IPC분류정보
국가/구분 |
United States(US) Patent
등록
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국제특허분류(IPC7판) |
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출원번호 |
US-0448970
(2012-04-17)
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등록번호 |
US-9026415
(2015-05-05)
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발명자
/ 주소 |
- Barley, Jonathan
- Morrow, Gregory
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출원인 / 주소 |
- Energy Solutions International, Inc.
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대리인 / 주소 |
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인용정보 |
피인용 횟수 :
0 인용 특허 :
4 |
초록
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A method of modeling a segment of a pipeline transporting a product comprising defining within the segment a plurality of discrete cells, each disposed between knots, preparing a system of equations relating the conservations of mass, momentum and energy for each cell along with equations for the li
A method of modeling a segment of a pipeline transporting a product comprising defining within the segment a plurality of discrete cells, each disposed between knots, preparing a system of equations relating the conservations of mass, momentum and energy for each cell along with equations for the liquid phase flow area of cells with tight, slack and minimum area flow modes, providing data relating to the product and the location and elevation of the cells, sensing a plurality of conditions within known cells, solving the system of equations, initiating a re-stepping process by re-assessing the flow modes of each cell and re-setting flow modes for cells with unstable flow modes, and re-solving the system of equations using stable flow modes. An embodiment of the method includes excepting one or more cells from the re-stepping portion where a recurrent pattern of flow mode change is detected.
대표청구항
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1. A computer program product for modeling a flow of a volatile product in a pipeline comprising a non-transitory computer readable storage medium having instructions embodied therewith, the program instructions executable by a processor to cause the processor to perform a method of modeling the flo
1. A computer program product for modeling a flow of a volatile product in a pipeline comprising a non-transitory computer readable storage medium having instructions embodied therewith, the program instructions executable by a processor to cause the processor to perform a method of modeling the flow of the volatile product through the pipeline, the method comprising: creating a system of equations interrelating the laws of conservation of mass, energy and momentum of the volatile product in a plurality of discrete cells defined within a modeled segment of the pipeline;providing a plurality of sensors at a plurality of known cells of the modeled segment and using each provided sensor to detect a condition of the volatile product in a cell of the modeled segment disposed adjacent to the sensor;beginning a time step by providing to the processor a first set of signals corresponding to the conditions of the volatile product detected by the plurality of sensors;providing to the processor data relating to a plurality of physical characteristics of the pipeline;providing to the processor data relating physical positions of the known cells of the modeled segment;providing to the processor data relating to properties of the volatile product comprising a vapor pressure of the volatile product, a viscosity of the liquid phase of the volatile product, and a density of the liquid phase of the volatile product;providing to the processor a product liquid phase minimum area threshold;solving the system of equations using the processor to model a state of the volatile product in each discrete cell of the modeled segment of the pipeline using the data relating the physical characteristics of the pipeline, the data relating the positions of the known cells of the modeled segment, the data relating the properties of the volatile product and the first set of signals corresponding to conditions of the volatile product in the known cells adjacent to each of the plurality of sensors;determining an initial flow mode of the volatile product in each discrete cell of the modeled segment and during a first time step to be one of minimum area flow mode, slack flow mode and tight flow mode, wherein minimum area flow mode indicates that the cell is substantially empty of the liquid phase of the volatile product, tight flow mode indicates that the cell is completely filled with the liquid phase of the volatile product, and slack flow mode indicates that the cell is partially filled with the liquid phase of the volatile product with an upwardly disposed portion of the cell containing a vaporous phase of the volatile product with the liquid phase moving there below in open channel flow;initiating a re-stepping process by providing to the processor a second set of signals corresponding to the conditions of the volatile product detected by the plurality of sensors;solving the system of equations using the processor to model the state of the volatile product in each cell of the modeled segment of the pipeline using the data relating the physical characteristics of the pipeline, the data relating the physical positions of the cells of the modeled segment, the data relating the properties of the volatile product and the second set of signals corresponding to the conditions of the volatile product in the cells disposed adjacent to the plurality of sensors;determining, for each cell of the modeled segment for which it has been determined that the