To investigate the explosion load characteristics and structural response law in a water mist environment in a cabin,explosion experiments are carried out.The weakening rates of the initial peak overpressure,quasistat...To investigate the explosion load characteristics and structural response law in a water mist environment in a cabin,explosion experiments are carried out.The weakening rates of the initial peak overpressure,quasistatic pressure and structural residual deflection increase with increasing working pressure of the water mist nozzle.Specifically,the weakening rate of the initial peak overpressure ranges from 7.8%to 31.0%,the quasistatic pressure weakening rate ranges from 29.2%to 41.0%,and the weakening rate of the center of the plate residual deflection ranges from 10.8%to 34.4%under the various working pressures of the nozzles.To further explore the effect of water mist explosion suppression,a method for three-dimensional numerical simulations of water mist weakening the explosion shock wave is established to explore the explosion load characteristics of the compartment and the bulkhead response law.On the basis of the dimension analysis method,empirical formulas are derived to predict the residual deflection thickness in the center of the bulkheads.These findings provide the fundamental basis for the appli-cation of water mist in anti-explosive protection.展开更多
In the centrifugal separations of drilling fluid,screw conveyor is a critical component to push and separate the sediment.The work performance and structural parameters of conveyor are immediately related to the produ...In the centrifugal separations of drilling fluid,screw conveyor is a critical component to push and separate the sediment.The work performance and structural parameters of conveyor are immediately related to the production capability,the working life and the separating effect of the centrifuge.The existing researches always use the theoretical calculation of the approximate loads to analyze the strength of conveyor,and it cannot reflect the stress situations accurately.In order to ensure the precise mastery of the working performance,this article obtained pressure distribution under working conditions from CFX evaluation and gained equivalent stress and deformation under several load conditions by using the ANSYS Workbench platform to check the strength of conveyor.The results showed that the influence of centrifugal hydraulic pressure was less than that of centrifugal force on the strength and deformation of conveyor.Besides,the maximum equivalent stress occurred at the inside of the feed opening,while the maximum deformation occurred at the conveyor blade edge of taper extremity.Furthermore,whether considered the feed opening or not,the computing model had a great influence on the analysis results,and the simplified loads had a great influence on the deformation analysis results.The methods and results from this article can provide reference for the design and the improvement of screw conveyor.展开更多
In this paper,the cores of outcropped black shale of Lower Silurian Longmaxi Fm in the Yibin area,Sichuan Basin,were taken as samples to investigate the effects of extraneous water on shale mechanics and seepage laws ...In this paper,the cores of outcropped black shale of Lower Silurian Longmaxi Fm in the Yibin area,Sichuan Basin,were taken as samples to investigate the effects of extraneous water on shale mechanics and seepage laws during the production of shale gas reservoirs.Firstly,the development of fractures in water saturated cores was observed by using a VHX-5000 optical superdepth microscope.Secondly,water,formation water and slick water,as well as the damage form and compression strength of water saturated/unsaturated cores were investigated by means of a uniaxial compression testing machine and a strain testing&analysis system.Finally,the effects of fluid-solid coupling on shale gas flowing performance in different water saturations were analyzed by using a DYQ-1 multi-function displacement device.Analysis on core components shows that the Longmaxi shale is a highly crushable reservoir with a high content of fragile minerals,so fracturing stimulation is suitable for it.Shale compression strength test reveals that the effects of deionized water,formation water and slick water on shale are different,so the compression strength of shale before being saturated is quite different from that after being saturated.Due to the existence of water,the compression strength of shale drops,so the shale can be fractured easily,more fractures are generated and thus its seepage capacity is improved.Experiments on shale gas seepage under different water saturations show that under the condition of fluid-solid coupling,the higher the water saturation is,the better the propagation and seepage capacity of micro-fractures in shale under the effect of pressure.To sum up,the existence of water is beneficial to fracturing stimulation of shale gas reservoirs and helps to achieve the goal of production improvement.展开更多
The lattice Boltzmann method(LBM)is implemented in the Particle Flow Code(PFC)as a pore-scale CFD module and coupled with the particulate discrete element assemblage in PFC using an immersed boundary scheme.The implem...The lattice Boltzmann method(LBM)is implemented in the Particle Flow Code(PFC)as a pore-scale CFD module and coupled with the particulate discrete element assemblage in PFC using an immersed boundary scheme.The implementation of LBM and LBM-PFC coupling is validated with the analytical solutions in a couple of hydrodynamics and fluid-particle interaction problems,i.e.,the accuracy of LBM as a CFD solver is verified by solving channel flow driven by a pressure gradient for which the closed-form solution is also derived;the accuracy of LBM-PFC coupling is validated by solving flow across a cylinder,Taylor-Couette flow,Karman vortex street,and fluid flow through a cylinder array.To demonstrate potential applications of this coupling code,a perforation cavity subjected to axial fluid flush is then tested,showing that the collapse and reconstruction of sand arch in the perforation cavity can be reproduced in this coupling system.The developed system is ready for exploring more complicated physical issues involved in sand production.展开更多
基金supported by the National Natural Science Foundation of China(grant numbers:52201334)sup-ported by National Key Laboratory of Ship Structural Safety(grant numbers:Naklas2024-KF015-s).
