阅读说明：本技术 水面船舶推进系统与辅机系统水下噪声贡献分离测试方法 (Underwater noise contribution separation test method for water surface ship propulsion system and auxiliary engine system ) 是由 武国启 程广福 吴伋 刘波 吕振望 张智鹏 于 2020-04-09 设计创作，主要内容包括：本发明的水面船舶推进系统与辅机系统水下噪声贡献分离测试方法,属于船舶水下噪声源测试分析技术领域,可解决水面船舶推进系统与辅机系统水下噪声实船测试方法的问题。本发明的主要技术特征在于,设计辅机系统运行状态相同的船舶匀速航行工况与停车滑行工况,通过水下噪声测试系统,测量匀速航行工况与停车滑行工况水下噪声,采用能量对比分析方法,获取推进系统噪声与辅机系统噪声。采用本发明的水面船舶推进系统与辅机系统水下噪声贡献分离测试方法,可准确分离船舶推进系统噪声与辅机系统噪声,满足水下噪声源贡献分离方法实船试验验证需求。(The invention discloses a method for separately testing underwater noise contribution of a surface ship propulsion system and an auxiliary engine system, belongs to the technical field of ship underwater noise source test analysis, and can solve the problem of a real ship test method of underwater noise of the surface ship propulsion system and the auxiliary engine system. The method is mainly technically characterized in that a ship constant-speed sailing working condition and a parking and sliding working condition with the same operation state of an auxiliary engine system are designed, underwater noises of the constant-speed sailing working condition and the parking and sliding working condition are measured through an underwater noise test system, and the noise of a propulsion system and the noise of the auxiliary engine system are obtained by adopting an energy comparison analysis method. By adopting the underwater noise contribution separation testing method for the water surface ship propulsion system and the auxiliary engine system, the noise of the ship propulsion system and the noise of the auxiliary engine system can be accurately separated, and the real ship test verification requirement of the underwater noise source contribution separation method is met.)

1. The method for separating and testing the underwater noise contribution of the water surface ship propulsion system and the auxiliary system is characterized in that a ship constant-speed sailing working condition and a parking and sliding working condition which are the same as the auxiliary system in operation state are designed, the underwater noise of the constant-speed sailing working condition and the parking and sliding working condition is measured through an underwater noise testing system, the noise of the propulsion system and the noise of the auxiliary system are obtained by adopting an energy comparison analysis method, and the separation of the underwater noise contribution of the propulsion system and the auxiliary system is realized.

2. The method of claim 1, wherein:

(1) designing test working conditions to be a ship constant-speed sailing working condition and a parking sliding working condition with the same operation state of an auxiliary engine system, wherein each test working condition is not less than 4 single passes, and the test of the left side and the right side is not less than 2 single passes respectively;

(2) selecting 1 or more hydrophones and a data acquisition instrument to construct an underwater sound measuring system, wherein the measuring frequency range of the underwater sound measuring system is 10Hz-50kHz, the measuring precision is not less than 16 bits, and the sampling rate is not less than 2.56 times of the maximum measuring frequency;

(3) selecting differential GPS equipment or underwater acoustic ranging equipment to establish a distance measuring system, wherein the distance measuring system can acquire the distance from a hydrophone to a ship to be measured in real time, and the distance measuring precision is better than 2 m;

(4) an underwater noise test system is composed of an underwater sound measurement system and a distance measurement system, and the measurement uncertainty is less than 3 dB;

(5) selecting a test sea area with water depth of more than 60m, sea condition of not more than 3 levels and background noise meeting the requirement that signal-to-noise ratio is more than 3 dB;

(6) the underwater noise testing system is distributed before measurement, the distribution depth of the hydrophones is more than 10m, if a plurality of hydrophones are adopted for measurement, the hydrophones are distributed at equal intervals along the depth direction relative to the same position of the water surface, and the interval is more than 10 m;

