CN110598342A - Method and device for detecting reasonability of setting of exhaust valve - Google Patents
Method and device for detecting reasonability of setting of exhaust valve Download PDFInfo
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- CN110598342A CN110598342A CN201910881889.1A CN201910881889A CN110598342A CN 110598342 A CN110598342 A CN 110598342A CN 201910881889 A CN201910881889 A CN 201910881889A CN 110598342 A CN110598342 A CN 110598342A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17D—PIPE-LINE SYSTEMS; PIPE-LINES
- F17D5/00—Protection or supervision of installations
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Abstract
The application discloses a method and a device for detecting reasonability of setting of an exhaust valve, and belongs to the technical field of transmission and distribution. The method comprises the following steps: for any exhaust valve on a target pipeline, acquiring the setting position of the exhaust valve, wherein the target pipeline comprises liquid and gas; acquiring first motion information of the liquid at a set position; acquiring second motion information of the gas at the setting position based on the first motion information; and determining whether the set position of the exhaust valve is reasonable or not based on the second motion information. According to the method and the device, the second motion information of the gas in the target pipeline at the set position is acquired through the first motion information of the liquid in the target pipeline at the set position where the exhaust valve is located, and whether the set position of the exhaust valve is reasonable or not can be detected according to the second motion information. Therefore, the technical scheme provided by the application has the advantages of low detection cost, high detection efficiency and strong universality, and is flexible.
Description
Technical Field
The application relates to the technical field of transmission and distribution, in particular to a method and a device for detecting reasonability of setting of an exhaust valve.
Background
In various transportation and distribution projects, such as urban water supply projects, farmland irrigation water distribution projects, petroleum transportation projects and the like, pipelines are often used as carriers to realize the transportation and distribution of liquid. Wherein, after liquid got into the pipeline, original gas in the pipeline can produce the motion under the effect of liquid, therefore pipeline along usually arranged one or more be used for with gas exhaust valve of pipeline to guarantee the safe handling of pipeline. Therefore, whether the arrangement position of the exhaust valve is reasonable or not is the key for ensuring the safety of the pipeline.
The related art provides a method of detecting the rationality of the arrangement of the exhaust valve. Aiming at a target pipeline to be detected, the method firstly manufactures a physical pipeline model, and the ratio of the size of the physical pipeline model to the size of the target pipeline is a reference value. And then, testing on the physical pipeline model to obtain the exhaust valve information of the physical pipeline model. And based on the hydraulic similarity law, converting the exhaust valve information of the physical pipeline model according to the reference values to obtain the exhaust valve information of the target pipeline. And finally, determining whether the arrangement position of each exhaust valve along the pipeline is reasonable or not according to the exhaust valve information of the target pipeline.
However, in the related art, a physical pipeline model needs to be manufactured for a target pipeline to be detected, so that the detection cost is high and the detection efficiency is low. In addition, the exhaust valve information of the target pipeline obtained through tests and calculation is only suitable for the target pipeline, so that the applicability is poor. It can be seen that the methods provided by the related art are not flexible enough.
Disclosure of Invention
The embodiment of the application provides a method and a device for detecting the reasonability of the setting of an exhaust valve, so as to solve the problem that the methods provided by the related art are not flexible enough. The technical scheme is as follows:
in one aspect, there is provided a method of detecting rationality of a setting of an exhaust valve, the method comprising:
acquiring the setting position of any exhaust valve on a target pipeline, wherein the target pipeline comprises liquid and gas;
acquiring first motion information of the liquid at the set position;
acquiring second motion information of the gas at the set position based on the first motion information;
and determining whether the setting position of the exhaust valve is reasonable or not based on the second motion information.
Optionally, the first motion information includes a liquid flow rate and a liquid flow cross-sectional area;
the acquiring first motion information of the liquid at the set position includes:
acquiring a first relation group according to the pipeline attribute information of the target pipeline;
and solving the first relation group to obtain the liquid flow velocity and the liquid flow cross section area of the liquid at the set position.
Optionally, the solving the first relation group to obtain the liquid flow velocity and the liquid flow cross-sectional area of the liquid at the setting position includes:
performing spatial dispersion on the first relation group to obtain a second relation group;
performing time dispersion on the second relation group to obtain a third relation group;
performing space-time dispersion on the third relation group to obtain a fourth relation group;
and solving the fourth relation group according to the inflow rate of the liquid flowing into the target pipeline and the outflow rate of the liquid flowing out of the target pipeline to obtain the liquid flow velocity and the liquid flow cross section area of the liquid at the set position.
Optionally, the second motion information includes a gas flow rate, a gas flow cross-sectional area, and a gas density;
the acquiring, based on the first motion information, second motion information of the gas at the setting position includes:
acquiring the gas flow cross-sectional area according to the liquid flow cross-sectional area;
acquiring a fifth relation group according to the pipeline attribute information and the gas flow cross section area;
and solving the fifth relation group to obtain the gas flow rate and the gas density of the gas at the set position.
