The water-inrush mechanism of strong water-guide collapse column in coal seam is studied based on the establishment of geological and mathematical models of "triangle" water-inrush mode. The geological backg...The water-inrush mechanism of strong water-guide collapse column in coal seam is studied based on the establishment of geological and mathematical models of "triangle" water-inrush mode. The geological background of Shuangliu mine is considered a prototype, similar simulation tests are adopted to analyze the water-inrush rules under this model, and the formation of water-guide channel and water-inrush process is investigated by examining the changes in rock resistivity. This work also uses the coupled cloud image derived from numerical simulation software to verify the results of simulation test. Results show that the numerical simulation of "triangle" water-inrush mode is consistent with the similar simulation. The "triangle" seepage area, which is located at the bottom of collapse columns and is connected to aquifer, is caused by the altered seepage direction and strengthened seepage actions after the overlapping of hydraulic transverse seepage in collapse column and hydraulic vertical seepage flow in aquifer. Under "triangle"water-inrush model, water-guide channel is formed by the communication between plastic failure zone of working face baseplate and"triangular" seepage area. Accordingly, the threatening water-inrush distance between working face and collapse column increases by 20 m compared with that of theoretical calculation.展开更多
Moisture removal slot configurations with three different opening widths are in turn set at the trailing edges of a turbine hollow guide vane.The flow fields are analyzed by two-phase flow numerical simulation of solv...Moisture removal slot configurations with three different opening widths are in turn set at the trailing edges of a turbine hollow guide vane.The flow fields are analyzed by two-phase flow numerical simulation of solving the steady three dimensional Reynolds averaged Navier-Stokes equations on the basis of the real water vapor thermo-physical properties,and the blade temperature field is solved by the fluid-solid coupling.Exergy parame- ter is introduced as a measure to evaluate the economic cost of energy conversion process.The results indicate that the bigger slot allow lower quality of hot steam in the case of the equivalent injected quantity,while it has a higher exergy effective efficiency of the mixing process in the cascade channels.The hot steam injecting at the trailing edges has an optimal injected mass flow rate for a relatively large slot,on this point the exergy effective efficiency is the maximum,namely the flow loss is the minimum.展开更多
Numerical method was applied to the unsteady flow simulation at the mid span of a two-stage low speed compressor,and the blade boundary layer flow under rotor/stator interaction was investigated.By the model of wake/b...Numerical method was applied to the unsteady flow simulation at the mid span of a two-stage low speed compressor,and the blade boundary layer flow under rotor/stator interaction was investigated.By the model of wake/boundary layer interaction provided in this paper,the simulated blade frictional force and the boundary layer turbulent kinetic energy,the influence of wake/potential flow interaction on the blade boundary layer flow was analyzed in detail.The results show that under the condition of rotor/stator interaction,the wake is able to induce the stator laminar boundary layer flow to develop into turbulent flow within a certain range of wake interaction.In the stator suction boundary layer,an undisturbed region occurs behind the rotor wake,which extends the laminar flow range,and the wake with high turbulent intensity has the capability to control the boundary layer separation under adverse pressure gradient.展开更多
基金Projects(51374093,51104058)supported by the National Natural Science Foundation of ChinaProject(2013CB227903)supported by the National Basic Research Program of China
文摘The water-inrush mechanism of strong water-guide collapse column in coal seam is studied based on the establishment of geological and mathematical models of "triangle" water-inrush mode. The geological background of Shuangliu mine is considered a prototype, similar simulation tests are adopted to analyze the water-inrush rules under this model, and the formation of water-guide channel and water-inrush process is investigated by examining the changes in rock resistivity. This work also uses the coupled cloud image derived from numerical simulation software to verify the results of simulation test. Results show that the numerical simulation of "triangle" water-inrush mode is consistent with the similar simulation. The "triangle" seepage area, which is located at the bottom of collapse columns and is connected to aquifer, is caused by the altered seepage direction and strengthened seepage actions after the overlapping of hydraulic transverse seepage in collapse column and hydraulic vertical seepage flow in aquifer. Under "triangle"water-inrush model, water-guide channel is formed by the communication between plastic failure zone of working face baseplate and"triangular" seepage area. Accordingly, the threatening water-inrush distance between working face and collapse column increases by 20 m compared with that of theoretical calculation.
文摘Moisture removal slot configurations with three different opening widths are in turn set at the trailing edges of a turbine hollow guide vane.The flow fields are analyzed by two-phase flow numerical simulation of solving the steady three dimensional Reynolds averaged Navier-Stokes equations on the basis of the real water vapor thermo-physical properties,and the blade temperature field is solved by the fluid-solid coupling.Exergy parame- ter is introduced as a measure to evaluate the economic cost of energy conversion process.The results indicate that the bigger slot allow lower quality of hot steam in the case of the equivalent injected quantity,while it has a higher exergy effective efficiency of the mixing process in the cascade channels.The hot steam injecting at the trailing edges has an optimal injected mass flow rate for a relatively large slot,on this point the exergy effective efficiency is the maximum,namely the flow loss is the minimum.
文摘Numerical method was applied to the unsteady flow simulation at the mid span of a two-stage low speed compressor,and the blade boundary layer flow under rotor/stator interaction was investigated.By the model of wake/boundary layer interaction provided in this paper,the simulated blade frictional force and the boundary layer turbulent kinetic energy,the influence of wake/potential flow interaction on the blade boundary layer flow was analyzed in detail.The results show that under the condition of rotor/stator interaction,the wake is able to induce the stator laminar boundary layer flow to develop into turbulent flow within a certain range of wake interaction.In the stator suction boundary layer,an undisturbed region occurs behind the rotor wake,which extends the laminar flow range,and the wake with high turbulent intensity has the capability to control the boundary layer separation under adverse pressure gradient.