(7) for the test of the constant-speed navigation working condition, the tested ship keeps the test working condition state and travels straight at a constant speed, the straight-line distance between a ship route and a hydrophone is 1 time of the ship length, the deviation is less than +/-10%, the measurement is started when the tested ship is 2 times of the ship length away from the straight transverse position, the measurement of parameters of the distance from the hydrophone to the tested ship is synchronously carried out, the tested ship passes through the straight transverse position according to the ship route, the measurement is finished when the ship is 2 times of the ship length away from the straight transverse position, and the next one-way test is prepared after the one-way measurement is finished until all the one-way tests of the constant-speed navigation working condition are finished;

(8) for the parking and sliding working condition test, except that the tested ship testing working condition states are different, other testing requirements are the same as the constant-speed sailing working condition, namely the ship sails linearly at a constant speed before measurement, when the measurement is started, the main engine is parked, the running states of other auxiliary engine systems are kept unchanged, the ship sails linearly by means of inertia, and after the measurement is finished, the main engine is started to recover the constant-speed sailing working condition state;

(9) taking the position from a host in the ship length direction to the midpoint of a propeller as an equivalent acoustic center of ship underwater noise, selecting the range of +/-45 degrees between the acoustic center and a hydrophone, taking the range as an underwater noise data analysis period, dividing the data analysis starting moment to the ending moment into a plurality of data windows, selecting the length of each data window according to 10-degree step length, respectively calculating the acoustic pressure level L 'of each data window according to 1/3oct frequency band within the frequency band of 10Hz-50kHz and corresponding center moments of-40 degrees, -35 degrees, …, -5 degrees, 0 degrees, +5 degrees, … degrees, +35 degrees and +40 degrees'_p+n(r_k，w_j，h_i，f_e) Wherein r is_kIs the kth single pass, w_jIs the jth data window, h_iIs the ith hydrophone, f_eIs the e-th band center frequency;

(10) calculating background noise according to equation (1)

In the formula, L_nstart(r_k，h_i，f_e) And L_nend(r_k，h_i，f_e) Scene noise before and after each single measurement is respectively measured;

(11) calculating the sound pressure level after the background noise is corrected according to the formula (2) and the formula (3) when the signal-to-noise ratio is more than 10dB and the signal-to-noise ratios are more than 3dB and less than 10dB respectively

L′_p(r_k，w_j，h_i，f_e)＝L′_p+n(r_k，w_j，h_i，f_e) (2)

(12) Calculating the equivalent sound center sound source level according to the formula (4) and the formula (5)

TL(D(r_k，w_j，h_i，f_e))＝20 log(D(r_k，w_j，h_i，f_e)) (4)

L_p(r_k，w_j，h_i，f_e)＝L′_p(r_k，w_j，h_i，f_e)+TL(D(r_k，w_j，h_i，f_e)) (5)

In the formula, D (r)_k，w_j，h_i，f_e) Distance between the hydrophone and the equivalent acoustic center;

(13) data averaging was performed according to equations (6), (7) and (8)

(14) Calculating underwater noise of test working condition according to formula (9)

(15) The propulsion system noise and the auxiliary machine system noise are calculated according to equations (10) and (11)

E_{p auxiliary}＝E_{P-shaped sliding block} (10)

E_{p push}＝E_{p is uniform}-E_{P-shaped sliding block} (11)

In the formula, E_{p is uniform}For underwater noise under uniform navigation conditions, E_{P-shaped sliding block}For underwater noise in the case of sliding while parking, E_{p push}For propulsion system noise, E_{p auxiliary}Is the noise of the auxiliary machinery system.

Technical Field

The invention belongs to the technical field of testing and analyzing underwater noise sources of ships.