Optionally, before acquiring the setting position of any exhaust valve on the target pipeline, the method further includes:
discretizing the target pipe into one or more cells;
the step of acquiring the setting position of any exhaust valve on the target pipeline comprises the following steps:
determining a distance between the exhaust valve and a reference end of the target conduit;
and determining the target cell where the exhaust valve is located from the one or more cells according to the distance between the exhaust valve and the reference end of the target pipeline.
Optionally, the determining whether the setting position of the exhaust valve is reasonable based on the second motion information includes:
determining the exhaust air speed of the exhaust valve according to the gas density;
and if the exhaust air speed is less than the reference value, determining that the setting position of the exhaust valve is reasonable.
Optionally, said determining an exhaust air velocity of said exhaust valve from said gas density comprises:
determining a gas pressure of the gas at the set location from the gas density;
if the gas pressure is greater than the atmospheric pressure and the gas pressure is less than the reference pressure, determining the exhaust air speed of the exhaust valve according to the following formula:
wherein, CdA flow coefficient of the exhaust valve is represented,represents the gas pressure, PatmRepresents the atmospheric pressure, R0Denotes the gas constant, T denotes the Kelvin temperature of the gas, Δ xiRepresents the length, p, of the target cell0Representing the air density in the exhaust valve.
Optionally, the method further comprises:
if the gas pressure is greater than the reference pressure, determining the exhaust air speed of the exhaust valve according to the following formula:
in another aspect, there is provided an apparatus for detecting rationality of setting of an exhaust valve, the apparatus comprising:
the first acquisition module is used for acquiring the setting position of any exhaust valve on a target pipeline, wherein the target pipeline comprises liquid and gas;
the second acquisition module is used for acquiring first motion information of the liquid at the setting position;
a third obtaining module, configured to obtain second motion information of the gas at the setting position based on the first motion information;
and the first determining module is used for determining whether the setting position of the exhaust valve is reasonable or not based on the second motion information.
Optionally, the first motion information includes a liquid flow rate and a liquid flow cross-sectional area;
the second acquiring module is configured to acquire first motion information of the liquid at the setting position, and includes: acquiring a first relation group according to the pipeline attribute information of the target pipeline; and solving the first relation group to obtain the liquid flow velocity and the liquid flow cross section area of the liquid at the set position.
Optionally, the second obtaining module is configured to perform spatial discretization on the first relationship group to obtain a second relationship group; performing time dispersion on the second relation group to obtain a third relation group; performing space-time dispersion on the third relation group to obtain a fourth relation group; and solving the fourth relation group according to the inflow rate of the liquid flowing into the target pipeline and the outflow rate of the liquid flowing out of the target pipeline to obtain the liquid flow velocity and the liquid flow cross section area of the liquid at the set position.
Optionally, the second motion information includes a gas flow rate, a gas flow cross-sectional area, and a gas density;
the third acquisition module is used for acquiring the gas flow cross section area according to the liquid flow cross section area; acquiring a fifth relation group according to the pipeline attribute information and the gas flow cross section area; and solving the fifth relation group to obtain the gas flow rate and the gas density of the gas at the set position.
Optionally, the apparatus further comprises a discretization module for discretizing the target conduit into one or more cells;
the first obtaining module is used for determining the distance between the exhaust valve and the reference end of the target pipeline; and determining the target cell where the exhaust valve is located from the one or more cells according to the distance between the exhaust valve and the reference end of the target pipeline.
Optionally, the first determining module is configured to determine an exhaust air speed of the exhaust valve according to the gas density; and if the exhaust air speed is less than the reference value, determining that the setting position of the exhaust valve is reasonable.
Optionally, the first determining module is configured to determine a gas pressure of the gas at the setting position according to the gas density; if the gas pressure is greater than the atmospheric pressure and the gas pressure is less than the reference pressure, determining the exhaust air speed of the exhaust valve according to the following formula:
wherein, CdA flow coefficient of the exhaust valve is represented,represents the gas pressure, PatmRepresents the atmospheric pressure, R0Denotes the gas constant, T denotes the Kelvin temperature of the gas, Δ xiRepresents the length, p, of the target cell0Representing the air density in the exhaust valve.
Optionally, the apparatus further comprises: a second determining module, configured to determine, if the gas pressure is greater than the reference pressure, an exhaust air speed of the exhaust valve according to the following formula:
the beneficial effects brought by the technical scheme provided by the embodiment of the application at least comprise:
according to the embodiment of the application, the second motion information of the gas in the target pipeline at the set position is obtained through the first motion information of the liquid in the target pipeline at the set position where the exhaust valve is located, and whether the set position of the exhaust valve is reasonable or not can be detected according to the second motion information. Therefore, the technical scheme provided by the application has the advantages of low detection cost, high detection efficiency and strong universality, and is flexible.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a flow chart of a method of detecting the rationality of an exhaust valve arrangement provided by an embodiment of the present application;
FIG. 2 is a schematic structural diagram of a pipeline simulation device provided in an embodiment of the present application;
FIG. 3 is a comparison graph of the calculated value and the measured value of the exhaust air speed of the exhaust valve 1 provided in the embodiment of the present application;
FIG. 4 is a comparison graph of the calculated value and the measured value of the exhaust air speed of the exhaust valve 2 according to the embodiment of the present application;
FIG. 5 is a comparison graph of the calculated value and the measured value of the exhaust air velocity of the exhaust valve 3 according to the embodiment of the present application;
FIG. 6 is a comparison graph of the calculated value and the measured value of the exhaust air velocity of the exhaust valve 4 according to the embodiment of the present application;
fig. 7 is a schematic structural diagram of a device for detecting the reasonability of the arrangement of an exhaust valve according to an embodiment of the application.
