介绍用平板探测器的数字射线照相(DR)技术和用柔性荧光体成像板的计算机射线照相(CR)技术,对锅炉类承压设备受压元件的对接焊缝进行射线实时成像(RTR)检测和质量评价的最新国际动态和应用现状,并与常规胶片射线照相作了比较。实验结果表...介绍用平板探测器的数字射线照相(DR)技术和用柔性荧光体成像板的计算机射线照相(CR)技术,对锅炉类承压设备受压元件的对接焊缝进行射线实时成像(RTR)检测和质量评价的最新国际动态和应用现状,并与常规胶片射线照相作了比较。实验结果表明:DR可有效取代图像增强器式射线实时成像,检测的锅炉管焊缝单壁厚度可达12mm。用像素间距200μm的平板探测器,当调制传递函数MTF>20%时,可获分辨率优于3线对/mm。CR技术不仅适用于薄板和中厚板焊缝的射线照相检测,还适于板厚100mm以上大厚度锅炉压力容器和压力管道受压元件的检测,射线源从常规的400kV以下的X射线机到直线加速器(≤6M eV),从Ir192到Co60同位素源均可使用,空间分辨率≤25μm,能满足A SM E法规规定的2%的射线照相灵敏度要求。展开更多
Combined with NMR,core experiment,slim-tube tests,nano-CT and oil composition analysis,the mechanism of CO(2) enhanced oil recovery had been studied.CO_(2) flooding under supercritical state could achieve higher oil r...Combined with NMR,core experiment,slim-tube tests,nano-CT and oil composition analysis,the mechanism of CO(2) enhanced oil recovery had been studied.CO_(2) flooding under supercritical state could achieve higher oil recovery.In the process of crude oil displaced by supercritical CO2,the average oil recovery was 46.98% at low displacement pressures and 73.35% at high displacement pressures.The permeability of cores after CO2 flooding was only 28%-64% of those before flooding.As to the expelled oil,the contents of asphaltenes and non-hydrocarbons decreased,and saturated hydrocarbons of above C25 were absent in some samples,indicating that they had been retained in cores as demonstrated by CT and NMR experiments.In slim-tube tests,the heavy components of oil were expelled when the pressure increased to 30 MPa.There was a reasonable bottom hole pressure(BHP) below which the heavy components driven out from the far-well zone would deposit in the near-well zone,and when the pressure was too high,the nonhydrocarbon detention may cause block.The smaller throat and worse physical properties the porous media had,the higher displacement pressure would be required to achieve a good oil displacement efficiency.The increase in displacement pressure or time of interaction between oil and CO2 could effectively enhance oil recovery.展开更多
In order to reduce high calibration pressure in hydroforming of components with too small radii, a method wasproposed to manufacture automotive hollow components with rectangular shape by relatively lower pressure. Th...In order to reduce high calibration pressure in hydroforming of components with too small radii, a method wasproposed to manufacture automotive hollow components with rectangular shape by relatively lower pressure. Theprocess is simulated and analyzed. It is thought that the friction force between the die surface and tube is a mainreason that high pressure is needed to form small radii. Using the method proposed in this paper, a petal-like sectionshape is first preformed so that the central zones of the four sides of the preform section do not contact with the diesides, thus the tube metal is easy to flow into the transition radii area in calibration stage. Moreover, a positive forcealong the sides is produced by the internal pressure, which is beneficial to overcome the friction force and push thematerial into the radii. Therefore, the pressure for forming the transition radii is greatly reduced and the componentswith small radii can be formed with relatively lower pressure. For the experimental case conducted in this paper, theforming pressure is reduced by about 28.6% than the estimated forming pressure.展开更多
Filtration tests were conducted on a granular bed filter with layered drawers filled with corundum particles with sizes between either 1 mm and 1.5 mm or 2 mm and 3 mm or with quartz sand particles with sizes between ...Filtration tests were conducted on a granular bed filter with layered drawers filled with corundum particles with sizes between either 1 mm and 1.5 mm or 2 mm and 3 mm or with quartz sand particles with sizes between 0.125 mm and 1.5 mm.Filtration velocity,filter particle thickness,and filter particle size were all found to influence the filtration efficiency and the pressure drop of both the fixed granular bed and the layered-drawer granular bed.Granular strata with different thickness ratios also strongly influenced the filtration efficiency and pressure drop.For a granular bed with two sizes of filter particles,the coarse granules in the upper layer capture dust with large particle sizes,while the fine granules in the lower layer capture dust with smaller particle sizes that passes through the filter cake and upper layer.Optimal operating conditions were determined at which the filtration efficiency was found to be 99.42%with a bed pressure drop of 320 Pa.展开更多