Background

Underwater noise caused by the navigation of water-surface ships such as commercial ships and the like is a main source of ocean noise pollution, the main source of the ship navigation underwater noise is found out, the main sound source is accurately separated, the contribution of the main sound source to the overall navigation underwater noise is found, and the method has important significance for controlling the ship underwater noise and reducing the ocean noise pollution. The water surface ship propulsion system (comprising a main engine, a propulsion shafting and a propeller) and an auxiliary engine system (other equipment and systems except the main engine, the propulsion shafting and the propeller) are main sound sources of ship navigation underwater noise, accurately separate the noise of the propulsion system and the noise of the auxiliary engine system, and are the premise and the basis for effectively implementing ship underwater noise control measures. At present, methods such as theoretical analysis, numerical calculation, model test, information analysis based on vibration noise test data and the like are mainly adopted for separating underwater noise contributions of sound sources such as a water surface ship propulsion system, an auxiliary engine system and the like, the contribution separation effect is verified by a real ship test, and a real ship test method for effectively realizing the contribution separation is not established. Therefore, it is necessary to establish a testing method capable of accurately separating underwater noise contributions of a surface ship propulsion system and an auxiliary engine system and meeting requirements of contribution separation method real ship test verification.

Disclosure of Invention

The invention aims to provide a method for testing the contribution of underwater noise of a water surface ship propulsion system and an auxiliary engine system, which can accurately separate the underwater noise of the real ship propulsion system and the auxiliary engine system and meet the requirements of contribution separation method real ship test verification, aiming at solving the problem that a real ship testing method for effectively separating the contribution of the underwater noise of the water surface ship propulsion system and the auxiliary engine system is not established at present.

In order to realize the purpose, the core of the invention is to design the constant-speed sailing working condition and the parking and sliding working condition of the surface ship, measure the underwater noise of the constant-speed sailing working condition and the parking and sliding working condition through an underwater noise test system, acquire the noise of a propulsion system and the noise of an auxiliary engine system by adopting an energy comparison analysis method, and realize the contribution separation of the underwater noise of the propulsion system and the auxiliary engine system.

The invention discloses a method for separately testing underwater noise contribution of a surface ship propulsion system and an auxiliary engine system, which comprises the following steps:

principle of test

The underwater noise of the ship under the condition of constant speed navigation is mainly the sum of the noise of a propulsion system and the noise of an auxiliary engine system:

E_{p is uniform}＝E_{p push}+E_{p auxiliary} (1)

In the formula, E_{p is uniform}Total underwater noise for the ship under uniform speed navigation conditions E_{p push}For marine propulsion system noise, E_{p auxiliary}Noise of a marine auxiliary engine system.

For the parking and sliding working condition, the propulsion system stops running, the ship sails by means of inertia, and at the moment, underwater noise mainly is noise of an auxiliary engine system:

E_{p auxiliary}＝E_{P-shaped sliding block} (2)

In the formula, E_{P-shaped sliding block}The underwater noise is under the working condition of the ship stopping and sliding. The noise energy difference between the constant-speed navigation working condition noise and the parking and sliding working condition noise is the noise of the propulsion system:

E_{p push}＝E_{p is uniform}-E_{P-shaped sliding block} (3)

Therefore, the underwater noise contribution separation of the propulsion system and the auxiliary engine system can be realized through the underwater noise test analysis of the constant-speed sailing working condition and the parking and sliding working condition of the ship.

(II) test conditions

The noise of a ship propulsion system and the noise of an auxiliary engine system generally change along with the speed, the contribution of the noise of the propulsion system and the noise of the auxiliary engine system is separated under a specific speed, and the navigation test working conditions comprise a constant-speed navigation working condition and a parking sliding working condition. For the constant-speed navigation working condition, the running states of the propulsion system and the auxiliary engine system are kept stable; and for the parking and sliding working condition, the propulsion system stops running, the ship sails by means of inertia, and the running state of the auxiliary engine system is the same as the constant-speed sailing working condition.

(III) test system

The underwater noise test system required by the invention mainly comprises an underwater sound measurement system and a distance measurement system, and the uncertainty of the measurement of the underwater noise test system is required to be less than 3 dB.

