CN115773473B - Monitoring system and monitoring method for natural gas leakage in tunnel - Google Patents

Monitoring system and monitoring method for natural gas leakage in tunnel Download PDF

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CN115773473B
CN115773473B CN202211245123.2A CN202211245123A CN115773473B CN 115773473 B CN115773473 B CN 115773473B CN 202211245123 A CN202211245123 A CN 202211245123A CN 115773473 B CN115773473 B CN 115773473B
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leakage
source
tunnel
gas
concentration
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CN115773473A (en
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阳东
漆琦
黄小美
郭鑫
李亮
吕山
臧子旋
彭世尼
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Chongqing University
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Abstract

本发明公开了一种隧道内天然气泄漏监测系统及监测方法,包括传感器、光缆、主机、报警装置和显示装置,传感器通过光缆与主机连接,主机分别和报警装置、显示装置相连,主机包括控制单元、泄漏源定位计算单元、泄漏源泄漏率反演计算单元和预警决策单元,泄漏源定位计算单元根据甲烷浓度数据对泄漏源位置进行定位,泄漏源泄漏率反演计算单元根据甲烷浓度数据对泄漏源泄漏率进行计算,预警决策单元根据甲烷浓度数据控制报警装置的启停,泄漏源定位结果和泄漏源泄漏率计算结果均输出至显示装置上。本发明实现高度自动化,由传感器自动检测,通过主机实时预警判断,效率高。在信息采集、运输、储存等环节均通过监测与预警系统进行,人为因素影响小。

The present invention discloses a natural gas leakage monitoring system and method in a tunnel, including a sensor, an optical cable, a host, an alarm device and a display device. The sensor is connected to the host through an optical cable, and the host is respectively connected to the alarm device and the display device. The host includes a control unit, a leakage source positioning calculation unit, a leakage source leakage rate inversion calculation unit and an early warning decision unit. The leakage source positioning calculation unit locates the leakage source according to the methane concentration data, the leakage source leakage rate inversion calculation unit calculates the leakage source leakage rate according to the methane concentration data, and the early warning decision unit controls the start and stop of the alarm device according to the methane concentration data. The leakage source positioning result and the leakage source leakage rate calculation result are both output to the display device. The present invention realizes high automation, automatic detection by the sensor, real-time early warning judgment by the host, and high efficiency. Information collection, transportation, storage and other links are all carried out through the monitoring and early warning system, and the influence of human factors is small.

Description

Monitoring system and monitoring method for natural gas leakage in tunnel
Technical Field
The invention relates to a natural gas leakage monitoring system in a tunnel and a monitoring method of the natural gas leakage monitoring system in the tunnel.
Background
Compressed natural gas and liquefied natural gas tank cars are one of the common transportation modes of natural gas, and are also the motive fuels for many vehicles. In the process of passing through the tunnel, if leakage is caused by accidents such as high temperature (such as fire), impact, pipe fitting falling and the like, flammable and explosive gas clouds are formed in the tunnel space, the formed flammable and explosive gas clouds possibly cause hypoxia and suffocation of personnel and frostbite, and the formed flammable and explosive gas clouds encounter ignition sources, dangerous accidents such as steam cloud explosion and the like can possibly occur in the tunnel, and the generated high-temperature smoke and overpressure can cause serious injury to personnel and property.
However, only the tunnel passing through the gas stratum is required to monitor the gas concentration in the highway tunnel design rule in China at present, but no universal requirement is made for monitoring the inflammable and explosive gas of the highway tunnel, so that the methane monitoring system in the tunnel is very necessary.
Disclosure of Invention
The first aim of the invention is to provide a natural gas leakage monitoring system in the tunnel, which can effectively monitor and early warn natural gas in the tunnel, position accident sites and improve accident handling efficiency.
The first object of the present invention is achieved by the following technical measures: the utility model provides a natural gas leakage monitoring system in tunnel, its characterized in that includes sensor, optical cable, host computer, alarm device and the display device that are used for gathering methane concentration, the sensor is a plurality of and is connected with the host computer through the optical cable, the host computer links to each other with alarm device, display device respectively, the host computer includes the control unit, leak source location calculation unit, leak source leakage rate inversion calculation unit and the early warning decision unit that are connected with it respectively, wherein, leak source location calculation unit is according to methane concentration data to leaking source position, leak source leakage rate inversion calculation unit is according to methane concentration data to leaking source leakage rate calculation, early warning decision unit is according to the start-stop of methane concentration data control alarm device, leak source location result and leak source leakage rate calculation result all output to display device.
