A Method for Constructing and Invoking a Database of Valve Opening-Flow Resistance Coefficient Functions

Abstract

The present invention provides a method for constructing and calling a valve opening - flow resistance coefficient function database. During the process of constructing the database, the influence of valve parameters and fluid flow states on the valve opening - flow resistance coefficient function is fully considered, and in combination with the simulation calculation of the ship pipeline network and the flow distribution debugging requirements during actual construction, accurate flow resistance data support is provided from the principle design stage to the actual production debugging stage of the shipbuilding process, reducing the probability of errors and waste of resources. In addition, the calling method based on the above - mentioned database provided by the present invention can accurately and quickly obtain the corresponding valve opening - flow resistance coefficient function through known valve parameters and fluid flow states, thereby obtaining the accurate valve opening value under a determined flow resistance coefficient, providing more accurate and convenient data support for ship production and construction, reducing the work difficulty of on - site debugging personnel, and saving production time.

Description

Technical Field

[0001] The present invention relates to the technical field of ship pipeline flow control, and in particular to a method for constructing and calling a valve opening-flow resistance coefficient function database. Background Art

[0002] As an important part of ship equipment, the ship pipeline network provides the required water, oil, steam and other media for ship equipment, plays the role of medium flow and energy exchange between ship systems, and is the bridge and link connecting various power equipment in the ship system. In the ship pipeline network system, there are a large number of pipelines, many types, and complex layout. The flow distribution process of the ship pipeline system can be regarded as the process of adjusting the valve opening. Adjusting the pipeline valve opening will cause the pipeline flow of the pipeline network to change, and this change is nonlinear and is closely related to multiple factors such as the ship pipeline structure size, valve opening, and the flow state of the fluid in the pipe. For the accuracy of the pipeline network simulation calculation, accurate valve flow resistance data is very important.

[0003] With the advancement of shipbuilding technology and the trend of larger ships, modern ship systems have become more sophisticated and complex, and the computational simulation of pipe network systems has also developed towards automation, complexity and precision. In recent years, the simulation calculation of fluid pipe networks in ships and related industries has also shown a trend of precision development. For example, in the invention patent CN1293332A, a pipeline database, a pipe joint database and a valve database are established. The corresponding data are stored in these databases, and the flow and pressure of each part of the pipeline can be calculated by combining the running calculation formula.

[0004] The increasing sophistication and complexity of ship pipe network systems has led to an increase in the difficulty of pipe network system design and debugging. Especially in the process of pipeline flow debugging, the adjustment of valve opening affects the entire system. The valve flow resistance coefficient will be affected by factors such as valve opening, valve size structure and flow state in the pipe, which increases the difficulty of flow regulation in the pipe network system. Especially in ship operation, during the actual assembly and use of the pipeline, the valve is usually normally open or normally closed. The valve opening is only adjusted during the pipeline flow distribution debugging process. In order to restore the flow in the pipe during debugging, a throttling orifice will be added during the actual assembly. However, because the valve flow resistance coefficient corresponding to a certain valve opening and fluid Reynolds number is unknown, the uncertainty of throttling orifice processing will increase, resulting in a waste of cost.

[0005] In the simulation calculation of pipeline network flow in currently disclosed patents, valves in pipeline segments are often incorporated into the calculation of the frictional resistance along the pipeline segments in a fully open or fully closed state. However, the resistance coefficient of a valve varies due to factors such as valve type, internal structure, nominal diameter, opening value, and the flow state within the pipeline. Although the above patents have established a valve database, they only define the valve resistance coefficient as a fixed value and do not consider the impact of changes in the valve opening value on the resistance coefficient and flow state, thus failing to meet the accuracy requirements of the ship system during the design and construction phases. Summary of the Invention

[0006] In view of the above-mentioned drawbacks of the prior art, the present invention provides a method for constructing and calling a valve opening - flow resistance coefficient function database. During the process of constructing the database, multiple parameters such as whether the valve has an opening indication, valve usage, valve internal structure, valve nominal diameter, and the flow state of the fluid are fully considered for their influence on the valve opening - flow resistance coefficient function. Combining the ship pipeline network simulation calculation with the flow distribution debugging requirements during actual construction enables accurate flow resistance data support from the principle design stage to the actual production debugging stage of the shipbuilding process, reducing the probability of errors and waste of resources. Additionally, the calling method based on the above database provided by the present invention can accurately and quickly obtain the corresponding valve opening - flow resistance coefficient function through known valve parameters and flow parameters, thereby obtaining the accurate valve opening value under a determined flow resistance coefficient, providing more precise and convenient data support for ship production and construction, reducing the work difficulty of on-site debugging personnel, and saving production time.

