Downhole working conditions of sucker rod pumping wells are automatically identified on a computer from the analysis of dynamometer cards. In this process, extraction of feature parameters and pattern classification a...Downhole working conditions of sucker rod pumping wells are automatically identified on a computer from the analysis of dynamometer cards. In this process, extraction of feature parameters and pattern classification are two key steps. The dynamometer card is firstly divided into four parts which include different production information according to the "four point method" used in actual oilfield production, and then the moment invariants for pattern recognition are extracted. An improved support vector machine (SVM) method is used for pattern classification whose error penalty parameter C and kernel function parameter g are optimally chosen by the particle swarm optimization (PSO) algorithm. The simulation results show the method proposed in this paper has good classification results.展开更多
A new technology of offshore oil rod pumping production is developed for offshore heavy oil recovery. A new type of miniature hydraulic pumping unit with long-stroke, low pumping speed and compact structure is designe...A new technology of offshore oil rod pumping production is developed for offshore heavy oil recovery. A new type of miniature hydraulic pumping unit with long-stroke, low pumping speed and compact structure is designed based on the spatial characteristics of offshore platforms. By combining the strengths of sinusoidal velocity curve and trapezoidal velocity curve, a kinematical model of the acceleration, the velocity and displacement of the pumping unit's hanging point is established. The results show that the pumping unit has good kinematic characteristics of smooth motion and small dynamic load. The multi-degree-of-freedom dynamic model of the single-well pumping unit is established. The first and second order natural frequencies of the sucker rod string subsystem and the pumping unit subsystem are studied. The results show that the first and the second order natural frequencies among the pumping rod string, pumping unit-platform subsystem and the dynamic excitation have differences over 5 times from each other, indicating that resonance phenomenon will not appear during the operation and the dynamic requirements for field use are met in the system.展开更多
Quality function deployment (QFD) is a quality system, that can help to design novel products that meet customers' needs. Theory of inventive problem solving (TRIZ) is a very powerful tool in helping to solve dif...Quality function deployment (QFD) is a quality system, that can help to design novel products that meet customers' needs. Theory of inventive problem solving (TRIZ) is a very powerful tool in helping to solve difficult technical problems encountered in the design process. Introducing QFD and TRIZ into the conceptual design of the pumping unit combines advantages of these two theories, therefore meeting different demands of different users. It can tell us “What should we do it” with QFD and “How should we do it” with TRIZ. The conceptual design method, which is based on QFD and TRIZ, is introduced andused to analyze and evaluate the conceptual design project of a pumping unit.展开更多
Attention is concentrated on how to perform the innovative design during the process of pumping unit conceptual design, and how to enhance design efficiency and inspire creativity. Aiming at the shortages of conceptua...Attention is concentrated on how to perform the innovative design during the process of pumping unit conceptual design, and how to enhance design efficiency and inspire creativity. Aiming at the shortages of conceptual design, introducing the theory of inventive problem solving (TRIZ) into the mechanical product design for producing innovative ideas, and using the advanced computer-aided technique, the intelligent decision support system (IDSS) based on TRIZ (TRIZ-IDSS) has been constructed. The construction method, system structure, conceptual production, decisionmaking and evaluation of the problem solving subsystem are discussed. The innovative conceptual design of pumping units indicates that the system can help the engineers open up a new space of thinking, overcome the thinking inertia, and put forward innovative design concepts. This system also can offer the scientific instructions for the innovative design of mechanical products.展开更多