initial flow mode is tight, if the pressure at an upslope knot of the cell is less than or equal to the vapor pressure of the volatile product and that the velocity of the volatile product at a downslope knot of the cell is directed out of the cell;resetting the flow mode, for each cell of the modeled segment for which it has been determined that the initial flow mode is tight and that the pressure at the upslope knot of the cell is less than or equal to the vapor pressure of the volatile product and that the velocity of the volatile product at the downslope knot of the cell is directed out of the cell, to slack;determining, for each cell of the modeled segment for which it has been determined that the initial flow mode is minimum area, if an area of a flow of the liquid phase of the volatile product at the downslope knot is greater than the product liquid phase minimum area threshold;resetting the flow mode, for each cell of the modeled segment for which it has been determined that the initial flow mode is minimum area and that the area of the flow of the liquid phase of the volatile product at the downslope knot is greater than the product liquid phase minimum area threshold, to slack;for each cell of the modeled segment for which it has been determined that the initial flow mode is slack, determining if the area of a flow of the liquid phase of the volatile product at the downslope knot of the cell is less than the product liquid phase minimum area threshold;resetting the flow mode, for each cell of the modeled segment for which it has been determined that the initial flow mode is slack and that the area of flow of the liquid phase of the volatile product at the downslope knot of the cell is less than the product liquid phase minimum area threshold, to minimum area;determining, for each cell of the modeled segment for which it has been determined that the initial flow mode is slack, if the determined flow area of the liquid phase of the volatile product at the downslope knot of the cell is greater than a cross-sectional area of the pipeline;resetting the flow mode, for each cell of the modeled segment for which it has been determined that the initial flow mode is slack and that the flow area of the liquid phase of the volatile product at the downslope knot of the cell is greater than the cross-sectional area of the pipeline, to tight;determining whether any cell of the modeled segment has been reset;re-solving, in response to a determination that at least one cell of the modeled segment has been reset, the system of equations using the processor to model the state of the volatile product in each cell of the modeled segment of the pipeline using the data relating the physical characteristics of the pipeline, the data relating the physical positions of the cells of the modeled segment, the data relating the properties of the volatile product and the second set of signals corresponding to conditions of the volatile product in the cells adjacent to the plurality of sensors:terminating the re-stepping process;updating a set of primitive variables with a new solution;updating a set of non-primitive variables with the new solution; andterminating the time step. 2. The computer program product of claim 1, said method further comprising: providing to the processor a maximum number of iterations to be performed where a flow mode of at least one cell changes from one of the initial flow mode and a flow mode of a prior iteration to a flow mode of an immediately subsequent iteration;determining a number of iterations performed in which the system of equations is solved;comparing the number of iterations performed to the maximum number of iterations to be performed; andterminating the re-stepping process in response to determining that a number of iterations performed equals the maximum number of iterations provided to the processor. 3. The computer program product of claim 1, said method further comprising: comparing a reset flow mode of each cell of the modeled segment for which the flow mode has been reset to a record of prior change in the flow mode for the cell;detecting a recurrent pattern of flow mode change for one or more cells of the modeled segment; andexcepting from the step of determining whether any cell of the modeled segment has been reset the cells of the modeled segment in which the recurrent pattern of flow mode change is detected;wherein the exception of the cells in which a recurrent pattern of flow mode change is detected enables the method to proceed to the updating of at least one of the primitive and non-primitive variables and to escape redundant iterations caused by an instability of one or more cells of the modeled segment. 4. The computer program product of claim 3, said method further comprising: providing to the processor one or more recurrent patterns of flow mode changes that enable one or more of the discrete cells to be excepted. 5. The computer program product of claim 1 wherein the step of providing a plurality of sensors at a plurality of known cells of the modeled segment and using each provided sensor to detect a condition of the volatile product in a cell adjacent to the sensor and within the modeled segment comprises: providing a first sensor at a first cell of the modeled segment;providing a second sensor at a last cell of the modeled segment;using the first sensor to detect a boundary condition of the volatile product in the first cell of the modeled segment; andusing the second sensor to detect a second boundary condition of the volatile product in the last cell of the modeled segment. 