Detailed Description
To make the objects, technical solutions and advantages of the present application more clear, embodiments of the present application will be described in further detail below with reference to the accompanying drawings.
The embodiment of the application provides a method for detecting reasonability of setting of an exhaust valve, and as shown in figure 1, the method comprises the following steps:
step 101, for any exhaust valve on a target pipeline, acquiring a setting position of the exhaust valve, wherein the target pipeline comprises liquid and gas.
Wherein the target pipeline is a pipeline for transporting liquid, and the liquid transported by the target pipeline includes, but is not limited to, water, oil, and the like. Before the target pipeline is put into use, the target pipeline is filled with gas, such as air or inert gas such as nitrogen filled according to actual needs. When liquid conveyed by the target pipeline enters the target pipeline from one end of the target pipeline, namely the target pipeline is put into use, the target pipeline comprises both liquid and gas, and the gas can move under the action of the liquid. Therefore, the target conduit is provided with one or more exhaust valves to facilitate the movement of the gas out of the conduit through the exhaust valves.
If the exhaust valves on the target pipeline are sparsely arranged (for example, the distance between the two exhaust valves is greater than 1000 meters), the original gas in the pipeline can not be discharged out of the pipeline in time, and the safety of pipeline operation is affected. On the contrary, if the exhaust valves are arranged more densely (for example, the distance between two exhaust valves is less than 500 meters), unnecessary waste is caused. Therefore, it is necessary to detect whether the installation position of each exhaust valve on the target pipeline is reasonable, and it is necessary to acquire the installation position of the exhaust valve for any exhaust valve on the target pipeline.
In practice, the position at which the exhaust valve is disposed may be a distance between the exhaust valve and a reference end of the target conduit. The reference end can be a liquid inflow end on the target pipeline and also can be a liquid outflow end on the target pipeline. The distance between the exhaust valve and the reference end of the target pipeline may be obtained by measuring the target pipeline in the detection process, or may be obtained according to design data of the target pipeline, and the obtaining manner of the distance is not limited in this embodiment.
In an alternative embodiment, before obtaining the setting position of the exhaust valve, the method provided by this embodiment further includes: the target pipe is discretized into one or more cells. The target pipeline can be subjected to space dispersion along the axial direction of the target pipeline, and the space dispersion step length used for dispersion is the length of the unit cell. In this embodiment, the spatial discrete step size is not limited, and can be set according to actual needs or experience. For example, the spatial discrete step size may be 1 m.
For one or more cells obtained by dispersion, different cells can be distinguished by i. Taking the example of discretizing the target pipe into N +1 cells (N is a positive integer), i is 0, 1, 2 … … N-1, N. In the N +1 cells, i is 1 and 2 … … N-1 is a general cell. The left border of a typical cell is i-1/2, and the right border is i +1/2, for example, a cell with i-2 has a left border of 3/2 and a right border of 5/2. In addition, i ═ 0 and i ═ N are both special cells. The left boundary of the cell, i-0, is 0, the right boundary is 1/2, and the left boundary of the cell is the inflow end boundary of the target pipeline. The left boundary of the cell is N-1/2, the right boundary is N, and the right boundary of the cell is the outflow end boundary of the target pipe.
After the one or more cells are obtained through the dispersion, the setting position of the exhaust valve can be represented by the obtained cells. That is, acquiring the set position of the exhaust valve includes: a distance between the exhaust valve and a reference end of the target conduit is determined. And determining the target cell where the exhaust valve is located from the one or more cells according to the distance between the exhaust valve and the reference end of the target pipeline.
And calculating the target cell where the exhaust valve is located by combining the space discrete step length for the distance between the exhaust valve and the reference end of the target pipeline, so as to determine the target cell. In the calculation process, the distance between the exhaust valve and the reference end of the target pipeline is used as a dividend, and the space discrete step length is used as a divisor to perform division calculation, so that the following two calculation results are obtained:
the first method comprises the following steps: and obtaining the quotient (namely, the quotient can be divided), and then the quotient is the target cell where the exhaust valve is located.
And the second method comprises the following steps: resulting in a quotient and remainder (i.e., not divisible), it is further determined whether the remainder is greater than half the spatial discrete step size. If the remainder is less than half of the space discrete step length, the quotient is the target cell where the exhaust valve is located; if the remainder is larger than half of the space discrete step length, (quotient +1) is the target unit cell where the exhaust valve is located.
