A method for fast prediction of noise environment in launch vehicle fairing
By using computational and experimental methods to rapidly predict the noise environment inside the launch vehicle fairing, the design problem of the noise environment inside the fairing of newly developed launch vehicles has been solved, supporting the rapid iteration of satellite design and newly developed launch vehicles.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI AEROSPACE SYST ENG INST
- Filing Date
- 2023-04-17
- Publication Date
- 2026-06-23
AI Technical Summary
Existing technologies cannot quickly and accurately predict the noise environment inside the fairing of newly developed launch vehicles, which leads to delays in satellite design. Simulation prediction methods are time-consuming and rely on detailed full-rocket structural models, making them unsuitable for rapid iteration of newly developed launch vehicles.
By acquiring the total noise of the jet stream at the center of the first-stage engine nozzle of the launch vehicle, and combining the fairing geometry and flight trajectory data, empirical formulas for noise attenuation and transmission and aerodynamic noise are used to calculate the noise environment inside the fairing. The total jet noise and sound insulation are determined by experimental and calculation methods, and the noise environment inside the fairing is quickly predicted.
It enables rapid and accurate prediction of the noise environment inside the fairing of a newly developed launch vehicle, providing a reliable basis for satellite design and supporting the rapid iterative design of the new launch vehicle.
Smart Images
Figure CN116541952B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of launch vehicle technology, and particularly relates to a method for rapid prediction of the noise environment inside the launch vehicle fairing. Background Technology
[0002] During the active flight phase of launch, the takeoff jet noise caused by the rocket's engine operation and the aerodynamic noise during transonic flight create a harsh noise environment within the fairing, adversely affecting the integrity of the satellite structure and the normal operation of onboard equipment. Therefore, at the initial stage of satellite design, corresponding mechanical environmental analysis and testing must be conducted based on the noise environment conditions provided by the launch vehicle system to ensure the satellite's adaptability to the appropriate flight noise environment. Thus, the rationality of the noise environment conditions within the fairing provided by the launch vehicle system has a significant impact on the satellite's design and development.
[0003] For existing launch vehicles, the noise environment conditions inside the fairing can be revised and improved based on actual flight telemetry data due to the availability of multiple flight telemetry data. However, for newly developed launch vehicles, since no flight tests have been conducted, it is impossible to design the noise environment conditions inside the fairing based on actual flight telemetry data. Furthermore, for satellites carrying newly developed launch vehicles, the noise environment conditions inside the fairing need to be provided during the launch vehicle development stage for satellite design. Therefore, for newly developed launch vehicles, the noise environment inside the fairing can only be addressed through prediction. Prediction of the noise environment inside the fairing typically employs methods such as the finite element method and statistical energy method for simulation prediction. However, simulation prediction requires a relatively detailed full-rocket structural model, and the simulation calculations are time-consuming, which is not conducive to the rapid iterative verification of newly developed launch vehicle designs. Summary of the Invention
[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a method for rapid prediction of the noise environment inside the fairing of a launch vehicle. This method can quickly predict the noise environment inside the fairing of a newly developed launch vehicle, thus solving the design problem of noise environment conditions inside the fairing of a newly developed launch vehicle.
[0005] To address the aforementioned technical problems, this invention discloses a method for rapid prediction of the noise environment inside a launch vehicle fairing, comprising:
[0006] Step 1: Obtain the total noise of the central jet stream from the nozzle of the first-stage engine of the launch vehicle;
[0007] Step 2: Determine the fairing feature interface based on the launch vehicle fairing geometry, and calculate the distance from the fairing feature interface to the interface where the core stage engine nozzle is located.
[0008] Step 3: Based on the total noise of the jet stream at the center of the first stage engine nozzle of the launch vehicle obtained in Step 1 and the distance from the fairing feature interface to the interface where the first stage engine nozzle is located calculated in Step 2, the external noise of the jet stream at the fairing feature interface is calculated using the empirical formula for noise attenuation and transmission.
[0009] Step 4: Based on the flight motion pressure on the outer surface of the fairing at different flight Mach speeds obtained from the flight trajectory calculation results of the launch vehicle, the maximum aerodynamic external noise of the fairing during the transonic flight phase is calculated using the empirical formula for aerodynamic noise.
[0010] Step 5: Based on the jet noise at the fairing feature interface obtained in Step 3 and the maximum aerodynamic noise of the fairing during the transonic flight phase calculated in Step 4, the maximum sound pressure level spectral envelope of the fairing is calculated.
[0011] Step 6: Based on the maximum sound pressure level spectral envelope of the fairing calculated in Step 5, and combined with the sound insulation of the fairing section, calculate the noise inside the fairing.