The invention can realize high automation, realizes real-time early warning judgment through the methane sensor and the host computer, and has high working efficiency. All links such as information acquisition, transportation, storage and the like are carried out through a monitoring and early warning system, no manual participation is needed, and the influence of human factors is small. The method can realize the early warning of natural gas leakage in the tunnel and the calculation of the position and the intensity of the leakage source, and meanwhile, the early warning of the natural gas leakage is carried out by utilizing the monitored methane concentration data, and the intensity and the position of the leakage source are inverted, so that the response time of accident disposal can be shortened, the early warning probability of the occurrence of the leakage accident is improved, and the pertinence and the effectiveness of the accident response measures are enhanced. The natural gas leakage source and leakage intensity are inverted by combining the monitored methane concentration data with a machine learning method, so that position and leakage intensity information can be provided for accident rescue and accident disposal, in addition, references can be provided for accident disposal measures, and a proper disaster relief scheme is provided by combining the calculated leakage source information.
The sensors are distributed on the inner wall of the tunnel at intervals along the length direction of the tunnel, and the distance between two adjacent sensors is calculated by the following steps:
S1, carrying out numerical simulation on the gas leakage diffusion process in the tunnel under different gas cloud volumes by using gas leakage diffusion numerical simulation software to obtain the distribution form of the gas cloud of the leaked gas in the tunnel;
S2, carrying out a numerical experiment on the gas explosion result by using gas explosion result calculation software so as to quantify the maximum explosion overpressure value generated by gas explosion in the tunnel under different leakage time lengths;
S3, mapping the maximum explosion overpressure value under different gas cloud volumes to a gas cloud volume range corresponding to the maximum explosion overpressure 20KPa (human body light injury);
and S4, taking the distance of the combustible gas cloud in the tunnel length direction at the moment as the maximum distance between adjacent sensors.
The second object of the present invention is to provide a monitoring method of the above-mentioned monitoring system for natural gas leakage in a tunnel.
The second object of the present invention is achieved by the following technical measures: the monitoring method of the natural gas leakage monitoring system in the tunnel is characterized by comprising the following steps of:
S1, monitoring methane concentration data by a sensor, and transmitting the methane concentration data to a host through an optical cable;
s2, the host receives the methane concentration data, and the methane concentration data is judged through the early warning decision unit to obtain a judging result;
S3, the alarm device responds to the judging result;
S4, a leakage source leakage rate inversion calculation unit in the host calculates the leakage source leakage rate, a leakage source positioning calculation unit calculates the leakage source leakage position, and a leakage source leakage rate calculation result and a leakage source positioning result are output to a display device.
In the step S2, the basis of the decision of the early warning decision unit is:
wherein: c i -methane concentration measured by the ith methane gas detector; LEL-lower explosion limit of methane gas, 5%.
In the step S4, the method specifically includes the steps of:
⑴ Calculating forward distribution of a flow field when the leakage source is in a static state, and obtaining concentration parameters of different moments in the gas leakage process at the positions of each monitoring point when the leakage source is in the static state;
⑵ Assuming that a leakage source in the tunnel is in a uniform motion state all the time from the beginning of entering the tunnel to the end of exiting the tunnel, calculating forward distribution of a flow field when the leakage source is in the uniform motion state, and obtaining concentration parameters of different moments in the gas leakage process at each monitoring point position when the leakage source is in the uniform motion state;
⑶ Assuming that the prior distribution function of the leakage source intensity and the leakage position is a uniform distribution function within a certain range;
⑷ Calculating likelihood functions of observation concentration distribution under the condition that the prior distribution of the leakage source intensity is established according to the observation data of each sensor;
⑸ Combining prior distribution, predicted concentration and observation data, and calculating posterior distribution approximate solution of source item leakage rate parameters by using Bayes theorem;
⑹ And calculating the leakage rate and the leakage position of the leakage source to be the corresponding values when the posterior distribution probability is maximum, and obtaining the inversion result of the leakage rate and the leakage position when the leakage source is in a static state and the inversion result of the leakage rate when the leakage source is in a uniform motion state.