Taking the reference end as the inflow end of the target pipeline, the distance between the exhaust valve and the reference end of the target pipeline is 120.4m, and the space discrete step size is 0.5m as an example, the quotient obtained by dividing 120.4 by 0.5 is 240, and the remainder is 0.4. Since 0.4 is greater than 0.25, the target cell where the exhaust valve is located is a cell where i is 241.
Of course, no matter how the setting position of the exhaust valve is obtained, after the setting position is obtained, the obtaining of the first movement information of the liquid at the setting position may be triggered, which is described in detail in step 102.
First motion information of the liquid at the set position is acquired, step 102.
The first motion information comprises liquid flow rate and liquid flow cross section area. After the liquid flows into the target pipe, the flow rate, the liquid flow velocity, and the liquid flow cross-sectional area of the liquid are different at each position in the pipe due to the influence of factors such as the inflow rate of the liquid when the liquid flows into the target pipe. Therefore, the liquid flow rate and the liquid flow cross-sectional area cannot be directly measured at the inflow end of the target pipe, and the measurement results are directly used as the liquid flow rate and the liquid flow cross-sectional area at the position where the exhaust valve is arranged.
Based on the above description, optionally, the present embodiment acquires the first motion information of the liquid at the setting position according to the following steps 1021 and 1022:
step 1021, acquiring a first relation group according to the pipeline attribute information of the target pipeline.
Wherein, the pipeline attribute information includes but is not limited to: radius r (m) of the target pipe, Manning roughness coefficient n (s/m) of the inner surface of the target pipe1/3) Relative height z of the tube bottom of the target tubeb(m) and the depth of water h (m) in the target pipeline. In this embodiment, r and n may be obtained by testing or calling design data, and z may be obtained by detecting with a water flow sensorb、h。
Then, the following first relation group can be obtained according to the pipeline attribute information:
wherein t is a time coordinate(s); x is a spatial coordinate (m); a. thewIs the flow cross-sectional area (m) of the liquid2)；uwIs the liquid flow rate (m/s); qwThe flow rate (m) of the liquid being over the cross section3S); zeta is the relative height (m) of the liquid in the target pipeline, and zeta ═ zb+ h; g is gravity acceleration (m/s)2) (ii) a R is hydraulic powerRadius (m), and R ═ AwP, P is wet circumference (m), when h < r,when r is less than h and less than 2r,the parameters already described above are not described in detail here.
It can be seen that in the first set of relationships, the liquid flow rate and the liquid flow cross-sectional area are unknown quantities. Therefore, the first set of relationships can be solved to obtain the liquid flow rate and the liquid flow cross-sectional area of the liquid at the set position, as detailed in step 1022.
And 1022, solving the first relation group to obtain the liquid flow rate and the liquid flow cross-sectional area of the liquid at the set position.
In step 101, the target pipe is discretized into one or more cells. Based on the same concept, in an alternative embodiment, the manner of solving the first relationship group includes the following steps a 1-a 4:
and A1, performing spatial dispersion on the first relation group to obtain a second relation group.
For simplicity of illustration, the two relationships in the first set of relationships can be collectively expressed as vector equation (1) as follows:
wherein the content of the first and second substances,
then, the vector equation (1) is spatially discretized, and the spatial discretization method includes, but is not limited to, a finite volume method, and then the integral expression (2) of the vector equation on any cell i obtained by discretization is as follows:
wherein, the second term on the left in expression (2) may be discretized into expression (3) as follows:
and (u) in the expression (3)wU)i+1/2Is the numerical flux of interface (i +1/2), (u)wU)i-1/2Is the numerical flux of interface (i-1/2). (u)wU)i+1/2Expression (4) which can be expressed as follows:
by subscript transformation, one can obtain (u)wU)i-1/2Is described in (1). Thereafter, the above expression (3) can be written as the following form (5) by merging the same items:
(uwU)i+1/2-(uwU)i-1/2＝aiUi-1+biUi+biUi+1 (5)
wherein:
in addition, the right first term in expression (1) may be discretized into expression (6) as follows:
the second term on the right in expression (1) may be discretized into expression (7) as follows:
therefore, according to expressions (2) to (7), expression (1) is an expression obtained by spatial discretization, that is, a second relationship group (8) obtained by spatial discretization of the first relationship group:
wherein, Δ xiFor the space discrete step size, the length of the general cell obtained by the discrete is equal to the space discrete step size.
And A2, performing time dispersion on the second relation group to obtain a third relation group.
After the second relation group (8) is obtained, continuing to perform time dispersion on the second relation group (8) to obtain a third relation group (9) as follows:
wherein n is a real time iteration step, and Δ t is a real time discrete step length.
Since the second relation group (8) has a hyperbolic attribute, the third relation group (9) cannot achieve unconditional convergence. In other words, the liquid flow rate and the liquid flow cross-sectional area cannot be determined directly from the third relation group (9). Therefore, the present embodiment further performs space-time dispersion on the third relation group (9), which is detailed in step a 3.
