This paper presents an experimental study result of flow field of a dual-channel burner. In order to solve the ubiquitous problem of bad rigidity of jets in dual-channel burners, wedges with different arrangements and...This paper presents an experimental study result of flow field of a dual-channel burner. In order to solve the ubiquitous problem of bad rigidity of jets in dual-channel burners, wedges with different arrangements and structural parameters were added to different positions at the outlet of the burners. Laser Particle Image Velocimetry (PIV) was used in this study to measure the flow field to investigate influence of the wedges on flow field of the dual-channel burner. Experimental study shows that fixing wedges at both right and left sides of the burner's outlet can increase the intensity of recirculation without changing the size of the recirculation zone and enhance the rigidity of jets via increasing speed of the two primary air jets at the outlet.展开更多
The self-similarity solutions of the Navier-Stokes equations are constructed for an incompressible laminar flow through a uniformly porous channel with retractable walls under a transverse magnetic field. The flow is ...The self-similarity solutions of the Navier-Stokes equations are constructed for an incompressible laminar flow through a uniformly porous channel with retractable walls under a transverse magnetic field. The flow is driven by the expanding or contracting walls with different permeability. The velocities of the asymmetric flow at the upper and lower walls are different in not only the magnitude but also the direction. The asymptotic solutions are well constructed with the method of boundary layer correction in two cases with large Reynolds numbers, i.e., both walls of the channel are with suction, and one of the walls is with injection while the other one is with suction. For small Reynolds number cases, the double perturbation method is used to construct the asymptotic solution. All the asymptotic results are finally verified by numerical results.展开更多
This research aims to simulate a gravity flow fractionation—the process to fractionate erythrocytes through gravitational field using ANSYS simulation software. A particular microfluidic channel was designed as a sep...This research aims to simulate a gravity flow fractionation—the process to fractionate erythrocytes through gravitational field using ANSYS simulation software. A particular microfluidic channel was designed as a separation device. The gravitational equilibrium conditions of the erythrocytes and gravitational field as the parameters were chosen, then deriving the erythrocytes’ path through numerical simulations. After the actual analog measurements, there is no big difference between the flow velocity and the pressure under +/–10% atmosphere condition. According to the simulation results, the particle with the size 8 μm (similar to the erythrocyte size) can be separated to the outside channel and discharged from the collecting area, other particles with the size 9 μm will stay in the fluid motion and can be collected in the final collection area for preservation. Through the analog analysis by using the software-ANSYS-Fluent, the complete flowing path of the particles and the feasibility of the Gravity-Flow Fractionation can be directly proven.展开更多
In the present study, a mathematical model of unsteady blood flow through parallel plate channel under the action of an applied constant transverse magnetic field is proposed. The model is subjected to heat source. An...In the present study, a mathematical model of unsteady blood flow through parallel plate channel under the action of an applied constant transverse magnetic field is proposed. The model is subjected to heat source. Analytical expressions are obtained by choosing the axial velocity;temperature distribution and the normal velocity of the blood depend on y and t only to convert the system of partial differential equations into system of ordinary differential equations under the conditions defined in our model. The model has been analyzed to find the effects of various parameters such as, Hartmann number, heat source parameter and Prandtl number on the axial velocity, temperature distribution and the normal velocity. The numerical solutions of axial velocity, temperature distributions and normal velocity are shown graphically for better understanding of the problem. Hence, the present mathematical model gives a simple form of axial velocity, temperature distribution and normal velocity of the blood flow so that it will help not only people working in the field of Physiological fluid dynamics but also to the medical practitioners.展开更多
This article presents a 2017 LiDAR-DEM guided 1-m resolution examination of field-surveyed elevation and soil property variations (5 × 5 m spacings) conducted in 1977 across a hummocky New Brunswick field used fo...This article presents a 2017 LiDAR-DEM guided 1-m resolution examination of field-surveyed elevation and soil property variations (5 × 5 m spacings) conducted in 1977 across a hummocky New Brunswick field used for potato production. This examination revealed that the field incurred minor elevation differences likely due to upslope erosion as revealed through increasing Sand % and CF % with increasing elevation, and increasing Silt % along low-lying areas. Soil moisture, field capacity, permanent wilting and nitrate nitrogen (NO<sub>3</sub>-N) also increased at downslope locations. Directly as well as indirectly, soil pH, ammonium nitrogen (NH<sub>4</sub>-N), Caesium<sup>137</sup> (Cs<sup>137</sup>) and Mehlich-3 extracted Ca, Mg, K, Fe, Mn, Cu, and Zn were likewise affected by topographic location. Factor analyzing these variables led to: 1) a Soil Loss Factor that captured 24% of the textural variations;2) a Soil-Cropping Factor accounting for 16% of the N, P, K, Ca, Mg, Mn variations;3) a Soil Organic Matter (SOM) Factor relating 9% of the in-field variations for SOM, Fe, Zn, Cu to via organo-metal complexation and low NO<sub>3</sub>-N retention. Many of the topographic variations increased or decreased with the metric DEM-projected depth-to-water index (DTW) index. This index was set to 0 along DEM-derived flow channels with minimum upslope flow-accumulation areas of 0.1, 0.25, 0.5, 1 or 4 ha. Among these, the DTW > 4 ha threshold was useful for reproducing the textural variations, while the DTW > 0.25 ha threshold assisted in capturing trends pertaining to moisture retention and elemental concentrations.展开更多
基金This paper is about a project financed by National Natural Science Foundation (No. 50476070).
