Aircraft environmental control system noise index decomposition secondary index determination method

Abstract

The invention belongs to the technical field of aircraft environmental control system acoustic design, and particularly relates to an aircraft environmental control system noise index decomposition secondary index determination method, which comprises the following steps: according to environmental control system noise composition, decomposing an environmental control system noise primary index into each cabin air outlet noise secondary index and an under-floor environmental control system component noise secondary index; and noise design of an aircraft environment control system and subsystems thereof can be effectively guided.

Description

Technical Field

[0001] The present application belongs to the technical field of acoustic design of aircraft environmental control systems, and specifically relates to a method for determining secondary indicators of aircraft environmental control system noise index decomposition. Background Art

[0002] When an aircraft is developed, overall cabin noise indicators will be proposed. Environmental control system noise is an important source of cabin noise. Therefore, during the specific design, the overall cabin noise indicators will be converted into environmental control system noise indicators to guide the noise design of the environmental control system.

[0003] However, the aircraft environmental control system is complex, including environmental control pipelines, compressors, turbines, fans and other subsystems. It is difficult to effectively guide the noise design of the aircraft environmental control system and its subsystems based only on the first-level indicator such as the environmental control system noise index.

[0004] This application is proposed in view of the above-mentioned technical defects. Summary of the invention

[0005] The purpose of this application is to provide a method for determining secondary indicators of aircraft environmental control system noise index decomposition, so as to be able to decompose the primary indicator of environmental control system noise into secondary indicators of subsystems, so as to effectively guide the noise design of aircraft environmental control system and its subsystems.

[0006] The technical solution of this application is:

[0007] A method for determining secondary indicators of aircraft environmental control system noise index decomposition, comprising:

[0008] Step 1: Convert the overall cabin noise index into the first-level index of environmental control system noise;

[0009] Step 2: List the direct sound field sound pressure level index L on the floor of each compartment I Calculation formula of

[0010] Step 3: List the diffuse sound field sound pressure level index L on the floor of each compartment D Calculation formula of

[0011] Step 4: Construct the direct sound field sound pressure level index L on the floor of each cabin I , the diffuse sound field sound pressure level index L on the floor of each compartment D , and the equation relationship between the first-level noise index L of the control system, calculate the second-level noise index L of the air outlet of each compartment W ;

[0012] Step 5: List the diffuse sound field sound pressure level index L under the floor of each compartment D 'Calculation formula;

[0013] Step 6: List the calculation formula for the sound pressure level index L' radiated from the underfloor environmental control components of each compartment to the passenger's ear position;

[0014] Step 7: Construct the diffuse sound field sound pressure level index L under the floor of each compartment D ', the sound pressure level index L' of the environmental control components under the floor of each compartment radiated to the passenger ear position, and the equation relationship between the first-level index L of the control system noise, and the calculation of the second-level index L of the environmental control system components under the floor W '.

[0015] According to at least one embodiment of the present application, in the above-mentioned method for determining the secondary index of the aircraft environmental control system noise index decomposition, step 1 is specifically as follows:

[0016] According to the overall cabin noise index, the turbulent boundary layer noise of each cabin section, engine noise and body sound insulation are used as input to calculate the first-level noise index L of the environmental control system.

[0017] According to at least one embodiment of the present application, in the above-mentioned method for determining the secondary index of the aircraft environmental control system noise index decomposition, step 1 is specifically as follows:

[0018] Take 10dBA lower than the overall cabin noise index as the first-level index L of the environmental control system noise.

[0019] According to at least one embodiment of the present application, in the above-mentioned method for determining the secondary index of the aircraft environmental control system noise index decomposition, step 1 is specifically as follows:

[0020] Based on the overall cabin noise index, the turbulent boundary layer noise of each cabin section, engine noise and fuselage sound insulation are used as input to calculate the first level index of the environmental control system noise;

[0021] Take 10dBA lower than the overall cabin noise index as the first-level index of the second environmental control system noise;

[0022] The smaller value of the first environmental control system noise level indicator and the second environmental control system noise level indicator is taken as the environmental control system noise level indicator L.

[0023] According to at least one embodiment of the present application, in the above-mentioned method for determining the secondary index of the aircraft environmental control system noise index decomposition, in step 2, the direct sound field sound pressure level index L on the floor of each cabin section is listed. I The calculation formula is as follows:

[0024] L I =L W -10log 10 (4πR 2 )+3;

[0025] in,

[0026] R is the distance between the passenger ears in each cabin section and the air outlet.

