The physical stability of solid-liquid fuel is a factor that needs to be considered for fuel product practicability for storage and transportation. To determine the Influence of liquid bridge force on physical stabili...The physical stability of solid-liquid fuel is a factor that needs to be considered for fuel product practicability for storage and transportation. To determine the Influence of liquid bridge force on physical stability, two detection devices were designed. The laws obtained from microscopic experiments are used to verify the physical stability of fuel under different component ratios. The liquid bridge force is found to increase with the droplet volume. Multiliquid bridges above one critical saturation can generate significant resultant forces compared to single-liquid bridges of the same volume. There exist four states of solid-liquid mixed fuel with increasing liquid saturation rate. The liquid bridge force between the solid and liquid plays a dominant role in the physical stability of the first three states. There may be two stages involved in the stratification process for state 4 fuel, and the liquid viscosity is another factor that cannot be ignored. In the process of selecting a fuel ratio, a larger liquid bridge force between the components can be obtained by properly improving the wetting effect so that the fuel shows better physical stability.展开更多
Extrudability and constructability are two important,yet contradictory issues pertaining to the construction of three-dimensional(3D)printing concrete.Extrudability is easily achieved when 3D printing cement mortar ha...Extrudability and constructability are two important,yet contradictory issues pertaining to the construction of three-dimensional(3D)printing concrete.Extrudability is easily achieved when 3D printing cement mortar has a high water content and low cohesion,but the printed structure is easily collapsible.However,a 3D printing cement mortar with a low water content and high cohesion has a relatively stable printed structure although the cement mortar might not be extrudable.This study proposes a particle-based method to simulate 3D printing mortar extrusion and construction as an overall planning tool for building design.First,a discrete element model with time-varying liquid bridge forces is developed to investigate the microscopic effects of these forces on global rheological properties.Next,a series of numerical simulations relevant to 3D printable mortar extrudability and constructability are carried out.The study demonstrates that the effects of time-varying liquid bridge forces on rheological properties and the resulting extrudability and constructability of 3D printing mortar are considerable.Furthermore,an optimized region that satisfies both the extrusion and construction requirements is provided for 3D printing industry as a reference.展开更多
Liquid bridge force acting between wet particles is an important property in particle characterization. This paper deals with liquid bridge force between either two unequal-sized spherical particles or a sphere and a ...Liquid bridge force acting between wet particles is an important property in particle characterization. This paper deals with liquid bridge force between either two unequal-sized spherical particles or a sphere and a flat plate under conditions where gravitational effect arising from bridge distortion is negligible. In order to calculate the force of the liquid bridge efficiently and accurately, expressions of liquid configuration and liquid bridge force were derived by building a mechanical model, which assumes the liquid bridge to be circular in shape between either two unequal-sized spheres or a sphere and a plane. To assess the accuracy of the numerical results of the calculated liquid bridge forces, they were compared to the nuhlished experimental data.展开更多
A pair of central moving spherical particles connected by a pendular liquid bridge with interstitial Newtonlan fluid is otten encountered in particulate coalescence process. In this paper, by assuming perfect-wet cond...A pair of central moving spherical particles connected by a pendular liquid bridge with interstitial Newtonlan fluid is otten encountered in particulate coalescence process. In this paper, by assuming perfect-wet condition, the effects of liquid volume and separation distance on static liquid bridge are analyzed, and the relation between rupture energy and liquid bridge volume is also studied. These points would be of significance in industrial processes related to adhesive particles.展开更多
Sintering behavior of micron-sized combusted iron powder is studied in a packed bed reactor,at various temperatures under inert(nitrogen)and reducing(hydrogen)conditions.Compression tests are subsequently used to quan...Sintering behavior of micron-sized combusted iron powder is studied in a packed bed reactor,at various temperatures under inert(nitrogen)and reducing(hydrogen)conditions.Compression tests are subsequently used to quantify the degree of sintering.A sintering model,based on the formation of a solid bridge through solid state surface diffusion of iron atoms,matches the experimental results.Sintering of combusted iron occurs at temperatures≥575°C in both nitrogen and hydrogen atmospheres and increases exponentially with temperature.The observed decrease in reduction rate at high temperatures is not caused by the sintering process but by the formation of wüstite as an intermediate species,leading to the formation of a dense iron layer.Iron whiskers form at high temperatures(≥700°C)in combination with low reduction rates(≤25 vol%H2),leading to the production of sub-micron fines.展开更多
The adhesive tensile stress between moist bulk iron ore solids and wall surfaces are critical to control and avoid blockage in large throughput material handling plants.In this study,an experimental system was designe...The adhesive tensile stress between moist bulk iron ore solids and wall surfaces are critical to control and avoid blockage in large throughput material handling plants.In this study,an experimental system was designed to investigate the adhesive tensile contact between a range of iron ore materials and wall lining specimens.The contact mechanism between the material specimen and the wall surface was initially characterised.The experimental results indicated that the adhesive tensile stress is dependent on both the moisture content and the applied major consolidation stress,with the former exhibiting more significant contribution to increasing the magnitude of stress.The surface roughness of the wall showed a negligible effect in determining the adhesive tensile stress.Additionally,the iron ore sample with a higher fines content was observed to be able to achieve a higher adhesive tensile stress compared to the coarse samples.Consequently,the insights resulting from the study demonstrated practical applicability through measures such as blending and/or beneficiation,which reduce the adhesive tensile stress and minimise blockages.展开更多
基金financial support from National Natural Science Foundation of China (Grant No. 12102197)。
文摘The physical stability of solid-liquid fuel is a factor that needs to be considered for fuel product practicability for storage and transportation. To determine the Influence of liquid bridge force on physical stability, two detection devices were designed. The laws obtained from microscopic experiments are used to verify the physical stability of fuel under different component ratios. The liquid bridge force is found to increase with the droplet volume. Multiliquid bridges above one critical saturation can generate significant resultant forces compared to single-liquid bridges of the same volume. There exist four states of solid-liquid mixed fuel with increasing liquid saturation rate. The liquid bridge force between the solid and liquid plays a dominant role in the physical stability of the first three states. There may be two stages involved in the stratification process for state 4 fuel, and the liquid viscosity is another factor that cannot be ignored. In the process of selecting a fuel ratio, a larger liquid bridge force between the components can be obtained by properly improving the wetting effect so that the fuel shows better physical stability.