[0007] To achieve the above object and other related objects, the present invention provides a method for constructing a valve opening - flow resistance coefficient function database, including the following steps:

[0008] S1: Construct a first - level database. In the first - level database, ship valves are divided into a first type of valve and a second type of valve. Among them, the first type of valve has no opening indication, and the second type of valve has an opening indication;

[0009] S2: Construct a second - level database under the first - level database. In the second - level database, the first type of valve and the second type of valve are classified according to different valve usages, and the first type of valve is further classified according to different internal structures;

[0010] S3: Construct a third - level database under the second - level database. In the third - level database, each type of the first type of valve with different internal structures is classified according to different nominal diameters, and each type of the second type of valve with different usages is classified according to different nominal diameters;

[0011] S4: Construct a fourth-level database under the third-level database. In the fourth-level database, the first type of valves and the second type of valves with different nominal diameters are classified according to different fluid flow states.

[0012] S5: Construct a fifth-level database under the fourth-level database. In the fifth-level database, different fluid flow states correspond to different valve opening-flow resistance coefficient functions, and the construction of the valve opening-flow resistance coefficient function database is completed.

[0013] Optionally, in step S2, according to different valve uses, the first type of valves is divided into globe valves and check valves, and the second type of valves is butterfly valves.

[0014] Optionally, in step S2, according to different internal structures of the valves, the globe valves are divided into straight-through valves and right-angle valves, and the check valves are divided into straight-through valves and right-angle valves.

[0015] Optionally, in step S3, the nominal diameters include DN15, DN20, DN25, DN32, DN40, DN50, DN65, DN80, DN100, DN125, DN150, DN175, DN200, DN250.

[0016] Optionally, in step S4, the Reynolds number is used to judge the fluid flow state.

[0017] Optionally, the Reynolds number is calculated based on the flow parameters, and the flow parameters include the pressure drop, flow rate, density, and viscosity of the fluid.

[0018] The present invention also provides a method for calling a valve opening-flow resistance coefficient function database, including the following steps:

[0019] S1: Provide a valve opening-flow resistance coefficient function database, and the database is the valve opening-flow resistance coefficient function database described in any one of the above.

[0020] S2: Determine the input parameters, and the input parameters include valve parameters and the flow parameters. Among them, the valve parameters include whether the valve has an opening indication, valve use, valve internal structure, and valve nominal diameter.

[0021] S3: In the valve opening-flow resistance coefficient function database, obtain the corresponding valve opening-flow resistance coefficient function according to the input parameters.

[0022] S4: Substitute the required flow resistance coefficient into the valve opening-flow resistance coefficient function in step S3 to obtain the valve opening value.

[0023] S5: Determine whether the valve opening value is reasonable. If it is reasonable, output the valve opening value; if it is not reasonable, after adjusting the input parameters in step S2, repeat steps S2 - S4 to recalculate the valve opening value until the calculated valve opening value is reasonable and then output it.

[0024] Optionally, in step S5, a reasonable valve opening value ranges from 0% to 100%.

[0025] The method for constructing and calling the valve opening - flow resistance coefficient function database provided by the present invention has at least the following beneficial effects:

[0026] The method for constructing the valve opening - flow resistance coefficient function database provided by the present invention fully considers the influence of multiple parameters such as whether the valve has an opening indication, the valve use, the valve internal structure, the valve nominal diameter, and the fluid flow state on the valve opening - flow resistance coefficient function. Combining the ship pipeline network simulation calculation and the flow distribution debugging requirements during actual construction enables accurate flow resistance data support from the principle design stage to the actual production debugging stage of the shipbuilding process, reduces the probability of errors, and reduces resource waste. In addition, the calling method based on the above - mentioned database provided by the present invention can accurately and quickly obtain the corresponding valve opening - flow resistance coefficient function through known valve parameters and flow parameters, thereby obtaining an accurate valve opening value under a determined flow resistance coefficient, providing more accurate and convenient data support for ship production and construction, reducing the work difficulty of on - site debugging personnel, and saving production time. Description of the Drawings

[0027] Figure 1 Shown is a flowchart of the method for constructing the valve opening - flow resistance coefficient function database provided in Embodiment 1.

[0028] Figure 2 Shown is a schematic diagram of the valve opening - flow resistance coefficient function database provided in Embodiment 1.