The invention calculates the forward distribution of the flow field when the leakage source is in a static state, and comprises the following steps:
① Adopting a CFD three-dimensional numerical simulation method for tunnel sections within 100m from a leakage source along the longitudinal direction, and respectively solving tunnel gas leakage concentration distribution at different leakage source intensities and leakage source positions;
② Adopting a simplified one-dimensional gas diffusion model at tunnel sections which are 100m away from the leakage source along the longitudinal direction, and respectively solving the leakage concentration distribution of tunnel gas at different leakage source intensities and leakage source positions;
③ And when the leakage source is in a static state, acquiring concentration parameters of different moments in the gas leakage process at the positions of each monitoring point calculated by the forward model.
The invention calculates the forward distribution of the flow field when the leakage source is in a uniform motion state, and comprises the following steps:
① The continuously released leakage concentration field in the tunnel is regarded as a continuous instant point source within a range along the longitudinal length of the tunnel under a certain time sequence, when the tunnel length is L, the continuously released leakage source intensity in the tunnel is q 0, the continuously released leakage source is regarded as an instant released point source at intervals of a certain distance deltax, the running speed of the tunnel is u 0, and the leakage quantity of each point source is calculated
② Respectively solving the inside of the tunnel by adopting a one-dimensional gas diffusion modelThe longitudinal concentration distribution of the flow field is sequentially released by the point sources at the time interval delta x/u 0;
③ And when the leakage source is in a uniform motion state, concentration parameters of different moments in the gas leakage process at the positions of each monitoring point calculated by the forward model are obtained.
The prior distribution function of the leakage source intensity and the leakage position is as follows:
Wherein:
p (Y k) -a priori distribution of leak source intensities;
w max -upper limit of estimated parameters;
W min -lower limit of estimation parameters.
The calculation formula of step ⑷ in the present invention is:
where C β represents the measured concentration value of the sensor, Representing the sensor value calculated using the forward model, σ f·k representing the standard deviation of the concentration data calculated using the forward model, and σ β·k representing the standard deviation of the concentration data measured using the sensor.
Compared with the prior art, the invention has the following remarkable effects:
⑴ The invention can realize high automation, realizes real-time early warning judgment through the methane sensor and the host computer, and has high working efficiency. All links such as information acquisition, transportation, storage and the like are carried out through a monitoring and early warning system, no manual participation is needed, and the influence of human factors is small.
⑵ The method can realize the early warning of natural gas leakage in the tunnel and the calculation of the position and the intensity of the leakage source, and meanwhile, the early warning of the natural gas leakage is carried out by utilizing the monitored methane concentration data, and the intensity and the position of the leakage source are inverted, so that the response time of accident disposal can be shortened, the early warning probability of the occurrence of the leakage accident is improved, and the pertinence and the effectiveness of the accident response measures are enhanced.
⑶ The invention uses the monitored methane concentration data to invert the natural gas leakage source and the leakage intensity by combining a machine learning method, can provide position and leakage intensity information for accident rescue and accident disposal, can provide reference for accident disposal measures, and provides a proper disaster relief scheme by combining the calculated leakage source information.
Drawings
The invention will now be described in further detail with reference to the drawings and to specific examples.
FIG. 1 is a schematic diagram of the composition and structure of a system for monitoring natural gas leakage in a tunnel according to the present invention;
FIG. 2 is a flow chart of the monitoring method of the present invention;
FIG. 3 is a flow chart of leak location and leak rate inversion of the present invention;
FIG. 4 is a graph showing the concentration distribution of the gas cloud obtained by numerical calculation according to the present invention;
FIG. 5 is a schematic diagram of the concentration calculation result of each measuring point obtained by calculating the constant motion leakage source by the forward model;
FIG. 6 is a schematic diagram of the calculation result of the concentration of each measuring point obtained by three-dimensional simulation calculation of the constant motion leakage source;
FIG. 7 is a schematic diagram of the leak source position inversion result of the leak source of the present invention in a stationary state;
FIG. 8 is a schematic diagram of the inversion result of the leakage source intensity of the leakage source in a uniform motion state.
