Optimization method for reducing the unusable amount of propellant caused by mixture ratio deviation

Abstract

The present invention relates to an optimization method for reducing the unusable amount of propellant caused by a mixture ratio deviation, comprising: S1, obtaining the unusable amount of propellant caused by the mixture ratio deviation based on the propellant mixture ratio, the mixture ratio deviation and the initial filling amount of the propellant; S2, adding fuel to optimize and reduce the unusable amount of propellant, obtaining the optimal additional fuel filling amount and the optimized unusable amount of propellant. The method of the present invention can effectively optimize and reduce the unusable amount of propellant caused by the mixture ratio deviation of large spacecraft.

Description

Technical Field

[0001] The present invention relates to the technical field of bipropellant propulsion systems, and in particular to an optimization method for reducing the unusable amount of propellant caused by mixing ratio deviation of a bipropellant propulsion system. Background Art

[0002] Spacecraft using bipropellant propulsion systems generally have a small amount of unusable propellant, of which the largest amount is caused by deviation in the propellant mixture ratio. Due to limitations in engine specific impulse, spacecraft weight, and other factors, there is an urgent need for efficient use of propellant in manned deep space exploration spacecraft. The unusable propellant in a bipropellant propulsion system is mainly composed of four parts: propellant tank residue, pipeline residue, unbalanced discharge from parallel tanks of the same component, and unusable propellant caused by deviation in the oxygen-fuel mixture ratio. Domestic research on the control of unusable propellant has mainly focused on reducing the unusable propellant caused by imbalance in tank discharge, but less research has been conducted on reducing the unusable propellant caused by deviation in the mixture ratio. Summary of the Invention

[0003] In order to reduce the amount of unusable propellant caused by mixture ratio deviation of large spacecraft, the present invention provides an optimization method for reducing the amount of unusable propellant caused by mixture ratio deviation.

[0004] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is:

[0005] The present invention provides an optimization method for reducing the unusable amount of propellant caused by mixing ratio deviation, comprising:

[0006] S1. Obtaining an unusable amount of propellant caused by the propellant mixture ratio deviation based on the propellant mixture ratio, the mixture ratio deviation, and the initial propellant filling amount;

[0007] S2. Add fuel to optimize and reduce the unusable amount of propellant, and obtain the optimal additional fuel amount and the optimized unusable amount of propellant.

[0008] According to one aspect of the present invention, the calculation model of the unusable amount of propellant caused by the mixture ratio deviation is:

[0009]

[0010] Where M represents the initial propellant filling amount, δσ represents the mixture ratio deviation, and σ represents the propellant mixing ratio.

[0011] According to one aspect of the present invention, the propellant includes an oxidizer and a fuel.

[0012] According to one aspect of the present invention, step S2 includes: increasing the fuel consumption oxidizer, and using the relationship between the additional fuel filling amount and the unavailable propellant amount to obtain the minimum value of the unavailable propellant amount, which is the optimized unavailable propellant amount, and the corresponding additional fuel filling amount, which is the optimal additional fuel filling amount.

[0013] According to one aspect of the present invention, the relationship between the additional fuel filling amount and the unusable propellant amount is: when the additional fuel filling amount is small, the unusable propellant amount decreases as the additional fuel filling amount increases, and the unusable propellant amount at this time is oxidizer; when the additional fuel filling amount increases to a certain level, the unusable propellant amount increases as the additional fuel filling amount increases, and the unusable propellant amount at this time is fuel.

[0014] According to one aspect of the present invention, the calculation model of the optimal additional fuel filling amount is:

[0015]

[0016] Where M represents the initial propellant filling amount, δσ represents the mixture ratio deviation, and σ represents the propellant mixing ratio.

[0017] According to one aspect of the present invention, the calculation model of the optimized unusable amount of propellant is:

[0018]

[0019] Where M represents the initial propellant filling amount, δσ represents the mixture ratio deviation, and σ represents the propellant mixing ratio.