Inspired by the modulation mechanism of neuroendocrine-immune system(NEIs),a novel structure of artificial neural network(ANN) named NEI-NN and its learning method are presented.The NEI-NN includes two parts,i.e.,posi...Inspired by the modulation mechanism of neuroendocrine-immune system(NEIs),a novel structure of artificial neural network(ANN) named NEI-NN and its learning method are presented.The NEI-NN includes two parts,i.e.,positive subnetwork(PSN) and negative sub-network(NSN).The neuron functions of PSN and NSN are designed according to the increased and decreased secretion functions of hormone,respectively.In order to make the novel neural network learn quickly,the novel neuron based on some characteristics of NEIs is also redesigned.Besides the normal input signals,two control signals are considered in the proposed solution.One is the enable/disable signal,and the other is the slope control signal.The former can modify the structure of NEI-NN,and the later can regulate the evolutionary speed of NEINN.The NEI-NN can obtain the optimized network structure by using error back-propagation(BP) learning algorithm.Since the modeling of the beam pumping unit is very difficult by using the conventional method,the modeling of bean bump unit is chosen to examine the performance of the NEI-NN.The experiment results show that the optimized structure and learning speed of NEI-NN are better than those of the conventional neural network.展开更多
Crank shaft net torque of pumping units is a volatile alternating load, while output torque of a general motor is basically constant. Thus, load characteristics of pumping units and motors are not able to "harmoniou...Crank shaft net torque of pumping units is a volatile alternating load, while output torque of a general motor is basically constant. Thus, load characteristics of pumping units and motors are not able to "harmoniously" match each other; this resulted in a higher output of the motor, lower efficiency, and higher energy consumption of the pumping units. A new six-bar linkage pumping unit is presented according to moment-changing theory. It allows to adjust automatically following the changes of polished rod load, and achieves small crank shaft curve fluctuation. The new pumping unit improves motor efficiency, reduces motor output power, and saves energy. According to the design scheme, kinematics and kinetics models of the new six-bar linkages pumping unit are built up. An optimum design on the main peoCormance parameters and functional analysis were peoCormed.展开更多
Because the load of the oil beam pumping unit driven by pure electric motor changes sharply during operation,the power of the driving motor does not match and the energy efficiency is low.In this paper,a new type of w...Because the load of the oil beam pumping unit driven by pure electric motor changes sharply during operation,the power of the driving motor does not match and the energy efficiency is low.In this paper,a new type of wind-driven hydro-motor hybrid power system is proposed.The motor and the hydraulic motor are jointly driven,and the energy is recovered by a hydraulic pump with controllable displacement,so that the speed of the driving motor is relatively stable.In order to control the fan speed and keep up with the drastic changes of the outside wind speed,a control strategy of hybrid power system based on wind speed feed-forward compensation is proposed.Through simulation and experimental results,the following conclusions can be drawn:to begin with,the mathematic model is proved to be effective;next,simulation studies show that the proposed feed-forward control method can improve the response rate as well as reduce the response lag.This research can be a reference for the application of the feed-forward control method on the hybrid power system of beam pumping unit.system.展开更多
In the process of designing a municipal rainwater and sewage pumping station,it is necessary to accurately grasp the design points,reasonably determine the scale of the rainwater and sewage pumping station,scientifica...In the process of designing a municipal rainwater and sewage pumping station,it is necessary to accurately grasp the design points,reasonably determine the scale of the rainwater and sewage pumping station,scientifically select the location and layout,and select materials reasonably.After completing the process design of the municipal rainwater and sewage pumping station and putting it into operation,in order to ensure the normal and stable operation of the pumping station,it is necessary to focus on strengthening the operation and management of diving equipment,cleaning equipment,and electromechanical equipment.The author analyzes the key points and specific design path of the process design of municipal rainwater and sewage pumping stations,and puts forward effective strategies for operation management,hoping to contribute to the scientific design and stable operation of municipal rainwater and sewage pumping stations.展开更多
The conventional beam pumping unh consumes a large amount of energy due to its unsmooth movement. In this work, we design a new energy-saving parallel four-bar pumping unit and derive the kinematic and dynamic law of ...The conventional beam pumping unh consumes a large amount of energy due to its unsmooth movement. In this work, we design a new energy-saving parallel four-bar pumping unit and derive the kinematic and dynamic law of the drive mechanism systematically by theoretical method. For the given target technical parameter, the theoretical results are verified by computer simulation, which shows that the simulation dynamic curves agree well with the theoretical ones and the calculated power consumption is low. Theoretical analysis shows that the newly designed pumping unit reduces average power by 28.8% compared with its conventional counterpart. The much lower theoretical energy consumption and the better dynamic performance indicate that the new energy-saving pumping unit is well designed and will have a significant application prospect.展开更多
