The present work is based on the comparative study between “Blade-Element- Momentum” (BEM) analysis and “Computational-Fluid-Dynamics” (CFD) analysis of small-scale horizontal axis wind turbine blade. In this stud...The present work is based on the comparative study between “Blade-Element- Momentum” (BEM) analysis and “Computational-Fluid-Dynamics” (CFD) analysis of small-scale horizontal axis wind turbine blade. In this study, the pitch is considered as fixed and rotor speed is variable. Firstly, the aerodynamic characteristics of three different specialized airfoils were analyzed to get optimum design parameters of wind turbine blade. Then BEM was performed with the application of the open source wind turbine design and performance computation software Q-Blade v0.6. After that, CFD simulation was done by Ansys CFX software. Here, k-ω “Shear-Stress-Transport” (SST) model was conducted for three-dimensional visualization of turbine performance. However, the best coefficient of performance was observed at 6o angle of attack. At this angle of attack, in the case of BEM, the highest coefficient of performance was 0.47 whereby CFD analysis, it was 0.43. Both studies showed good performance prediction which was a positive step to accelerate the continuous revolution in wind energy sector.展开更多
The splitter blades are widely used in axial compressors and play an active role in the improvement of the overall performance of compressors. However, little research on the application of splitter blades to small ax...The splitter blades are widely used in axial compressors and play an active role in the improvement of the overall performance of compressors. However, little research on the application of splitter blades to small axial flow fans is conducted. This paper designs a splitter blade small axial flow fan (model B) with a small axial flow fan as the prototype fan (model A) by adding short blades at the second half part of the passageway among long blades of model A. The steady simulation for the two models was conducted with the help of RNG k-ε turbulence model provided by software Fluent, and static characteristics and internal flow characteristics of the two models were compared and analyzed. Results show that splitter blades can improve the unsteady flow in the small flow rate region and also have a positive role to increase static pressure rise and efficiency in the higher flow rate region. The variation of static pressure gradient on the meridian plane in model B is well-distributed. The static pressure on the blade surface of model B distributes more uniformly. Splitter blades can suppress the secondary flow from pressure side to suction side in the leading edge because the pressure difference between suction side and pressure side in model B is generally lower than that of model A. And it also can restrain the vortex shedding and flow separation, and further it may be able to get the aerodynamic noise lower because static pressure gradient on the blade surface is well-distributed and the vortex shedding is not developed. Therefore, the performance of the fan with splitter blades is better than that of the prototype fan. The findings of this paper can be a basis for the design of high performance small axial flow fans.展开更多
AIM: To report the long-term outcomes of combined excisional goniotomy and manual small incision cataract surgery(MSICS).METHODS: This is a retrospective case series of patients with open angle glaucoma and visually s...AIM: To report the long-term outcomes of combined excisional goniotomy and manual small incision cataract surgery(MSICS).METHODS: This is a retrospective case series of patients with open angle glaucoma and visually significant cataracts that underwent combined excisional goniotomy and MSICS with one-year follow-up. The medical history, demographic information, and clinical characteristics of each case were recorded. Data regarding changes in vision, intraocular pressure(IOP), the number of glaucoma medications, and the evolution of the disease after surgery were reported. RESULTS: Three patients, with open angle glaucoma and cataracts underwent combined excisional goniotomy and MSICS without adverse events. All patients had improvement in vision compared to baseline measurements. The range of IOP at baseline was from 14 to 18 mm Hg and decrease to a range of 10 to 14 mm Hg after one year of follow-up. Additionally, two patients also decreased their dependence on IOP-lowering medications at the last follow up visit with one patient maintaining baseline level of medication use.CONCLUSION: A combination of excisional goniotomy and MSICS illustrates both the safety and efficacy to treat patients with visually significant cataract and glaucoma. This procedure allows for a more cost-effective surgical approach that matches the needs of resource strained territories around the globe.展开更多
文摘The present work is based on the comparative study between “Blade-Element- Momentum” (BEM) analysis and “Computational-Fluid-Dynamics” (CFD) analysis of small-scale horizontal axis wind turbine blade. In this study, the pitch is considered as fixed and rotor speed is variable. Firstly, the aerodynamic characteristics of three different specialized airfoils were analyzed to get optimum design parameters of wind turbine blade. Then BEM was performed with the application of the open source wind turbine design and performance computation software Q-Blade v0.6. After that, CFD simulation was done by Ansys CFX software. Here, k-ω “Shear-Stress-Transport” (SST) model was conducted for three-dimensional visualization of turbine performance. However, the best coefficient of performance was observed at 6o angle of attack. At this angle of attack, in the case of BEM, the highest coefficient of performance was 0.47 whereby CFD analysis, it was 0.43. Both studies showed good performance prediction which was a positive step to accelerate the continuous revolution in wind energy sector.
文摘The splitter blades are widely used in axial compressors and play an active role in the improvement of the overall performance of compressors. However, little research on the application of splitter blades to small axial flow fans is conducted. This paper designs a splitter blade small axial flow fan (model B) with a small axial flow fan as the prototype fan (model A) by adding short blades at the second half part of the passageway among long blades of model A. The steady simulation for the two models was conducted with the help of RNG k-ε turbulence model provided by software Fluent, and static characteristics and internal flow characteristics of the two models were compared and analyzed. Results show that splitter blades can improve the unsteady flow in the small flow rate region and also have a positive role to increase static pressure rise and efficiency in the higher flow rate region. The variation of static pressure gradient on the meridian plane in model B is well-distributed. The static pressure on the blade surface of model B distributes more uniformly. Splitter blades can suppress the secondary flow from pressure side to suction side in the leading edge because the pressure difference between suction side and pressure side in model B is generally lower than that of model A. And it also can restrain the vortex shedding and flow separation, and further it may be able to get the aerodynamic noise lower because static pressure gradient on the blade surface is well-distributed and the vortex shedding is not developed. Therefore, the performance of the fan with splitter blades is better than that of the prototype fan. The findings of this paper can be a basis for the design of high performance small axial flow fans.
文摘AIM: To report the long-term outcomes of combined excisional goniotomy and manual small incision cataract surgery(MSICS).METHODS: This is a retrospective case series of patients with open angle glaucoma and visually significant cataracts that underwent combined excisional goniotomy and MSICS with one-year follow-up. The medical history, demographic information, and clinical characteristics of each case were recorded. Data regarding changes in vision, intraocular pressure(IOP), the number of glaucoma medications, and the evolution of the disease after surgery were reported. RESULTS: Three patients, with open angle glaucoma and cataracts underwent combined excisional goniotomy and MSICS without adverse events. All patients had improvement in vision compared to baseline measurements. The range of IOP at baseline was from 14 to 18 mm Hg and decrease to a range of 10 to 14 mm Hg after one year of follow-up. Additionally, two patients also decreased their dependence on IOP-lowering medications at the last follow up visit with one patient maintaining baseline level of medication use.CONCLUSION: A combination of excisional goniotomy and MSICS illustrates both the safety and efficacy to treat patients with visually significant cataract and glaucoma. This procedure allows for a more cost-effective surgical approach that matches the needs of resource strained territories around the globe.
