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Vortices within a Three-Dimensional Separation in an Axial Flow Stator of a Diagonal Flow Fan
Kinoue, Yoichi,Shiomi, Norimasa,Setoguchi, Toshiaki Korean Society for Fluid machinery 2011 International journal of fluid machinery and syste Vol.4 No.2
Experimental and numerical investigations were conducted for an internal flow in an axial flow stator of a diagonal flow fan. A corner separation near the hub surface and the suction surface of a stator blade was focused on, and further, three-dimensional vortices in separated flow were investigated by the numerical analysis. At low flow rate of 80% of the design flow rate, a corner separation of the stator between the suction surface and the hub surface can be found in both experimental and calculated results. Separation vortices are observed in the limiting streamline patterns both on the blade suction and on the hub surfaces at 80% of the design flow rate in the calculated results. It also can be observed in the streamline pattern that both vortices from the blade suction surface and from the hub surface keep vortex structures up to far locations from these wall surfaces. An attempt to explain the vortices within a three-dimensional separation is introduced by using vortex filaments.
Experimental Investigation on Separated Flows of Axial Flow Stator and Diagonal Flow Rotor
Kinoue, Yoichi,Shiomi, Norimasa,Setoguchi, Toshiaki,Jin, Yingzi Korean Society for Fluid machinery 2009 International journal of fluid machinery and syste Vol.2 No.3
Experimental investigations were conducted for the internal flows of the axial flow stator and diagonal flow rotor. Corner separation near the hub surface and the suction surface of stator blade are mainly focused on. For the design flow rate, the values of the axial velocity and the total pressure at stator outlet decrease between near the suction surface and near the hub surface by the influence of corner wall. For the flow rate of 80-90% of the design flow rate, the corner separation of the stator between the suction surface and the hub surface is observed, which becomes widely spread for 80% of the design flow rate. At rotor outlet for 81% of the design flow rate, the low axial velocity region grows between near the suction surface of rotor and the casing surface because of the tip leakage flow of the rotor.
Design and Experimental Studies of Radial-Outflow Type Diagonal Flow Fan
Kinoue, Yoichi,Shiomi, Norimasa,Setoguchi, Toshiaki Korean Society for Fluid machinery 2013 International journal of fluid machinery and syste Vol.6 No.1
In order to apply the design method of diagonal flow fan based on axial flow design to the design of radial-outflow type diagonal flow fan which has lower specific speed of 600-700 [$min^{-1}$, $m^3/min$, m], radial-outflow type diagonal flow fan which specific speed was 670 [$min^{-1}$, $m^3/min$, m] was designed by a quasi three-dimensional design method. Experimental investigations were conducted by fan characteristics test, flow surveys by a five-hole probe and a hot wire probe. Fan characteristics test agreed well with the design values. In the flow survey at rotor outlet, the characteristic region was observed. Two flow phenomena are considered as the cause of the characteristic region, one is tip leakage vortex near rotor tip and another is pressure surface separation on the rotor blade.
Design and Experimental Studies of Radial-Outflow Type Diagonal Flow Fan
Yoichi Kinoue,Norimasa Shiomi,Toshiaki Setoguchi 한국유체기계학회 2013 International journal of fluid machinery and syste Vol.6 No.1
In order to apply the design method of diagonal flow fan based on axial flow design to the design of radial-outflow type diagonal flow fan which has lower specific speed of 600-700 [min-1, m3/min, m], radial-outflow type diagonal flow fan which specific speed was 670 [min-1, m3/min, m] was designed by a quasi three-dimensional design method. Experimental investigations were conducted by fan characteristics test, flow surveys by a five-hole probe and a hot wire probe. Fan characteristics test agreed well with the design values. In the flow survey at rotor outlet, the characteristic region was observed. Two flow phenomena are considered as the cause of the characteristic region, one is tip leakage vortex near rotor tip and another is pressure surface separation on the rotor blade.
Yoichi Kinoue,Masaki Sakaguchi,Tengen Murakami,Yasutaka Imai,Shuichi Nagata,Norimasa Shiomi,Manabu Takao 한국유체기계학회 2019 International journal of fluid machinery and syste Vol.12 No.4
The bi-directional impulse turbine and the bi-directional flow collector for tidal energy conversion is investigated in this paper. The bi-directional impulse turbine with fixed guide vanes is adopted because the turbine has a high efficiency and an advantage of maintenance. The turbine characteristics of the combined system of impulse turbine and collector are investigated experimentally by using the water tunnel. This system is proved to produce the power by a tidal flow experimentally. Three types of flow collector A, B and C are investigated, where the maximum radius of collector A is smaller than the ones of collector B and C. The velocity ratio of collector A is much smaller than the one for the cases of collector B and collector C, and the output power of collector A is very small compared to the other collectors. Nevertheless, the effect of flow collector is large because velocity ratio of collector A is much larger than the one without collector. Among three cases of 0.5, 0.6 and 0.7 of hub-to-tip ratio, the difference of turbine performance is not so large, but it is observed that the case for0.5 of hub-to-tip ratio has inferior performance and the case for 0.6 of hub-to-tip ratio has the performance among them. Further, the comparison of circulating water tank test and towing tank test was done to show the effect of choking ratio of cross sectional area of channel.