[0020] Beneficial effects:

[0021] According to the solution of the present invention, an optimization method for reducing the unavailable propellant amount caused by the mixture ratio deviation of the bipropellant propulsion system is implemented by increasing the fuel, and a calculation model for the minimum unavailable propellant amount and the optimal fuel filling amount caused by the mixture ratio deviation of the bipropellant propulsion system is established. This can effectively avoid the problem of excessive unavailable propellant amount caused by the mixture ratio deviation of existing large spacecraft, and has been successfully applied to the assessment and control of unavailable propellant amount of manned spacecraft, which helps to determine and optimize the available amount of propellant for attitude and orbit control during the flight phase and the initial propellant filling amount, and establish clear constraint conditions for spacecraft flight mission planning. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0023] Figure 1 A flow chart schematically illustrating an optimization method for reducing the unusable amount of propellant caused by a mixture ratio deviation according to an embodiment of the present invention;

[0024] Figure 2 A diagram schematically showing the relationship between the unusable amount of propellant and the increase in the additional fuel filling amount according to one embodiment of the present invention;

[0025] Figure 3 A diagram schematically showing the relationship between the unusable amount of propellant before optimization, the unusable amount of propellant after optimization, and the propellant mixing ratio according to one embodiment of the present invention;

[0026] Figure 4 A diagram schematically shows the relationship between the unusable amount of propellant before optimization, the unusable amount of propellant after optimization, and the propellant mixing ratio deviation according to one embodiment of the present invention. DETAILED DESCRIPTION

[0027] The description of the embodiments in this specification should be combined with the corresponding drawings, which should be considered a complete part of this specification. In the drawings, the shapes and thicknesses of the embodiments may be exaggerated and indicated for simplicity or convenience. Furthermore, the various structural components in the drawings will be described separately. It is worth noting that components not shown in the drawings or not described in words are known to those of ordinary skill in the art.

[0028] The description of the embodiments herein and any references to directions and orientations are for ease of description only and are not to be construed as limiting the scope of the present invention. The following description of the preferred embodiments may involve combinations of features, which may exist independently or in combination. The present invention is not specifically limited to the preferred embodiments. The scope of the present invention is defined by the claims.

[0029] like Figure 1 As shown, the optimization method for reducing the unusable amount of propellant caused by the mixture ratio deviation of this embodiment includes the following steps:

[0030] S1. Obtaining an unusable amount of propellant caused by the propellant mixture ratio deviation based on the propellant mixture ratio, the mixture ratio deviation, and the initial propellant filling amount;

[0031] S2. Add fuel to optimize and reduce the unusable amount of propellant, and obtain the optimal additional fuel amount and the optimized unusable amount of propellant.

[0032] In this embodiment, the propellant comprises an oxidizer and a fuel. Assuming the oxidizer density of the bipropellant propulsion system is ρ1, the fuel density is ρ2, and the nominal isochoric mixing ratio σ = ρ1 / ρ2 ≥ 1, the total mass of propellant injected at this isochoric mixing ratio is M. In practice, due to variations in pipeline layout, length, and flow resistance, the actual propellant mixing ratio will vary slightly. The actual mixing ratio can be expressed as σ ± δσ.

[0033] In step S1, the calculation model of the unusable amount of propellant P caused by the obtained mixture ratio deviation is:

[0034]

[0035] Where M represents the initial propellant filling amount, δσ represents the mixture ratio deviation, and σ represents the propellant mixing ratio.

[0036] In order to reduce the above-mentioned unusable amount of propellant, step S2 specifically includes: increasing the fuel consumption of oxidizer, and using the relationship between the additional fuel filling amount and the unusable amount of propellant to obtain the optimized unusable amount of propellant and the optimal additional fuel filling amount. By increasing the fuel consumption of oxidizer, it is ensured that the oxidizer is consumed first, and the lighter density fuel is left, thereby reducing the unusable amount of propellant. Assuming that the mass of the added fuel is m, the masses of the oxidizer and fuel initially filled in the spacecraft are respectively and

[0037] When the fuel overfill is low, the oxidizer residue is high, and the unusable propellant decreases as the fuel overfill increases. At this point, the unusable propellant is equal to the oxidizer residue. When the fuel overfill increases to a certain level, the fuel residue is high, and the unusable propellant increases as the fuel overfill increases. At this point, the unusable propellant is equal to the fuel residue. Therefore, there is a minimum value for the unusable propellant caused by mixture ratio deviation, which is the optimized unusable propellant, and the corresponding fuel overfill is the optimal fuel overfill.

[0038] In step S2, the calculation model of the optimal additional fuel filling amount obtained when the unavailable amount of propellant is the smallest is:

[0039]

[0040] Where M represents the initial propellant filling amount, δσ represents the mixture ratio deviation, and σ represents the propellant mixing ratio.