A unit pump test bench is developed on an in-line pump test platform. The bench is composed of pump adapting assembly, fuel supply subsystem, lubricating subsystem and a control unit. A crank angle domain injection co...A unit pump test bench is developed on an in-line pump test platform. The bench is composed of pump adapting assembly, fuel supply subsystem, lubricating subsystem and a control unit. A crank angle domain injection control method is given out and the control accuracy can be 0.1° crank degree. The bench can test both mechanical unit pump and electronic unit pump. A test model-PLD12 electronic unit pump is tested. Full pump delivery map and some influence factors test is done. Experimental results show that the injection quantity is linear with the delivery angle. The quantity change rate is 15% when fuel temperature increases 30 ℃. The delivery quantity per cycle increases 30 mg at 28 V drive voltage. The average delivery difference for two same type pumps is 5 %. Test results show that the bench can be used for unit pump verification.展开更多
The kinetic characteristics of the clamping unit of plastic injection molding machine that is controlled by close loop with newly developed double speed variable pump unit are investigated. Considering the wide variat...The kinetic characteristics of the clamping unit of plastic injection molding machine that is controlled by close loop with newly developed double speed variable pump unit are investigated. Considering the wide variation of the cylinder equivalent mass caused by the transmission ratio of clamping unit and the severe instantaneous impact force acted on the cylinder during the mold closing and opening process, an adaptive control principle of parameter and structure is proposed to improve its kinetic performance. The adaptive correlation between the acceleration feedback gain and the variable mass is derived. The pressure differential feedback is introduced to improve the dynamic performance in the case of small inertia and heavy impact load. The adaptation of sum pressure to load is used to reduce the energy loss of the system. The research results are verified by the simulation and experiment, The investigation method and the conclusions are also suitable for the differential cylinder system controlled by the traditional servo pump unit.展开更多
The high working junction temperature of power component is the most common reason of its failure. So the thermal design is of vital importance in electronic control unit (ECU) design. By means of circuit simulation...The high working junction temperature of power component is the most common reason of its failure. So the thermal design is of vital importance in electronic control unit (ECU) design. By means of circuit simulation, the thermal design of ECU for electronic unit pump (EUP) fuel system is applied. The power dissipation model of each power component in the ECU is created and simulated. According to the analyses of simulation results, the factors which affect the power dissipation of components are analyzed. Then the ways for reducing the power dissipation of power components are carried out. The power dissipation of power components at different engine state is calculated and analyzed. The maximal power dissipation of each power component in all possible engine state is also carried out based on these simulations. A cooling system is designed based on these studies. The tests show that the maximum total power dissipation of ECU drops from 43.2 W to 33.84 W after these simulations and optimizations. These applications of simulations in thermal design of ECU can greatly increase the quality of the design, save the design cost and shorten design time展开更多
A real-time operating system (RTOS), also named OS, is designed based on the hardware platform of MC68376, and is implemented in the electronic control system for unit pump in diesel engine. A parallel and time-base...A real-time operating system (RTOS), also named OS, is designed based on the hardware platform of MC68376, and is implemented in the electronic control system for unit pump in diesel engine. A parallel and time-based task division method is introduced and the multi-task software architecture is built in the software system for electronic unit pump (EUP) system. The V-model software development process is used to control algorithm of each task. The simulation results of the hardware-in-the-loop simulation system (HILSS) and the engine experimental results show that the OS is an efficient real-time kernel, and can meet the real-time demands of EUP system; The built multi-task software system is real-time, determinate and reliable. V-model development is a good development process of control algorithms for EUP system, the control precision of control system can be ensured, and the development cycle and cost are also decreased.展开更多
