Method and device for determining particle size in spacecraft plume

Abstract

The application provides a spacecraft wake cloud particle size determination method and device, and the method comprises the following steps: for a target particle micro-cluster in a wake cloud of a spacecraft engine, determining the number of particle collisions of particles in the target particle micro-cluster on a given motion path under the condition of the given motion path; and determining the final radius of the particles in the target particle micro-cluster after the particles collide and generate particle fusion according to the number of particle collisions. According to the scheme, the particle size in the wake cloud can be determined more accurately.

Description

Technical Field

[0001] This invention relates to the field of data processing technology, and in particular to a method and apparatus for determining the particle size in a spacecraft contrail cloud. Background Technology

[0002] With the increasing prevalence of aerospace activities, contrails caused by exhaust gases from aircraft and rocket engines have gradually attracted widespread attention. Contrail formation involves complex water vapor phase changes and is influenced by various conditions. To further examine the contrail diffusion state and analyze its signal characteristics, it is necessary to analyze the particle scale during the contrail diffusion process.

[0003] Currently, the Euler discrete phase model is used to calculate the particle scale in contrails, but the calculated results are significantly smaller than the actual particle scale. Therefore, there is an urgent need to provide a more accurate method for determining the particle scale. Summary of the Invention

[0004] This invention provides a method and apparatus for determining the particle size in a spacecraft contrail, which can more accurately determine the particle size in the contrail.

[0005] In a first aspect, embodiments of the present invention provide a method for determining the particle size in a spacecraft contrail cloud, comprising:

[0006] For a target particle cluster in the contrail of a spacecraft engine, under a given motion path, determine the number of particle collisions that occur between the particles in the target particle cluster on the given motion path.

[0007] Based on the number of particle collisions, the final radius of the particles in the target particle cluster after collision and particle fusion is determined.

[0008] Secondly, embodiments of the present invention also provide a device for determining the particle size in a spacecraft contrail cloud, comprising:

[0009] The collision number determination unit is used to determine the number of particle collisions that occur between particles in a target particle cluster on a given motion path, given a given motion path.

[0010] The radius determination unit is used to determine the final radius of the particles in the target particle cluster after collision and particle fusion, based on the number of particle collisions.

[0011] Thirdly, embodiments of the present invention also provide an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it implements the method described in any embodiment of this specification.

[0012] Fourthly, embodiments of the present invention also provide a computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to perform the methods described in any embodiment of this specification.

[0013] This invention provides a method and apparatus for determining the particle size in a spacecraft contrail. Since particles in a contrail collide with other particles during their motion, and fusion may occur after these collisions, the number of particle collisions along a given path can be determined. Based on this collision count, the final radius of the particle after collision and fusion can be determined. Therefore, this method fully considers the state of particle collision and fusion, resulting in a more accurate calculated particle radius. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a flowchart of a method for determining the particle size in a spacecraft contrail cloud, provided by an embodiment of the present invention.

[0016] Figure 2 This is a schematic diagram of a trajectory cloud flow field provided in an embodiment of the present invention;

[0017] Figure 3 This is a hardware architecture diagram of an electronic device provided in an embodiment of the present invention;

[0018] Figure 4 This is a structural diagram of a device for determining the particle size in a spacecraft contrail cloud, provided in an embodiment of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] Please refer to Figure 1This invention provides a method for determining the particle size in a spacecraft contrail cloud, the method comprising:

[0021] Step 100: For the target particle cluster in the contrail of the spacecraft engine, under a given motion path condition, determine the number of particle collisions that occur between the particles in the target particle cluster on the given motion path.

[0022] Step 102: Determine the final radius of the particles in the target particle cluster after collision and particle fusion based on the number of particle collisions.

[0023] In this embodiment of the invention, since particles in the contrail cloud collide with other particles during their movement, and fusion may occur after the collisions, the number of particle collisions in the target particle cluster along the given path can be determined under a given path. Then, based on this number of collisions, the final radius of the particle after collision and fusion can be determined. Therefore, this scheme fully considers the state of particle collision and fusion, resulting in a more accurate calculated particle radius.