And A3, performing space-time dispersion on the third relation group to obtain a fourth relation group.
In the embodiment, the space-time discretization can be performed on the third relation group based on a two-time step method, so that the following fourth relation group (10) is obtained from the third relation group (9):
wherein p is a virtual time iteration step, and Δ τ is a virtual time discrete step length. In the fourth relation group (10), if the virtual time iteration step converges, the first item on the left side of the fourth relation group (10) tends to 0, so that the fourth relation group (10) can realize unconditional absolute convergence. Therefore, the fourth relationship group (4) is solved in step a 4.
And step A4, solving a fourth relation group according to the inflow rate of the liquid flowing into the pipeline and the outflow rate of the liquid flowing out of the target pipeline to obtain the liquid flow velocity and the liquid flow cross section area of the liquid at the set position.
As is apparent from the above description, the fourth relationship group (10) is in the form of a vector, and therefore the fourth relationship group (10) can also be expressed as the following expression (11):
wherein λ ═ Δ t/Δ xiIs the ratio of the real time discrete step to the space discrete step, and ω ═ Δ t/Δ τ is the ratio of the real time discrete step to the virtual time discrete step.
In addition, the first and second substrates are,the expression of (a) is as follows:
in the case where the target pipe space is divided into N +1 cells, the target discharge valve is located at the target position, and the target cell is a general cell (i: 1, 2, … … N-1), the liquid flow rate of the target cell can be calculated according to expression (11)Flow rate of liquidAnd cross-sectional area of liquid flow
Further, if the target cell is located at the special cell i ═ 0, the left interface of the cell is the left interface of the target pipeline, and therefore the inflow Q at the left interface of the target pipeline needs to be combined0，givenTo express (u) in the above expression (3)wU)i-1/2Thus, expression (12) obtained by rewriting expression (11) is obtained as follows, and the liquid flow rate with the cell i of 0 can be obtained by solving expression (12)Flow rate of liquidAnd cross-sectional area of liquid flow
Expression (12) corresponds toAndrespectively as follows:
accordingly, if the target cell is located in the special cell i ═ N, the right interface of the cell is the right interface of the target pipeline, and therefore, the flow rate at the right interface of the target pipeline and the flow rate Q of the liquid flowing out of the target pipeline need to be obtained by means of flow meter detection and the likeN，g1venRepresents (u) in the above expression (3)wU)i+1/2Thereby obtaining a summary chartExpression (13) obtained by rewriting expression (11) is as follows, and the liquid flow rate of cell i ═ N can be obtained by solving from expression (13)Flow rate of liquidAnd cross-sectional area of liquid flow
It can be seen that no matter where the exhaust valve is disposed on the target pipeline, the first movement information of the liquid at the disposed position of the exhaust valve can be obtained through step 102. Therefore, the second movement information of the gas at the setting position can be further obtained based on the first movement information, see step 103.
And 103, acquiring second motion information of the gas at the setting position based on the first motion information.
The second motion information comprises gas flow rate, gas flow cross section area and gas density. In the implementation, the second motion information of the gas is obtained based on the first motion information of the liquid just because the gas flow rate, the gas flow cross-sectional area and the gas density are difficult to obtain through measurement.
Optionally, acquiring second motion information of the gas at the set position based on the first motion information comprises: acquiring the gas flow cross-sectional area according to the liquid flow cross-sectional area; acquiring a fifth relation group according to the pipeline attribute information and the gas flow cross section area; and solving the fifth relation group to obtain the gas flow rate and the gas density of the gas at the set position.
At the setting position, the sum of the gas flow cross-sectional area and the liquid flow cross-sectional area is the radial cross-sectional area of the target pipeline, and the radial cross-sectional area can be half of the target pipeline obtained in the aboveAnd calculating the diameter r. By AaThe gas flow cross-sectional area is shown, and the radial cross-sectional area of the target pipeline is shown by A, so that the gas flow cross-sectional area Aa＝A-Aw. Further, the pipe attribute information may include, in addition to the information described in the above-described step 1021: flow coefficient C of the exhaust valvedExhaust area A of the exhaust valvev(m2) And a target pipe length l (m).
Therefore, the following fifth relation group (14) can be obtained according to the pipeline attribute information and the gas flow cross-section area:
wherein t is a time coordinate, x is a space coordinate, and Pa is a gas pressure (P)a)，ρaIs gas density (kg/m)3) T is the gas temperature uaAs the flow rate of the gas,the gas mass (kg/(m · s)), R, discharged from the exhaust valve per unit length of the target pipe per unit time*Is a gas constant, R*＝2.866×102J/(mol. K). The above-described parameters are not described in detail herein.
In addition, the calculation in the expression is performed according to the following formula:
wherein, PatmAt atmospheric pressure, R0Is a gas constant, R0＝0.029×R*8.314J/(mol K). In this embodiment, the reason is thatIs introduced into the expression of (a), thus enabling the target pipeline to have a length LIs kg/(m.s), and further such thatCan be used in the fifth set of relationships (14) to facilitate subsequent resolution of gas density and gas flow rate.