Detailed Description
The invention discloses a natural gas leakage monitoring system in a tunnel, which is shown in fig. 1, and comprises a sensor 1 for collecting methane concentration, an optical cable 2, a host computer 3, an alarm device 4 and a display device (not shown in the figure), wherein the sensor 1 is distributed on the inner wall of the tunnel at intervals along the length direction of the tunnel, the host computer 3 and the alarm device 4 are arranged in a cabinet 5, the sensor 1 is a plurality of and is connected with the host computer 3 through the optical cable 2, the host computer 3 is respectively connected with the alarm device 4 and the display device, the host computer 3 comprises a control unit, a leakage source positioning calculation unit, a leakage source leakage rate inversion calculation unit and an early warning decision unit which are respectively connected with the control unit, the leakage source positioning calculation unit positions the leakage source according to methane concentration data, the early warning decision unit controls the starting and stopping of the alarm device according to the methane concentration data, and the leakage source positioning result and the leakage source leakage rate calculation result are output to the display device.
As shown in fig. 2, the system for monitoring natural gas leakage in the tunnel is installed, specifically:
1. Determining a sensor arrangement pitch in a longitudinal direction:
(1) Modeling is carried out according to tunnel structure data, the length (X) width (Y) height (Z) of a highway tunnel numerical experiment model in the embodiment is 200m multiplied by 6m respectively, and a gas leakage diffusion numerical simulation software is used for carrying out numerical simulation on a compressed natural gas leakage diffusion process in the tunnel so as to obtain a distribution form of gas and cloud of leakage gas in the tunnel.
(2) According to the gas cloud concentration distribution at different moments obtained by natural gas leakage and diffusion numerical simulation, numerical experiments are carried out on gas explosion results by using gas explosion result calculation software, the calculation results are shown in fig. 4, and numerical experiments are carried out on the gas explosion results by using the gas explosion result calculation software so as to quantify the maximum explosion overpressure value generated by gas explosion in tunnels under different leakage time lengths.
(3) And mapping the maximum explosion overpressure value under different gas cloud volumes to a gas cloud volume range corresponding to the maximum explosion overpressure of 20KPa (human light injury).
(4) Taking the distance of the combustible gas cloud in the tunnel length direction at this time as the arrangement pitch of the methane concentration sensors, assuming that the arrangement pitch of the methane concentration sensors obtained in the present case is 20m, 9 methane concentration sensors are total in the present embodiment model.
2. And arranging the monitoring system according to the arrangement interval of the sensors in the longitudinal direction, and monitoring the data in real time.
The monitoring method of the natural gas leakage monitoring system in the tunnel specifically comprises the following steps:
S1, when methane gas generated by tank wagon leakage diffuses in a tunnel, a sensor monitors real-time methane concentration data, and the methane concentration data is transmitted to a host through an optical cable;
s2, the host receives the methane concentration data, and the methane concentration data is judged through the early warning decision unit to obtain a judging result; the basis of the judgment of the early warning decision unit is as follows:
wherein: c i -methane concentration measured by the ith methane gas detector; LEL-lower explosion limit of methane gas, 5%.
S3, the alarm device responds to the judging result;
S4, a leakage source leakage rate inversion calculation unit in the host calculates the leakage source leakage rate, a leakage source positioning calculation unit calculates the leakage source leakage position, and a leakage source leakage rate calculation result and a leakage source positioning result are output to the display device.
As shown in fig. 3, calculating the leak source leak rate and the leak source leak location specifically includes:
⑴ Calculating forward distribution of a flow field when the leakage source is in a static state, and obtaining concentration parameters of different moments in the gas leakage process at the positions of each monitoring point when the leakage source is in the static state;
in this example, the leak source intensities were calculated to be respectively 0.1kg/s, 0.2kg/s, 0.3kg/s, 0.4kg/s, 0.5kg/s, 0.6kg/s, 0.7kg/s, 0.8kg/s, 0.9kg/s, and 1.0kg/s, and the leak positions were forward distribution of stationary leak source flow fields every 5m in the tunnel space.
