The extensively built long-distance water transmission pipelines have become the main water sources for urban areas. To ensure the reliability and safety of the water supply, from the viewpoint of overall management, ...The extensively built long-distance water transmission pipelines have become the main water sources for urban areas. To ensure the reliability and safety of the water supply, from the viewpoint of overall management, it would be necessary to establish a system of information management for the pipeline. The monitoring, calculating and analyzing functions of the system serve to give controlling instructions and safe operating rules to the automatic equipment and technician, making sure the resistance coefficient distribution along the pipeline is reasonable; the hydraulic state transition is smooth when operating conditions change or water supply accidents occur, avoiding the damage of water hammer. This paper covered the composition structures of the information management system of long-distance water transmission pipelines and the functions of the subsystems, and finally elaborated on the approaches and steps of building a mathematics model for the analysis of dynamic hydraulic status.展开更多
According to the engineering investigation of long-distance oil and gas pipelines, the criterions and measures of route selection are drawn as follows： the flat landform is the first choice in route alignment. The fo...According to the engineering investigation of long-distance oil and gas pipelines, the criterions and measures of route selection are drawn as follows： the flat landform is the first choice in route alignment. The foot of mountain is the first choice when the route passes by the valley. The route should pass by but the shady and deposited slope and not in sunny and erosive slope as possible as it can. The pipeline should be vertical to contour climbing and descending the mountain except steep slope. Tunnel can be used in crossing foothill. Perpendicularly traversing the river is better than beveling; the worst choice is to put the pipeline along the river. Bypass is the best choice in karsts area. The order of route selection should be pre-choosing, investigation, optimization and adjustment.展开更多
The oilfield construction and long-distance oil pipeline engineering has been developed extensively in China. The risk assessment of oil industry will, however, be an important objective to cope with the development o...The oilfield construction and long-distance oil pipeline engineering has been developed extensively in China. The risk assessment of oil industry will, however, be an important objective to cope with the development of oil industry , The risk assessment of oil industry has many subjects worthy to be studied.The major purpose of the paper is to research the risk cases of long-distance oil pipeline engineering in Ganshu and Shaanxi provinces.展开更多
This paper uses a reduced model for simulating propagation of acoustic signals in fluid filled pipelines. The study allows a better understanding of the multipath environment found in a pipeline system with the goal o...This paper uses a reduced model for simulating propagation of acoustic signals in fluid filled pipelines. The study allows a better understanding of the multipath environment found in a pipeline system with the goal of finding optimum solutions for monitoring the pipeline integrity. Data provided both from the simplified model and from an equivalent experimental test rig are implemented using classical time delay estimation algorithms. It is observed an improved accuracy when closing gradually the pipeline end as a result of cancelling the multipath effect at the system＇s terminal.展开更多
A practical approach is discussed for sub-sea pipeline monitoring and leak detection based on the real time transient model . The characteristic method of transient simulation is coupled with the Extended Kalman Filt...A practical approach is discussed for sub-sea pipeline monitoring and leak detection based on the real time transient model . The characteristic method of transient simulation is coupled with the Extended Kalman Filter to estimate the system state where the only observed data are inlet and outlet flow rate and pressure. Because EKF has a time variant track under the non-stationary stochastic process with additive Gaussian noise, the high sensitivity of RTTM to non-stationary operating condition is reduced. A leak location recursion estimation formula is presented based on the real time observed data. The results of 27 groups of test data indicate that the procedure presented is sensitive to a wide range of detectable leak sizes and has a low average relative error of leak location .展开更多
On July 4 2002, a project attracting world attention, i.e., the West-East Gas Pipeline Project was declared in full-scale commencement. The project will write history with its enormous social and economic benefits.