[0029] Figure 3 Shown is a relationship diagram of Reynolds number - valve opening value - flow resistance coefficient in Embodiment 1.

[0030] Figure 4 Shown is a flowchart of the method for calling the valve opening - flow resistance coefficient function database provided in Embodiment 2.

[0031] Explanation of Component Labels

[0032] 101 First - level database

[0033] 102 Second - level database

[0034] 103 Third - level database

[0035] 104 Fourth - level database

[0036] 105 Fifth-level database Specific implementation manners

[0037] The following uses specific examples to illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0038] It should be noted that the diagrams provided in this embodiment only illustrate the basic concept of the present invention in a schematic manner. Although only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation, the form, quantity, positional relationship, and ratio of each component in actual implementation can be arbitrarily changed on the premise of implementing the technical solution of the present invention, and the component layout form may also be more complex.

[0039] Embodiment 1

[0040] This embodiment provides a method for constructing a valve opening - flow resistance coefficient function database, as Figure 1 shown, including the following steps:

[0041] S1: Construct a first-level database. In the first-level database, ship valves are divided into a first type of valve and a second type of valve. Among them, the first type of valve has no opening indication, and the second type of valve has an opening indication;

[0042] As an example, common ship valves can be divided into two categories according to whether they have an opening indication. One category is valves without an opening indication, that is, the operator can only judge the opening value of the valve by experience; the other category is valves with an opening indication, that is, the operator can accurately know the opening value of the valve according to the opening indication.

[0043] As Figure 2 shown, construct a first-level database 101. In the first-level database 101, ship valves are divided into a first type of valve and a second type of valve. Among them, the first type of valve has no opening indication, and the second type of valve has an opening indication.

[0044] S2: Construct a second-level database under the first-level database. In the second-level database, the first type of valve and the second type of valve are classified according to different valve uses, and the first type of valve is further classified according to different internal structures of the valve;

[0045] As Figure 2As shown, a second-level database 102 is constructed under the first-level database 101, that is, the first type of valves and the second type of valves are further classified according to different valve uses and different internal structures of the valves.

[0046] First, the first type of valves and the second type of valves are classified according to different valve uses. In this embodiment, the first type of valves are divided into globe valves and check valves, and the second type of valves are butterfly valves. In other alternative embodiments, the first type of valves and the second type of valves can be divided into more categories, which will not be elaborated here.

[0047] Next, the first type of valves are further classified according to different internal structures of the valves. In this embodiment, the globe valves are further divided into straight-through valves and angle valves, and the check valves are also divided into straight-through valves and angle valves.

[0048] S3: A third-level database is constructed under the second-level database. In the third-level database, each type of the first type of valves with different internal structures is classified according to different nominal diameters, and each type of the second type of valves with different uses is classified according to different nominal diameters;

[0049] As Figure 2 shown, a third-level database 103 is constructed under the second-level database 102. In the third-level database 103, the valves are further classified according to different nominal diameters. In this embodiment, the nominal diameters include DN15, DN20, DN25, DN32, DN40, DN50, DN65, DN80, DN100, DN125, DN150, DN175, DN200, DN250. In other alternative embodiments, the nominal diameters can have other values.

[0050] As an example, in the third-level database 103, the straight-through globe valves, angle globe valves, straight-through check valves, angle check valves and butterfly valves are all classified according to the nominal diameters DN15, DN20, DN25, DN32, DN40, DN50, DN65, DN80, DN100, DN125, DN150, DN175, DN200, DN250.

[0051] S4: A fourth-level database is constructed under the third-level database. In the fourth-level database, the first type of valves and the second type of valves with different nominal diameters are classified according to different fluid flow states;

[0052] As an example, the flow resistance coefficient of a valve is not only affected by the valve opening and the structural dimensions of the valve inside the pipe, but is also closely related to the flow state of the fluid in the valve. When the fluid is in a laminar state, each point in the fluid can be regarded as a linear motion without mutual interference, and the flow velocity is distributed in a trapezoidal state along the pipe wall; while when the fluid is in a turbulent state, the individual particles of the fluid are mixed with each other, forming a vortex motion state. The flow state of the fluid is generally reflected by the Reynolds number Re, and the relationship among the Reynolds number - valve opening value - flow resistance coefficient is as Figure 3 shown. Therefore, classifying valves according to the flow state of the fluid in the fourth-level database 104 can obtain a more accurate valve opening value when the flow resistance coefficient is determined.