The underwater acoustic measurement system mainly comprises 1 or more hydrophones and a data acquisition instrument. The measurement frequency range and the measurement precision of the hydrophone and the data acquisition instrument need to meet the requirements of underwater acoustic testing, or the measurement frequency range is 10Hz-50kHz, the measurement precision is not less than 16 bits, and the sampling rate is not less than 2.56 times of the maximum measurement frequency.

The distance measurement system mainly comprises differential GPS equipment or underwater acoustic distance measurement equipment, the distance from the hydrophone to the ship to be measured can be obtained in real time, and the distance measurement precision is superior to 2 m.

(IV) test method

For the test of the uniform-speed navigation working condition, the underwater sound measuring system and the distance measuring system are arranged before measurement, the arrangement depth of the hydrophones is more than 10m, if a plurality of hydrophones are adopted for measurement, the hydrophones are arranged at equal intervals along the depth direction relative to the same position of the water surface, and the interval is more than 10 m. After the ship is laid, the ship to be tested keeps constant-speed straight line navigation under the test working condition state, the straight-line distance between a ship route and a hydrophone is 1 time of the ship length, and the deviation is less than +/-10%. And starting measurement when the distance between the ship to be measured and the ship is 2 times of the ship length, synchronously measuring parameters such as the distance between a hydrophone and the ship to be measured, enabling the ship to be measured to pass through the transverse position according to the ship route, and ending the measurement when the ship is 2 times of the ship length away from the transverse position. After the one-way measurement is finished, the ship to be measured is far away from the hydrophone and turns to prepare for the next one-way measurement. The background noise is measured before and after each single-pass test, the test of the constant-speed navigation working condition is not less than 4 single-passes in total, wherein the test of the port side and the starboard side is not less than 2 single-passes respectively, and the test process and the requirement of each single-pass are the same.

For the test of the parking sliding working condition, except that the test working condition states of the tested ship are different, other test requirements are the same as the constant-speed sailing working condition. Before measurement, the ship sails linearly at a constant speed, when measurement is started, the main engine stops, the operation states of other auxiliary engine systems are kept unchanged, the ship sails linearly by means of inertia, after the measurement is finished, the main engine is started, the working condition state of constant-speed sailing is recovered, the ship is turned, and the next one-way measurement is prepared.

(V) measurement conditions

During measurement, the ship test working condition state is stable, the water depth of a test sea area is more than 60m, the sea condition is not more than 3 grades, and the measurement signal-to-noise ratio is more than 3 dB.

(VI) data analysis

And taking the position from the host in the ship length direction to the midpoint of the propeller as an equivalent acoustic center of the ship underwater noise, and selecting the range of the acoustic center and the hydrophone angle within +/-45 degrees as an underwater noise data analysis time period. Dividing the data analysis starting time to the ending time into a plurality of data windows, selecting the length of each data window according to 10 degree step length, respectively calculating the sound pressure level L 'of each data window according to 1/3oct frequency band within the frequency band of 10Hz-50kHz, wherein the corresponding center time is-40 degrees, -35 degrees, …, -5 degrees, 0 degrees, +5 degrees, …, +35 degrees and +40 degrees'_p+n(r_k，w_j，h_i，f_e) Wherein r is_kIs the kth single pass, w_jIs the jth data window, h_iIs the ith hydrophone, f_eIs the e-th band center frequency.

The background noise is calculated as equation (4):

in the formula, L_nstart(r_k，h_i，f_e) And L_nend(r_k，h_i，f_e) The background noise before and after each single measurement is respectively. When the signal-to-noise ratio is larger than 10dB, the measurement data is corrected according to the formula (5):

L′_p(r_k，w_j，h_i，f_e)＝L′_p+n(r_k，w_j，h_i，f_e) (5)

of formula (II) to'_p(r_k，w_j，h_i，f_e) The corrected sound pressure level for the background noise. When the signal-to-noise ratio is larger than 3dB and smaller than 10dB, the measurement data is corrected according to the formula (6):

equivalent acoustic center sound source level L_p(r_k，w_j，h_i，f_e) Push buttonEquation (7) calculates:

L_p(r_k，w_j，h_i，f_e)＝L′_p(r_k，w_j，h_i，f_e)+TL(D(r_k，w_j，h_i，f_e)) (7)

wherein TL (D (r)_k，w_j，h_i，f_e) D (r) is a propagation loss_k，w_j，h_i，f_e) The hydrophone is spaced from the equivalent acoustic center. The acoustic propagation loss is calculated by equation (8):

TL(D(r_k，w_j，h_i，f_e))＝20log(D(r_k，w_j，h_i，f_e)) (8)

the sound source levels measured by the hydrophones are averaged according to energy, the sound source levels measured by the data windows are averaged according to energy, and the sound source levels measured in each single pass are averaged according to linearity:

where I, J, K are the number of hydrophones, the number of data windows, and the number of single passes, respectively. The energy of 1/3oct band of underwater noise under test conditions is calculated by equation (12):

the underwater noise under the constant-speed sailing working condition and the parking and sliding working condition can be obtained by the formula (12), and the noise of the propulsion system and the noise of the auxiliary engine system can be obtained by substituting the formula (2) and the formula (3).

The method has the advantages that the noise of the ship propulsion system and the noise of the auxiliary engine system can be accurately separated through the comparison test of the constant-speed sailing working condition and the parking and sliding working condition, and the real ship test verification requirement of the underwater noise source contribution separation method is met.

Drawings

FIG. 1 is a schematic diagram of a ship underwater noise testing and analyzing method in the invention.

FIG. 2 shows the separation of typical bulk carrier propulsion system noise from auxiliary engine system noise contributions in the present invention.

FIG. 3 illustrates a typical bulk carrier propulsion system noise to auxiliary engine system noise contribution ratio of the present invention.

Detailed Description

The method for testing the underwater noise contribution of the surface ship propulsion system and the auxiliary engine system in a separated mode is explained in detail with reference to the embodiment. The surface vessel in this embodiment is a typical bulk carrier.

With reference to the examples, as shown in fig. 1, the specific embodiments of the present invention are as follows:

(1) 3 hydrophones and a data acquisition instrument are selected to build the underwater sound measuring system, the hydrophones 1 are distributed at the same position relative to the water surface according to different depths, the depths are 15m, 30m and 45m respectively, the measuring frequency range of the underwater sound measuring system is 10Hz-50kHz, the measuring precision is not less than 16 bits, and the sampling rate is not less than 2.56 times of the maximum measuring frequency.

(2) And selecting a differential GPS ranging method, respectively arranging differential GPS equipment at the position of the hydrophone corresponding to the water surface and the ship 2 to be measured, and constructing a distance measuring system, so that the distance from the hydrophone to the ship 2 to be measured can be obtained in real time, the measuring precision is better than 2m, and the measurement uncertainty of an underwater noise testing system consisting of the underwater sound measuring system and the distance measuring system is less than 3 dB.

(3) The test working conditions of the ship 2 to be tested are an 11kn economic sailing working condition and an 11kn parking and sliding working condition, the depth of the selected test sea area is more than 70m, the sea condition is not more than 3 grades, and the background noise meets the requirement that the signal-to-noise ratio is more than 3 dB.

(4) Firstly, carrying out an underwater noise test under a constant-speed navigation working condition, before the test, measuring and testing sea area background noise by an underwater acoustic measurement system, keeping a tested ship 2 in a working condition state for constant-speed linear navigation, wherein the normal and transverse distance 4 between a ship route 3 and a hydrophone 1 is 1 time of ship length, and the deviation is less than +/-10%. And starting to measure 6 when the distance between the ship 2 to be measured and the horizontal position 5 is 2 times of the ship length 7, synchronously measuring parameters such as the underwater acoustic signal, the distance between the hydrophone 1 and the ship 2 to be measured, enabling the ship 2 to be measured to pass through the horizontal position 5 according to the ship route 3, and ending to measure 8 when the distance between the ship 2 to be measured and the horizontal position 5 is 2 times of the ship length 7. After the one-way measurement is finished, the ship 2 to be measured is turned away from the hydrophone 1 to prepare for the next one-way measurement, and meanwhile, the underwater acoustic measurement system measures and tests the background noise of the sea area. Each single pass test procedure and requirements were the same, for a total of 4 single pass tests, with 2 single pass tests on each of the port and starboard sides.