Yoichi Kinoue,Yuya Matsumoto,Masaki Sakaguchi,Norimasa Shiomi 한국유체기계학회 2021 International journal of fluid machinery and syste Vol.14 No.1
In order to examine the fundamental characteristics of a corner separation in a decelerating cascade flow, an experimental apparatus was made and the three-dimensional separation around a NACA65 blade in a decelerating channel flow was investigated experimentally. Effect of stagger angle of 14 deg. and 10 deg. on the channel flow was focused on. The experimental investigation by the five-hole probe showed that the accumulations of the low energy fluid was seen around the corner part and the overturning flow due to the secondary flow existed for 14 deg. of stagger angle, whereas the accumulations of the low energy fluid were seen at around midspan for 10 deg. of stagger angle. PIV measurement showed that various focus-type separations were seen in the flow for 10 deg. of stagger angle and three-dimensional vortex structure was considered by using a vortex filament.
Vortex Features in a Half-ducted Axial Fan with Large Bellmouth (Effect of Tip Clearance)
Shiomi, Norimasa,Kinoue, Yoichi,Setoguchi, Toshiaki,Kaneko, Kenji Korean Society for Fluid machinery 2011 International journal of fluid machinery and syste Vol.4 No.3
In order to clarify the features of tip leakage vortex near blade tip region in a half-ducted axial fan with large bellmouth, the experimental investigation was carried out using a 2-dimensional LDV system. Three sizes of tip clearance (TC) were tested: those sizes were 1mm (0.55% of blade chord length at blade tip), 2mm (1.11% of blade chord length at blade tip) and 4mm (2.22% of blade chord length at blade tip), and those were shown as TC=1mm, TC=2mm and TC=4mm, respectively. Fan characteristic tests and the velocity field measurements were done for each TC. Pressure - flow-rate characteristics and two-dimensional velocity vector maps were shown. The vortex trace and the vortex intensity distribution were also illustrated. As a result, a large difference on the pressure - flow-rate characteristics did not exist for three tip clearance sizes. In case of TC=4mm, the tip leakage vortex was outflow to downstream of rotor was not confirmed at the small and reference flow-rate conditions. Only at the large flow-rate condition, its outflow to downstream of rotor existed. In case of TC=2mm, overall vortex behaviors were almost the same ones in case of TC=4mm. However, the vortex trace inclined toward more tangential direction. In case of TC=1mm, the clear vortex was not observed for all flow-rate conditions.
Effect of Vortex Design on a Half-Ducted Axial Flow Fan (In the case of forced vortex design)
Kaji, Atsushi,Kinoue, Yoichi,Shiomi, Norimasa,Setoguchi, Toshiaki Korean Society for Fluid machinery 2018 International journal of fluid machinery and syste Vol.11 No.1
An improvement of the half-ducted axial flow fan design by applying the forced vortex design to the rotor blade was conducted by CFD. The quasi three-dimensional flow theory was applied for the half-ducted fan design, and the meridional flow was calculated by the method of streamline curvature. When the radial balance equations from hub to tip was solved, the vortex design was changed from the constant-whirl-velocity design to the forced vortex design in reference to our previous experimental results of the half-ducted fan's internal flow. The analysis of the three-dimensional internal flow fields of the half-ducted fan designed by adopting the forced vortex design was conducted. As a result of CFD, the efficiency ${\eta}$ of the fan was about 1-3 % larger at the flow rate coefficient ${\phi}$ of 0.158-0.343 than the constant-whirl-velocity design.
Effect of Vortex Design on a Half-Ducted Axial Flow Fan
Atsushi Kaji,Yoichi Kinoue,Norimasa Shiomi,Toshiaki Setoguchi 한국유체기계학회 2018 International journal of fluid machinery and syste Vol.11 No.1
An improvement of the half-ducted axial flow fan design by applying the forced vortex design to the rotor blade was conducted by CFD. The quasi three-dimensional flow theory was applied for the half-ducted fan design, and the meridional flow was calculated by the method of streamline curvature. When the radial balance equations from hub to tip was solved, the vortex design was changed from the constant-whirl-velocity design to the forced vortex design in reference to our previous experimental results of the half-ducted fan’s internal flow. The analysis of the three-dimensional internal flow fields of the half-ducted fan designed by adopting the forced vortex design was conducted. As a result of CFD, the efficiency η of the fan was about 1-3 % larger at the flow rate coefficient ø of 0.158-0.343 than the constant-whirl-velocity design.
Effect of Inlet Geometry on Fan Performance and Inlet Flow Fields in a Semi-opened Axial Fan
Liu, Pin,Shiomi, Norimasa,Kinoue, Yoichi,Setoguchi, Toshiaki,Jin, Ying-Zi Korean Society for Fluid machinery 2014 International journal of fluid machinery and syste Vol.7 No.2
In order to clarify the effect of inlet bellmouth size of semi-opened type axial fan on its performance and flow fields around rotor, fan test and flow field measurements using hotwire anemometer were carried out for 6 kinds of bellmouth size. As results of fan test, the shaft power curve hardly changed, even if the bellmouth size changed. On the other hand, the pressure-rise near best efficiency point became small with the bellmouth size decreasing. Therefore, the value of maximum efficiency became small as the bellmouth size decreased. As results of flow field measurements at fan inlet, the main flow region with large meridional velocity existed near blade tip when the bellmouth size was large. As bellmouth size became smaller, the meridional velocity at fan inlet became smaller and the one at outside of blade tip became larger. As results of flow field measurements at fan outlet, the main flow region existed near rotor hub side.