文摘This paper presents an experimental study result of flow field of a dual-channel burner. In order to solve the ubiquitous problem of bad rigidity of jets in dual-channel burners, wedges with different arrangements and structural parameters were added to different positions at the outlet of the burners. Laser Particle Image Velocimetry (PIV) was used in this study to measure the flow field to investigate influence of the wedges on flow field of the dual-channel burner. Experimental study shows that fixing wedges at both right and left sides of the burner's outlet can increase the intensity of recirculation without changing the size of the recirculation zone and enhance the rigidity of jets via increasing speed of the two primary air jets at the outlet.
基金Project supported by the National Natural Science Foundation of China(Nos.91430106 and11771040)the Fundamental Research Funds for the Central Universities of China(No.06500073)
文摘The self-similarity solutions of the Navier-Stokes equations are constructed for an incompressible laminar flow through a uniformly porous channel with retractable walls under a transverse magnetic field. The flow is driven by the expanding or contracting walls with different permeability. The velocities of the asymmetric flow at the upper and lower walls are different in not only the magnitude but also the direction. The asymptotic solutions are well constructed with the method of boundary layer correction in two cases with large Reynolds numbers, i.e., both walls of the channel are with suction, and one of the walls is with injection while the other one is with suction. For small Reynolds number cases, the double perturbation method is used to construct the asymptotic solution. All the asymptotic results are finally verified by numerical results.
文摘This research aims to simulate a gravity flow fractionation—the process to fractionate erythrocytes through gravitational field using ANSYS simulation software. A particular microfluidic channel was designed as a separation device. The gravitational equilibrium conditions of the erythrocytes and gravitational field as the parameters were chosen, then deriving the erythrocytes’ path through numerical simulations. After the actual analog measurements, there is no big difference between the flow velocity and the pressure under +/–10% atmosphere condition. According to the simulation results, the particle with the size 8 μm (similar to the erythrocyte size) can be separated to the outside channel and discharged from the collecting area, other particles with the size 9 μm will stay in the fluid motion and can be collected in the final collection area for preservation. Through the analog analysis by using the software-ANSYS-Fluent, the complete flowing path of the particles and the feasibility of the Gravity-Flow Fractionation can be directly proven.
文摘In the present study, a mathematical model of unsteady blood flow through parallel plate channel under the action of an applied constant transverse magnetic field is proposed. The model is subjected to heat source. Analytical expressions are obtained by choosing the axial velocity;temperature distribution and the normal velocity of the blood depend on y and t only to convert the system of partial differential equations into system of ordinary differential equations under the conditions defined in our model. The model has been analyzed to find the effects of various parameters such as, Hartmann number, heat source parameter and Prandtl number on the axial velocity, temperature distribution and the normal velocity. The numerical solutions of axial velocity, temperature distributions and normal velocity are shown graphically for better understanding of the problem. Hence, the present mathematical model gives a simple form of axial velocity, temperature distribution and normal velocity of the blood flow so that it will help not only people working in the field of Physiological fluid dynamics but also to the medical practitioners.
文摘This article presents a 2017 LiDAR-DEM guided 1-m resolution examination of field-surveyed elevation and soil property variations (5 × 5 m spacings) conducted in 1977 across a hummocky New Brunswick field used for potato production. This examination revealed that the field incurred minor elevation differences likely due to upslope erosion as revealed through increasing Sand % and CF % with increasing elevation, and increasing Silt % along low-lying areas. Soil moisture, field capacity, permanent wilting and nitrate nitrogen (NO<sub>3</sub>-N) also increased at downslope locations. Directly as well as indirectly, soil pH, ammonium nitrogen (NH<sub>4</sub>-N), Caesium<sup>137</sup> (Cs<sup>137</sup>) and Mehlich-3 extracted Ca, Mg, K, Fe, Mn, Cu, and Zn were likewise affected by topographic location. Factor analyzing these variables led to: 1) a Soil Loss Factor that captured 24% of the textural variations;2) a Soil-Cropping Factor accounting for 16% of the N, P, K, Ca, Mg, Mn variations;3) a Soil Organic Matter (SOM) Factor relating 9% of the in-field variations for SOM, Fe, Zn, Cu to via organo-metal complexation and low NO<sub>3</sub>-N retention. Many of the topographic variations increased or decreased with the metric DEM-projected depth-to-water index (DTW) index. This index was set to 0 along DEM-derived flow channels with minimum upslope flow-accumulation areas of 0.1, 0.25, 0.5, 1 or 4 ha. Among these, the DTW > 4 ha threshold was useful for reproducing the textural variations, while the DTW > 0.25 ha threshold assisted in capturing trends pertaining to moisture retention and elemental concentrations.
