In order to evaluate the effects of mesh generation techniques and grid convergence on pump performance in centrifugal pump model, three widely used mesh styles including structured hexahedral, unstructured tetrahedra...In order to evaluate the effects of mesh generation techniques and grid convergence on pump performance in centrifugal pump model, three widely used mesh styles including structured hexahedral, unstructured tetrahedral and hybrid prismatic/tetrahedral meshes were generated for a centrifugal pump model. And quantitative grid convergence was assessed based on a grid convergence index(GCI), which accounts for the degree of grid refinement. The structured, unstructured or hybrid meshes are found to have certain difference for velocity distributions in impeller with the change of grid cell number. And the simulation results have errors to different degrees compared with experimental data. The GCI-value for structured meshes calculated is lower than that for the unstructured and hybrid meshes. Meanwhile, the structured meshes are observed to get more vortexes in impeller passage.Nevertheless, the hybrid meshes are found to have larger low-velocity area at outlet and more secondary vortexes at a specified location than structured meshes and unstructured meshes.展开更多
To better evaluate the three-dimensional bay health and predict the dynamic bay health conditions, a concept of numerical bay health was introduced and a method of numerical bay health evaluation（NBHE） was developed...To better evaluate the three-dimensional bay health and predict the dynamic bay health conditions, a concept of numerical bay health was introduced and a method of numerical bay health evaluation（NBHE） was developed.To support the NBHE method, a numerical bay health index（NBHI） system was constructed, which assess the natural and socio-economic effects on the entire bay. Five index groups are combined to formulate the NBHI,including geometry, hydrodynamics and sediment dynamics, bio-ecology, water quality and socio-economy.Each group has different number of indices selected and weighted using AHP method according to their importance. Data were mainly synthesized from a variety of numerical models together with monitoring programs, which provide superior to other approaches in discriminating data integrity and predicting data in future. The NBHE method using NBHI system was applied in the Yueqing Bay during spring tide in April 2007.According to the NBHE results, Sta. A, at the surface level of the estuarine mouth, has a healthy geometry condition, sub-healthy hydrodynamic and sediment dynamic condition, and unhealthy water quality and bioecology conditions. The integrated healthy score at Sta. A indicates its sub-healthy condition.展开更多
基金Projects(51109095,51179075,51309119)supported by the National Natural Science Foundation of ChinaProject(BE2012131)supported by Science and Technology Support Program of Jiangsu Province,China
文摘In order to evaluate the effects of mesh generation techniques and grid convergence on pump performance in centrifugal pump model, three widely used mesh styles including structured hexahedral, unstructured tetrahedral and hybrid prismatic/tetrahedral meshes were generated for a centrifugal pump model. And quantitative grid convergence was assessed based on a grid convergence index(GCI), which accounts for the degree of grid refinement. The structured, unstructured or hybrid meshes are found to have certain difference for velocity distributions in impeller with the change of grid cell number. And the simulation results have errors to different degrees compared with experimental data. The GCI-value for structured meshes calculated is lower than that for the unstructured and hybrid meshes. Meanwhile, the structured meshes are observed to get more vortexes in impeller passage.Nevertheless, the hybrid meshes are found to have larger low-velocity area at outlet and more secondary vortexes at a specified location than structured meshes and unstructured meshes.
基金The Key National Project under contract No.009zx07424-001Doctoral Fund of Ministry of Education of China under contract No.2012101110108+2 种基金MEL Visiting Fellowship Programthe Fundamental Research Funds for the Central UniversitiesZhejiang Provincial Natural Science Foundation of China under contract No.LQ16D060002
文摘To better evaluate the three-dimensional bay health and predict the dynamic bay health conditions, a concept of numerical bay health was introduced and a method of numerical bay health evaluation（NBHE） was developed.To support the NBHE method, a numerical bay health index（NBHI） system was constructed, which assess the natural and socio-economic effects on the entire bay. Five index groups are combined to formulate the NBHI,including geometry, hydrodynamics and sediment dynamics, bio-ecology, water quality and socio-economy.Each group has different number of indices selected and weighted using AHP method according to their importance. Data were mainly synthesized from a variety of numerical models together with monitoring programs, which provide superior to other approaches in discriminating data integrity and predicting data in future. The NBHE method using NBHI system was applied in the Yueqing Bay during spring tide in April 2007.According to the NBHE results, Sta. A, at the surface level of the estuarine mouth, has a healthy geometry condition, sub-healthy hydrodynamic and sediment dynamic condition, and unhealthy water quality and bioecology conditions. The integrated healthy score at Sta. A indicates its sub-healthy condition.