[0027] According to at least one embodiment of the present application, in the above-mentioned method for determining the secondary index of the aircraft environmental control system noise index decomposition, in step 3, the diffuse sound field sound pressure level index L on the floor of each cabin section is listed. D The calculation formula is as follows:

[0028]

[0029] in,

[0030] A is the total sound absorption of each compartment.

[0031] According to at least one embodiment of the present application, in the above-mentioned method for determining secondary indicators of aircraft environmental control system noise index decomposition, step three includes:

[0032]

[0033] in,

[0034] s i is the sound absorption surface area on the floor of the i-th compartment;

[0035] a i is the floor sound absorption coefficient in the i-th compartment;

[0036] n is the number of compartments.

[0037] According to at least one embodiment of the present application, in the above-mentioned method for determining the secondary index of the aircraft environmental control system noise index decomposition, in step 4, the direct sound field sound pressure level index L on the floor of each cabin section is constructed. I , the diffuse sound field sound pressure level index L on the floor of each compartment D , and the equation relationship between the first-level noise index L of the control system, calculate the second-level noise index L of the air outlet of each compartment W , specifically:

[0038]

[0039] According to at least one embodiment of the present application, in the above-mentioned method for determining the secondary index of the aircraft environmental control system noise index decomposition, in step 5, the diffuse sound field sound pressure level index L under the floor of each cabin section is listed. D The calculation formula of ' is as follows:

[0040]

[0041] in,

[0042] A' is the total sound absorption under the floor of each compartment.

[0043] According to at least one embodiment of the present application, in the above-mentioned method for determining the secondary index of the aircraft environmental control system noise index decomposition, in step 6, the calculation formula of the sound pressure level index L' radiated from the environmental control components under the floor of each cabin section to the passenger ear position is listed, specifically:

[0044]

[0045] in,

[0046] TL is the sound transmission loss of the floor of each compartment;

[0047] S' is the floor area of ​​each compartment.

[0048] According to at least one embodiment of the present application, in the above-mentioned method for determining the secondary index of the aircraft environmental control system noise index decomposition, in step seven, the diffuse sound field sound pressure level index L under the floor of each cabin section is constructed. D ', the sound pressure level index L' of the environmental control components under the floor of each compartment radiated to the passenger ear position, and the equation relationship between the first-level index L of the control system noise, and the calculation of the second-level index L of the environmental control system components under the floor W ', specifically:

[0049]

[0050] According to at least one embodiment of the present application, in the above-mentioned method for determining the secondary index of the aircraft environmental control system noise index decomposition, the secondary index L of the air outlet noise of each cabin section W Corresponding to the index requirements for broadband noise caused by environmental control pipes and nozzles and harmonic noise caused by compressors, turbines and fans;

[0051] Secondary noise index of underfloor environmental control system components L W 'Corresponds to the index requirements for radiated noise caused by system components such as underfloor environmental control system boxes and fans.

[0052] According to at least one embodiment of the present application, in the above-mentioned method for determining the secondary index of the aircraft environmental control system noise index decomposition, the aircraft fuselage compartment is divided into multiple typical areas, and the secondary index L of the air outlet noise of each compartment is calculated respectively. W , Noise level 2 index of underfloor environmental control system components L W 'The secondary indicators are calculated.

[0053] According to at least one embodiment of the present application, in the above-mentioned method for determining secondary indicators of aircraft environmental control system noise index decomposition, the aircraft fuselage compartment is divided into multiple typical areas, specifically four typical areas.

[0054] According to at least one embodiment of the present application, in the above-mentioned method for determining secondary indicators of aircraft environmental control system noise index decomposition, the four typical areas include:

[0055] FWD area: the fuselage frame section corresponding to the section from fuselage section 1 frame to the wing leading edge;

[0056] WNG area: the fuselage frame section corresponding to the section from the wing leading edge to the wing trailing edge;

[0057] AFT Front area: the front half of the wing trailing edge section from the fuselage frame section to the rounded end frame;

[0058] AFT Rear area: The rear half of the wing trailing edge section from the fuselage frame section to the circular end frame.