[0024] The following is about the above. Figure 1 The execution method is described.

[0025] Within the contrail of a spacecraft engine, there is a two-phase flow field consisting of gas and droplets. Since the droplets are very small, similar to the size of molecules, a molecular collision probability model can be established based on the distribution of condensed droplets, referencing molecular dynamics collision probability models. In other words, it is assumed that in the calculated contrail flow field, starting from the engine nozzle exit, a newly generated particle moves along a given path, colliding with and merging with other particles along that path. Please refer to [reference needed]. Figure 2 The diagram shows the trajectory cloud flow field. l is the given motion path (the trajectory of the particle in the flow field), and s is the actual motion path of the particle. In reality, the particle motion is random, tortuous and irregular. In the process of realizing collision simulation, the relationship between s and l can be corrected by the collision path coefficient.

[0026] Assume that in a two-phase flow field of gas and droplets, the droplets moving from the nozzle exit are of number density N. 01 Radius r 01 A cluster of droplets; the droplets that collide with it while moving along a given path have a number density of N. 02 Radius r 02 For a small droplet, the velocity difference between two droplet clusters is denoted as dv. Considering a region with a certain length, width, and height, the probability that a small droplet in this region at time t will collide with and be absorbed by another droplet at time t+Δt is:

[0027]

[0028] Based on this, for a target particle cluster in the contrail of a spacecraft engine, under a given motion path condition, the number of particle collisions that occur in the target particle cluster on the given motion path can be determined.

[0029] In this embodiment of the invention, the number of particle collisions that occur in the target particle cluster along the given motion path includes the following three cases:

[0030] Case 1: If only internal collisions are considered, then the number of particle collisions is the number of internal collisions that occur between particles within the target particle cluster.

[0031] Case 2: If only external collisions are considered, then the number of particle collisions is the number of external collisions that occur between particles in the target particle cluster and particles in other particle clusters on the given motion path.

[0032] Case 3: Considering both internal and external collisions, the number of particle collisions is the sum of the number of internal collisions in Case 1 and the number of external collisions in Case 2.

[0033] Preferably, the number of particle collisions considers both internal and external collisions. Therefore, for case three above, step 102 may include the following steps 1020-1022:

[0034] Step 1020: Calculate the number of internal collisions, and calculate the final internal particle radius of the target particle cluster after the particles undergo internal collisions based on the number of internal collisions.

[0035] In one implementation, the number of internal collisions Cn1 is calculated using the following formula:

[0036] Cn1=k s ·π(2r1) 2 N1·dl

[0037] Where, k s denoted as the particle collision path coefficient, r1 as the radius of the particles in the target particle cluster before the particle collision, N1 as the number density of the target particle cluster before the particle collision, and dl as the search length of the given motion path.

[0038] It should be noted that when only considering the first scenario mentioned above, the number of internal collisions can also be calculated using the above formula.

[0039] In this embodiment of the invention, after determining the number of internal collisions, the final internal particle radius is calculated as follows:

[0040] After each internal collision, the radius of the particles in the target particle cluster after the current internal collision is calculated according to the following formula:

[0041] r 1post =((1+C n1 )(r 1pre ) 3 ) 1 / 3

[0042] Where, r 1post Let r be the radius of the particles in the target particle cluster after the internal collision. 1pre The radius of the particles in the target particle cluster prior to the internal collision occurred;

[0043] If the number of internal collisions accumulated after the current internal collision is equal to the number of internal collisions, then the radius of the particle in the target particle cluster after the current internal collision is taken as the final internal particle radius; otherwise, the calculation process for the next internal collision is initiated based on the radius of the particle in the target particle cluster after the current internal collision.