① Adopting a CFD three-dimensional numerical simulation method for tunnel sections within 100m from a leakage source along the longitudinal direction, and respectively solving tunnel gas leakage concentration distribution at different leakage source intensities and leakage source positions;
② Adopting a simplified one-dimensional gas diffusion model at tunnel sections which are 100m away from a leakage source along the longitudinal direction, adopting a time front and center difference method to calculate an equation, and programming to solve the tunnel gas leakage concentration distribution at different leakage source intensities and leakage source positions;
③ And when the leakage source is in a static state, extracting concentration parameters in the gas leakage process at the positions of monitoring points calculated by the forward model, wherein each measuring point records data once every 20s, and the leakage duration is 600s.
⑵ Assuming that a leakage source in the tunnel is in a uniform motion state all the time from the beginning of entering the tunnel to the end of exiting the tunnel, calculating forward distribution of a flow field when the leakage source is in the uniform motion state, and obtaining concentration parameters of different moments in the gas leakage process at each monitoring point position when the leakage source is in the uniform motion state;
in this embodiment, when the intensities of the leakage sources in the tunnel are calculated to be 0.1kg/s, 0.2kg/s, 0.3kg/s, 0.4kg/s, 0.5kg/s, 0.6kg/s, 0.7kg/s, 0.8kg/s, 0.9kg/s, and 1.0kg/s, respectively, the flow field forward distribution when the leakage sources are in a motion state is calculated assuming that the leakage sources are in a uniform motion state from the beginning of entering the tunnel to the beginning of exiting the tunnel.
① Regarding a continuously released leakage concentration field in a tunnel as a continuous instant point source within a range of the longitudinal length of the tunnel under a certain time sequence, regarding the continuously released leakage source as a point source at intervals of 5m when the length of the tunnel is 200m and the strength of the continuously released leakage source in the tunnel is 0.1kg/s, and calculating the leakage quantity of each point source as Deltax/u 0·q0 = 0.03kg when the speed of a travelling crane in the tunnel is 60 km/h;
② And (3) respectively solving longitudinal concentration distribution of the flow field after 39 point sources are released in the tunnel by adopting a one-dimensional gas diffusion model, wherein the leakage duration is 60s, and recording data every 1s, wherein when the leakage source intensity is 0.9kg/s, the calculation result is shown in figure 5.
③ And when the leakage source is in a uniform motion state, concentration parameters of different moments in the gas leakage process at the positions of each monitoring point calculated by the forward model are obtained.
And obtaining concentration distribution of each measuring point at each moment by adopting a three-dimensional numerical experiment method, and taking the concentration distribution as a sensor measurement concentration value calculated by inversion. For a static leakage source in a tunnel, the leakage concentration in the tunnel is 0.26kg/s, and the position of the leakage source is 50m; for the in-tunnel moving state leakage source, the leakage concentration was 0.77kg/s, and the calculation result is shown in FIG. 6.
⑶ Assuming that the prior distribution function of the leakage source intensity and the leakage position is a uniform distribution function within a certain range;
The calculation formula is as follows:
Wherein:
p (Y k) -a priori distribution of leak source intensities;
w max -upper limit of estimated parameters;
W min -lower limit of estimation parameters.
When the leakage source is in a static state, the prior distribution of the leakage source strength is compliant with U [0,1], and the prior distribution of the leakage source position is compliant with U [0, 200]; when the leakage source is in a uniform motion state, the prior distribution of the leakage source intensity is compliant with U [0,1].
⑷ According to the observation data of each sensor, calculating a likelihood function of the observation concentration distribution under the condition that the prior distribution of the leakage source intensity is established, wherein the calculation formula is as follows:
Namely:
Wherein the method comprises the steps of The j-th measured concentration value representing the i-th sensor,The j-th measured concentration value of the i-th sensor calculated by using the forward model is represented, sigma is the standard deviation between the calculated concentration and the measured concentration of the forward model, the error is set to be the same order of magnitude as the measured concentration, and the standard deviation is assumed to be the same as the measured concentration.