A slip-line field solution is presented for the ultimate bearing capacity of the pipeline on a purely-cohesive clay soil, taking into account the circular configuration of the pipe, the pipe embedment, and the pipe-so...A slip-line field solution is presented for the ultimate bearing capacity of the pipeline on a purely-cohesive clay soil, taking into account the circular configuration of the pipe, the pipe embedment, and the pipe-soil interfacial cohesion. The derived bearing capacity factors for a smooth rigid pipe limit to those for the conventional rectangular strip footing while the pipe embedment approaches zero. Parametric studies indicate that, the pipe-soil interfacial properties have much influence on the bearing capacity for the pipe foundation on clayedy soils.展开更多
For a water supply system with long-distance diversion pipelines, in addition to the water hammer problems that occur beyond pumps, the safety of the water diversion pipeline in front of pumps also deserves attention....For a water supply system with long-distance diversion pipelines, in addition to the water hammer problems that occur beyond pumps, the safety of the water diversion pipeline in front of pumps also deserves attention. In this study, a water hammer protection scheme combined with an overflow surge tank and a regulating valve was developed. A mathematical model of the overflow surge tank was developed, and an analytical formula for the height of the overflow surge tank was derived. Furthermore, a practical water supply project was used to evaluate the feasibility of the combined protection scheme and analyze the sensitivity of valve regulation rules. The results showed that the combined protection scheme effectively reduced the height of the surge tank, lessened the difficulties related to construction, and reduced the necessary financial investment for the project. The two-stage closing rule articulated as fast first and then slow could minimize the overflow volume of the surge tank when the power failure occurred, while the two-stage opening rule articulated as slow first and then fast could be more conducive to the safety of the water supply system when the pump started up.展开更多
A mathematical model is presented for the charging-up process in an air-entrapped pipeline with moving boundary conditions. A coordinate transformation technique is employed to reduce fluid motion in time-dependent do...A mathematical model is presented for the charging-up process in an air-entrapped pipeline with moving boundary conditions. A coordinate transformation technique is employed to reduce fluid motion in time-dependent domains to ones in time-independent domains. The nonlinear hyperbolic partial differential equations governing the unsteady motion of fluid combined with an equation for transient shear stress between the pipe wall and the flowing fluid are solved by the method of lines. Results show that ignoring elastic effects overestimates the maximum pressure and underestimates the maximum front velocity of filling fluid. The peak pressure of the entrapped air is sensitive to the length of the initial entrapped air pocket.展开更多
Software process is a framework for effective and timely delivery of software system. The framework plays a crucial role for software success. However, the development of large-scale software still faces the crisis of...Software process is a framework for effective and timely delivery of software system. The framework plays a crucial role for software success. However, the development of large-scale software still faces the crisis of high risks, low quality, high costs and long cycle time. This paper proposed a three-phase parallel-pipelining software process model for improving speed and productivity, and reducing software costs and risks without sacrificing software quality. In this model, two strategies were presented. One strategy, based on subsystem-cost priority, was used to prevent software development cost wasting and to reduce software complexity as well; the other strategy, used for balancing subsystem complexity, was designed to reduce the software complexity in the later development stages. Moreover, the proposed function-detailed and workload-simplified subsystem pipelining software process model presents much higher parallelity than the concurrent incremental model. Finally, the component-based product line technology not only ensures software quality and further reduces cycle time, software costs, and software risks but also sufficiently and rationally utilizes previous software product resources and enhances the competition ability of software development organizations.展开更多
基金Hi-Tech Research and Development Program of China (863 Program)(2002AA601140)
文摘The extensively built long-distance water transmission pipelines have become the main water sources for urban areas. To ensure the reliability and safety of the water supply, from the viewpoint of overall management, it would be necessary to establish a system of information management for the pipeline. The monitoring, calculating and analyzing functions of the system serve to give controlling instructions and safe operating rules to the automatic equipment and technician, making sure the resistance coefficient distribution along the pipeline is reasonable; the hydraulic state transition is smooth when operating conditions change or water supply accidents occur, avoiding the damage of water hammer. This paper covered the composition structures of the information management system of long-distance water transmission pipelines and the functions of the subsystems, and finally elaborated on the approaches and steps of building a mathematics model for the analysis of dynamic hydraulic status.
文摘According to the engineering investigation of long-distance oil and gas pipelines, the criterions and measures of route selection are drawn as follows： the flat landform is the first choice in route alignment. The foot of mountain is the first choice when the route passes by the valley. The route should pass by but the shady and deposited slope and not in sunny and erosive slope as possible as it can. The pipeline should be vertical to contour climbing and descending the mountain except steep slope. Tunnel can be used in crossing foothill. Perpendicularly traversing the river is better than beveling; the worst choice is to put the pipeline along the river. Bypass is the best choice in karsts area. The order of route selection should be pre-choosing, investigation, optimization and adjustment.
