This paper has attempted to study a mechanism of three-dimensional flow around a horizontal axis wind turbine(HAWT) rotor blade. An experimental study of the flow phenomenon in the vicinity of the wind turbine blade i...This paper has attempted to study a mechanism of three-dimensional flow around a horizontal axis wind turbine(HAWT) rotor blade. An experimental study of the flow phenomenon in the vicinity of the wind turbine blade is a challenging endeavor. In this research, the HAWT model with 2.4 m diameter was tested in the large wind tunnel. The flow around the rotating blade surface was measured simultaneously for three velocity components, and two probes were used for the synchronized measurement of three-dimensional flow components. The local velocity was detected for the single seeding particle measured in the point where three pairs of laser beams intersected. Blade sections of interest in this study are composed of radial positions r/R = 0.3, 0.5 and 0.7. Optimum and low tip speed ratio flow characteristics were also compared. The velocity flow vector, skin friction coefficient and bound circulation were calculated from LDV measurements, and the experimental research showed reasonably and clearly the experimental results.展开更多
The purpose of this study is to make clear the behavior of swirling pipe flows with non-circular section. We have investigated experimentally and numerically the swirling flows in a rectangular channel with aspect rat...The purpose of this study is to make clear the behavior of swirling pipe flows with non-circular section. We have investigated experimentally and numerically the swirling flows in a rectangular channel with aspect ratio of 1.3, which is one of the typical pipe flow with non-circular section. In this paper, experimental apparatus with water circulation system is produced, and LDV measurement of the swirling flows is performed in order to clarify the mean velocities and turbulent quantity with higher accuracy. In addition, flow visualization for movement of vortex core region in the swirling flows is carried out using tracer method. Moreover, large eddy simulation (LES) of the flow field is made and compared with the experimental results. As results of these investigations, the behavior of the swirling flows in the rectangular channel is totally discussed.展开更多
The axial and tangential velocities of gas and particle phases and particle concentration for turbulent swirling and recirculating gas-particle (simulating gas-droplet) flows in a cold model of a dual-inlet sudden-exp...The axial and tangential velocities of gas and particle phases and particle concentration for turbulent swirling and recirculating gas-particle (simulating gas-droplet) flows in a cold model of a dual-inlet sudden-expansion combustor with partially tangential central tubes, proposed by the present authors, were measured by using a 2-D LDV system and a laser optic fiber system combined with a sampling probe. The results show that there are both gas and particle strongly reverse flows and swirling flows in the head part of the combustor. The velocity slip between gas and particle phases is remarkable. The particle concentration is higher near the wall and lower near the axis. There are two peaks in the concentration profiles near the inlet tubes. The above-obtained flow characteristics are favorable to ignition, flame stabilization and combustion. The results can also be used to validate the numerical modeling.展开更多
The gas and particle time-averaged velocity rand RMS fluctuation velocity of swirling gas-particle flows in a spouting-cyclone combustor were measured by a hot-ball probe and a conventional LDV system. The results sho...The gas and particle time-averaged velocity rand RMS fluctuation velocity of swirling gas-particle flows in a spouting-cyclone combustor were measured by a hot-ball probe and a conventional LDV system. The results show large velocity slip between the two phases both in tangential and axial directions and high nonisotropic turbulence of the two phases were also observed which is favorable to coal combustion. The particle RMS fluctuation velocity is higher than the gas RMS fluctuation velocity only in some regions of the flow field.展开更多
文摘This paper has attempted to study a mechanism of three-dimensional flow around a horizontal axis wind turbine(HAWT) rotor blade. An experimental study of the flow phenomenon in the vicinity of the wind turbine blade is a challenging endeavor. In this research, the HAWT model with 2.4 m diameter was tested in the large wind tunnel. The flow around the rotating blade surface was measured simultaneously for three velocity components, and two probes were used for the synchronized measurement of three-dimensional flow components. The local velocity was detected for the single seeding particle measured in the point where three pairs of laser beams intersected. Blade sections of interest in this study are composed of radial positions r/R = 0.3, 0.5 and 0.7. Optimum and low tip speed ratio flow characteristics were also compared. The velocity flow vector, skin friction coefficient and bound circulation were calculated from LDV measurements, and the experimental research showed reasonably and clearly the experimental results.
基金two Grants-in-aid for Science Research with No. l1750808 fromMinistry of Education of JaPan and No. 98KK-023from MAZDA Fou
文摘The purpose of this study is to make clear the behavior of swirling pipe flows with non-circular section. We have investigated experimentally and numerically the swirling flows in a rectangular channel with aspect ratio of 1.3, which is one of the typical pipe flow with non-circular section. In this paper, experimental apparatus with water circulation system is produced, and LDV measurement of the swirling flows is performed in order to clarify the mean velocities and turbulent quantity with higher accuracy. In addition, flow visualization for movement of vortex core region in the swirling flows is carried out using tracer method. Moreover, large eddy simulation (LES) of the flow field is made and compared with the experimental results. As results of these investigations, the behavior of the swirling flows in the rectangular channel is totally discussed.
基金F oundation of Astronautical Sci. & Tech.China(Project 90 -16 )
文摘The axial and tangential velocities of gas and particle phases and particle concentration for turbulent swirling and recirculating gas-particle (simulating gas-droplet) flows in a cold model of a dual-inlet sudden-expansion combustor with partially tangential central tubes, proposed by the present authors, were measured by using a 2-D LDV system and a laser optic fiber system combined with a sampling probe. The results show that there are both gas and particle strongly reverse flows and swirling flows in the head part of the combustor. The velocity slip between gas and particle phases is remarkable. The particle concentration is higher near the wall and lower near the axis. There are two peaks in the concentration profiles near the inlet tubes. The above-obtained flow characteristics are favorable to ignition, flame stabilization and combustion. The results can also be used to validate the numerical modeling.
文摘The gas and particle time-averaged velocity rand RMS fluctuation velocity of swirling gas-particle flows in a spouting-cyclone combustor were measured by a hot-ball probe and a conventional LDV system. The results show large velocity slip between the two phases both in tangential and axial directions and high nonisotropic turbulence of the two phases were also observed which is favorable to coal combustion. The particle RMS fluctuation velocity is higher than the gas RMS fluctuation velocity only in some regions of the flow field.
