Inner Mongolia is abundant in geothermal resources,but the development and utilization of medium-depth geothermal resources for clean heating in winter is still in the preliminary stage compared with the neighboring p...Inner Mongolia is abundant in geothermal resources,but the development and utilization of medium-depth geothermal resources for clean heating in winter is still in the preliminary stage compared with the neighboring provinces.In this paper,a recently developed geothermal heating system using the Mesozoic sandstone reservoirs in Baokang of Kailu Basin,Eastern Inner Mongolia was investigated,a threedimensional geological model of a pair of production and injection well was established,and numerical simulations on the long term operation performance were conducted and verified by pumping test and water level recovery test data.The effects of flow rates,the direction of wells,injection temperature and ratios on the flow field and water level in the thermal reservoir were analyzed.The results show that considering a 30-year operation period and a production rate from 90 m^(3)/h to 110 m^(3)/h,the optimum well spacing can be increased from 225 m to 245 m,with an average value of 235 m.With the decrease of the injection temperature,the cold front of the injection water has an increasing influence on the temperature in the production well.A complete injection or the principle of production according to injection is recommended in order to maintain the long-term operation stability.In addition,the location of the injection well should be arranged in the downstream of the natural flow field.The present results can provide a useful guide for the optimum design and performance prediction of geothermal wells,thus maintaining the production and injection balance and promoting the sustainable development and utilization of medium-depth and deep geothermal resources.展开更多
Mathematical models are disappointing due to uneven distribution of the air gap magnetic field and significant un- modeled dynamics in magnetic bearing systems. The effectiveness of control deteriorates based on an in...Mathematical models are disappointing due to uneven distribution of the air gap magnetic field and significant un- modeled dynamics in magnetic bearing systems. The effectiveness of control deteriorates based on an inaccurate mathematical model, creating slow response speed and high jitter. To solve these problems, a model-free adaptive control (MFAC) scheme is proposed for a three-degree-of-freedom hybrid magnetic bearing (3-DoF HMB) control system. The scheme for 3-DoF HMB depends only on the control current and the objective balanced position, and it does not involve any model information. The design process of a parameter estimation algorithm is model-free, based directly on pseudo-partial-derivative (PPD) derived online from the input and output data information. The rotor start-of-suspension position of the HMB is regulated by auxiliary bearings with different inner diameters, and two kinds of operation situations (linear and nonlinear areas) are present to analyze the validity of MFAC in detail. Both simulations and experiments demonstrate that the proposed MFAC scheme handles the 3-DoF HMB control system with start-of-suspension response speed, smaller steady state error, and higher stability.展开更多
基金supported by China Geological Survey Program(DD20190128)Natural Science Foundation of Hebei Province(No.E2022202082)。
文摘Inner Mongolia is abundant in geothermal resources,but the development and utilization of medium-depth geothermal resources for clean heating in winter is still in the preliminary stage compared with the neighboring provinces.In this paper,a recently developed geothermal heating system using the Mesozoic sandstone reservoirs in Baokang of Kailu Basin,Eastern Inner Mongolia was investigated,a threedimensional geological model of a pair of production and injection well was established,and numerical simulations on the long term operation performance were conducted and verified by pumping test and water level recovery test data.The effects of flow rates,the direction of wells,injection temperature and ratios on the flow field and water level in the thermal reservoir were analyzed.The results show that considering a 30-year operation period and a production rate from 90 m^(3)/h to 110 m^(3)/h,the optimum well spacing can be increased from 225 m to 245 m,with an average value of 235 m.With the decrease of the injection temperature,the cold front of the injection water has an increasing influence on the temperature in the production well.A complete injection or the principle of production according to injection is recommended in order to maintain the long-term operation stability.In addition,the location of the injection well should be arranged in the downstream of the natural flow field.The present results can provide a useful guide for the optimum design and performance prediction of geothermal wells,thus maintaining the production and injection balance and promoting the sustainable development and utilization of medium-depth and deep geothermal resources.
基金Project supported by the National Natural Science Foundation of China (Nos. 51707082 and 51607080), the Natural Science Foundation of Jiangsu Province, China (Nos. BK20170546 and BK20150510), the China Postdoctoral Science Foundation (No. 2017M620192), and the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Mathematical models are disappointing due to uneven distribution of the air gap magnetic field and significant un- modeled dynamics in magnetic bearing systems. The effectiveness of control deteriorates based on an inaccurate mathematical model, creating slow response speed and high jitter. To solve these problems, a model-free adaptive control (MFAC) scheme is proposed for a three-degree-of-freedom hybrid magnetic bearing (3-DoF HMB) control system. The scheme for 3-DoF HMB depends only on the control current and the objective balanced position, and it does not involve any model information. The design process of a parameter estimation algorithm is model-free, based directly on pseudo-partial-derivative (PPD) derived online from the input and output data information. The rotor start-of-suspension position of the HMB is regulated by auxiliary bearings with different inner diameters, and two kinds of operation situations (linear and nonlinear areas) are present to analyze the validity of MFAC in detail. Both simulations and experiments demonstrate that the proposed MFAC scheme handles the 3-DoF HMB control system with start-of-suspension response speed, smaller steady state error, and higher stability.