With complex fractured-vuggy heterogeneous structures, water has to be injected to facilitate oil pro- duction. However, the effect of different water injection modes on oil recovery varies. The limitation of existing...With complex fractured-vuggy heterogeneous structures, water has to be injected to facilitate oil pro- duction. However, the effect of different water injection modes on oil recovery varies. The limitation of existing numerical simulation methods in representing fractured- vuggy carbonate reservoirs makes numerical simulation difficult to characterize the fluid flow in these reservoirs. In this paper, based on a geological example unit in the Tahe Oilfield, a three-dimensional physical model was designed and constructed to simulate fluid flow in a fractured-vuggy reservoir according to similarity criteria. The model was validated by simulating a bottom water drive reservoir, and then subsequent water injection modes were optimized. These were continuous （constant rate）, intermittent, and pulsed injection of water. Experimental results reveal that due to the unbalanced formation pressure caused by pulsed water injection, the swept volume was expanded and consequently the highest oil recovery increment was achieved. Similar to continuous water injection, intermit- tent injection was influenced by factors including the connectivity of the fractured-vuggy reservoir, well depth, and the injection-production relationship, which led to a relative low oil recovery. This study may provide a constructive guide to field production and for the devel- opment of the commercial numerical models specialized for fractured-vuggy carbonate reservoirs.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 cycle fuel injection quantity is accurately measured for electronic unit pump （EUP） operating at high, middle and low speeds by using displacement method based on EFS instantaneous mono-injector qualifier. On th...The cycle fuel injection quantity is accurately measured for electronic unit pump （EUP） operating at high, middle and low speeds by using displacement method based on EFS instantaneous mono-injector qualifier. On the basis of the experi- mental data about fuel injection quantity and fuel pressure, the variation of inconsistency in fuel injection quantity of EUP and the influence factors in different operating conditions are concluded. The results show that the inconsistency is lowest in maximum torque condition, while on the start and maximum power conditions, it is higher.展开更多
Double pipe heat exchangers(DPHEs)are normally utilized in various manufacturing uses owing to their simple design and low maintenance requirements.For that,performance enhancement by improved heat transfer is ongoing...Double pipe heat exchangers(DPHEs)are normally utilized in various manufacturing uses owing to their simple design and low maintenance requirements.For that,performance enhancement by improved heat transfer is ongoing.Air injections are a good strategy for enhancing the thermal performance of the DPHE.In the present work,the influence of air bubble injection in a DPHE was experimentally investigated,and the system’s hydrothermal performance improvement parameters were evaluated.Two modes were designed,manufactured,and used to conduct the experiments.The first mode was conducted with no air injection,named a single phase mode,while in the second mode,air was injected into the annulus of DPHE throughout different perforated rings on the side of the annular.Three different ring types were used and coded as R-1,R-2,and R-3,with an added case of insertion of the three rings inside the annulus.The airflow rate was fixed at 1.5 LPM with a 25○C inlet temperature.Also,the hot water rate in the inner pipe was maintained continuously at 3 LPM with a controlled 70○C temperature at the inlet.Five different cold water flow rates,3,3.5,4,4.5,and 5 LPM,in the annulus,were considered with a controlled inlet temperature at 17○C.Additionally,the effectiveness of the heat exchanger,the number of transfer units(NTU),and the overall heat transfer were predicted and considered for performance evaluation and comparison.The outcomes proved that the injection of air and the bubbly flow creation in the heat exchanger’s hot side is an effective method to strengthen the DPHE performance.Moreover,the total heat transfer coefficient was enhanced by 41%in R-1,58.8%in R-2,and 40.1%in R-3 at 4 LPM of cold water.The optimal ring,which yielded the most improvement,was R-2,achieving a 65%improvement in NTU,with a maximum enhancement in effectiveness of 56%.展开更多