[0044] For example, assuming there are 3 internal collisions, after the first collision, the particle radius is calculated according to the above formula and then updated for the first time. The particle radius after the second collision is calculated using the above formula and the particle radius updated for the first time, and then updated for the second time. The particle radius after the third collision is calculated using the above formula and the particle radius updated for the second time, and this particle radius after the third collision is taken as the final internal particle radius.

[0045] It should be noted that when only the above case one is considered, the calculated final internal particle radius is determined as the final radius of the particles in the target particle cluster after collision and particle fusion.

[0046] Step 1022: Calculate the number of external collisions, and calculate the final radius of the particles in the target particle cluster after the external collisions based on the number of external collisions and the final internal particle radius.

[0047] In one implementation, the number of external collisions Cn2 is calculated using the following formula:

[0048] Cn2=k s ·π(r1+r2) 2 N2·dv·dt

[0049]

[0050]

[0051] Where, k s Here, r1 is the radius of the particle in the target particle cluster before the particle collision, r2 is the radius of the particle in other particle clusters that collide with the particle in the target particle cluster along the given motion path, N2 is the number density of the other particle clusters before the particle collision, dv and dt are intermediate parameters, and k is the particle collision path coefficient. v is the particle velocity fluctuation coefficient, (u,v,w) are the velocities in the three directions in the three-axis coordinate system, and dl is the search length of the given motion path.

[0052] It should be noted that when only considering case two above, the number of external collisions can also be calculated using the above formula.

[0053] After calculating the number of external collisions, the final radius r of the particles in the target particle cluster after the external collisions can be calculated using the following formula. fin :

[0054] r fin =((r 1fin ) 3 +(C n2 ·r2) 3 ) 1 / 3

[0055] Where, r 1fin Cn2 is the final internal particle radius, Cn2 is the number of external collisions, and r2 is the radius of the particles in other particle clusters that collide with the particles in the target particle cluster on the given motion path.

[0056] It should be noted that, when only considering case two above, the final radius r of the particles in the target particle cluster after an external collision can be calculated using the following formula. fin :

[0057] r fin =C n2 ·r2

[0058] Wherein, Cn2 is the number of external collisions, and r2 is the radius of the particles in other particle clusters that collide with the particles in the target particle cluster on the given motion path.

[0059] like Figure 3 , Figure 4 As shown, this invention provides a device for determining the particle size in a spacecraft contrail. The device can be implemented in software, hardware, or a combination of both. From a hardware perspective, such as... Figure 3The diagram shown is a hardware architecture diagram of an electronic device for determining particle size in a spacecraft contrail cloud, provided by an embodiment of the present invention. Besides... Figure 3 In addition to the processor, memory, network interface, and non-volatile memory shown, the electronic device in the embodiment may also include other hardware, such as a forwarding chip responsible for processing packets. Taking software implementation as an example, such as... Figure 4 As shown, a device in a logical sense is formed by the CPU of its host electronic device reading the corresponding computer program from non-volatile memory into memory and running it. This embodiment provides a device for determining the particle size in a spacecraft contrail cloud, comprising:

[0060] The collision number determination unit 401 is used to determine the number of particle collisions that occur in the target particle micro-cluster on the given motion path under a given motion path condition for the target particle micro-cluster in the contrail cloud of the spacecraft engine.

[0061] The radius determination unit 402 is used to determine the final radius of the particles in the target particle cluster after collision and particle fusion, based on the number of particle collisions.

[0062] In one embodiment of the present invention, the number of particle collisions that occur in the target particle cluster on the given motion path includes: the number of internal collisions of particles within the target particle cluster; and / or the number of external collisions of particles in the target particle cluster with particles in other particle clusters on the given motion path.

[0063] In one embodiment of the present invention, when the number of particle collisions includes the number of internal collisions and the number of external collisions, the radius determination unit is specifically used for:

[0064] Calculate the number of internal collisions, and calculate the final internal particle radius of the target particle cluster after the particles undergo internal collisions based on the number of internal collisions;

[0065] The number of external collisions is calculated, and based on the number of external collisions and the final internal particle radius, the final radius of the particles in the target particle cluster after the external collisions is calculated.