In addition, the solving process for the fifth relation group (14) also includes space dispersion, time dispersion and space-time dispersion, and the solving process is as follows:
the fifth set of relationships (14) is represented as a vector equation as follows:
wherein the content of the first and second substances,
and performing spatial discretization on the vector expression, wherein each cell i obtained by the spatial discretization has the following expression (15):
wherein the content of the first and second substances,
when P is presentatm＜Pa，i＜1.894PatmWhen S is presentout，iExpressed as the following equation:
when P is presenta，i＞1.894PatmWhen S is presentout，iExpressed as the following equation:
performing time dispersion on expression (15) to obtain expression (16) as follows:
wherein n is a real time iteration step and a real time discrete step length.
Then, performing space-time dispersion on the expression (16) to obtain the following expression (17):
the expression (17) can also be expressed as the following relationship group (18):
wherein the content of the first and second substances,andthe expression of (a) is as follows:
the above-described relation group (18) is also applied to a case where the target cell in which the target exhaust valve is located is a general cell (i: 1, 2, … … N-1), taking as an example the target pipe space is dispersed into N +1 cells. In other words, the gas density of the general cell can be calculated by the above-mentioned relation group (18)And gas flow rateAnd for the case that the target unit cell is located at the special unit cell i-0, the left interface of the unit cell is the left interface of the target pipeline, no gas enters, so that the following expression (19) which is obtained by rewriting the expression (18) can be obtained, and the gas flow rate of the unit cell i-0 can be obtained by solving the expression (19)And density of gas
Corresponding toAndrespectively as follows:
correspondingly, for the case that the target unit cell is located in the special unit cell i ═ N, the right interface of the unit cell is the right interface of the target pipeline, and the mass m of the discharged gas per unit time at the right interface of the target pipeline is obtained by means of measurement and the likeN，givenThus, an expression (20) rewritten by the expression (18) can be obtained as follows, and the gas flow rate of cell i ═ N can be solved from the expression (19)And density of gas
Corresponding toAndrespectively as follows:
after the second movement information of the gas at the setting position is obtained, it may be further determined whether the setting position of the exhaust valve is reasonable based on the obtained second movement information, see step 104.
And 104, determining whether the setting position of the exhaust valve is reasonable or not based on the second motion information.
Because the gas can be discharged from the exhaust valve, whether the setting position of the exhaust valve is reasonable or not can be determined according to the exhaust air speed of the exhaust valve. It should be noted that the exhaust air speed of the exhaust valve can also be measured by a measuring instrument. In practice, however, the target pipeline may have hundreds of exhaust valves, and the measurement of hundreds of exhaust valves is time-consuming, labor-consuming and costly. Therefore, it is necessary to determine whether the set position of the exhaust valve is reasonable based on the second motion information as explained in the present embodiment.
In an alternative embodiment, determining whether the set position of the exhaust valve is reasonable based on the second motion information includes: determining the exhaust air speed of the exhaust valve according to the air density in the second motion information; and if the exhaust air speed is less than the reference value, determining that the setting position of the exhaust valve is reasonable.
If the exhaust air speed of the exhaust valve is larger than the reference value, the exhaust air speed indicates that the exhaust pipelines are too many, so that the arrangement position of the exhaust valve is not reasonable, and the number of the exhaust valves on the target pipeline should be increased. Accordingly, if the exhaust air speed of the exhaust valve is less than the reference value, the setting position of the exhaust valve can be determined to be reasonable. In an implementation, the reference value may be the size of the exhaust wind speed peak allowed by the exhaust valve, may also be a multiple of the size of the allowed exhaust wind speed peak, for example, a multiple of 0.9, 1.1, or any value set according to actual needs or experience, and the embodiment does not limit the reference value.
Further, the exhaust air speed of the exhaust valve is determined according to the air density, and the following optional modes are included:
first, the gas pressure of the gas at the set position is determined from the gas density, which is related to the gas pressure as follows:
then, if the gas pressure is greater than the atmospheric pressure and less than the reference pressure, determining the exhaust air speed of the exhaust valve according to the following formula:
wherein, CdThe flow coefficient of the exhaust valve is represented,representing the gas pressure, PatmDenotes atmospheric pressure, R0Denotes the gas constant, T denotes the temperature of the gas, Δ xiDenotes the length of the target cell, p0Indicating the air density in the exhaust valve.