[0012] The aforementioned method for rapid prediction of noise environment inside the launch vehicle fairing also includes:
[0013] The total noise of the central jet stream from the nozzle of the first-stage engine of a launch vehicle is determined by experimental or computational methods.
[0014] The sound insulation of the fairing section is determined by experimental or calculation methods.
[0015] In the aforementioned rapid prediction method for the noise environment inside the launch vehicle fairing, the total noise of the central jet stream from the core stage engine nozzle of the launch vehicle is determined through experimental methods, including:
[0016] Conduct test firings of the core first-stage engine of a launch vehicle;
[0017] The total noise of the jet stream at the center of the nozzle of the first stage engine of the launch vehicle was extracted from the test results of the test.
[0018] In the aforementioned rapid prediction method for the noise environment inside the launch vehicle fairing, the total noise of the central jet stream from the core stage engine nozzle of the launch vehicle is determined through calculation, including:
[0019] The noise Z at the center of the nozzle of a single-core stage engine is calculated using the following formula. 0a :
[0020] Z 0a =120+10log 10 (αFV)-R
[0021] Where F represents the thrust of a single core stage engine, V represents the jet velocity of a single core stage engine, α represents the jet acoustic efficiency factor of a single core stage engine, and R represents the jet direction factor related to the jet direction and frequency of a single core stage engine.
[0022] Then, the total noise of the central jet stream from the nozzles of n core stage engines, i.e., the total noise Z0 of the central jet stream from the nozzles of the launch vehicle's core stage engines, is:
[0023] Z0 = 10 × log 10 (n×10 Z0a / 10 ).
[0024] In the aforementioned rapid prediction method for the noise environment inside the launch vehicle fairing, the sound insulation of the fairing section is determined through experimental methods, including:
[0025] Conduct full-scale fairing noise tests;
[0026] The sound insulation of the fairing section was extracted from the full-scale fairing noise test results.
[0027] In the aforementioned rapid prediction method for the noise environment inside the launch vehicle fairing, the sound insulation of the fairing section is determined through experimental or calculation methods, including:
[0028] A full-scale simulation analysis model of the fairing was established using the finite element method and the statistical energy method.
[0029] Based on the full-size simulation analysis model of the fairing, acoustic-vibration coupling analysis and calculation were carried out to obtain the sound insulation of the fairing section.
[0030] In the aforementioned method for rapid prediction of the noise environment inside the launch vehicle fairing, the empirical formula for noise attenuation and transmission is expressed as follows:
[0031]
[0032] Where Z0 represents the total noise of the central jet stream from the core stage engine nozzle of the launch vehicle, L represents the distance from the fairing feature interface to the interface where the core stage engine nozzle is located, Z L This represents the external noise of the jet stream at the characteristic interface of the fairing, where B is a constant.
[0033] In the aforementioned rapid prediction method for the noise environment inside the launch vehicle fairing, based on the flight kinematic pressure on the outer surface of the fairing at different flight Mach velocities obtained from the launch vehicle's flight trajectory calculations, the maximum external aerodynamic noise of the fairing during the transonic flight phase is calculated using empirical formulas for aerodynamic noise, including:
[0034] Based on the flight trajectory calculations of the launch vehicle, the corresponding flight kinematic pressures on the outer surface of the fairing at different Mach velocities are obtained. Using the following empirical formula for aerodynamic noise, the aerodynamic external noise L of the fairing at different Mach velocities during the transonic flight phase is calculated. P :
[0035]
[0036] Where M represents the flight Mach number, q represents the flight kinematic pressure on the outer surface of the fairing corresponding to the flight Mach number M, and C q Indicates the pulsating pressure coefficient;
[0037] The maximum value of the fairing aerodynamic external noise at different flight Mach speeds is taken as the maximum aerodynamic external noise L of the fairing during transonic flight. Pmax .
[0038] In the aforementioned rapid prediction method for the noise environment inside the launch vehicle fairing, based on the external noise of the jet at the fairing characteristic interface obtained in step 3 and the maximum aerodynamic external noise of the fairing during the transonic flight phase calculated in step 4, the maximum sound pressure level spectral envelope of the fairing is calculated, including:
[0039] Determine the sound pressure level spectrum of the jet external noise at the fairing feature interface obtained in step 3, and the sound pressure level spectrum of the maximum aerodynamic external noise of the fairing during the transonic flight phase calculated in step 4.
[0040] The maximum envelope of the sound pressure level spectrum of the jet external noise at the characteristic interface of the fairing and the maximum sound pressure level spectrum of the maximum aerodynamic external noise of the fairing during transonic flight are taken as the maximum sound pressure level spectrum envelope Z of the fairing. pw .