6. The computer program product of claim 5 wherein the boundary condition detected by the first sensor is at least one of velocity and pressure of the volatile product within the first cell. 7. The computer program product of claim 6 wherein the boundary condition detected by the second sensor is at least one of velocity and pressure of the volatile product within the last cell. 8. The computer program product of claim 5 wherein a third sensor is provided to detect a condition of the volatile product within at least one of the first and last cell of the modeled segment. 9. The computer program product of claim 8 wherein the third sensor is a temperature sensor. 10. The computer program product of claim 1, said method further comprising the step of initiating a subsequent time step. 11. The computer program product of claim 1 wherein the product liquid phase minimum area threshold is two percent of a cross-sectional flow area within the modeled segment of the pipeline. 12. The computer program product of claim 1 wherein the product liquid phase minimum area threshold is one percent of a cross-sectional flow area within the modeled segment of the pipeline. 13. The computer program product of claim 1 wherein the volatile product is oil. 14. The computer program product of claim 1 wherein the data relating the physical characteristics of the pipeline comprises data relating an inner diameter of the pipeline, a roughness of the pipeline, a wall thickness and pressure/thermal expansion coefficients of at least one of the pipeline and the volatile product, a specific heat capacity of the volatile product, a density of the volatile product and a thermal conductivity of the volatile product. 15. The computer program product of claim 1 wherein the data relating the physical positions of the cells of the modeled segment comprises data relating a plurality of locations of the cells along a length of the pipeline and a plurality of elevations of the cells relative to a known elevational datum. 16. A computer program product for modeling a flow of a volatile product through a pipeline, the computer program product comprising a non-transitory computer readable storage medium having program instructions embodied therewith, the program instructions executable by a processor to cause the processor to perform a method comprising: defining a model segment comprising a plurality of discrete cells;creating a system of equations interrelating a conservation of mass, energy and momentum of the volatile product in the plurality of discrete cells within the modeled segment;providing a first sensor at a first cell at a first end of the modeled segment to detect a pressure of the volatile product within the first cell;providing a second sensor at a last cell at a second end of the modeled segment to detect a pressure of the volatile product within a second cell;providing a third sensor at one of the plurality of cells of the modeled segment to detect a condition of the volatile product within the one of the plurality of cells;providing to the processor a first signal corresponding to the pressure of the volatile product in the first cell;providing to the processor a second signal corresponding to the pressure of the volatile product in the last cell;providing to the processor a third signal corresponding to the condition of the volatile product within the one of the plurality of cells;providing to the processor data relating to a plurality of physical characteristics of the pipeline;providing to the processor data relating physical locations of the plurality of discrete cells of the modeled segment;providing to the processor data relating properties of the volatile product comprising a vapor pressure of the volatile product, a viscosity of the liquid phase of the volatile product, and a density of the liquid phase of the volatile product;providing to the processor a product liquid phase minimum area threshold;solving the system of equations using the processor to model a state of the volatile product in each discrete cell of the modeled segment using the data relating the physical characteristics of the pipeline, the data relating the locations of the cells of the modeled segment, the data relating the properties of the volatile product and the first, second and third signals corresponding to the pressures and the condition of the volatile product in the known cells adjacent the sensors;using the solved system of equations to determine an initial flow mode of the volatile product in each discrete cell of the modeled segment and at a time at which each of the detected pressures were detected by the first and second sensors and a time at which the detected condition was detected by the third sensor to be one of minimum area flow mode, slack flow mode and tight flow mode, wherein minimum area flow mode indicates that the cell is substantially empty of the liquid phase of the volatile product, tight flow mode indicates that the cell is completely filled with the liquid phase of the volatile product, and slack flow mode indicates that the cell is partially filled with the liquid phase of the volatile product with an upwardly disposed portion of the cell containing a vaporous phase of the volatile product with the liquid phase moving there below in open channel flow;initiating a re-stepping process by providing to the processor a fourth signal corresponding to the pressure of the volatile product within the first cell, a fifth signal corresponding to the pressure of the volatile product within the last cell and a sixth signal corresponding to the condition of the volatile product within the one of the plurality of cells, the fourth, fifth and sixth signals relating to pressures and a condition at a time subsequent to the time to which the first, second