Through the research on several carbonate reservoirs developed in the Middle East, the basic characteristics of different types of carbonate reservoirs are determined, and a set of high-efficiency water injection deve...Through the research on several carbonate reservoirs developed in the Middle East, the basic characteristics of different types of carbonate reservoirs are determined, and a set of high-efficiency water injection development options and strategies are presented. Hidden baffles and barriers exist in carbonate reservoirs in the Middle East, so the reservoirs could be divided into different separated development units based on the baffles and barriers characteristics. Flexible and diverse profile control techniques such as high angle wells and simple and applicative zonal water injection have been introduced to improve the control and development degree of reservoirs. Three principal water injection development methods suitable for different carbonate reservoirs in the Middle East are proposed, including the combination of crestal gas injection and peripheral water injection, bottom interval injection and top interval production(buoyancy underpinning), and "weak point and strong plane" area well pattern. Based on the characteristics of very low shale content, fast and far pressure transmission in the Middle East carbonate reservoirs, a large well-spacing flood pattern is recommended, and reasonable development strategies have been made such as moderate water injection rate and maintaining reasonable production pressure drawdown and voidage replacement ratio, so as to maximize the recovery of reservoirs in the none or low water cut period.展开更多
Injecting water into the main pipeline is a common method to prevent the ammonium salt corrosion in hydrogenation units.The use of spray nozzle can enhance the effects of washing ammonium salt and reduce the risk of a...Injecting water into the main pipeline is a common method to prevent the ammonium salt corrosion in hydrogenation units.The use of spray nozzle can enhance the effects of washing ammonium salt and reduce the risk of ammonium salt corrosion.The droplet atomization and evaporation model were used to investigate the mixing process of injecting water and gas-oil mixture in a high-pressure environment.The effects of some key parameters including fluid velocity,temperature,and droplet volume fraction on the mixing and vaporization process were analyzed.Numerical simulation results show that with the increase of injecting water flow rate,the fluid velocity increases and the temperature decreases continuously.When the mass flow rate of injecting water is 1.5 t/h,the droplet has the maximum evaporation efficiency and the volume fraction reaches a minimum value.Besides,with the increase of atomization angle and droplet size,the mean velocity and the temperature of fluid decrease continuously.The increase of atomization angle or the decrease of droplet size will accelerate the evaporation process of droplets and reduce the droplet volume fraction,which indicates that the droplet slip velocity and the contact area are the key factors affecting the droplet evaporation rate.展开更多
The electric energy injection from a pulsed power supply to a planar type of dielectric barrier discharge（DBD） reactor at atmospheric pressure was studied. Relations of the energy injection with barrier materials, b...The electric energy injection from a pulsed power supply to a planar type of dielectric barrier discharge（DBD） reactor at atmospheric pressure was studied. Relations of the energy injection with barrier materials, barrier thickness, peak voltage, gap distance, electrode area,and operation temperature were experimentally investigated. The energy injection is a function of relative permittivity, barrier thickness, peak voltage, gap distance, and electrode area. The influence of operation temperature on energy injection is slight in the range of 27-300℃ but becomes obvious in the range of 300-500℃. A model was established using which the energy injection can be easily predicted.展开更多
A direct injection low compression ratios diesel rotary engine is designed and studied to find the appropriate application of the electronic controlled high pressure common rail injection system. Current development f...A direct injection low compression ratios diesel rotary engine is designed and studied to find the appropriate application of the electronic controlled high pressure common rail injection system. Current development focuses on the applied fuel injection and ignition strategies, especially concerning the combustion configurations of injectors, ignition source, and combustion chamber. The prototype engine, equipped with Bosch common rail system and high performance electronic control unit （ECU）, is designed correspondingly. Studies show that the integration of a common rail injection system and the main and pilot duel injectors configurations, assisted with glow plug ignition device and flexible ECU, represents a promising approach to improve the potential of the low compression ratios diesel rotary engine. Currently the engine can run at 6 kr · min^-1 steadily and the power is about 68 kW/（4 kr ·min^- 1）.展开更多
电磁脉冲(Electromagnetic pulses,EMPs)耦合进入发动机电控单元(Electronic control unit,ECU)的主要方式是通过线束传导,大电流注入(Bulk current injection,BCI)是控制器敏感度测试的标准试验方法。为了在设计阶段对电控单元的电磁...电磁脉冲(Electromagnetic pulses,EMPs)耦合进入发动机电控单元(Electronic control unit,ECU)的主要方式是通过线束传导,大电流注入(Bulk current injection,BCI)是控制器敏感度测试的标准试验方法。为了在设计阶段对电控单元的电磁脉冲防护设计进行优化,提出了基于线束传导规律的虚拟注入方法。该方法由基于一维卷积神经网络(Convolutional neural network,CNN)的线束传导预测模型及仿真电路实现,线束传导预测模型基于一维卷积神经网络,训练模型所用数据集为BCI试验采集的注入电流信号与调理电路输入端口响应信号,仿真电路在软件Multisim中建立。选择注入电流信号输入至预测模型,得到端口的预测信号,将该信号“注入”到仿真电路输入端口,通过监测仿真电路输出端口信号分析发动机电控系统是否发生电磁敏感现象。结果表明,预测信号与实际测量信号的误差不超过5.8%,虚拟注入结果与BCI试验结果一致,并与试验中观测的敏感现象吻合。该方法可以在设计阶段快速分析电控单元各模块的电磁敏感度,为电控单元的电磁脉冲防护设计提供参考依据。展开更多
基金supported by China National Science and Technology Major Project(2011ZX05009-004,2011ZX05014-003)National Key Basic Research and Development Program(973 Program),China(2011CB201006)Science Foundation of China University of Petroleum,Beijing(2462014YJRC053)
