67 Minimum filling pressure (MPa) 9 10 11 12 13 14 15 16 17 18 19 Remaining in-flight start time s 6.66 22.91 37.78 51.44 64.04 75.70 86.52 96.56 105.98 114.76 122.99

[0113] Step 5: Compare the volume of oxygen required to fill the oxygen cylinder under different ambient temperatures and corresponding highest and lowest filling pressures with the volume of the oxygen cylinder to determine whether the oxygen cylinder's oxygen-carrying performance can meet the requirements.

[0114] The volume of oxygen required to fill the oxygen cylinder under different ambient temperatures and their corresponding highest and lowest filling pressures is smaller than the volume of the oxygen cylinder itself. The remaining air start-up time is greater than 0, and the oxygen cylinder's oxygen-carrying performance can meet the requirements.

[0115] The method for determining the oxygen-carrying performance of the oxygen cylinder in the oxygen replenishment subsystem of the aircraft propulsion system disclosed in the above embodiments takes into account the remaining unusable oxygen in the oxygen cylinder and calculates the oxygen-carrying performance of the oxygen cylinder using the van der Waals actual gas state equation. This method can efficiently and accurately determine whether the oxygen-carrying performance of the oxygen cylinder meets the requirements, providing effective guidance for the design of the oxygen replenishment subsystem and avoiding serious consequences such as insufficient engine oxygen supply, unsuccessful in-flight start-up, and excessive weight.

[0116] The technical solution of this application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. A method for determining the oxygen-carrying performance of an oxygen cylinder in an oxygen replenishment subsystem of an aircraft propulsion system, characterized in that, include: Step 1: Calculate the oxygen demand m1 for air starting of the engine; Step 2: Calculate the remaining unusable oxygen mass m2 in the oxygen cylinder; in, M is the molar mass of oxygen; V m0 The molar volume of the oxygen cylinder at the operating temperature and pressure. V0 is the volume of the oxygen cylinder; Step 3: Calculate the total mass of oxygen needed to fill the oxygen cylinder, m = m1 + m2; Step 4: Calculate the volume of oxygen required to fill the oxygen cylinder under different ambient temperatures and their corresponding highest and lowest filling pressures; in, V h The volume of oxygen required to fill the oxygen cylinder at the ambient temperature and the corresponding maximum filling pressure. ρ h The density of oxygen at the ambient temperature of the oxygen cylinder and its corresponding maximum filling pressure; p h This refers to the maximum filling pressure corresponding to the ambient temperature of the oxygen cylinder. 'a' is a phenomenological parameter that measures the intermolecular attraction of oxygen molecules; b is the volume contained within the oxygen molecule itself; V mh This represents the molar volume of oxygen at ambient temperature and its corresponding maximum filling pressure. R is the ideal gas constant; T1 is the ambient temperature of the oxygen cylinder; in, V l The volume of oxygen required to fill the oxygen cylinder at the ambient temperature and the corresponding minimum filling pressure. ρ l The density of oxygen at the ambient temperature of the oxygen cylinder and its corresponding minimum filling pressure; p l This refers to the minimum filling pressure corresponding to the ambient temperature of the oxygen cylinder. V ml This represents the molar volume of oxygen at ambient temperature and its corresponding minimum filling pressure. Step 5: Compare the volume of oxygen required to fill the oxygen cylinder under different ambient temperatures and corresponding highest and lowest filling pressures with the volume of the oxygen cylinder to determine whether the oxygen cylinder's oxygen-carrying performance can meet the requirements.

2. The method for determining the oxygen-carrying performance of the oxygen cylinder in the oxygen replenishment subsystem of an aircraft propulsion system according to claim 1, characterized in that, In step one, m1 = v × t × n; in, v represents the mass rate of oxygen replenishment required for engine air start-up. t represents the oxygen replenishment time for each engine start-up in the air; n represents the number of times the engine needs to be started and replenished with oxygen during air traffic control.

3. The method for determining the oxygen-carrying performance of the oxygen cylinder in the oxygen replenishment subsystem of an aircraft propulsion system according to claim 2, characterized in that, In step two, in, p0 represents the minimum pressure at the oxygen cylinder inlet when the oxygen supply subsystem is operating normally. T0 is the working temperature of the oxygen cylinder.

4. The method for determining the oxygen-carrying performance of the oxygen cylinder in the oxygen replenishment subsystem of an aircraft propulsion system according to claim 3, characterized in that, The oxygen supplementation subsystem operates at a normal p0 value of 2 MPa. The oxygen cylinder operating temperature T0 is taken as the lowest operating temperature.

5. The method for determining the oxygen-carrying performance of the oxygen cylinder in the oxygen replenishment subsystem of an aircraft propulsion system according to claim 4, characterized in that, The phenomenological parameter 'a', which measures the intermolecular attraction of oxygen molecules, is taken as 0.138m. 6 ·Pa·mol -2 ; The volume b contained within the oxygen molecule itself is taken as 3.18 × 10⁻⁶. -5 m 3 ·mol -1 ; The ideal gas constant R is taken as 8.314 Pa·m. 3 ·mol -1 ·K -1 .

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