Water-assisted injection molding(WAIM),a newly developed fluid-assisted injection molding technology has drawn more and more attentions for the energy saving,short cooling circle time and high quality of products.Exis...Water-assisted injection molding(WAIM),a newly developed fluid-assisted injection molding technology has drawn more and more attentions for the energy saving,short cooling circle time and high quality of products.Existing research for the process of WAIM has shown that the pressure control of the injecting water is mostly important for the WAIM.However,the proportional pressure control for the WAIM system is quite complex due to the existence of nonlinearities in the water hydraulic system.In order to achieve better pressure control performance of the injecting water to meet the requirements of the WAIM,the proportional pressure control of the WAIM system is investigated both numerically and experimentally.A newly designed water hydraulic system for WAIM is first modeled in AMEsim environment,the load characteristics and the nonlinearities of water hydraulic system are both considered,then the main factors affecting the injecting pressure and load flow rate are extensively studied.Meanwhile,an open-loop model-based compensation control strategy is employed to regulate the water injection pressure and a feedback proportional integrator controller is further adopted to achieve better control performance.In order to verify the AMEsim simulation results WAIM experiment for particular Acrylonitrile Butadiene Styrene(ABS) parts is implemented and the measured experimental data including injecting pressure and flow rate results are compared with the simulation.The good coincidence between experiment and simulation shows that the AMEsim model is accurate,and the tracking performance of the load pressure indicates that the proposed control strategy is effective for the proportional pressure control of the nonlinear WAIM system.The proposed proportional pressure control strategy and the conclusions drawn from simulation and experiment contribute to the application of water hydraulic proportional control and WAIM technology.展开更多
A new approach is demonstrated in which soft experimentation can be performed for MMP measurements, thus replacing the common practice of slim tube displacement laboratory experiments. Recovery potential from oil rese...A new approach is demonstrated in which soft experimentation can be performed for MMP measurements, thus replacing the common practice of slim tube displacement laboratory experiments. Recovery potential from oil reservoirs by miscible flue gas injection was studied by slim tube and field-scale numerical simulation using two flue gases and seven crude oils sampled at different depths in three candidate reservoirs. The soft experimentations were conducted using Eclipse300<sup>TM</sup>, a three-phase compositional simulator. This study investigates minimum miscibility pressure (MMP), a significant miscible gas injection project screening tool. Successful design of the project is contingent to the accurate determination of the MMP. This study evaluates effects of important factors such as injection pressure, oil component composition, and injection gas composition on the MMP and recovery efficiency for slim tube and field-scale displacements. Two applicable MMP correlations were used for comparison and validation purposes.展开更多
通许区块山西组发育深部煤层,与浅层煤层气相比含气量高、游离气丰富,割理裂隙发育,压裂施工过程中滤失大、易形成短缝、加砂困难。前期采用浅层煤层气常规压裂技术压裂施工压力高,加砂困难,压后效果不理想。针对深部煤层储层特征及改...通许区块山西组发育深部煤层,与浅层煤层气相比含气量高、游离气丰富,割理裂隙发育,压裂施工过程中滤失大、易形成短缝、加砂困难。前期采用浅层煤层气常规压裂技术压裂施工压力高,加砂困难,压后效果不理想。针对深部煤层储层特征及改造难点,开展了深部煤层气压前注入压降和原地应力测试,获取煤层参数,为压裂设计参数优化提供依据;同时,通过室内实验、数值模拟研究,探索试验了饱填砂压裂技术。现场A井山1煤层采用“大排量、大规模、饱填砂”体积压裂设计思路完成压裂施工,施工排量最高20 m 3/min,入地液量4315 m 3,加砂量347 m 3,是常规压裂加砂强度的7倍,压后最高日产气量7299 m 3,累计产气量71509 m 3,效果显著。该技术的试验成功,为深部煤层气压裂提供了技术指导。展开更多