The performance of the electronic unit pump (EUP) diesel engine is studied, it will be used in the integrated powertrain and its multi parameters are controllable. Both the theoretical analysis and experiment research...The performance of the electronic unit pump (EUP) diesel engine is studied, it will be used in the integrated powertrain and its multi parameters are controllable. Both the theoretical analysis and experiment research are taken. A control unit for the fuel quantity and timing in crankshaft domain is designed on this basis and the engine experiment test has been done. For the constant speed camshaft driving EUP system, the fuel quantity will increase as the supply angle goes up and injection timing has no effect. The control precision can reach 1°CA. The full injection timing MAP and engine peak performance curves are made successfully.展开更多
The flow and thermal breakthrough phenomenon in a forced external circulation standing column well(FECSCW)directly affects heat transfer efficiency and load-carrying capacity.A numerical model for FECSCW is developed ...The flow and thermal breakthrough phenomenon in a forced external circulation standing column well(FECSCW)directly affects heat transfer efficiency and load-carrying capacity.A numerical model for FECSCW is developed to analyze the migration of the temperature and velocity front under the flow and thermal breakthrough.The results indicated that thermal breakthrough began after simulation running 2.5 min and was completely formed after 12 min.The inlet water,which directly entered the production well without heat exchange with the aquifer,accounted for 12.8%.When the porosity of the backfill material decreased from 0.35 to 0,the coefficient of per-formance(COP)of the heat pump unit increased by 1.6%on average,and the thermal breakthrough strength decreased by an average of 45.3%within 25 min.Where seepage velocity near the well wall was greater than 1×10^(−3) m·s^(−1),faster velocity front migration was observed,while the migration advantage of the temperature front was more prominent outside of this region.Through quantitative analysis of flow and thermal breakthrough,temperature and velocity front migration,and COP change of heat pump unit,theoretical suggestions were pro-vided for the thermal transfer mechanism near the thermal well wall.The extended research in this study can be applied to the design and optimization of forced external circulation standing column well system.展开更多
基金support from the Key Project of the National Natural Science Foundation of China (61034005)Postgraduate Scientific Research and Innovation Projects of Basic Scientific Research Operating Expenses of Ministry of Education (N100604001)
文摘Downhole working conditions of sucker rod pumping wells are automatically identified on a computer from the analysis of dynamometer cards. In this process, extraction of feature parameters and pattern classification are two key steps. The dynamometer card is firstly divided into four parts which include different production information according to the "four point method" used in actual oilfield production, and then the moment invariants for pattern recognition are extracted. An improved support vector machine (SVM) method is used for pattern classification whose error penalty parameter C and kernel function parameter g are optimally chosen by the particle swarm optimization (PSO) algorithm. The simulation results show the method proposed in this paper has good classification results.
基金financially supported by the National Natural Science Foundation of China(Grant No.51174224)the National Science and Technology Major Projects of Oil and Gas(Grant Nos.2016ZX05066 and 2016ZX05042)the Natural Science Foundation of Shandong Province(Grant No.ZR2014El015)
文摘A new technology of offshore oil rod pumping production is developed for offshore heavy oil recovery. A new type of miniature hydraulic pumping unit with long-stroke, low pumping speed and compact structure is designed based on the spatial characteristics of offshore platforms. By combining the strengths of sinusoidal velocity curve and trapezoidal velocity curve, a kinematical model of the acceleration, the velocity and displacement of the pumping unit's hanging point is established. The results show that the pumping unit has good kinematic characteristics of smooth motion and small dynamic load. The multi-degree-of-freedom dynamic model of the single-well pumping unit is established. The first and second order natural frequencies of the sucker rod string subsystem and the pumping unit subsystem are studied. The results show that the first and the second order natural frequencies among the pumping rod string, pumping unit-platform subsystem and the dynamic excitation have differences over 5 times from each other, indicating that resonance phenomenon will not appear during the operation and the dynamic requirements for field use are met in the system.