[0041] In step S2, the optimized (minimum) unusable amount of propellant is obtained as

[0042]

[0043] Where M represents the initial propellant filling amount, δσ represents the mixture ratio deviation, and σ represents the propellant mixing ratio.

[0044] This embodiment takes the optimization analysis of the unusable amount of propellant in a manned spacecraft propulsion system as an example. Assuming the propellant mixing ratio σ = 1.65, the mixing ratio deviation δσ = 0.024, and the constant volume propellant filling amount M = 20000 kg, the additional fuel filling amount m and the remaining amount of oxidizer in the tank Δm are given. o and the remaining fuel amount Δm f As the additional fuel filling amount m increases, the relationship changes as follows Figure 2 As shown. When the additional fuel filling amount is small, the remaining amount of oxidizer in the tank is the unusable amount of propellant; when the additional fuel filling amount increases to a certain level, the remaining amount of fuel is the unusable amount of propellant. The unusable amount of propellant caused by the mixture ratio deviation has a minimum value, at which the additional fuel filling amount m e =27.77kg, minimum unusable propellant quantity P e =135.98 kg. Compared with the unusable amount of propellant P = 181.13 kg before optimization, the unusable amount of propellant is reduced or decreased by 45.15 kg after optimization by the above method.

[0045] In order to further analyze and verify the optimization effect of the optimization method for reducing the unusable amount of propellant caused by the mixture ratio deviation, the unusable amount of propellant before and after optimization was analyzed when the propellant mixture ratio deviation was fixed. The unusable amount of propellant before optimization P and the unusable amount of propellant after optimization P were e The relationship with the propellant mixing ratio σ is as follows: Figure 3 As shown in Figure 2, it can be seen that the optimization method can significantly reduce the unusable amount of propellant, and the larger the propellant mixing ratio, the more obvious the optimization effect. Secondly, the unusable amount of propellant before and after optimization when the propellant mixing ratio is fixed is analyzed. The unusable amount of propellant before optimization P and the unusable amount of propellant after optimization P are the same. e The relationship with the propellant mixture ratio deviation δσ is as follows: Figure 4 As shown in the figure, it can be seen that with the increase of the mixture ratio deviation, the unusable amount of propellant increases. At the same time, the unusable amount of propellant reduced by optimization is greater, and the optimization effect is more obvious.

[0046] The serial numbers of the above-mentioned steps involved in the method of the present invention do not mean the order of execution of the method. The execution order of each step should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An optimization method for reducing the unusable amount of propellant caused by a mixture ratio deviation, comprising: S1. Based on the propellant mixing ratio, the mixing ratio deviation and the initial filling amount of the propellant, obtain the unusable amount of propellant caused by the mixing ratio deviation; S2. Add fuel to optimize and reduce the unusable amount of propellant, and obtain the optimal additional fuel filling amount and the optimized unusable amount of propellant; The calculation model of the unusable amount of propellant caused by the mixing ratio deviation is: Where M represents the initial amount of propellant, δσ represents the mixture ratio deviation, and σ represents the propellant mixture ratio; The calculation model of the optimal additional fuel filling amount is: Where M represents the initial amount of propellant, δσ represents the mixture ratio deviation, and σ represents the propellant mixture ratio; The calculation model of the optimized unusable amount of propellant is: Where M represents the initial amount of propellant, δσ represents the mixing ratio deviation, and σ represents the propellant mixing ratio.

2. The method according to claim 1, characterized in that The propellant includes an oxidizer and a fuel.

3. The method according to claim 2, characterized in that The step S2 includes: increasing the fuel consumption oxidizer, and using the relationship between the additional fuel filling amount and the unavailable propellant amount to obtain the minimum value of the unavailable propellant amount, which is the optimized unavailable propellant amount, and the corresponding additional fuel filling amount, which is the optimal additional fuel filling amount.

4. The method according to claim 3, characterized in that The relationship between the additional fuel filling amount and the unusable propellant amount is: when the additional fuel filling amount is small, the unusable propellant amount decreases with the increase of the additional fuel filling amount, and the unusable propellant at this time is the oxidizer; when the additional fuel filling amount increases to a certain extent, the unusable propellant amount increases with the increase of the additional fuel filling amount, and the unusable propellant at this time is the fuel.

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