水电站过渡过程计算中水轮机尾水管进口最小压强须控制在-8 m H2O以上,以防止危险的水柱分离。对于水泵水轮机,压力脉动大且成份复杂,确定此最小压强时应该计入哪些压力脉动尚无明确答案。针对某直锥尾水管水泵水轮机模型,在转轮进口施...水电站过渡过程计算中水轮机尾水管进口最小压强须控制在-8 m H2O以上,以防止危险的水柱分离。对于水泵水轮机,压力脉动大且成份复杂,确定此最小压强时应该计入哪些压力脉动尚无明确答案。针对某直锥尾水管水泵水轮机模型,在转轮进口施加不同脉动流速,分析尾水管进口空化腔生成发展规律。发现尾水管最大空化腔体积与进口脉动流速频率相关;随频率增大,空腔体积有先快速增大后缓慢减小变化趋势;空化腔变化周期受压力脉动频率和尾水管出口压强波动共同影响。在实际转轮进口可能的压力脉动频率对尾水管空化腔波动都有较大影响,但频率与尾水涡频率一致时会有共振效应。尾水管水锤波动是产生空腔涡的根本因素。展开更多
基金supported by National Natural Science Foundation of China (Grant No. 50775199)National Hi-tech Research and Development Program of China (863 Program,Grant No. 2008AA042703)
文摘Water-assisted injection molding(WAIM),a newly developed fluid-assisted injection molding technology has drawn more and more attentions for the energy saving,short cooling circle time and high quality of products.Existing research for the process of WAIM has shown that the pressure control of the injecting water is mostly important for the WAIM.However,the proportional pressure control for the WAIM system is quite complex due to the existence of nonlinearities in the water hydraulic system.In order to achieve better pressure control performance of the injecting water to meet the requirements of the WAIM,the proportional pressure control of the WAIM system is investigated both numerically and experimentally.A newly designed water hydraulic system for WAIM is first modeled in AMEsim environment,the load characteristics and the nonlinearities of water hydraulic system are both considered,then the main factors affecting the injecting pressure and load flow rate are extensively studied.Meanwhile,an open-loop model-based compensation control strategy is employed to regulate the water injection pressure and a feedback proportional integrator controller is further adopted to achieve better control performance.In order to verify the AMEsim simulation results WAIM experiment for particular Acrylonitrile Butadiene Styrene(ABS) parts is implemented and the measured experimental data including injecting pressure and flow rate results are compared with the simulation.The good coincidence between experiment and simulation shows that the AMEsim model is accurate,and the tracking performance of the load pressure indicates that the proposed control strategy is effective for the proportional pressure control of the nonlinear WAIM system.The proposed proportional pressure control strategy and the conclusions drawn from simulation and experiment contribute to the application of water hydraulic proportional control and WAIM technology.
文摘A new approach is demonstrated in which soft experimentation can be performed for MMP measurements, thus replacing the common practice of slim tube displacement laboratory experiments. Recovery potential from oil reservoirs by miscible flue gas injection was studied by slim tube and field-scale numerical simulation using two flue gases and seven crude oils sampled at different depths in three candidate reservoirs. The soft experimentations were conducted using Eclipse300<sup>TM</sup>, a three-phase compositional simulator. This study investigates minimum miscibility pressure (MMP), a significant miscible gas injection project screening tool. Successful design of the project is contingent to the accurate determination of the MMP. This study evaluates effects of important factors such as injection pressure, oil component composition, and injection gas composition on the MMP and recovery efficiency for slim tube and field-scale displacements. Two applicable MMP correlations were used for comparison and validation purposes.
文摘通许区块山西组发育深部煤层,与浅层煤层气相比含气量高、游离气丰富,割理裂隙发育,压裂施工过程中滤失大、易形成短缝、加砂困难。前期采用浅层煤层气常规压裂技术压裂施工压力高,加砂困难,压后效果不理想。针对深部煤层储层特征及改造难点,开展了深部煤层气压前注入压降和原地应力测试,获取煤层参数,为压裂设计参数优化提供依据;同时,通过室内实验、数值模拟研究,探索试验了饱填砂压裂技术。现场A井山1煤层采用“大排量、大规模、饱填砂”体积压裂设计思路完成压裂施工,施工排量最高20 m 3/min,入地液量4315 m 3,加砂量347 m 3,是常规压裂加砂强度的7倍,压后最高日产气量7299 m 3,累计产气量71509 m 3,效果显著。该技术的试验成功,为深部煤层气压裂提供了技术指导。
文摘水电站过渡过程计算中水轮机尾水管进口最小压强须控制在-8 m H2O以上,以防止危险的水柱分离。对于水泵水轮机,压力脉动大且成份复杂,确定此最小压强时应该计入哪些压力脉动尚无明确答案。针对某直锥尾水管水泵水轮机模型,在转轮进口施加不同脉动流速,分析尾水管进口空化腔生成发展规律。发现尾水管最大空化腔体积与进口脉动流速频率相关;随频率增大,空腔体积有先快速增大后缓慢减小变化趋势;空化腔变化周期受压力脉动频率和尾水管出口压强波动共同影响。在实际转轮进口可能的压力脉动频率对尾水管空化腔波动都有较大影响,但频率与尾水涡频率一致时会有共振效应。尾水管水锤波动是产生空腔涡的根本因素。