文摘With complex fractured-vuggy heterogeneous structures, water has to be injected to facilitate oil pro- duction. However, the effect of different water injection modes on oil recovery varies. The limitation of existing numerical simulation methods in representing fractured- vuggy carbonate reservoirs makes numerical simulation difficult to characterize the fluid flow in these reservoirs. In this paper, based on a geological example unit in the Tahe Oilfield, a three-dimensional physical model was designed and constructed to simulate fluid flow in a fractured-vuggy reservoir according to similarity criteria. The model was validated by simulating a bottom water drive reservoir, and then subsequent water injection modes were optimized. These were continuous （constant rate）, intermittent, and pulsed injection of water. Experimental results reveal that due to the unbalanced formation pressure caused by pulsed water injection, the swept volume was expanded and consequently the highest oil recovery increment was achieved. Similar to continuous water injection, intermit- tent injection was influenced by factors including the connectivity of the fractured-vuggy reservoir, well depth, and the injection-production relationship, which led to a relative low oil recovery. This study may provide a constructive guide to field production and for the devel- opment of the commercial numerical models specialized for fractured-vuggy carbonate reservoirs.
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 cycle fuel injection quantity is accurately measured for electronic unit pump （EUP） operating at high, middle and low speeds by using displacement method based on EFS instantaneous mono-injector qualifier. On the basis of the experi- mental data about fuel injection quantity and fuel pressure, the variation of inconsistency in fuel injection quantity of EUP and the influence factors in different operating conditions are concluded. The results show that the inconsistency is lowest in maximum torque condition, while on the start and maximum power conditions, it is higher.
文摘Double pipe heat exchangers(DPHEs)are normally utilized in various manufacturing uses owing to their simple design and low maintenance requirements.For that,performance enhancement by improved heat transfer is ongoing.Air injections are a good strategy for enhancing the thermal performance of the DPHE.In the present work,the influence of air bubble injection in a DPHE was experimentally investigated,and the system’s hydrothermal performance improvement parameters were evaluated.Two modes were designed,manufactured,and used to conduct the experiments.The first mode was conducted with no air injection,named a single phase mode,while in the second mode,air was injected into the annulus of DPHE throughout different perforated rings on the side of the annular.Three different ring types were used and coded as R-1,R-2,and R-3,with an added case of insertion of the three rings inside the annulus.The airflow rate was fixed at 1.5 LPM with a 25○C inlet temperature.Also,the hot water rate in the inner pipe was maintained continuously at 3 LPM with a controlled 70○C temperature at the inlet.Five different cold water flow rates,3,3.5,4,4.5,and 5 LPM,in the annulus,were considered with a controlled inlet temperature at 17○C.Additionally,the effectiveness of the heat exchanger,the number of transfer units(NTU),and the overall heat transfer were predicted and considered for performance evaluation and comparison.The outcomes proved that the injection of air and the bubbly flow creation in the heat exchanger’s hot side is an effective method to strengthen the DPHE performance.Moreover,the total heat transfer coefficient was enhanced by 41%in R-1,58.8%in R-2,and 40.1%in R-3 at 4 LPM of cold water.The optimal ring,which yielded the most improvement,was R-2,achieving a 65%improvement in NTU,with a maximum enhancement in effectiveness of 56%.
文摘Through the research on several carbonate reservoirs developed in the Middle East, the basic characteristics of different types of carbonate reservoirs are determined, and a set of high-efficiency water injection development options and strategies are presented. Hidden baffles and barriers exist in carbonate reservoirs in the Middle East, so the reservoirs could be divided into different separated development units based on the baffles and barriers characteristics. Flexible and diverse profile control techniques such as high angle wells and simple and applicative zonal water injection have been introduced to improve the control and development degree of reservoirs. Three principal water injection development methods suitable for different carbonate reservoirs in the Middle East are proposed, including the combination of crestal gas injection and peripheral water injection, bottom interval injection and top interval production(buoyancy underpinning), and "weak point and strong plane" area well pattern. Based on the characteristics of very low shale content, fast and far pressure transmission in the Middle East carbonate reservoirs, a large well-spacing flood pattern is recommended, and reasonable development strategies have been made such as moderate water injection rate and maintaining reasonable production pressure drawdown and voidage replacement ratio, so as to maximize the recovery of reservoirs in the none or low water cut period.