[0066] In one embodiment of the present invention, the number of internal collisions Cn1 is calculated by the following formula:

[0067] Cn1=k s ·π(2r1) 2 N1·dl

[0068] Where, k sdenoted as the particle collision path coefficient, r1 as the radius of the particles in the target particle cluster before the particle collision, N1 as the number density of the target particle cluster before the particle collision, and dl as the search length of the given motion path.

[0069] In one embodiment of the present invention, when the radius determination unit performs the calculation of the final internal particle radius of the particles in the target particle cluster after internal collisions based on the number of internal collisions, it specifically includes:

[0070] After each internal collision, the radius of the particles in the target particle cluster after the current internal collision is calculated according to the following formula:

[0071] r 1post =((1+C n1 )(r 1pre ) 3 ) 1 / 3

[0072] Where, r 1post Let r be the radius of the particles in the target particle cluster after the internal collision. 1pre The radius of the particles in the target particle cluster prior to the internal collision occurred;

[0073] If the number of internal collisions accumulated after the current internal collision is equal to the number of internal collisions, then the radius of the particle in the target particle cluster after the current internal collision is taken as the final internal particle radius; otherwise, the calculation process for the next internal collision is initiated based on the radius of the particle in the target particle cluster after the current internal collision.

[0074] In one embodiment of the present invention, the number of external collisions Cn2 is calculated by the following formula:

[0075] Cn2=k s ·π(r1+r2) 2 N2·dv·dt

[0076]

[0077]

[0078] Where, k s Here, r1 is the radius of the particle in the target particle cluster before the particle collision, r2 is the radius of the particle in other particle clusters that collide with the particle in the target particle cluster along the given motion path, N2 is the number density of the other particle clusters before the particle collision, dv and dt are intermediate parameters, and k is the particle collision path coefficient. vis the particle velocity fluctuation coefficient, (u,v,w) are the velocities in the three directions in the three-axis coordinate system, and dl is the search length of the given motion path.

[0079] In one embodiment of the present invention, the final radius r of the particles in the target particle cluster after an external collision is calculated by the following formula. fin :

[0080] r fin =((r 1fin ) 3 +(C n2 ·r2) 3 ) 1 / 3

[0081] Where, r 1fin Cn2 is the final internal particle radius, Cn2 is the number of external collisions, and r2 is the radius of the particles in other particle clusters that collide with the particles in the target particle cluster on the given motion path.

[0082] It is understood that the structures illustrated in the embodiments of the present invention do not constitute a specific limitation on a device for determining the particle size in a spacecraft contrail. In other embodiments of the present invention, a device for determining the particle size in a spacecraft contrail may include more or fewer components than illustrated, or combine some components, or split some components, or arrange different components. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0083] The information interaction and execution process between the modules in the above-mentioned device are based on the same concept as the method embodiment of the present invention, and the specific details can be found in the description of the method embodiment of the present invention, and will not be repeated here.

[0084] This invention also provides an electronic device, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements a method for determining the particle size in a spacecraft contrail cloud according to any embodiment of this invention.

[0085] This invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform a method for determining the particle size in a spacecraft contrail cloud according to any embodiment of this invention.

[0086] Specifically, a system or apparatus equipped with a storage medium may be provided, on which software program code implementing the functions of any of the embodiments described above is stored, and the computer (or CPU or MPU) of the system or apparatus may read and execute the program code stored in the storage medium.

[0087] In this case, the program code read from the storage medium can itself implement the function of any of the above embodiments, and therefore the program code and the storage medium storing the program code constitute part of the present invention.

[0088] Examples of storage media used to provide program code include floppy disks, hard disks, magneto-optical disks, optical disks (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), magnetic tapes, non-volatile memory cards, and ROMs. Alternatively, program code can be downloaded from a server computer via a communication network.