文摘Quality function deployment (QFD) is a quality system, that can help to design novel products that meet customers' needs. Theory of inventive problem solving (TRIZ) is a very powerful tool in helping to solve difficult technical problems encountered in the design process. Introducing QFD and TRIZ into the conceptual design of the pumping unit combines advantages of these two theories, therefore meeting different demands of different users. It can tell us “What should we do it” with QFD and “How should we do it” with TRIZ. The conceptual design method, which is based on QFD and TRIZ, is introduced andused to analyze and evaluate the conceptual design project of a pumping unit.
文摘Attention is concentrated on how to perform the innovative design during the process of pumping unit conceptual design, and how to enhance design efficiency and inspire creativity. Aiming at the shortages of conceptual design, introducing the theory of inventive problem solving (TRIZ) into the mechanical product design for producing innovative ideas, and using the advanced computer-aided technique, the intelligent decision support system (IDSS) based on TRIZ (TRIZ-IDSS) has been constructed. The construction method, system structure, conceptual production, decisionmaking and evaluation of the problem solving subsystem are discussed. The innovative conceptual design of pumping units indicates that the system can help the engineers open up a new space of thinking, overcome the thinking inertia, and put forward innovative design concepts. This system also can offer the scientific instructions for the innovative design of mechanical products.
基金the Key Project of the National Natural Science Foundation of China(No.61134009)National Natural Science Foundations of China(Nos.61473078,61271001)+5 种基金Program for Changjiang Scholars from the Ministry of Education,ChinaSpecialized Research Fund for Shanghai Leading Talents,ChinaProject of the Shanghai Committee of Science and Technology,China(No.13JC1407500)the Fundamental Research Funds for the Central Universities,China(No.09CX04026A)Excellent Youth and Middle Age Scientists Fund of Shandong Province,China(No.BS2010DX038)Fundamental Research Funds for the Central Universities,China(No.14CX02171A)
文摘Inspired by the modulation mechanism of neuroendocrine-immune system(NEIs),a novel structure of artificial neural network(ANN) named NEI-NN and its learning method are presented.The NEI-NN includes two parts,i.e.,positive subnetwork(PSN) and negative sub-network(NSN).The neuron functions of PSN and NSN are designed according to the increased and decreased secretion functions of hormone,respectively.In order to make the novel neural network learn quickly,the novel neuron based on some characteristics of NEIs is also redesigned.Besides the normal input signals,two control signals are considered in the proposed solution.One is the enable/disable signal,and the other is the slope control signal.The former can modify the structure of NEI-NN,and the later can regulate the evolutionary speed of NEINN.The NEI-NN can obtain the optimized network structure by using error back-propagation(BP) learning algorithm.Since the modeling of the beam pumping unit is very difficult by using the conventional method,the modeling of bean bump unit is chosen to examine the performance of the NEI-NN.The experiment results show that the optimized structure and learning speed of NEI-NN are better than those of the conventional neural network.
文摘Crank shaft net torque of pumping units is a volatile alternating load, while output torque of a general motor is basically constant. Thus, load characteristics of pumping units and motors are not able to "harmoniously" match each other; this resulted in a higher output of the motor, lower efficiency, and higher energy consumption of the pumping units. A new six-bar linkage pumping unit is presented according to moment-changing theory. It allows to adjust automatically following the changes of polished rod load, and achieves small crank shaft curve fluctuation. The new pumping unit improves motor efficiency, reduces motor output power, and saves energy. According to the design scheme, kinematics and kinetics models of the new six-bar linkages pumping unit are built up. An optimum design on the main peoCormance parameters and functional analysis were peoCormed.