[0041] In the aforementioned rapid prediction method for the noise environment inside the launch vehicle fairing, the calculation formula for the noise inside the fairing is as follows:
[0042] Z pn =Z pw -ΔZ
[0043] Among them, Z pn The noise level inside the fairing is represented by ΔZ, which represents the sound insulation of the fairing section. pw This represents the spectral envelope of the fairing's maximum sound pressure level.
[0044] The present invention has the following advantages:
[0045] This invention discloses a method for rapid prediction of the noise environment inside a launch vehicle fairing, which can quickly predict the noise environment inside a newly developed launch vehicle fairing and solve the design problem of noise environment conditions inside a newly developed launch vehicle fairing. Attached Figure Description
[0046] Figure 1 This is a flowchart illustrating the steps of a method for rapid prediction of noise environment inside a launch vehicle fairing according to an embodiment of the present invention;
[0047] Figure 2 This is a schematic diagram of the total noise of the central jet stream from the nozzle of a first-stage engine of a launch vehicle according to an embodiment of the present invention;
[0048] Figure 3 This is a schematic diagram of external noise from the jet at a characteristic interface of the fairing in an embodiment of the present invention;
[0049] Figure 4 This is a schematic diagram of the maximum aerodynamic external noise of the fairing during transonic flight in an embodiment of the present invention;
[0050] Figure 5 This is a schematic diagram of the maximum external noise envelope of a fairing in an embodiment of the present invention;
[0051] Figure 6 This is a schematic diagram comparing the maximum external noise envelope and the internal noise of a fairing in an embodiment of the present invention. Detailed Implementation
[0052] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments disclosed herein will be described in further detail below with reference to the accompanying drawings.
[0053] like Figure 1 In this embodiment, the method for rapid prediction of the noise environment inside the launch vehicle fairing includes:
[0054] Step 1: Obtain the total noise of the center jet stream from the nozzle of the first-stage engine of the launch vehicle.
[0055] In this embodiment, the total noise Z0 of the central jet stream from the nozzle of the first-stage engine of the launch vehicle core can be determined by experimental or computational methods, such as... Figure 2 As shown.
[0056] The test method is as follows: Conduct a test run of the first stage engine of the launch vehicle core; extract the total noise of the central jet stream of the first stage engine nozzle from the test results of the launch vehicle core engine core.
[0057] The calculation method is as follows:
[0058] The noise Z at the center of the nozzle of a single-core stage engine is calculated using the following formula. 0a :
[0059] Z 0a =120+10log 10 (αFV)-R
[0060] Then, the total noise of the central jet stream from the nozzles of n core stage engines, i.e., the total noise Z0 of the central jet stream from the nozzles of the launch vehicle's core stage engines, is:
[0061] Z0 = 10 × log 10 (n×10 Z0a / 10 )
[0062] Where F represents the thrust of a single core stage engine, V represents the jet velocity of a single core stage engine, α represents the jet acoustic efficiency factor of a single core stage engine, and R represents the jet direction factor related to the jet direction and frequency of a single core stage engine.
[0063] Step 2: Determine the fairing feature interface based on the launch vehicle fairing geometry, and calculate the distance from the fairing feature interface to the interface where the core stage engine nozzle is located.
[0064] In this embodiment, the center surface of the fairing section can be selected as the fairing feature interface based on the geometric configuration of the launch vehicle fairing; then, based on the overall design structure of the launch vehicle, the distance L from the fairing feature interface to the interface where the core stage engine nozzle is located can be calculated.
[0065] Step 3: Based on the total noise of the jet stream at the center of the first stage engine nozzle of the launch vehicle obtained in Step 1 and the distance from the fairing feature interface to the interface where the first stage engine nozzle is located calculated in Step 2, the external noise of the jet stream at the fairing feature interface is calculated using the empirical formula for noise attenuation and transmission.
[0066] In this embodiment, the empirical formula for noise attenuation and transmission is expressed as follows:
[0067]
[0068] Among them, Z L This represents the external noise of the jet stream at the characteristic interface of the fairing, where B is a constant.
[0069] Preferably, when B = 3.2, the external noise of the jet at the characteristic interface of the fairing can be calculated. like Figure 3 As shown.
[0070] Step 4: Based on the flight motion pressure on the outer surface of the fairing at different flight Mach velocities obtained from the flight trajectory calculation results of the launch vehicle, the maximum aerodynamic external noise of the fairing during the transonic flight phase is calculated using the empirical formula for aerodynamic noise.