[0053] As an example, the Reynolds number Re can be calculated from the pressure drop P, flow rate Q, density ρ, and viscosity μ of the fluid. Taking a globe valve with a nominal diameter of DN32 as an example, it can be divided into four categories according to different flow states of the fluid, and the Reynolds numbers Re are 166558.5, 395161.4, 623764.4, and 852367.4 respectively. In other alternative embodiments, it can be divided into more categories, and the values of the Reynolds number Re can be different from the above values.

[0054] S5: Construct a fifth-level database under the fourth-level database. In the fifth-level database, different flow states of the fluid correspond to different valve opening - flow resistance coefficient functions, and the construction of the valve opening - flow resistance coefficient function database is completed.

[0055] As an example, the resistance coefficient ξ of the valve is expressed by formula (1):

[0056]

[0057] where, ΔH - local head loss, m; u - flow velocity, obtained by measuring the flow rate Q m / s.

[0058] The valve opening value α is expressed by formula (2):

[0059]

[0060] where, A1 - cross-sectional area of the pipe segment; A2 - area of the valve.

[0061] Combining the energy equation (3) and the momentum equation (4), it can be obtained that when the pipe area is determined, the resistance coefficient ξ is a function of the valve opening α, that is, ξ = F(α). The energy equation (3) and the momentum equation (4) are as follows:

[0062]

[0063] (P1 + ρgZ1)A1 - (P2 + ρgZ2)A2 = ρQ(a 02 v2 - a 01 v1) (4)

[0064] where a1, a2, a 01 , a 02 are all constants.

[0065] When adjusting the valve opening α, the water flow state inside the valve presents a complex turbulent state, generating a vortex area and a separated recirculation area in the pipeline, resulting in a head loss. Therefore, the relationship between the valve opening α and the resistance coefficient ξ cannot be simply expressed by a general formula. Instead, the resistance coefficient ξ needs to be measured through experiments, and a mathematical model of the variation of the valve resistance coefficient ξ with the valve opening α is obtained through data fitting, as shown in Equation (5).

[0066]

[0067] where c0, c1, and c2 are undetermined coefficients, which are closely related to the valve diameter and the fluid flow state inside the pipe. The specific values need to be obtained through fitting of experimental data. Therefore, a fifth-level database 105 is constructed under the fourth-level database 104. In the fifth-level database 105, different fluid flow states correspond to different valve opening-flow resistance coefficient functions, thus completing the construction of the valve opening-flow resistance coefficient function database.

[0068] In this embodiment, taking a certain type of globe valve as an example, the valve opening-flow resistance coefficient function database is shown in Table 1.

[0069] Table 1 Valve Opening-Flow Resistance Coefficient Function Database of a Certain Type of Globe Valve

[0070]

[0071] Embodiment 2

[0072] This embodiment provides a method for calling a valve opening-flow resistance coefficient function database, as Figure 4 shown, including the following steps:

[0073] S1: Provide a valve opening-flow resistance coefficient function database;

[0074] As an example, provide a valve opening-flow resistance coefficient function database, which is the valve opening-flow resistance coefficient function database provided in Embodiment 1. For the specific content of the database, please refer to the description of Embodiment 1 and will not be elaborated here.

[0075] S2: Determine the input parameters, where the input parameters include valve parameters and the flow parameters. Among them, the valve parameters include whether the valve has an opening indication, valve usage, internal valve structure, and nominal diameter of the valve;

[0076] As an example, to determine the valve parameters, refer to Figure 2 As shown, first select the first type of valve or the second type of valve in the first-level database 101. If the first type of valve is selected, then further determine to select a straight-through globe valve / angle globe valve / straight-through check valve / angle check valve in the second-level database 102; then, select a suitable nominal diameter in the third-level database 103. Specifically, the nominal diameter is determined by the actual selection of the valve in production and design. If the second type of valve is selected, first select a butterfly valve in the second-level database 102, and then select a suitable nominal diameter in the third-level database 103.

[0077] As an example, to determine the flow parameters, the flow parameters include the pressure drop P, flow rate Q, density ρ, and viscosity μ of the fluid. According to the above flow parameters, the Reynolds number Re can be calculated, and the corresponding Reynolds number Re can be found in the fourth-level database 104.

[0078] S3: In the valve opening - flow resistance coefficient function database, obtain the corresponding valve opening - flow resistance coefficient function according to the input parameters;

[0079] As an example, combining the valve parameters and the flow parameters, the corresponding valve opening - flow resistance coefficient function can be found in the fifth-level database 105 At this time, c0, c1, and c2 are all known coefficients, as shown in Table 1 for example.