文摘To investigate the explosion load characteristics and structural response law in a water mist environment in a cabin,explosion experiments are carried out.The weakening rates of the initial peak overpressure,quasistatic pressure and structural residual deflection increase with increasing working pressure of the water mist nozzle.Specifically,the weakening rate of the initial peak overpressure ranges from 7.8%to 31.0%,the quasistatic pressure weakening rate ranges from 29.2%to 41.0%,and the weakening rate of the center of the plate residual deflection ranges from 10.8%to 34.4%under the various working pressures of the nozzles.To further explore the effect of water mist explosion suppression,a method for three-dimensional numerical simulations of water mist weakening the explosion shock wave is established to explore the explosion load characteristics of the compartment and the bulkhead response law.On the basis of the dimension analysis method,empirical formulas are derived to predict the residual deflection thickness in the center of the bulkheads.These findings provide the fundamental basis for the appli-cation of water mist in anti-explosive protection.
基金This research is supported by the Major Cultivation Foundation of Sichuan Education Department(13ZA0179).
文摘In the centrifugal separations of drilling fluid,screw conveyor is a critical component to push and separate the sediment.The work performance and structural parameters of conveyor are immediately related to the production capability,the working life and the separating effect of the centrifuge.The existing researches always use the theoretical calculation of the approximate loads to analyze the strength of conveyor,and it cannot reflect the stress situations accurately.In order to ensure the precise mastery of the working performance,this article obtained pressure distribution under working conditions from CFX evaluation and gained equivalent stress and deformation under several load conditions by using the ANSYS Workbench platform to check the strength of conveyor.The results showed that the influence of centrifugal hydraulic pressure was less than that of centrifugal force on the strength and deformation of conveyor.Besides,the maximum equivalent stress occurred at the inside of the feed opening,while the maximum deformation occurred at the conveyor blade edge of taper extremity.Furthermore,whether considered the feed opening or not,the computing model had a great influence on the analysis results,and the simplified loads had a great influence on the deformation analysis results.The methods and results from this article can provide reference for the design and the improvement of screw conveyor.
基金Project supported by the National Natural Science Foundation of China(Grant No 11472246)the National program on Key Basic Research project of China(973 program)(Grant No.2013CB228002).
文摘In this paper,the cores of outcropped black shale of Lower Silurian Longmaxi Fm in the Yibin area,Sichuan Basin,were taken as samples to investigate the effects of extraneous water on shale mechanics and seepage laws during the production of shale gas reservoirs.Firstly,the development of fractures in water saturated cores was observed by using a VHX-5000 optical superdepth microscope.Secondly,water,formation water and slick water,as well as the damage form and compression strength of water saturated/unsaturated cores were investigated by means of a uniaxial compression testing machine and a strain testing&analysis system.Finally,the effects of fluid-solid coupling on shale gas flowing performance in different water saturations were analyzed by using a DYQ-1 multi-function displacement device.Analysis on core components shows that the Longmaxi shale is a highly crushable reservoir with a high content of fragile minerals,so fracturing stimulation is suitable for it.Shale compression strength test reveals that the effects of deionized water,formation water and slick water on shale are different,so the compression strength of shale before being saturated is quite different from that after being saturated.Due to the existence of water,the compression strength of shale drops,so the shale can be fractured easily,more fractures are generated and thus its seepage capacity is improved.Experiments on shale gas seepage under different water saturations show that under the condition of fluid-solid coupling,the higher the water saturation is,the better the propagation and seepage capacity of micro-fractures in shale under the effect of pressure.To sum up,the existence of water is beneficial to fracturing stimulation of shale gas reservoirs and helps to achieve the goal of production improvement.
基金The lattice Boltzmann method was implemented in Particle Flow Code when YH was working for Itasca Consulting Group,Inc.
文摘The lattice Boltzmann method(LBM)is implemented in the Particle Flow Code(PFC)as a pore-scale CFD module and coupled with the particulate discrete element assemblage in PFC using an immersed boundary scheme.The implementation of LBM and LBM-PFC coupling is validated with the analytical solutions in a couple of hydrodynamics and fluid-particle interaction problems,i.e.,the accuracy of LBM as a CFD solver is verified by solving channel flow driven by a pressure gradient for which the closed-form solution is also derived;the accuracy of LBM-PFC coupling is validated by solving flow across a cylinder,Taylor-Couette flow,Karman vortex street,and fluid flow through a cylinder array.To demonstrate potential applications of this coupling code,a perforation cavity subjected to axial fluid flush is then tested,showing that the collapse and reconstruction of sand arch in the perforation cavity can be reproduced in this coupling system.The developed system is ready for exploring more complicated physical issues involved in sand production.