Or, optionally, if the gas pressure is greater than the reference pressure, determining the exhaust air speed of the exhaust valve according to the following formula:
next, an application method of the detection exhaust valve provided in this embodiment is described by using a simulation experiment apparatus as shown in fig. 2, taking water as an example of the liquid:
in the simulation experiment apparatus shown in fig. 2, the apparatus includes: an organic glass tube (Manning roughness n is 0.0088) with the diameter of 240mm and the length of 303m is arranged between the upstream water tank and the downstream water tank and is used as a tube section, and the organic glass tube is provided with an inflow regulation section, an upstream 22.8mm multiplied by 22.8mm square culvert transition section (namely a rectangular tube section between the upstream water tank and the pipeline), an electromagnetic flowmeter, a surge shaft, an exhaust valve 1-4, a downstream 22.8mm multiplied by 22.8mm square culvert transition section (namely a rectangular tube section between the pipeline and the downstream water tank) and an outflow regulation valve. In addition, water stabilizing grids can be arranged in the upstream water tank and the downstream water tank to adjust the water level of the water tanks. The exhaust valve arranged on the organic glass tube is of a circular caliber, the diameter of the exhaust valve is 24mm, and the peak value of the allowed exhaust wind speed is 6 m/s.
TABLE 1 pipe System parameters
The water inlet flow in the control pipe section is 0.00402m3And/s, mounting a wind speed transmitter at each exhaust valve to measure the exhaust wind speed, and recording the exhaust wind speed of each exhaust valve, wherein the recorded exhaust wind speed is used for comparing with the exhaust wind speed calculated in the embodiment. Then, a comparison graph of each exhaust valve is drawn according to the recorded exhaust wind speed and the wind speed calculated in the present embodiment. Wherein, the comparison graph at the exhaust valve 1 is shown in figure 3, the comparison graph at the exhaust valve 2 is shown in figure 4, the comparison graph at the exhaust valve 3 is shown in figure 5, and the comparison graph at the exhaust valve 4 is shown in figure 6. Because the peak value of the exhaust air speed allowed by the exhaust valve is 6m/s, the exhaust air speed of each exhaust valve does not exceed the peak value, and the arrangement positions of 4 exhaust valves on the pipeline are reasonable.
As can be seen from fig. 3 to 6, the exhaust air speed calculated in this embodiment is closer to the measured value, so that whether the installation position of the exhaust valve is reasonable or not is detected according to the exhaust air speed calculated in this embodiment, and the obtained detection result is more accurate. Therefore, the detection method provided by the embodiment is not only more flexible, but also has higher accuracy of the detection result and higher feasibility.
To sum up, this application obtains the second motion information of gas in the target pipeline at this set position department through the first motion information of the liquid in the target pipeline at the set position department at discharge valve place, and whether it is reasonable according to this second motion information alright detection discharge valve's set position again. Therefore, the technical scheme provided by the application has the advantages of low detection cost, high detection efficiency and strong universality, and is flexible.
Based on the same conception, the embodiment of the application also provides a device for detecting the reasonability of the setting of the exhaust valve, and as shown in fig. 7, the device comprises:
the first obtaining module 701 is used for obtaining the setting position of any exhaust valve on a target pipeline, wherein the target pipeline comprises liquid and gas;
a second acquiring module 702, configured to acquire first motion information of the liquid at the setting position;
a third obtaining module 703, configured to obtain second motion information of the gas at the setting position based on the first motion information;
a first determination module 704 configured to determine whether the set position of the exhaust valve is reasonable based on the second motion information.
Optionally, the first motion information includes a liquid flow rate and a liquid flow cross-sectional area;
a second obtaining module 702, configured to obtain first motion information of the liquid at the setting position, including: acquiring a first relation group according to the pipeline attribute information of the target pipeline; and solving the first relation group to obtain the liquid flow velocity and the liquid flow cross section area of the liquid at the set position.
Optionally, the second obtaining module 702 is configured to perform spatial discretization on the first relationship group to obtain a second relationship group; performing time dispersion on the second relation group to obtain a third relation group; performing space-time dispersion on the third relation group to obtain a fourth relation group; and solving the fourth relation group according to the inflow rate of the liquid flowing into the target pipeline and the outflow rate of the liquid flowing out of the target pipeline to obtain the liquid flow velocity and the liquid flow cross section area of the liquid at the set position.
Optionally, the second motion information includes a gas flow rate, a gas flow cross-sectional area, and a gas density;
the third obtaining module 703 is configured to obtain a gas flow cross-sectional area according to the liquid flow cross-sectional area; acquiring a fifth relation group according to the pipeline attribute information and the gas flow cross section area; and solving the fifth relation group to obtain the gas flow rate and the gas density of the gas at the set position.
Optionally, the apparatus further comprises a discretization module for discretizing the target conduit into one or more cells;
a first obtaining module 701, configured to determine a distance between the exhaust valve and a reference end of the target pipeline; and determining the target cell where the exhaust valve is located from the one or more cells according to the distance between the exhaust valve and the reference end of the target pipeline.
Optionally, a first determining module 704 for determining an exhaust air speed of the exhaust valve according to the gas density; and if the exhaust air speed is less than the reference value, determining that the setting position of the exhaust valve is reasonable.
Optionally, a first determining module 704 for determining a gas pressure of the gas at the setting position according to the gas density; if the gas pressure is greater than the atmospheric pressure and the gas pressure is less than the reference pressure, determining the exhaust air speed of the exhaust valve according to the following formula:
wherein, CdThe flow coefficient of the exhaust valve is represented,representing the gas pressure, PatmRepresenting atmospheric pressure, R representing the gas constant, T representing the Kelvin temperature of the gas, Δ xiDenotes the length of the target cell, p0Indicating the air density in the exhaust valve.
