Aiming at the problems such as more repeatedly design and longer design cycle, in this paper, the similarity theory was introduced to the design process of the key structures of flotation machine. The impeller and U-s...Aiming at the problems such as more repeatedly design and longer design cycle, in this paper, the similarity theory was introduced to the design process of the key structures of flotation machine. The impeller and U-shaped tank of flotation machine system were analyzed as similarity unit. Meanwhile, the level of similarity of the units and the similarity of the system were calculated. Based on the analysis of the impeller and the size of U-shaped tank, the similarity criteria were derived. The derived conclusions are： （1） The relationship between the diameter of the impeller and the volume of the tank was power function and calculated as the similarity criteria of the impeller; （2） The relationship between the ratio between the U-shaped tank＇s cross-sectional area and impeller＇s diameter and the volume of the tank was power function and calculated as the similarity criterions of the U-shaped tank. Using the similarity criterion combined with computer technology and database technology to realize part and system serialization design. The results show that the research can efficiency. avoid repeatedly design, shorten design cycle, and raise the design展开更多
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
By the theory of complex functions, a dynamic problem on the edges of a mode Ι crack subjected to moving unit-step loads are investigated. The Riemann-Hilbert problem is easily formulated by the ways of self-similar ...By the theory of complex functions, a dynamic problem on the edges of a mode Ι crack subjected to moving unit-step loads are investigated. The Riemann-Hilbert problem is easily formulated by the ways of self-similar functions. The analytical solution obtained is rather simple and concise. After the solution was utilized by superposition theorem, the relevant solution on the case of arbitrary loading can be obtained.展开更多
Cement paste with low water/cement ratio of 0.3 was observed using AFM. It is found that C-S-H has self similarity trait from scanning scale 20 um×20 um down to 300 nm× 300 nm, and the feature of C-S-H at la...Cement paste with low water/cement ratio of 0.3 was observed using AFM. It is found that C-S-H has self similarity trait from scanning scale 20 um×20 um down to 300 nm× 300 nm, and the feature of C-S-H at large scale is very similar to those smaller scales. It can be concluded that C-S-H is composed with some fundamental spherical globule, the fundamental globules agglomerate into bigger ones, moreover the bigger ones agglomerate into even bigger one. A C-S-H globule fractal model was put forward to describe the self similarity of the C-S-H globule, which can be used to reveal how the C-S-H globule contacts with each other.展开更多
基金Supported by National Natural Science Foundation of China (Grant No.51275145)
文摘Aiming at the problems such as more repeatedly design and longer design cycle, in this paper, the similarity theory was introduced to the design process of the key structures of flotation machine. The impeller and U-shaped tank of flotation machine system were analyzed as similarity unit. Meanwhile, the level of similarity of the units and the similarity of the system were calculated. Based on the analysis of the impeller and the size of U-shaped tank, the similarity criteria were derived. The derived conclusions are： （1） The relationship between the diameter of the impeller and the volume of the tank was power function and calculated as the similarity criteria of the impeller; （2） The relationship between the ratio between the U-shaped tank＇s cross-sectional area and impeller＇s diameter and the volume of the tank was power function and calculated as the similarity criterions of the U-shaped tank. Using the similarity criterion combined with computer technology and database technology to realize part and system serialization design. The results show that the research can efficiency. avoid repeatedly design, shorten design cycle, and raise the design
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.
文摘By the theory of complex functions, a dynamic problem on the edges of a mode Ι crack subjected to moving unit-step loads are investigated. The Riemann-Hilbert problem is easily formulated by the ways of self-similar functions. The analytical solution obtained is rather simple and concise. After the solution was utilized by superposition theorem, the relevant solution on the case of arbitrary loading can be obtained.
文摘Cement paste with low water/cement ratio of 0.3 was observed using AFM. It is found that C-S-H has self similarity trait from scanning scale 20 um×20 um down to 300 nm× 300 nm, and the feature of C-S-H at large scale is very similar to those smaller scales. It can be concluded that C-S-H is composed with some fundamental spherical globule, the fundamental globules agglomerate into bigger ones, moreover the bigger ones agglomerate into even bigger one. A C-S-H globule fractal model was put forward to describe the self similarity of the C-S-H globule, which can be used to reveal how the C-S-H globule contacts with each other.