(5) And then carrying out an underwater noise test under the parking and sliding working condition, before the test, measuring the background noise of the test sea area by an underwater acoustic measurement system, and carrying out straight line navigation on the ship 2 to be tested according to the constant-speed navigation working condition state, wherein the normal and transverse distance 4 between a ship line 3 and a hydrophone 1 is 1 time of the ship length, and the deviation is less than +/-10%. And when the distance 5 between the ship 2 to be measured and the horizontal position is 2 times of the ship length 7, starting to measure 6, synchronously measuring parameters such as underwater acoustic signals, the distance from the hydrophone 1 to the ship 2 to be measured and the like, stopping the main engine, keeping the running state of other auxiliary engine systems unchanged, and navigating the ship linearly by means of inertia. The ship 2 under test passes through the trim position 5 along the course 3, and the measurement 8 is finished when the ship 2 under test is 2 times the length 7 of the ship away from the trim position 5. After the one-way measurement is finished, the host is started, the constant-speed navigation working condition state is recovered, the ship 2 to be measured is turned away from the hydrophone 1 to prepare for the next one-way measurement, and meanwhile, the underwater acoustic measurement system measures and tests the background noise of the sea area. Each single pass test procedure and requirements were the same, for a total of 4 single pass tests, with 2 single pass tests on each of the port and starboard sides.

(6) And performing data analysis after the test is finished, taking the position from the host in the ship length direction to the midpoint of the propeller as an underwater noise equivalent sound center 9 of the ship, and selecting a sound center and hydrophone angle within a range of +/-45 degrees 10 as an underwater noise data analysis time interval 11. Dividing the data analysis starting time 12 to the data analysis ending time 13 into a plurality of data windows, wherein the length of each data window is selected according to 10-degree step length, and the corresponding central time is-40 degrees-35 °, …, -5 °, 0 °, +5 °, …, +35 °, +40 °, each data window sound pressure level L 'being calculated in the 1/3oct frequency band within the 10Hz-50kHz band'_p+n(r_k，w_j，h_i，f_e)。

(7) Calculating the background noise L according to equation (4)_n(r_k，h_i，f_e) The background noise corrected sound pressure level L 'is calculated according to the formula (5) or the formula (6)'_p(r_k，w_j，h_i，f_e) Calculating the equivalent sound center sound source level L according to the formula (7)_p(r_k，w_j，h_i，f_e) Data averaging is carried out according to the formula (9), the formula (10) and the formula (11), underwater noise under the constant-speed sailing working condition and the parking and sliding working condition is calculated according to the formula (12), and noise of a propulsion system and noise of an auxiliary machine system are calculated according to the formula (2) and the formula (3).

According to the underwater noise contribution separation test method for the surface ship propulsion system and the auxiliary engine system, the propulsion system noise, the auxiliary engine system noise separation result and the contribution ratio of the propulsion system noise and the auxiliary engine system noise to the overall underwater noise under the 11kn economic sailing condition of the typical bulk cargo ship in the embodiment are shown in fig. 2 and 3. According to the contribution separation result of the embodiment, the contribution separation test method for the underwater noise of the water surface ship propulsion system and the auxiliary system can realize the effective separation of the propulsion system noise and the auxiliary system noise in the frequency range of 10Hz-50kHz, and meets the real ship test verification requirement of the contribution separation method.

Finally, it should be noted that the above embodiments are only used to illustrate the general process of implementing the technology of the present invention, and are not limited. Although the present invention has been described in detail, those skilled in the art should understand that they can make modifications and equivalents without departing from the spirit and scope of the present invention, and that they are within the scope of the appended claims.