Optionally, the apparatus further comprises: the second determination module is used for determining the exhaust air speed of the exhaust valve according to the following formula if the air pressure is greater than the reference pressure:
in summary, in this embodiment, the second motion information of the gas in the target pipeline at the setting position is obtained through the first motion information of the liquid in the target pipeline at the setting position where the exhaust valve is located, and then whether the setting position of the exhaust valve is reasonable or not can be detected according to the second motion information. Therefore, the technical scheme provided by the application has the advantages of low detection cost, high detection efficiency and strong universality, and is flexible.
All the above optional technical solutions may be combined arbitrarily to form the optional embodiments of the present disclosure, and are not described herein again.
The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims (10)
1. A method of detecting the rationality of an exhaust valve setting, the method comprising:
acquiring the setting position of any exhaust valve on a target pipeline, wherein the target pipeline comprises liquid and gas;
acquiring first motion information of the liquid at the set position;
acquiring second motion information of the gas at the set position based on the first motion information;
and determining whether the setting position of the exhaust valve is reasonable or not based on the second motion information.
2. The method of claim 1, wherein the first motion information comprises a liquid flow rate and a liquid flow cross-sectional area;
the acquiring first motion information of the liquid at the set position includes:
acquiring a first relation group according to the pipeline attribute information of the target pipeline;
and solving the first relation group to obtain the liquid flow velocity and the liquid flow cross section area of the liquid at the set position.
3. The method of claim 2, wherein solving the first set of relationships to obtain the liquid flow rate and the liquid flow cross-sectional area of the liquid at the set location comprises:
performing spatial dispersion on the first relation group to obtain a second relation group;
performing time dispersion on the second relation group to obtain a third relation group;
performing space-time dispersion on the third relation group to obtain a fourth relation group;
and solving the fourth relation group according to the inflow rate of the liquid flowing into the target pipeline and the outflow rate of the liquid flowing out of the target pipeline to obtain the liquid flow velocity and the liquid flow cross section area of the liquid at the set position.
4. The method of claim 3, wherein the second motion information comprises gas flow rate, gas flow cross-sectional area, and gas density;
the acquiring, based on the first motion information, second motion information of the gas at the setting position includes:
acquiring the gas flow cross-sectional area according to the liquid flow cross-sectional area;
acquiring a fifth relation group according to the pipeline attribute information and the gas flow cross section area;
and solving the fifth relation group to obtain the gas flow rate and the gas density of the gas at the set position.
5. The method according to any one of claims 1-4, wherein said obtaining a set position of said exhaust valve for any exhaust valve on said target duct further comprises:
discretizing the target pipe into one or more cells;
the step of acquiring the setting position of any exhaust valve on the target pipeline comprises the following steps:
determining a distance between the exhaust valve and a reference end of the target conduit;
and determining the target cell where the exhaust valve is located from the one or more cells according to the distance between the exhaust valve and the reference end of the target pipeline.
6. The method of claim 5, wherein determining whether the exhaust valve is located at a reasonable setting position based on the second motion information comprises:
determining the exhaust air speed of the exhaust valve according to the gas density;
and if the exhaust air speed is less than the reference value, determining that the setting position of the exhaust valve is reasonable.
7. The method of claim 6, wherein said determining an exhaust air velocity of said exhaust valve based on said gas density comprises:
determining a gas pressure of the gas at the set location from the gas density;
if the gas pressure is greater than the atmospheric pressure and the gas pressure is less than the reference pressure, determining the exhaust air speed of the exhaust valve according to the following formula:
wherein, CdA flow coefficient of the exhaust valve is represented,represents the gas pressure, PatmRepresents the atmospheric pressure, R0Denotes the gas constant, T denotes the Kelvin temperature of the gas, Δ xiRepresents the length, p, of the target cell0Representing the air density in the exhaust valve.
8. The method of claim 7, further comprising:
if the gas pressure is greater than the reference pressure, determining the exhaust air speed of the exhaust valve according to the following formula:
9. an apparatus for detecting the rationality of a setting of an exhaust valve, characterized in that the apparatus comprises:
the first acquisition module is used for acquiring the setting position of any exhaust valve on a target pipeline, wherein the target pipeline comprises liquid and gas;
the second acquisition module is used for acquiring first motion information of the liquid at the setting position;
a third obtaining module, configured to obtain second motion information of the gas at the setting position based on the first motion information;
and the first determining module is used for determining whether the setting position of the exhaust valve is reasonable or not based on the second motion information.
10. The apparatus of claim 9, further comprising:
a discretization module for discretizing the target pipe into one or more cells;
the first obtaining module is used for determining the distance between the exhaust valve and the reference end of the target pipeline; and determining the target cell where the exhaust valve is located from the one or more cells according to the distance between the exhaust valve and the reference end of the target pipeline.
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