McDonnell Douglas Aerospace(MDA)high-lift model is widely used in the study of multi-element airfoil,while there is still short knowledge of ice accretion and water impingement on it.In this paper,based on two-phase f...McDonnell Douglas Aerospace(MDA)high-lift model is widely used in the study of multi-element airfoil,while there is still short knowledge of ice accretion and water impingement on it.In this paper,based on two-phase flow theory,two numerical models were presented by using both Eulerian approach and Lagrangian approach,respectively,in order to predict the water impingement efficiency on a two-dimensional(2D)multi-element high-lift airfoil.Both computational results were validated with the experiment data,which shown good agreements in the impingement limitations and tendency.The trend that how the attack angle and droplet diameter affect the feather of local water impingement characteristics on the different elements of MDA were further investigated.As shown in this research,the trends that the local impingement intensity and extent on flap of MDA varied differently as in general understanding due to the complex structures of flow field,which should be careful cognized in design of the ice protection system.展开更多
At jet pressures ranging from 80 to 120 MPa, submerged water jets are investigated by numerical simulation and experiment. Numerical simulation enables a systematic analysis of major flow parameters such as jet veloci...At jet pressures ranging from 80 to 120 MPa, submerged water jets are investigated by numerical simulation and experiment. Numerical simulation enables a systematic analysis of major flow parameters such as jet velocity, turbulent kinetic energy as well as void fraction of cavitation. Experiments facilitate an objective assessment of surface morphology, micro hardness and surface roughness of the impinged samples. A comparison is implemented between submerged and non-submerged water jets. The results show that submerged water jet is characterized by low velocity magnitudes relative to non-submerged water jet at the same jet pressure. Shear effect serves as a key factor underlying the inception of cavitation in submerged water jet stream. Predicted annular shape of cavity zone is substantiated by local height distributions associated with experimentally obtained footprints. As jet pressure increases, joint contribution of jet kinetic energy and cavitation is demonstrated. While for non-submerged water jet, impingement force stems exclusively from flow velocity.展开更多
我国滨海核电厂(nuclear power plants,NNPs)取水安全形势严峻,取水产生的卷吸效应在一定程度上会对海洋生物造成损伤,已逐渐引起重视。调研了我国典型核电厂已发生的取水堵塞事件、取水卷吸影响等,结合取水工程海域流场特征、海洋生物...我国滨海核电厂(nuclear power plants,NNPs)取水安全形势严峻,取水产生的卷吸效应在一定程度上会对海洋生物造成损伤,已逐渐引起重视。调研了我国典型核电厂已发生的取水堵塞事件、取水卷吸影响等,结合取水工程海域流场特征、海洋生物卷吸数据等分析了取水对海洋生物的潜在影响并提出了可能的应对措施,为减缓取水卷吸及保障取水安全提供依据。展开更多
基金Many thanks to Prof.Tom Shih at Purdue University for providing guidance in grid generation and flow field simulation and the financial support from The Fundamental Research Funds for the Central Universities at Beihang University,number:YWF-14-JTXY-009.
文摘McDonnell Douglas Aerospace(MDA)high-lift model is widely used in the study of multi-element airfoil,while there is still short knowledge of ice accretion and water impingement on it.In this paper,based on two-phase flow theory,two numerical models were presented by using both Eulerian approach and Lagrangian approach,respectively,in order to predict the water impingement efficiency on a two-dimensional(2D)multi-element high-lift airfoil.Both computational results were validated with the experiment data,which shown good agreements in the impingement limitations and tendency.The trend that how the attack angle and droplet diameter affect the feather of local water impingement characteristics on the different elements of MDA were further investigated.As shown in this research,the trends that the local impingement intensity and extent on flap of MDA varied differently as in general understanding due to the complex structures of flow field,which should be careful cognized in design of the ice protection system.
基金Projects(51205171,51376081)supported by the National Natural Science Foundation of ChinaProject(1201026B)supported by the Postdoctoral Science Foundation of Jiangsu Province,China
文摘At jet pressures ranging from 80 to 120 MPa, submerged water jets are investigated by numerical simulation and experiment. Numerical simulation enables a systematic analysis of major flow parameters such as jet velocity, turbulent kinetic energy as well as void fraction of cavitation. Experiments facilitate an objective assessment of surface morphology, micro hardness and surface roughness of the impinged samples. A comparison is implemented between submerged and non-submerged water jets. The results show that submerged water jet is characterized by low velocity magnitudes relative to non-submerged water jet at the same jet pressure. Shear effect serves as a key factor underlying the inception of cavitation in submerged water jet stream. Predicted annular shape of cavity zone is substantiated by local height distributions associated with experimentally obtained footprints. As jet pressure increases, joint contribution of jet kinetic energy and cavitation is demonstrated. While for non-submerged water jet, impingement force stems exclusively from flow velocity.
文摘我国滨海核电厂(nuclear power plants,NNPs)取水安全形势严峻,取水产生的卷吸效应在一定程度上会对海洋生物造成损伤,已逐渐引起重视。调研了我国典型核电厂已发生的取水堵塞事件、取水卷吸影响等,结合取水工程海域流场特征、海洋生物卷吸数据等分析了取水对海洋生物的潜在影响并提出了可能的应对措施,为减缓取水卷吸及保障取水安全提供依据。