⑸ The posterior distribution approximation solution of the source term leak rate parameter, p (Y k|β)=(p(Yk)p(β|Yk))/(p (β)), is calculated using bayesian theorem in combination with the prior distribution, the predicted concentration and the observed data, where p (Y k) is the prior distribution and p (β|y k) is the likelihood function.
⑹ And (3) performing curve fitting according to the calculated probability values at each leakage source intensity and position, and taking the maximum probability value of the fitted curve as an inversion result. For a stationary leakage source, the leakage source position inversion result is shown in FIG. 7, the leakage source position inversion result is 39.95m, the error is 10.05m, the leakage source intensity inversion result is 0.17kg/s, and the error is 0.07kg/s; and for the leakage source in a uniform motion state, obtaining the leakage source intensity corresponding to the probability maximum value after fitting, wherein the error is 0.064kg/s, and the leakage source intensity inversion result is shown in figure 8.
The embodiments of the present invention are not limited thereto, and the present invention may be modified, substituted or altered in various other forms according to the general knowledge and conventional means of the art, which fall within the scope of the claims of the present invention.

Claims (7)

1.一种隧道内天然气泄漏监测系统,其特征在于:它包括用于采集甲烷浓度的传感器、光缆、主机、报警装置和显示装置,所述传感器为若干个并通过光缆与主机连接,所述主机分别和报警装置、显示装置相连,所述主机包括控制单元、分别与之连接的泄漏源定位计算单元、泄漏源泄漏率反演计算单元和预警决策单元,其中,所述泄漏源定位计算单元根据甲烷浓度数据对泄漏源位置进行定位,所述泄漏源泄漏率反演计算单元根据甲烷浓度数据对泄漏源泄漏率进行计算,所述预警决策单元根据甲烷浓度数据控制报警装置的启停,泄漏源定位结果和泄漏源泄漏率计算结果均输出至显示装置上;1. A natural gas leak monitoring system in a tunnel, characterized in that: it includes sensors for collecting methane concentration, optical cables, a main unit, an alarm device, and a display device; the sensors are multiple and connected to the main unit via optical cables; the main unit is connected to the alarm device and the display device respectively; the main unit includes a control unit, a leak source location calculation unit, a leak source leakage rate inversion calculation unit, and an early warning decision unit respectively connected thereto; wherein, the leak source location calculation unit locates the leak source based on methane concentration data; the leak source leakage rate inversion calculation unit calculates the leak source leakage rate based on methane concentration data; the early warning decision unit controls the activation and deactivation of the alarm device based on methane concentration data; and both the leak source location result and the leak source leakage rate calculation result are output to the display device. 所述传感器沿着隧道的长度方向间隔分布在隧道内壁上,相邻两传感器的间距通过以下步骤计算得到:The sensors are spaced apart along the length of the tunnel on the inner wall of the tunnel, and the distance between two adjacent sensors is calculated through the following steps: S1、利用气体泄漏扩散数值模拟软件对不同气云体积下的隧道内部气体泄漏扩散过程进行数值模拟,得到隧道内部泄漏燃气气云分布形态;S1. The gas leakage and diffusion process inside the tunnel under different gas cloud volumes was numerically simulated using gas leakage and diffusion numerical simulation software to obtain the distribution pattern of leaked gas cloud inside the tunnel. S2、利用气体爆炸后果计算软件对气体爆炸后果进行数值实验,以量化不同泄漏时长下隧道内发生气体爆炸产生的最大爆炸超压值;S2. Numerical experiments were conducted on the consequences of gas explosions using gas explosion consequence calculation software to quantify the maximum explosion overpressure value generated by gas explosions in tunnels under different leakage durations. S3、根据不同气云体积下的最大爆炸超压值,映射到对应最大爆炸超压20KPa时的气云体积范围;S3. Based on the maximum explosion overpressure value under different gas cloud volumes, map it to the gas cloud volume range at the corresponding maximum explosion overpressure of 20 kPa. S4、将此时可燃气云在隧道长度方向上的距离作为相邻传感器的最大间距。