Red mud has relatively small solid particles （d50= 13.02 μm） and will flow in paste form under high pressure during pipeline transport. Red mud belongs to a two-phase flow of materials with high viscosity and a hig...Red mud has relatively small solid particles （d50= 13.02 μm） and will flow in paste form under high pressure during pipeline transport. Red mud belongs to a two-phase flow of materials with high viscosity and a high concentration of non-sedimentation, homogeneous solid-liquids. It is difficult to test its rheological properties under atmospheric pressure. Measurements such as rotational viscometry can not reflect the real state of the material when it is flowing in a pipe. Tested rheological parameters are somewhat higher than the actual values. In our investigation, grain shape, distinctive modality and grain size distribution of red mud were tested. Based on the principle of tube measurement, rheological experiments on red mud at different concentrations were carried out by using our independently developed tube-type pressure theology test facility, and obtained constitutive equations. We conclude that red mud behaves as non-Newtonian pseudo-plastic fluid in pipe flows. Its consistency and power-law indices vary considerably with different concentrations.展开更多
Seafloor topography and heat flux show clear dependence on the age of seafloor. A half-space cooling (HSC) model can reproduce seafloor topography and heat flux data for younger seafloor, but for older seafloor the ob...Seafloor topography and heat flux show clear dependence on the age of seafloor. A half-space cooling (HSC) model can reproduce seafloor topography and heat flux data for younger seafloor, but for older seafloor the observations show reduced variations with the age in comparison with the HSC model predictions. The deviation was attributed to the sub-lithospheric small-scale (SSC) convection first by Par- sons and McKenzie (1978). While there is little doubt that the SSC can enhance heat flux at relatively old seafloor, ques- tions were raised as to whether or not the SSC can actually lead to a reduced topography. In this study, the effects of SSC on seafloor topography and heat flux are investigated by formulating a 2-D thermal convection model that is parallel to plate motion. Instead of using closed boundary conditions, which will bring large pressure effects because of return flow, a flow through boundary condition is adopted. The results show that although the SSC enhances the surface heat flux, it has little effects on topography for the fluids with a more realistic rheology. The reason for this is that the SSC trans- ports the heat from the bottom to the top and cools down the whole fluids, and with the existence of a stagnant lid, the whole effects on topography are negligible.展开更多
文摘Red mud has relatively small solid particles （d50= 13.02 μm） and will flow in paste form under high pressure during pipeline transport. Red mud belongs to a two-phase flow of materials with high viscosity and a high concentration of non-sedimentation, homogeneous solid-liquids. It is difficult to test its rheological properties under atmospheric pressure. Measurements such as rotational viscometry can not reflect the real state of the material when it is flowing in a pipe. Tested rheological parameters are somewhat higher than the actual values. In our investigation, grain shape, distinctive modality and grain size distribution of red mud were tested. Based on the principle of tube measurement, rheological experiments on red mud at different concentrations were carried out by using our independently developed tube-type pressure theology test facility, and obtained constitutive equations. We conclude that red mud behaves as non-Newtonian pseudo-plastic fluid in pipe flows. Its consistency and power-law indices vary considerably with different concentrations.
文摘Seafloor topography and heat flux show clear dependence on the age of seafloor. A half-space cooling (HSC) model can reproduce seafloor topography and heat flux data for younger seafloor, but for older seafloor the observations show reduced variations with the age in comparison with the HSC model predictions. The deviation was attributed to the sub-lithospheric small-scale (SSC) convection first by Par- sons and McKenzie (1978). While there is little doubt that the SSC can enhance heat flux at relatively old seafloor, ques- tions were raised as to whether or not the SSC can actually lead to a reduced topography. In this study, the effects of SSC on seafloor topography and heat flux are investigated by formulating a 2-D thermal convection model that is parallel to plate motion. Instead of using closed boundary conditions, which will bring large pressure effects because of return flow, a flow through boundary condition is adopted. The results show that although the SSC enhances the surface heat flux, it has little effects on topography for the fluids with a more realistic rheology. The reason for this is that the SSC trans- ports the heat from the bottom to the top and cools down the whole fluids, and with the existence of a stagnant lid, the whole effects on topography are negligible.