and third signals relate;solving the system of equations using the processor to model the state of the volatile product in each cell of the modeled segment of the pipeline using the data relating the physical characteristics of the pipeline, the data relating the physical positions of the cells of the modeled segment, the data relating the properties of the volatile product and the fourth, fifth and sixth signals corresponding to pressures and the condition of the volatile product in the cells disposed adjacent to the sensors;using the solved system of equations to determine, for each cell of the modeled segment for which it has been determined that the initial flow mode is tight, if the pressure at an upslope knot of the cell is less than or equal to the vapor pressure of the volatile product and that the velocity of the volatile product at a downslope knot of the cell is directed out of the cell;resetting the flow mode, for each cell of the modeled segment for which it has been determined that the initial flow mode is tight and that the pressure at the upslope knot of the cell is less than or equal to the vapor pressure of the volatile product and that the velocity of the volatile product at the downslope knot of the cell is directed out of the cell, to slack;using the solved system of equations to determine, for each cell of the modeled segment for which it has been determined that the initial flow mode is minimum area, if an area of a flow of the liquid phase of the volatile product at the downslope knot is greater than the product liquid phase minimum area threshold;resetting the flow mode, for each cell of the modeled segment for which it has been determined that the initial flow mode is minimum area and that the area of the flow of the liquid phase of the volatile product at the downslope knot is greater than the product liquid phase minimum area threshold, to slack;for each cell of the modeled segment for which it has been determined that the initial flow mode is slack, determining if the area of flow of the liquid phase of the volatile product at the downslope knot of the cell is less than the product liquid phase minimum area threshold;resetting the flow mode, for each cell of the modeled segment for which it has been determined that the initial flow mode is slack and that the area of flow of the liquid phase of the volatile product at the downslope knot of the cell is less than the product liquid phase minimum area threshold, to minimum area;using the solved system of equations to determine, for each cell of the modeled segment for which it has been determined that the initial flow mode is slack, if the determined flow area of the liquid phase of the volatile product at the downslope knot of the cell is greater than a cross-sectional area of the pipeline;resetting the flow mode, for each cell of the modeled segment for which it has been determined that the initial flow mode is slack and that the flow area of the liquid phase of the volatile product at the downslope knot of the cell is greater than the cross-sectional area of the pipeline, to tight;determining whether the flow mode of any cell of the modeled segment has been reset from a previously determined flow mode for that cell;re-solving, in response to a determination that at least one cell of the modeled segment has been reset from the previously determined flow mode, the system of equations using the processor to model the state of the volatile product in each cell of the modeled segment of the pipeline using the data relating the physical characteristics of the pipeline, the data relating the physical locations of the cells of the modeled segment, the data relating the properties of the volatile product and a second set of signals corresponding to conditions of the volatile product in the cells adjacent to the plurality of sensors;terminating the re-stepping process;updating a set of primitive variables with the new solution; andupdating a set of non-primitive variables with a new solution. 17. The computer program product of claim 16 wherein the third sensor is a temperature sensor. 18. The computer program product of claim 17 wherein the third sensor is disposed adjacent to the first cell of the modeled segment. 19. The computer program product of claim 16, said method further comprising, in response to the determination that one of the initial flow mode and a previously determined flow mode of at least one cell of the modeled segment has been reset from the one of the initial flow mode and the previously determined flow mode for that cell: determining whether changes in a flow mode of the at least one cell of the modeled segment for which it has been determined that a flow mode has been reset from one of the initial flow mode and the previously determined flow mode for that cell, exhibit an alternating pattern; andexcepting from the step of determining whether the flow mode of any cell of the modeled segment has been reset from one of the initial flow mode and the previously determined flow mode for that cell each cell for which it has been determined that changes in the flow mode of the cell exhibit a recurring pattern. 20. The computer program product of claim 19 wherein the step of determining whether the flow mode of any cell of the modeled segment has been reset from the previously determined flow mode for that cell and all subsequent steps listed thereafter and preceding the step of updating a set of primitive variables with the new solution are repeated until no non-excepted cells of the modeled segment exhibit a flow mode change from the previously determined flow mode for that cell.
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