S4. The distance of the combustible gas cloud along the tunnel length direction at this time is taken as the maximum spacing between adjacent sensors. 2.一种权利要求1所述隧道内天然气泄漏监测系统的监测方法,其特征在于具体包括以下步骤:2. A monitoring method for the natural gas leak monitoring system in a tunnel as described in claim 1, characterized by comprising the following steps: S1、传感器监测到甲烷浓度数据,通过光缆将甲烷浓度数据传输至主机;S1. The sensor detects methane concentration data and transmits the methane concentration data to the host via optical fiber. S2、主机接收甲烷浓度数据,通过预警决策单元对甲烷浓度数据进行判断,得到判定结果;S2. The host receives methane concentration data, and the early warning decision unit judges the methane concentration data to obtain the judgment result; S3、所述报警装置对判定结果进行响应;S3. The alarm device responds to the judgment result; S4、所述主机内的泄漏源泄漏率反演计算单元对泄漏源泄漏率进行计算,泄漏源定位计算单元对泄漏源泄漏位置进行计算,并将泄漏源泄漏率计算结果和泄漏源定位结果输出到显示装置上;S4. The leakage source leakage rate inversion calculation unit in the host calculates the leakage rate of the leakage source, the leakage source location calculation unit calculates the leakage location of the leakage source, and outputs the leakage rate calculation result and the leakage source location result to the display device. 在所述步骤S4中,计算泄漏源泄漏率和泄漏源泄漏位置具体包括:In step S4, calculating the leakage rate and leakage location of the leakage source specifically includes: ⑴计算泄漏源处于静止状态时的流场正演分布,得到泄漏源处于静止状态时各监测点位置处燃气泄漏过程中不同时刻的浓度参数;(1) Calculate the forward modeling distribution of the flow field when the leak source is in a static state, and obtain the concentration parameters of the gas at different times during the gas leakage process at each monitoring point when the leak source is in a static state; ⑵假设隧道内泄漏源从进入隧道开始至出隧道后一直处于匀速运动状态,计算泄漏源处于匀速运动状态时的流场正演分布,得到泄漏源处于匀速运动状态时各监测点位置处燃气泄漏过程中不同时刻的浓度参数;(2) Assuming that the leak source in the tunnel is in a state of uniform motion from the time it enters the tunnel until it exits the tunnel, calculate the forward modeling distribution of the flow field when the leak source is in a state of uniform motion, and obtain the concentration parameters of the gas at different times during the gas leakage process at each monitoring point when the leak source is in a state of uniform motion. ⑶假设泄漏源强度和泄漏位置的先验分布函数为一定范围内的均匀分布函数;(3) Assume that the prior distribution functions of the leakage source intensity and leakage location are uniform distribution functions within a certain range; ⑷根据各传感器的观测数据计算泄漏源强度先验分布成立条件下的观测浓度分布的似然函数;(4) Calculate the likelihood function of the observed concentration distribution under the condition that the prior distribution of the leakage source intensity holds, based on the observation data of each sensor; ⑸结合先验分布、预测浓度和观测数据,利用贝叶斯定理计算源项泄漏率参数的后验分布近似解;(5) Combining prior distribution, predicted concentration and observation data, Bayes' theorem is used to calculate the approximate solution of the posterior distribution of the source term leakage rate parameter; ⑹计算泄漏源泄漏率和泄漏位置的取值为后验分布概率最大时的对应的值,得到泄漏源处于静止状态时的泄漏率与泄漏位置反演结果、以及泄漏源处于匀速运动状态时的泄漏率反演结果。(6) Calculate the leakage rate and leakage location of the leakage source and the corresponding values when the posterior probability is the maximum. Obtain the leakage rate and leakage location inversion results when the leakage source is in a static state, and the leakage rate inversion results when the leakage source is in a uniform motion state. 3.根据权利要求2所述的监测方法,其特征在于:在所述步骤S2中,所述预警决策单元判定的依据是:3. The monitoring method according to claim 2, characterized in that: in step S2, the basis for the early warning decision unit's determination is: 式中:Ci——第i个甲烷气体探测器测到的甲烷浓度;LEL——甲烷气体爆炸下限,5%。Where: Ci — methane concentration detected by the i-th methane gas detector; LEL — lower explosive limit of methane gas, 5%. 