[0071] In this embodiment, the aerodynamic external noise L of the fairing at different flight Mach velocities obtained from the launch vehicle's flight trajectory calculations can be calculated using the following empirical formula for aerodynamic noise, based on the flight kinematic pressure on the fairing's outer surface at different flight Mach velocities during the transonic flight phase. P :
[0072]
[0073] Where M represents the flight Mach number, q represents the flight kinematic pressure on the outer surface of the fairing corresponding to the flight Mach number M, and C q This represents the pulsating pressure coefficient.
[0074] Furthermore, the maximum value of the fairing aerodynamic external noise at different flight Mach speeds is taken as the maximum aerodynamic external noise L of the fairing during transonic flight. Pmax .
[0075] Preferred, C q =0.02, M=1.1, q=2.06*10 4 When Pa, L is calculated at this time. P =144.92dB, and this value is the maximum value throughout the flight, then L Pmax =144.92dB, such as Figure 4 As shown.
[0076] Step 5: Based on the external noise of the jet stream at the fairing characteristic interface obtained in Step 3 and the maximum aerodynamic external noise of the fairing during the transonic flight phase calculated in Step 4, the maximum sound pressure level spectral envelope of the fairing is calculated.
[0077] In this embodiment, firstly, the sound pressure level spectrum of the jet external noise at the fairing characteristic interface obtained in step 3, and the sound pressure level spectrum of the maximum aerodynamic external noise of the fairing during the transonic flight phase calculated in step 4 are determined; then, the maximum envelope of the sound pressure level spectrum of the jet external noise at the fairing characteristic interface and the sound pressure level spectrum of the maximum aerodynamic external noise of the fairing during the transonic flight phase are taken as the envelope Z of the maximum sound pressure level spectrum of the fairing. pw ,like Figure 5 As shown.
[0078] Step 6: Based on the maximum sound pressure level spectral envelope of the fairing calculated in Step 5, and combined with the sound insulation of the fairing section, calculate the noise inside the fairing.
[0079] In this embodiment, the sound insulation of the fairing section can be determined by experimental or calculation methods.
[0080] The test method is as follows: conduct a full-size fairing noise test; extract the sound insulation of the fairing section from the full-size fairing noise test results.
[0081] The calculation method is as follows: A full-size simulation analysis model of the fairing is established using the finite element method and the statistical energy method; based on the full-size simulation analysis model of the fairing, acoustic-vibration coupling analysis is carried out to obtain the sound insulation of the fairing section.
[0082] The formula for calculating the noise inside the fairing is as follows:
[0083] Z pn =Z pw -ΔZ
[0084] Among them, Z pn ΔZ represents the noise level inside the fairing, and ΔZ represents the sound insulation of the fairing section.
[0085] Preferably, if the sound insulation ΔZ of the fairing section is 4.6 dB, then the noise Z inside the fairing will be... pn Z pn =Z pw -4.6dB, such as Figure 6 As shown.
[0086] This invention discloses a method for rapid prediction of the noise environment inside a launch vehicle fairing, which has been successfully applied in the development of a new generation of solid-propellant launch vehicles, providing an important reference for the design of noise environment conditions inside the fairing.
[0087] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.
[0088] The contents not described in detail in this specification are common knowledge to those skilled in the art.
Claims
1. A method for fast prediction of the noise environment inside a launch vehicle fairing, characterized in that, The method comprises the following steps: Step 1, obtaining the total noise of the core stage engine nozzle center jet of the launch vehicle; Step 2, determining the fairing characteristic interface according to the geometric configuration of the fairing of the launch vehicle, and calculating the distance from the fairing characteristic interface to the interface where the core stage engine nozzle is located; Step 3, based on the total noise of the core stage engine nozzle center jet of the launch vehicle obtained in step 1 and the distance from the fairing characteristic interface to the interface where the core stage engine nozzle is located calculated in step 2, the jet noise outside the fairing characteristic interface is calculated by using a noise attenuation transfer empirical formula; Step 4, according to the corresponding fairing outer surface flight dynamic pressure at different flight Mach numbers obtained from the flight trajectory calculation result of the launch vehicle, the maximum aerodynamic external noise of the fairing in the transonic flight stage is calculated by using an aerodynamic noise empirical formula; Step 5, based on the jet noise outside the fairing characteristic interface obtained in step 3 and the maximum aerodynamic external noise of the fairing in the transonic flight stage calculated in step 4, the maximum sound pressure level spectral envelope of the fairing is calculated; Step 6, based on the maximum sound pressure level spectral envelope of the fairing calculated in step 5, and combined with the sound insulation of the fairing cabin section, the internal noise of the fairing is calculated.