文摘The oilfield construction and long-distance oil pipeline engineering has been developed extensively in China. The risk assessment of oil industry will, however, be an important objective to cope with the development of oil industry , The risk assessment of oil industry has many subjects worthy to be studied.The major purpose of the paper is to research the risk cases of long-distance oil pipeline engineering in Ganshu and Shaanxi provinces.
文摘This paper uses a reduced model for simulating propagation of acoustic signals in fluid filled pipelines. The study allows a better understanding of the multipath environment found in a pipeline system with the goal of finding optimum solutions for monitoring the pipeline integrity. Data provided both from the simplified model and from an equivalent experimental test rig are implemented using classical time delay estimation algorithms. It is observed an improved accuracy when closing gradually the pipeline end as a result of cancelling the multipath effect at the system＇s terminal.
文摘A practical approach is discussed for sub-sea pipeline monitoring and leak detection based on the real time transient model . The characteristic method of transient simulation is coupled with the Extended Kalman Filter to estimate the system state where the only observed data are inlet and outlet flow rate and pressure. Because EKF has a time variant track under the non-stationary stochastic process with additive Gaussian noise, the high sensitivity of RTTM to non-stationary operating condition is reduced. A leak location recursion estimation formula is presented based on the real time observed data. The results of 27 groups of test data indicate that the procedure presented is sensitive to a wide range of detectable leak sizes and has a low average relative error of leak location .
文摘On July 4 2002, a project attracting world attention, i.e., the West-East Gas Pipeline Project was declared in full-scale commencement. The project will write history with its enormous social and economic benefits.
基金supported by the National Natural Science Foundation of China(10872198,50509022)
文摘A slip-line field solution is presented for the ultimate bearing capacity of the pipeline on a purely-cohesive clay soil, taking into account the circular configuration of the pipe, the pipe embedment, and the pipe-soil interfacial cohesion. The derived bearing capacity factors for a smooth rigid pipe limit to those for the conventional rectangular strip footing while the pipe embedment approaches zero. Parametric studies indicate that, the pipe-soil interfacial properties have much influence on the bearing capacity for the pipe foundation on clayedy soils.
基金supported by the National Natural Science Foundation of China(Grants No.52179062 and 51879087).
文摘For a water supply system with long-distance diversion pipelines, in addition to the water hammer problems that occur beyond pumps, the safety of the water diversion pipeline in front of pumps also deserves attention. In this study, a water hammer protection scheme combined with an overflow surge tank and a regulating valve was developed. A mathematical model of the overflow surge tank was developed, and an analytical formula for the height of the overflow surge tank was derived. Furthermore, a practical water supply project was used to evaluate the feasibility of the combined protection scheme and analyze the sensitivity of valve regulation rules. The results showed that the combined protection scheme effectively reduced the height of the surge tank, lessened the difficulties related to construction, and reduced the necessary financial investment for the project. The two-stage closing rule articulated as fast first and then slow could minimize the overflow volume of the surge tank when the power failure occurred, while the two-stage opening rule articulated as slow first and then fast could be more conducive to the safety of the water supply system when the pump started up.
文摘A mathematical model is presented for the charging-up process in an air-entrapped pipeline with moving boundary conditions. A coordinate transformation technique is employed to reduce fluid motion in time-dependent domains to ones in time-independent domains. The nonlinear hyperbolic partial differential equations governing the unsteady motion of fluid combined with an equation for transient shear stress between the pipe wall and the flowing fluid are solved by the method of lines. Results show that ignoring elastic effects overestimates the maximum pressure and underestimates the maximum front velocity of filling fluid. The peak pressure of the entrapped air is sensitive to the length of the initial entrapped air pocket.
文摘Software process is a framework for effective and timely delivery of software system. The framework plays a crucial role for software success. However, the development of large-scale software still faces the crisis of high risks, low quality, high costs and long cycle time. This paper proposed a three-phase parallel-pipelining software process model for improving speed and productivity, and reducing software costs and risks without sacrificing software quality. In this model, two strategies were presented. One strategy, based on subsystem-cost priority, was used to prevent software development cost wasting and to reduce software complexity as well; the other strategy, used for balancing subsystem complexity, was designed to reduce the software complexity in the later development stages. Moreover, the proposed function-detailed and workload-simplified subsystem pipelining software process model presents much higher parallelity than the concurrent incremental model. Finally, the component-based product line technology not only ensures software quality and further reduces cycle time, software costs, and software risks but also sufficiently and rationally utilizes previous software product resources and enhances the competition ability of software development organizations.