4.根据权利要求3所述的监测方法,其特征在于:计算泄漏源处于静止状态时的流场正演分布包括以下步骤:4. The monitoring method according to claim 3, characterized in that: calculating the forward distribution of the flow field when the leakage source is in a static state includes the following steps: ①在距离泄漏源沿纵向100m内的隧道段采用CFD三维数值模拟方法,分别对不同泄漏源强度与泄漏源位置处的隧道燃气泄漏浓度分布进行求解;① The CFD three-dimensional numerical simulation method was used to solve the tunnel gas leakage concentration distribution at different leakage source intensities and locations in the tunnel section within 100m of the leakage source along the longitudinal direction; ②在距离泄漏源沿纵向100m以外的隧道段采用简化的一维气体扩散模型,分别对不同泄漏源强度与泄漏源位置处的隧道燃气泄漏浓度分布进行求解;② In the tunnel section more than 100m away from the leak source along the longitudinal direction, a simplified one-dimensional gas diffusion model is used to solve the tunnel gas leakage concentration distribution at different leak source intensities and locations; ③获得泄漏源处于静止状态时,由正演模型计算的各监测点位置处燃气泄漏过程中不同时刻的浓度参数。③ Obtain the concentration parameters of gas at different times during the gas leakage process at each monitoring point location calculated by the forward model when the leakage source is in a static state. 5.根据权利要求4所述的监测方法,其特征在于:计算泄漏源处于匀速运动状态时的流场正演分布包括以下步骤:5. The monitoring method according to claim 4, characterized in that: calculating the forward distribution of the flow field when the leakage source is in uniform motion includes the following steps: ①将隧道内连续释放的泄漏浓度场视作连续瞬时点源在一定时间序列下沿着隧道纵向长度范围内,当隧道长度为L,隧道内连续释放的泄漏源强度为q0,将连续释放的泄漏源每隔一定距离Δx视作一个瞬时释放的点源,隧道设计行车速度为u0,计算每个点源泄漏量大小为 ① Consider the continuously released leakage concentration field within the tunnel as a continuous instantaneous point source along the longitudinal length of the tunnel within a certain time series. When the tunnel length is L, the intensity of the continuously released leakage source within the tunnel is q<sub>0</sub> . Consider the continuously released leakage source at regular intervals Δx as an instantaneous point source. The tunnel's design traffic speed is u <sub>0 </sub>. Calculate the leakage amount at each point source. ②采用一维气体扩散模型分别求解隧道内个点源以时间间隔△x/u0依次释放后的流场纵向浓度分布;② A one-dimensional gas diffusion model is used to solve the problem of gas diffusion within the tunnel. The longitudinal concentration distribution of the flow field after each point source releases sequentially at time intervals Δx/ u0 ; ③获得泄漏源处于匀速运动状态时,由正演模型计算的各监测点位置处燃气泄漏过程中不同时刻的浓度参数。③ Obtain the concentration parameters of gas at different times during the gas leakage process at each monitoring point location calculated by the forward model when the leakage source is in a state of uniform motion. 6.根据权利要求5所述的监测方法,其特征在于:所述泄漏源强度和泄漏位置的先验分布函数为:6. The monitoring method according to claim 5, characterized in that: the prior distribution functions of the leakage source intensity and leakage location are: 式中:In the formula: p(Yk)——泄漏源强度的先验分布;p( Yk ) — Prior distribution of leakage source strength; Wmax——估计参数的上限值; Wmax — the upper limit of the estimated parameters; Wmin——估计参数的下限值。W min — the lower limit of the estimated parameters. 7.根据权利要求6所述的监测方法,其特征在于:所述步骤⑷的计算公式是:7. The monitoring method according to claim 6, characterized in that: the calculation formula for step (4) is: 其中Cβ表示传感器的测量浓度值,表示利用正演模型计算出来的传感器数值,σf·k表示正演模型计算出的浓度数据标准差,σβ·k表示利用传感器测得的浓度数据标准差。Where represents the measured concentration value of the sensor, σ <sub>f</sub>·k represents the sensor value calculated using the forward model, σ<sub>β</sub>·k represents the standard deviation of the concentration data calculated using the forward model, and σ <sub>β</sub>·k represents the standard deviation of the concentration data measured using the sensor.
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