文摘介绍用平板探测器的数字射线照相(DR)技术和用柔性荧光体成像板的计算机射线照相(CR)技术,对锅炉类承压设备受压元件的对接焊缝进行射线实时成像(RTR)检测和质量评价的最新国际动态和应用现状,并与常规胶片射线照相作了比较。实验结果表明:DR可有效取代图像增强器式射线实时成像,检测的锅炉管焊缝单壁厚度可达12mm。用像素间距200μm的平板探测器,当调制传递函数MTF>20%时,可获分辨率优于3线对/mm。CR技术不仅适用于薄板和中厚板焊缝的射线照相检测,还适于板厚100mm以上大厚度锅炉压力容器和压力管道受压元件的检测,射线源从常规的400kV以下的X射线机到直线加速器(≤6M eV),从Ir192到Co60同位素源均可使用,空间分辨率≤25μm,能满足A SM E法规规定的2%的射线照相灵敏度要求。
基金financial support from the National Science and Technology Major Project (2017ZX05013-001, 2017ZX05069003, 2017ZX05049005-004)Ministry of Science and Technology of PetroChina (2021ZZ01-03, kt2021-09-05, 2021DJ1806, 2017E-1514, 2018E-11-05)。
文摘Combined with NMR,core experiment,slim-tube tests,nano-CT and oil composition analysis,the mechanism of CO(2) enhanced oil recovery had been studied.CO_(2) flooding under supercritical state could achieve higher oil recovery.In the process of crude oil displaced by supercritical CO2,the average oil recovery was 46.98% at low displacement pressures and 73.35% at high displacement pressures.The permeability of cores after CO2 flooding was only 28%-64% of those before flooding.As to the expelled oil,the contents of asphaltenes and non-hydrocarbons decreased,and saturated hydrocarbons of above C25 were absent in some samples,indicating that they had been retained in cores as demonstrated by CT and NMR experiments.In slim-tube tests,the heavy components of oil were expelled when the pressure increased to 30 MPa.There was a reasonable bottom hole pressure(BHP) below which the heavy components driven out from the far-well zone would deposit in the near-well zone,and when the pressure was too high,the nonhydrocarbon detention may cause block.The smaller throat and worse physical properties the porous media had,the higher displacement pressure would be required to achieve a good oil displacement efficiency.The increase in displacement pressure or time of interaction between oil and CO2 could effectively enhance oil recovery.
文摘In order to reduce high calibration pressure in hydroforming of components with too small radii, a method wasproposed to manufacture automotive hollow components with rectangular shape by relatively lower pressure. Theprocess is simulated and analyzed. It is thought that the friction force between the die surface and tube is a mainreason that high pressure is needed to form small radii. Using the method proposed in this paper, a petal-like sectionshape is first preformed so that the central zones of the four sides of the preform section do not contact with the diesides, thus the tube metal is easy to flow into the transition radii area in calibration stage. Moreover, a positive forcealong the sides is produced by the internal pressure, which is beneficial to overcome the friction force and push thematerial into the radii. Therefore, the pressure for forming the transition radii is greatly reduced and the componentswith small radii can be formed with relatively lower pressure. For the experimental case conducted in this paper, theforming pressure is reduced by about 28.6% than the estimated forming pressure.
基金This work was funded by the National Key Research and Development Program of China(Fund project No.2018YFB0605901).
文摘Filtration tests were conducted on a granular bed filter with layered drawers filled with corundum particles with sizes between either 1 mm and 1.5 mm or 2 mm and 3 mm or with quartz sand particles with sizes between 0.125 mm and 1.5 mm.Filtration velocity,filter particle thickness,and filter particle size were all found to influence the filtration efficiency and the pressure drop of both the fixed granular bed and the layered-drawer granular bed.Granular strata with different thickness ratios also strongly influenced the filtration efficiency and pressure drop.For a granular bed with two sizes of filter particles,the coarse granules in the upper layer capture dust with large particle sizes,while the fine granules in the lower layer capture dust with smaller particle sizes that passes through the filter cake and upper layer.Optimal operating conditions were determined at which the filtration efficiency was found to be 99.42%with a bed pressure drop of 320 Pa.