[0080] S4: Substitute the required flow resistance coefficient into the valve opening - flow resistance coefficient function in step S3 to obtain the valve opening value;

[0081] As an example, substitute the required flow resistance coefficient ξ into formula (5), so that the specific valve opening value α can be obtained.

[0082] S5: Determine whether the valve opening value is reasonable. If it is reasonable, output the valve opening value; if it is not reasonable, after adjusting the input parameters in step S2, repeat steps S2 - S4 to recalculate the valve opening value until the calculated valve opening value is reasonable and then output.

[0083] As an example, determine whether the valve opening value α calculated in step S4 is reasonable. Specifically, if the valve opening value α is between 0% and 100%, then the valve opening value α is reasonable, and output the valve opening value α.

[0084] As an example, if the valve opening value α calculated in step S4 is unreasonable, the designer changes the pipeline network design, such as changing the pipeline diameter, adjusting the pipeline layout, selecting valves with different resistance coefficients, or changing the pump head-flow rate, etc., which results in changes in the input parameters in step S2; then, according to the changed input parameters, steps S2 to S4 are repeated to recalculate the valve opening value α until the calculated valve opening value α is reasonable and then output.

[0085] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A method for constructing a valve opening-flow resistance coefficient function database, characterized in that, It includes the following steps: S1: Construct a first-level database. In the first-level database, ship valves are divided into a first type of valve and a second type of valve. Among them, the first type of valve has no opening indication, and the second type of valve has an opening indication. S2: Construct a second-level database under the first-level database. In the second-level database, the first type of valve and the second type of valve are classified according to different valve uses, and the first type of valve is further classified according to different internal structures of the valve. S3: Construct a third-level database under the second-level database. In the third-level database, each type of the first type of valve with different internal structures is classified according to different nominal diameters, and each type of the second type of valve with different uses is classified according to different nominal diameters. S4: Construct a fourth-level database under the third-level database. In the fourth-level database, the first type of valve and the second type of valve with different nominal diameters are classified according to different flow states of the fluid. S5: Construct a fifth-level database under the fourth-level database. In the fifth-level database, different flow states of the fluid correspond to different valve opening-flow resistance coefficient functions, and the construction of the valve opening-flow resistance coefficient function database is completed.

2. The method for constructing a valve opening - flow resistance coefficient function database according to claim 1, wherein, In step S2, according to different valve uses, the first type of valve is divided into globe valves and check valves, and the second type of valve is a butterfly valve.

3. The method for constructing a valve opening-flow resistance coefficient function database according to claim 2, wherein, In step S2, according to different internal structures of the valve, the globe valve is divided into a straight-through valve and a right-angle valve, and the check valve is divided into a straight-through valve and a right-angle valve.

4. The method for constructing a valve opening-flow resistance coefficient function database according to claim 1, wherein In step S3, the nominal diameters include DN15, DN20, DN25, DN32, DN40, DN50, DN65, DN80, DN100, DN125, DN150, DN175, DN200, DN250.

5. The method for constructing a valve opening - flow resistance coefficient function database according to claim 1, wherein In step S4, the Reynolds number is used to judge the flow state of the fluid.

6. The method for constructing a valve opening - flow resistance coefficient function database according to claim 5, characterized in that, The Reynolds number is calculated based on flow parameters, and the flow parameters include the pressure drop, flow rate, density, and viscosity of the fluid.

7. A method for calling a valve opening - flow resistance coefficient function database, characterized in that, It includes the following steps: S1: Provide a valve opening-flow resistance coefficient function database, and the database is the valve opening-flow resistance coefficient function database described in any one of claims 1 to 6. S2: Determine input parameters, and the input parameters include valve parameters and the flow parameters. Among them, the valve parameters include whether the valve has an opening indication, valve use, valve internal structure, and valve nominal diameter. S3: In the valve opening-flow resistance coefficient function database, obtain the corresponding valve opening-flow resistance coefficient function according to the input parameters. S4: Substitute the required flow resistance coefficient into the valve opening-flow resistance coefficient function in step S3 to obtain the valve opening value. S5: Judge whether the valve opening value is reasonable. If it is reasonable, output the valve opening value; if it is not reasonable, after adjusting the input parameters in step S2, repeat steps S2 to S4, recalculate the valve opening value until the calculated valve opening value is reasonable and then output it.

8. The method for calling the valve opening-flow resistance coefficient function database according to claim 7, characterized in that, In step S5, the reasonable valve opening value is between 0% and 100%.

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