基金This project was supported by the Science Research Foundation of Inner Mongolia University for the nationalities grant no.NMDGP1704 the Inner Mongolia nature Science Foundation(grant no.2016MS0622)National nature Science Foundation grant no.51865046Science and technology innovation leading project of Inner Mongolia grant no.KCBJ2018028。
文摘Because the load of the oil beam pumping unit driven by pure electric motor changes sharply during operation,the power of the driving motor does not match and the energy efficiency is low.In this paper,a new type of wind-driven hydro-motor hybrid power system is proposed.The motor and the hydraulic motor are jointly driven,and the energy is recovered by a hydraulic pump with controllable displacement,so that the speed of the driving motor is relatively stable.In order to control the fan speed and keep up with the drastic changes of the outside wind speed,a control strategy of hybrid power system based on wind speed feed-forward compensation is proposed.Through simulation and experimental results,the following conclusions can be drawn:to begin with,the mathematic model is proved to be effective;next,simulation studies show that the proposed feed-forward control method can improve the response rate as well as reduce the response lag.This research can be a reference for the application of the feed-forward control method on the hybrid power system of beam pumping unit.system.
文摘In the process of designing a municipal rainwater and sewage pumping station,it is necessary to accurately grasp the design points,reasonably determine the scale of the rainwater and sewage pumping station,scientifically select the location and layout,and select materials reasonably.After completing the process design of the municipal rainwater and sewage pumping station and putting it into operation,in order to ensure the normal and stable operation of the pumping station,it is necessary to focus on strengthening the operation and management of diving equipment,cleaning equipment,and electromechanical equipment.The author analyzes the key points and specific design path of the process design of municipal rainwater and sewage pumping stations,and puts forward effective strategies for operation management,hoping to contribute to the scientific design and stable operation of municipal rainwater and sewage pumping stations.
基金Supported by the Ministry of Science and Technology Innovation Fund for SMEs (09C26214204812)the Venture Capital Fund for SMEs (09C26154204991)
文摘The conventional beam pumping unh consumes a large amount of energy due to its unsmooth movement. In this work, we design a new energy-saving parallel four-bar pumping unit and derive the kinematic and dynamic law of the drive mechanism systematically by theoretical method. For the given target technical parameter, the theoretical results are verified by computer simulation, which shows that the simulation dynamic curves agree well with the theoretical ones and the calculated power consumption is low. Theoretical analysis shows that the newly designed pumping unit reduces average power by 28.8% compared with its conventional counterpart. The much lower theoretical energy consumption and the better dynamic performance indicate that the new energy-saving pumping unit is well designed and will have a significant application prospect.
基金the Ministerial Level Advanced Research Foundation (404050301 .4)
文摘A unit pump test bench is developed on an in-line pump test platform. The bench is composed of pump adapting assembly, fuel supply subsystem, lubricating subsystem and a control unit. A crank angle domain injection control method is given out and the control accuracy can be 0.1° crank degree. The bench can test both mechanical unit pump and electronic unit pump. A test model-PLD12 electronic unit pump is tested. Full pump delivery map and some influence factors test is done. Experimental results show that the injection quantity is linear with the delivery angle. The quantity change rate is 15% when fuel temperature increases 30 ℃. The delivery quantity per cycle increases 30 mg at 28 V drive voltage. The average delivery difference for two same type pumps is 5 %. Test results show that the bench can be used for unit pump verification.
基金This project is supported by National Natural Science Foundation of China (No.50275102)Opening Foundation of State Key Lab of Fluid Power Transmission and Control of Zhejiang University, China (No.GZKF2002004).