基金sponsored by the National Natural Science Foundation of China (Grant Nos.52178299 and 51325802).
文摘Extrudability and constructability are two important,yet contradictory issues pertaining to the construction of three-dimensional(3D)printing concrete.Extrudability is easily achieved when 3D printing cement mortar has a high water content and low cohesion,but the printed structure is easily collapsible.However,a 3D printing cement mortar with a low water content and high cohesion has a relatively stable printed structure although the cement mortar might not be extrudable.This study proposes a particle-based method to simulate 3D printing mortar extrusion and construction as an overall planning tool for building design.First,a discrete element model with time-varying liquid bridge forces is developed to investigate the microscopic effects of these forces on global rheological properties.Next,a series of numerical simulations relevant to 3D printable mortar extrudability and constructability are carried out.The study demonstrates that the effects of time-varying liquid bridge forces on rheological properties and the resulting extrudability and constructability of 3D printing mortar are considerable.Furthermore,an optimized region that satisfies both the extrusion and construction requirements is provided for 3D printing industry as a reference.
基金supported by the Science Foundation of Chinese Universitythe Zhejiang Provincial Natural Science Foundation of China (Grant No. Y1100636)
文摘Liquid bridge force acting between wet particles is an important property in particle characterization. This paper deals with liquid bridge force between either two unequal-sized spherical particles or a sphere and a flat plate under conditions where gravitational effect arising from bridge distortion is negligible. In order to calculate the force of the liquid bridge efficiently and accurately, expressions of liquid configuration and liquid bridge force were derived by building a mechanical model, which assumes the liquid bridge to be circular in shape between either two unequal-sized spheres or a sphere and a plane. To assess the accuracy of the numerical results of the calculated liquid bridge forces, they were compared to the nuhlished experimental data.
文摘A pair of central moving spherical particles connected by a pendular liquid bridge with interstitial Newtonlan fluid is otten encountered in particulate coalescence process. In this paper, by assuming perfect-wet condition, the effects of liquid volume and separation distance on static liquid bridge are analyzed, and the relation between rupture energy and liquid bridge volume is also studied. These points would be of significance in industrial processes related to adhesive particles.
文摘Sintering behavior of micron-sized combusted iron powder is studied in a packed bed reactor,at various temperatures under inert(nitrogen)and reducing(hydrogen)conditions.Compression tests are subsequently used to quantify the degree of sintering.A sintering model,based on the formation of a solid bridge through solid state surface diffusion of iron atoms,matches the experimental results.Sintering of combusted iron occurs at temperatures≥575°C in both nitrogen and hydrogen atmospheres and increases exponentially with temperature.The observed decrease in reduction rate at high temperatures is not caused by the sintering process but by the formation of wüstite as an intermediate species,leading to the formation of a dense iron layer.Iron whiskers form at high temperatures(≥700°C)in combination with low reduction rates(≤25 vol%H2),leading to the production of sub-micron fines.
文摘The adhesive tensile stress between moist bulk iron ore solids and wall surfaces are critical to control and avoid blockage in large throughput material handling plants.In this study,an experimental system was designed to investigate the adhesive tensile contact between a range of iron ore materials and wall lining specimens.The contact mechanism between the material specimen and the wall surface was initially characterised.The experimental results indicated that the adhesive tensile stress is dependent on both the moisture content and the applied major consolidation stress,with the former exhibiting more significant contribution to increasing the magnitude of stress.The surface roughness of the wall showed a negligible effect in determining the adhesive tensile stress.Additionally,the iron ore sample with a higher fines content was observed to be able to achieve a higher adhesive tensile stress compared to the coarse samples.Consequently,the insights resulting from the study demonstrated practical applicability through measures such as blending and/or beneficiation,which reduce the adhesive tensile stress and minimise blockages.