[0059] This application has at least the following beneficial technical effects:

[0060] A method for determining secondary indicators of aircraft environmental control system noise index decomposition is provided. According to the noise composition of the environmental control system, the primary indicator of the environmental control system noise is decomposed into secondary indicators of the air outlet noise of each cabin section and secondary indicators of the noise of the environmental control system components under the floor, which can effectively guide the noise design of the aircraft environmental control system and its subsystems. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is a schematic diagram of a method for determining secondary indicators of aircraft environmental control system noise index decomposition provided in an embodiment of the present application.

[0062] In order to better illustrate the present embodiment, some contents of the drawings may be omitted, which is only used for illustrative purposes and should not be construed as limiting the present application. DETAILED DESCRIPTION

[0063] In order to make the technical solution and advantages of the present application clearer, the technical solution of the present application will be described in further detail in detail and in detail with reference to the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present application, which are only used to explain the present application, not to limit the present application. It should be noted that, for the convenience of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design.

[0064] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of this application shall have the usual meanings understood by those of ordinary skill in the art to which this application belongs. The words used in the description of this application to indicate orientation are only used to indicate relative directions or positional relationships. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. The word "include" used in the description of this application indicates that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, but does not exclude other elements or objects.

[0065] In addition, it should be noted that, unless otherwise clearly specified and limited, the words "installation", "connection" and similar terms used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Technical personnel in the field can understand its specific meaning in this application according to the specific circumstances.

[0066] A method for determining secondary indicators of aircraft environmental control system noise index decomposition, such as Figure 1 shown.

[0067] According to the contribution of environmental control system noise to cabin noise, the environmental control system noise can be decomposed into broadband noise caused by environmental control pipes and nozzles, harmonic noise caused by compressors, turbines and fans, and radiated noise caused by system components such as the underfloor environmental control system box section and fans.

[0068] Among them, the broadband noise caused by environmental control pipelines and nozzles is transmitted into the cabin in the form of aerodynamic noise at the air outlet; the harmonic noise caused by the compressor, turbine and fan is transmitted into the cabin in the form of aerodynamic noise at the air outlet; the radiated noise caused by system components such as the underfloor environmental control system box section and fan is transmitted into the cabin through the floor.

[0069] According to the noise composition of the environmental control system, the first-level index of the environmental control system noise can be decomposed into the second-level index of the noise of the air outlets of each compartment and the second-level index of the noise of the environmental control system components under the floor.

[0070] Among them, the secondary indicators of the air outlet noise of each compartment correspond to the index requirements of the broadband noise caused by the environmental control pipelines and nozzles and the harmonic noise caused by the compressor, turbine and fan, which can be the first acoustic subsystem requirements; the secondary indicators of the noise of the underfloor environmental control system components correspond to the index requirements of the radiated noise caused by the underfloor environmental control system box section and fan and other system components, which can be the second acoustic subsystem requirements.

[0071] Step 1: Convert the overall cabin noise index into the first-level index L of the environmental control system noise.

[0072] According to the overall cabin noise index, the turbulent boundary layer noise of each cabin section, engine noise and body sound insulation can be used as input to calculate the first-level index L of the environmental control system noise. The data format should generally be A-weighted sound pressure level.

[0073] Based on experience, we can take 10dBA lower than the overall cabin noise index as the first-level index L of the environmental control system noise.

[0074] The smaller value of the above two can also be taken as the first-level indicator L of the environmental control system noise.

[0075] Step 2: List the direct sound field sound pressure level index L on the floor of each compartment I Calculation formula.

[0076] L I =L W -10log 10 (4πR 2 )+3;

[0077] in,

[0078] L W It is the secondary index of the noise at the air outlet of each compartment;

[0079] R is the distance between the passenger ears in each cabin section and the air outlet.

[0080] Step 3: List the diffuse sound field sound pressure level index L on the floor of each compartment D Calculation formula.

[0081]

[0082] in,

[0083] A is the total sound absorption of each compartment.

[0084]

[0085] in,

[0086] s i is the sound absorption surface area on the floor of the i-th compartment;

[0087] a i is the floor sound absorption coefficient in the i-th compartment;

[0088] n is the number of compartments.