2. The launch vehicle fairing interior noise environment quick prediction method of claim 1, wherein, Further comprising: determining the total noise of the core stage engine nozzle center jet of the launch vehicle by a test method or a calculation method; determining the sound insulation of the fairing cabin section by a test method or a calculation method.
3. The launch vehicle fairing interior noise environment quick prediction method of claim 2, wherein, The total noise of the core stage engine nozzle center jet of the launch vehicle is determined by a test method, comprising: carrying out a core stage engine test of the launch vehicle; extracting the total noise of the core stage engine nozzle center jet of the launch vehicle from the test results of the core stage engine of the launch vehicle.
4. The launch vehicle fairing interior noise environment quick prediction method of claim 2, wherein, The total noise of the core stage engine nozzle center jet of the launch vehicle is determined by a calculation method, comprising: The jet noise Z of the center jet of the single-core first-stage engine nozzle is calculated by the following formula 0a : Z 0a = 120 + 10 log 10 (αFV)-R wherein F represents the thrust of a single core stage engine, V represents the jet velocity of a single core stage engine, a represents the jet sound efficiency factor of a single core stage engine, and R represents the jet direction factor related to the jet direction and frequency of a single core stage engine; then, the total noise of the core stage engine nozzle center jet of n core stage engines, that is, the total noise of the core stage engine nozzle center jet of the launch vehicle Z0 is:
5. The launch vehicle fairing interior noise environment quick prediction method of claim 2, wherein, The sound insulation of the fairing cabin section is determined by a test method, comprising: carrying out a full-size fairing noise test; extracting the sound insulation of the fairing cabin section from the test results of the full-size fairing noise test.
6. The launch vehicle fairing interior noise environment quick prediction method of claim 2, wherein, The sound insulation of the fairing cabin section is determined by a test method or a calculation method, comprising: establishing a full-size simulation analysis model of the fairing by using a finite element method and a statistical energy method; carrying out a sound-vibration coupling analysis and calculation based on the full-size simulation analysis model of the fairing to obtain the sound insulation of the fairing cabin section.
7. The launch vehicle fairing interior noise environment quick prediction method of claim 1, wherein, The noise attenuation transfer empirical formula is as follows: Wherein, Z0 represents the total noise of the core stage engine nozzle center jet of the launch vehicle, L represents the distance from the fairing characteristic interface to the interface where the core stage engine nozzle is located, Z L represents the jet noise outside the fairing characteristic interface, and B is a constant.
8. The launch vehicle fairing interior noise environment quick prediction method of claim 1, wherein, According to the corresponding fairing outer surface flight dynamic pressure at different flight Mach numbers obtained from the flight trajectory calculation result of the launch vehicle, the maximum aerodynamic external noise of the fairing in the subsonic flight stage is calculated by using an aerodynamic noise empirical formula, comprising: According to the flight trajectory calculation results of the carrier rocket, the corresponding flight pressure outside the fairing surface at different flight Mach numbers is obtained, and the following empirical formula of aerodynamic noise is used to calculate the aerodynamic external noise of the fairing at different flight Mach numbers in the transonic flight stage P : wherein M represents a flight Mach number, q represents a flight dynamic pressure on the outside surface of the fairing corresponding to the flight Mach number M, C q represents a pulsation pressure coefficient; The maximum value of the fairing aerodynamic external noise at different flight Mach numbers is taken as the maximum fairing aerodynamic external noise L during the transonic flight stage Pmax .
9. The launch vehicle fairing interior noise environment quick prediction method of claim 1, wherein, Based on the jet noise outside the fairing characteristic interface obtained in step 3 and the maximum aerodynamics external noise of the fairing in the transonic flight stage calculated in step 4, the fairing maximum sound pressure level spectral envelope is calculated, comprising: Determine the sound pressure level spectrum of the jet external noise at the fairing feature interface obtained in step 3, and the sound pressure level spectrum of the maximum aerodynamic external noise of the fairing during the transonic flight phase calculated in step 4. The maximum envelope of the sound pressure level spectrum of the external noise of the jet at the interface of the fairing features and the maximum sound pressure level spectrum of the external noise of the fairing during the transonic flight phase, as the maximum sound pressure level spectrum envelope of the fairing Z pw .
10. The launch vehicle fairing interior noise environment quick prediction method of claim 1, wherein, The formula for calculating the noise inside the fairing is as follows: Z pn = Z pw - ΔZ where Z pn represents the noise inside the fairing, ΔZ represents the sound reduction index of the fairing cabin section, Z pw represents the maximum sound pressure level spectrum envelope of the fairing.