[0089] Furthermore, it should be clear that not only can the program code read by the computer be executed, but also the operating system or other components operating on the computer can be instructed based on the program code to perform some or all of the actual operations, thereby realizing the function of any of the embodiments described above.

[0090] Furthermore, it is understood that the program code read from the storage medium is written to the memory set in the expansion board inserted into the computer or to the memory set in the expansion module connected to the computer. Then, based on the instructions of the program code, the CPU or other components installed on the expansion board or expansion module execute some and all of the actual operations, thereby realizing the function of any of the above embodiments.

[0091] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0092] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium includes various media that can store program code, such as ROM, RAM, magnetic disk, or optical disk.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for determining the particle size in a spacecraft contrail cloud, characterized in that, include: For a target particle cluster in the contrail of a spacecraft engine, under a given motion path, determine the number of particle collisions that occur between the particles in the target particle cluster on the given motion path. Based on the number of particle collisions, determine the final radius of the particles in the target particle cluster after collision and particle fusion; The number of particle collisions that occur in the target particle cluster on the given motion path includes: the number of internal collisions that occur within the target particle cluster; and / or the number of external collisions that occur between the particles in the target particle cluster and particles in other particle clusters on the given motion path. When the number of particle collisions includes the number of internal collisions and the number of external collisions, determining the final radius of the particles in the target particle cluster after collision and particle fusion based on the number of particle collisions includes: calculating the number of internal collisions and calculating the final internal particle radius of the particles in the target particle cluster after internal collisions based on the number of internal collisions; calculating the number of external collisions and calculating the final radius of the particles in the target particle cluster after external collisions based on the number of external collisions and the final internal particle radius.

2. The method according to claim 1, characterized in that, The number of internal collisions It is calculated using the following formula: in, For particle collision path coefficients, The radius of the particles in the target particle cluster before the particle collision occurs. This refers to the number density of the target particle cluster before the particle collision occurs. The search length for the given motion path.

3. The method according to claim 2, characterized in that, The step of calculating the final internal particle radius of the target particle cluster after internal collisions based on the number of internal collisions includes: After each internal collision, the radius of the particles in the target particle cluster after the current internal collision is calculated according to the following formula: in, This refers to the radius of the particles within the target particle cluster after the internal collision. The radius of the particles in the target particle cluster prior to the internal collision occurred; If the number of internal collisions accumulated after the current internal collision is equal to the number of internal collisions, then the radius of the particle in the target particle cluster after the current internal collision is taken as the final internal particle radius; otherwise, the calculation process for the next internal collision is initiated based on the radius of the particle in the target particle cluster after the current internal collision.

4. The method according to claim 1, characterized in that, The number of external collisions It is calculated using the following formula: in, For particle collision path coefficients, The radius of the particles in the target particle cluster before the particle collision occurs. Let be the radius of the particles in other particle clusters that collide externally with the particles in the target particle cluster along the given motion path. This represents the number density of the other particle clusters before the particle collision occurs. , For intermediate parameters, The particle velocity fluctuation coefficient. Let be the velocity in the three directions in the three-axis coordinate system. The search length for the given motion path.

5. The method according to claim 1, characterized in that, The final radius of the particles in the target particle cluster after an external collision is calculated using the following formula. : in, The final internal particle radius, The number of external collisions. The radius of the particles in other particle clusters that collide with the particles in the target particle cluster on the given motion path.

6. A device for determining the particle size in a spacecraft contrail cloud, characterized in that, For performing the method as described in any one of claims 1-5 above, comprising: The collision number determination unit is used to determine the number of particle collisions that occur between particles in a target particle cluster on a given motion path, given a given motion path. The radius determination unit is used to determine the final radius of the particles in the target particle cluster after collision and particle fusion, based on the number of particle collisions.

7. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, and the processor, when executing the computer program, implements the method as described in any one of claims 1-5.

8. A computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to perform the method of any one of claims 1-5.

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