[0089] Step 4: Construct the direct sound field sound pressure level index L on the floor of each cabin I , the diffuse sound field sound pressure level index L on the floor of each compartment D , and the equation relationship between the first-level noise index L of the control system, calculate the second-level noise index L of the air outlet of each compartment W .

[0090]

[0091] Step 5: List the diffuse sound field sound pressure level index L under the floor of each compartment D 'Calculation formula.

[0092]

[0093] in,

[0094] L W'It is the secondary indicator of noise of underfloor environmental control system components;

[0095] A' is the total sound absorption under the floor of each compartment, which can be calculated by referring to the total sound absorption A of each compartment.

[0096] Step 6: List the calculation formula for the sound pressure level index L' radiated from the underfloor environmental control components of each cabin section to the passenger ear level.

[0097]

[0098] in,

[0099] TL is the sound transmission loss of the floor of each compartment;

[0100] S' is the floor area of ​​each compartment.

[0101] Step 7: Construct the diffuse sound field sound pressure level index L under the floor of each compartment D ', the sound pressure level index L' of the environmental control components under the floor of each compartment radiated to the passenger ear position, and the equation relationship between the first-level index L of the control system noise, and the calculation of the second-level index L of the environmental control system components under the floor W '.

[0102]

[0103] When the above-mentioned method for determining the secondary index of the noise index decomposition of the aircraft environmental control system is specifically applied, in order to ensure that the amount of data is moderate and easy to process, the fuselage compartment of the aircraft can be divided into four typical areas, and the secondary index L of the air outlet noise of each compartment is calculated respectively. W , Noise level 2 index of underfloor environmental control system components L W 'The secondary indicators are calculated, and the four typical areas include:

[0104] FWD area: the fuselage frame section corresponding to the section from fuselage section 1 frame to the wing leading edge;

[0105] WNG area: the fuselage frame section corresponding to the section from the wing leading edge to the wing trailing edge;

[0106] AFT Front area: the front half of the wing trailing edge section from the fuselage frame section to the rounded end frame;

[0107] AFT Rear area: The rear half of the wing trailing edge section from the fuselage frame section to the circular end frame.

[0108] The method for determining secondary indicators of aircraft environmental control system noise index decomposition disclosed in the above embodiment decomposes the primary indicator of environmental control system noise into secondary indicators of noise at the air outlets of each cabin section and secondary indicators of noise of underfloor environmental control system components according to the noise composition of the environmental control system, which can effectively guide the noise design of the aircraft environmental control system and its subsystems.

[0109] So far, the technical solution of the present 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 the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present 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 fall within the scope of protection of the present application.

Claims

1. A method for determining secondary indicators of aircraft environmental control system noise index decomposition, characterized in that: include: Step 1: Convert the overall cabin noise index into the first-level index of environmental control system noise; Step 2: List the direct sound field sound pressure level index L on the floor of each compartment I Calculation formula of Step 3: List the diffuse sound field sound pressure level index L on the floor of each compartment D Calculation formula of Step 4: Construct the direct sound field sound pressure level index L on the floor of each cabin I , the diffuse sound field sound pressure level index L on the floor of each compartment D , and the equation relationship between the first-level noise index L of the control system, calculate the second-level noise index L of the air outlet of each compartment W ; Step 5: List the diffuse sound field sound pressure level index L under the floor of each compartment D 'Calculation formula; Step 6: List the calculation formula for the sound pressure level index L' radiated from the underfloor environmental control components of each compartment to the passenger's ear position; Step 7: Construct the diffuse sound field sound pressure level index L under the floor of each compartment D ', the sound pressure level index L' of the environmental control components under the floor of each compartment radiated to the passenger ear position, and the equation relationship between the first-level index L of the control system noise, and the calculation of the second-level index L of the environmental control system components under the floor W '.

2. The method for determining secondary indicators of aircraft environmental control system noise index decomposition according to claim 1, characterized in that: Step 1 is as follows: According to the overall cabin noise index, the turbulent boundary layer noise of each cabin section, engine noise and body sound insulation are used as input to calculate the first-level noise index L of the environmental control system.

3. The method for determining secondary indicators of aircraft environmental control system noise index decomposition according to claim 2, characterized in that: Step 1 is as follows: Take 10dBA lower than the overall cabin noise index as the first-level index L of the environmental control system noise.