基金The authors acknowledge supports from the National Natural Science Foundation of China(Grant No.51806198,No.U1909216,No.52176048,No.51876194)the Zhejiang Provincial Natural Science Foundation(Grant No.LY21E060011)the Fundamental Research Funds of Zhejiang Sci-Tech University(Grant No.2021Q020).
文摘Injecting water into the main pipeline is a common method to prevent the ammonium salt corrosion in hydrogenation units.The use of spray nozzle can enhance the effects of washing ammonium salt and reduce the risk of ammonium salt corrosion.The droplet atomization and evaporation model were used to investigate the mixing process of injecting water and gas-oil mixture in a high-pressure environment.The effects of some key parameters including fluid velocity,temperature,and droplet volume fraction on the mixing and vaporization process were analyzed.Numerical simulation results show that with the increase of injecting water flow rate,the fluid velocity increases and the temperature decreases continuously.When the mass flow rate of injecting water is 1.5 t/h,the droplet has the maximum evaporation efficiency and the volume fraction reaches a minimum value.Besides,with the increase of atomization angle and droplet size,the mean velocity and the temperature of fluid decrease continuously.The increase of atomization angle or the decrease of droplet size will accelerate the evaporation process of droplets and reduce the droplet volume fraction,which indicates that the droplet slip velocity and the contact area are the key factors affecting the droplet evaporation rate.
基金supported by National Natural Science Foundation of China(No.11575159)National Natural Science Foundation of China(No.51206146)+1 种基金Zhejiang Provincial Natural Science Foundation of China(No.LY13B070004)Program for Zhejiang Leading Team of S&T Innovation(No.2013TD07)
文摘The electric energy injection from a pulsed power supply to a planar type of dielectric barrier discharge（DBD） reactor at atmospheric pressure was studied. Relations of the energy injection with barrier materials, barrier thickness, peak voltage, gap distance, electrode area,and operation temperature were experimentally investigated. The energy injection is a function of relative permittivity, barrier thickness, peak voltage, gap distance, and electrode area. The influence of operation temperature on energy injection is slight in the range of 27-300℃ but becomes obvious in the range of 300-500℃. A model was established using which the energy injection can be easily predicted.
基金This project is supported by the Commission of Science Technology and Industry for National Defense, China(No.MKPT-02-291).
文摘A direct injection low compression ratios diesel rotary engine is designed and studied to find the appropriate application of the electronic controlled high pressure common rail injection system. Current development focuses on the applied fuel injection and ignition strategies, especially concerning the combustion configurations of injectors, ignition source, and combustion chamber. The prototype engine, equipped with Bosch common rail system and high performance electronic control unit （ECU）, is designed correspondingly. Studies show that the integration of a common rail injection system and the main and pilot duel injectors configurations, assisted with glow plug ignition device and flexible ECU, represents a promising approach to improve the potential of the low compression ratios diesel rotary engine. Currently the engine can run at 6 kr · min^-1 steadily and the power is about 68 kW/（4 kr ·min^- 1）.
文摘电磁脉冲(Electromagnetic pulses,EMPs)耦合进入发动机电控单元(Electronic control unit,ECU)的主要方式是通过线束传导,大电流注入(Bulk current injection,BCI)是控制器敏感度测试的标准试验方法。为了在设计阶段对电控单元的电磁脉冲防护设计进行优化,提出了基于线束传导规律的虚拟注入方法。该方法由基于一维卷积神经网络(Convolutional neural network,CNN)的线束传导预测模型及仿真电路实现,线束传导预测模型基于一维卷积神经网络,训练模型所用数据集为BCI试验采集的注入电流信号与调理电路输入端口响应信号,仿真电路在软件Multisim中建立。选择注入电流信号输入至预测模型,得到端口的预测信号,将该信号“注入”到仿真电路输入端口,通过监测仿真电路输出端口信号分析发动机电控系统是否发生电磁敏感现象。结果表明,预测信号与实际测量信号的误差不超过5.8%,虚拟注入结果与BCI试验结果一致,并与试验中观测的敏感现象吻合。该方法可以在设计阶段快速分析电控单元各模块的电磁敏感度,为电控单元的电磁脉冲防护设计提供参考依据。