文摘The kinetic characteristics of the clamping unit of plastic injection molding machine that is controlled by close loop with newly developed double speed variable pump unit are investigated. Considering the wide variation of the cylinder equivalent mass caused by the transmission ratio of clamping unit and the severe instantaneous impact force acted on the cylinder during the mold closing and opening process, an adaptive control principle of parameter and structure is proposed to improve its kinetic performance. The adaptive correlation between the acceleration feedback gain and the variable mass is derived. The pressure differential feedback is introduced to improve the dynamic performance in the case of small inertia and heavy impact load. The adaptation of sum pressure to load is used to reduce the energy loss of the system. The research results are verified by the simulation and experiment, The investigation method and the conclusions are also suitable for the differential cylinder system controlled by the traditional servo pump unit.
文摘The high working junction temperature of power component is the most common reason of its failure. So the thermal design is of vital importance in electronic control unit (ECU) design. By means of circuit simulation, the thermal design of ECU for electronic unit pump (EUP) fuel system is applied. The power dissipation model of each power component in the ECU is created and simulated. According to the analyses of simulation results, the factors which affect the power dissipation of components are analyzed. Then the ways for reducing the power dissipation of power components are carried out. The power dissipation of power components at different engine state is calculated and analyzed. The maximal power dissipation of each power component in all possible engine state is also carried out based on these simulations. A cooling system is designed based on these studies. The tests show that the maximum total power dissipation of ECU drops from 43.2 W to 33.84 W after these simulations and optimizations. These applications of simulations in thermal design of ECU can greatly increase the quality of the design, save the design cost and shorten design time
文摘A real-time operating system (RTOS), also named OS, is designed based on the hardware platform of MC68376, and is implemented in the electronic control system for unit pump in diesel engine. A parallel and time-based task division method is introduced and the multi-task software architecture is built in the software system for electronic unit pump (EUP) system. The V-model software development process is used to control algorithm of each task. The simulation results of the hardware-in-the-loop simulation system (HILSS) and the engine experimental results show that the OS is an efficient real-time kernel, and can meet the real-time demands of EUP system; The built multi-task software system is real-time, determinate and reliable. V-model development is a good development process of control algorithms for EUP system, the control precision of control system can be ensured, and the development cycle and cost are also decreased.
文摘The performance of the electronic unit pump (EUP) diesel engine is studied, it will be used in the integrated powertrain and its multi parameters are controllable. Both the theoretical analysis and experiment research are taken. A control unit for the fuel quantity and timing in crankshaft domain is designed on this basis and the engine experiment test has been done. For the constant speed camshaft driving EUP system, the fuel quantity will increase as the supply angle goes up and injection timing has no effect. The control precision can reach 1°CA. The full injection timing MAP and engine peak performance curves are made successfully.
基金This work was supported by the National Natural Science Foundation of China(41002085,41602278)China Postdoctoral Science Founda-tion(2016M601129)North China University of Technology Programs(18XN154-006,110052972027-031).
文摘The flow and thermal breakthrough phenomenon in a forced external circulation standing column well(FECSCW)directly affects heat transfer efficiency and load-carrying capacity.A numerical model for FECSCW is developed to analyze the migration of the temperature and velocity front under the flow and thermal breakthrough.The results indicated that thermal breakthrough began after simulation running 2.5 min and was completely formed after 12 min.The inlet water,which directly entered the production well without heat exchange with the aquifer,accounted for 12.8%.When the porosity of the backfill material decreased from 0.35 to 0,the coefficient of per-formance(COP)of the heat pump unit increased by 1.6%on average,and the thermal breakthrough strength decreased by an average of 45.3%within 25 min.Where seepage velocity near the well wall was greater than 1×10^(−3) m·s^(−1),faster velocity front migration was observed,while the migration advantage of the temperature front was more prominent outside of this region.Through quantitative analysis of flow and thermal breakthrough,temperature and velocity front migration,and COP change of heat pump unit,theoretical suggestions were pro-vided for the thermal transfer mechanism near the thermal well wall.The extended research in this study can be applied to the design and optimization of forced external circulation standing column well system.