4. The method for determining secondary indicators of aircraft environmental control system noise index decomposition according to claim 3, characterized in that: Step 1 is as follows: Based on the overall cabin noise index, the turbulent boundary layer noise of each cabin section, engine noise and fuselage sound insulation are used as input to calculate the first level index of the environmental control system noise; Take 10dBA lower than the overall cabin noise index as the first-level index of the second environmental control system noise; The smaller value of the first environmental control system noise level indicator and the second environmental control system noise level indicator is taken as the environmental control system noise level indicator L.

5. The method for determining secondary indicators of aircraft environmental control system noise index decomposition according to claim 4, characterized in that: In step 2, the direct sound field sound pressure level index L on the floor of each compartment is listed. I The calculation formula is as follows: L I =L W -10log 10 (4πR 2 )+3; in, R is the distance between the passenger ears in each cabin section and the air outlet.

6. The method for determining secondary indicators of aircraft environmental control system noise index decomposition according to claim 5, characterized in that: In step 3, the diffuse sound field sound pressure level index L on the floor of each compartment is listed. D The calculation formula is as follows: in, A is the total sound absorption of each compartment.

7. The method for determining secondary indicators of aircraft environmental control system noise index decomposition according to claim 6, characterized in that: In step three, there are: in, s i is the sound absorption surface area on the floor of the i-th compartment; a i is the floor sound absorption coefficient in the i-th compartment; n is the number of compartments.

8. The method for determining secondary indicators of aircraft environmental control system noise index decomposition according to claim 7, characterized in that: In step 4, the direct sound field sound pressure level index L on the floor of each compartment is constructed. I , the diffuse sound field sound pressure level index L on the floor of each compartment D , and the equation relationship between the first-level noise index L of the control system, calculate the second-level noise index L of the air outlet of each compartment W , specifically:

9. The method for determining secondary indicators of aircraft environmental control system noise index decomposition according to claim 8, characterized in that: In step 5, the diffuse sound field sound pressure level index L under the floor of each compartment is listed. D The calculation formula of ' is as follows: in, A' is the total sound absorption under the floor of each compartment.

10. The method for determining secondary indicators of aircraft environmental control system noise index decomposition according to claim 9, characterized in that: In step 6, the calculation formula for the sound pressure level index L' radiated from the underfloor environmental control components of each compartment to the passenger's ear position is listed, specifically: in, TL is the sound transmission loss of the floor of each compartment; S' is the floor area of ​​each compartment.

11. The method for determining secondary indicators of aircraft environmental control system noise index decomposition according to claim 10, characterized in that: In step 7, the diffuse sound field sound pressure level index L under the floor of each compartment is constructed. D ', the sound pressure level index L' of the environmental control components under the floor of each compartment radiated to the passenger ear position, and the equation relationship between the first-level index L of the control system noise, and the calculation of the second-level index L of the environmental control system components under the floor W ', specifically:

12. The method for determining secondary indicators of aircraft environmental control system noise index decomposition according to claim 11, characterized in that: Secondary index of noise at each compartment outlet L W Corresponding to the index requirements for broadband noise caused by environmental control pipelines and nozzles and harmonic noise caused by compressors, turbines and fans; Secondary noise index of underfloor environmental control system components L W 'Corresponds to the index requirements for radiated noise caused by system components such as underfloor environmental control system boxes and fans.

13. The method for determining secondary indicators of aircraft environmental control system noise index decomposition according to claim 12, characterized in that: The aircraft fuselage compartment is divided into several typical areas, and the secondary index L of the air outlet noise of each compartment is calculated. W , Noise level 2 index of underfloor environmental control system components L W 'The secondary indicators are calculated.

14. The method for determining secondary indicators of aircraft environmental control system noise index decomposition according to claim 13, characterized in that: The aircraft fuselage compartment is divided into multiple typical areas, specifically four typical areas.

15. The method for determining secondary indicators of aircraft environmental control system noise index decomposition according to claim 14, characterized in that: Four typical areas include: FWD area: the fuselage frame section corresponding to the section from fuselage section 1 frame to the wing leading edge; WNG area: the fuselage frame section corresponding to the section from the wing leading edge to the wing trailing edge; AFT Front area: the front half of the wing trailing edge section from the fuselage frame section to the rounded end frame; AFT Rear area: The rear half of the wing trailing edge section from the fuselage frame section to the rounded end frame.

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