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Author

Toshihiko Shakouchi

Bio: Toshihiko Shakouchi is an academic researcher from Mie University. The author has contributed to research in topics: Jet (fluid) & Nozzle. The author has an hindex of 10, co-authored 102 publications receiving 358 citations.


Papers
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Journal ArticleDOI
TL;DR: In this article, a new pneumatic type ultra fine classifier is proposed and the relation between the performance and the flow condition is investigated by flow visualization with the tuft grid and oil dot methods and the measurement of gas velocity.

29 citations

Journal ArticleDOI
TL;DR: In this paper, a 1/5 scale jet pump test loop for Boiling Water Reactor (BWR) was used and intensive tests were conducted focusing on the types of driving nozzles and shapes of the throat.
Abstract: Jet pumps, driven by a Primary-Loop Recirculation (PLR) Pump, have been widely used in Boiling Water Reactor (BWR) plants to recirculate the reactor core coolant. A jet pump consists of a driving nozzle, a bell-mouth, a throat and a diffuser. The improvement of the jet pump efficiency for BWR plants brings an economic advantage because it reduces the operating power cost of the PLR pump. In order to improve the efficiency of the BWR jet pump, a 1/5 scale jet pump test loop for BWR plant was used and intensive tests were conducted focusing on the types of driving nozzles and shapes of the throat. These test data were used for CFD flow analysis code verification. The analytical data showed good agreement with the test results. After the analytical model verification, improvement of jet pump efficiency was conducted. It was shown by the CFD analysis that the peak efficiency of the improved jet pump will be 36% with the tapered throat.

27 citations

Journal ArticleDOI
TL;DR: In this paper, the oscillation of a two-dimensional jet attaching to the wall is investigated under the periodic infinitesimal fluctuation in pressure within a bubble between the jet and the wall.
Abstract: The oscillation of a two-dimensional jet attaching to the wall is investigated under the periodic infinitesimal fluctuation in pressure within a bubble between the jet and the wall. The analysis, using a linearized equation of motion, shows that the amplitude of the oscillating jet increase along the jet axis and decreases with an increasing frequency of pressure fluctuation within a bubble. The resonance can not be found between the fluctuation of the pressure and the oscillation of the jet. The phase-lag tends to increase with an increasing frequency of pressure fluctuation. These results are in good agreement with the experimental ones.

26 citations

Patent
30 Mar 2010
TL;DR: In this article, a pressure adjusting tank is installed in a circulation path of a microbubble generator, and large size bubbles are floatingly separated and collected into an upper space in the tank.
Abstract: PROBLEM TO BE SOLVED: To solve the problems of a microbubble generator which is likely to cause bumping when non-microbubbles are delivered together with microbubbles, and which discharges to the atmosphere the non-microbubble gas, in generating gas microbubbles such as carbon dioxide, for example.SOLUTION: A pressure adjusting tank is installed in a circulation path of a microbubble generator. Large size bubbles are floatingly separated and collected into an upper space in the tank. A microbubble generating nozzle which sucks the gas in the upper space and returns it into a liquid as microbubbles is installed in the upper part of the pressure adjusting tank.

20 citations

Journal ArticleDOI
TL;DR: In this article, a hybrid scheme of a sixth order compact scheme in the streamwise direction and Fourier series in the cross section was used to simulate a mixture of two jets, where the distance between two jets was fixed at six times the jet diameter and the inclination angle of the jets was changed from 45 to 70 deg.
Abstract: In order to develop an efficient jet mixing method, direct numerical simulations of combined jets are carried out. The Reynolds number defined with a nozzle diameter is Re = 1 500. Spatial discretization is performed by adopting a hybrid scheme of a sixth order compact scheme in the streamwise direction and Fourier series in the cross section. The distance between two jets is fixed at six times the jet diameter, and the inclination angle of the jets is changed from 45 to 70 deg. The results reveal that the turbulence intensity increases with a decrease in the inclination angle and that the jet width increases via jet excitation. These findings suggest that the diverse requirements of jet mixing control can be satisfied by a flexible combination of jets.

15 citations


Cited by
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Journal ArticleDOI
TL;DR: In particular, the symmetry plane that exists between two parallel plane jets may appear to affect the flow field in much the same way as a solid wall does in a reattaching offset jet as discussed by the authors.
Abstract: Two parallel plane air jets and offset air jets have several common features such as the existence of a subatmospheric pressure region and the formation of a flow recirculation zone adjacent to the nozzle plate. In particular, the symmetry plane that exists between two parallel plane jets may appear to affect the flow field in much the same way as a solid wall does in a reattaching offset jet. It is obvious, however, that there are significant differences far downstream from the nozzles because the two parallel plane jets will combine to form a single free jet while the offset jet will develop into a wall jet. Differences in the near field between these two jet configurations with a separation ratio of 2.125 are examined here under identical initial flow exit conditions through laser Doppler anemometer measurements of the mean velocity components, turbulence intensities, and Reynolds shear stress. The results indicate that the wall exerts significant retarding and turbulence suppression effects on the offset jet in the flow development region. Through the use of comparisons, the interaction of two inner shear layers on both sides of the symmetry plane in two parallel plane jets results in a much more turbulent near field than that of the offset jet.

131 citations

Journal ArticleDOI
TL;DR: A review of the current status of computation of turbulent impinging jet heat transfer is presented in this paper, where the effects of different subgrid scale models, boundary conditions, numerical schemes, grid distribution, and size of the computational domain adopted in various large eddy simulations of this flow configuration are reviewed in detail.
Abstract: A review of the current status of computation of turbulent impinging jet heat transfer is presented. It starts with a brief introduction to flow and heat transfer characteristics of jet impinging flows considering the simplest jet impinging geometry: normal impingement of a single jet into a flat surface. Subsequently, a review of recent computational studies related to the same geometry is presented. The effects of different subgrid scale models, boundary conditions, numerical schemes, grid distribution, and size of the computational domain adopted in various large eddy simulations of this flow configuration are reviewed in detail. A review of direct numerical simulation of the same geometry is also presented. Further, some recent attempts in Reynolds-averaged Navier–Stokes modeling of impinging flows are also reviewed. A review of computation of other complex impinging flows is also presented. The review concludes with a listing of some important findings and future directions in the computation of impi...

130 citations

Journal ArticleDOI
TL;DR: In this paper, the authors analyzed the properties of microbubbles from the perspective of appli- cation, and the correlations to predict the volumetric mass transfer coef- ficient have been presented.
Abstract: Microbubble-based methods, in recent times, have been widely used for purification of water and wastewater. Microbubbles have several physicochemi- cal properties, which make them eminently suitable for wastewater treatment. In this review, these properties have been analyzed in detail from the perspective of appli- cation. Various types of microbubble generators and their operation principles have been discussed. The transport of gas into the aqueous phase has been explained, and the correlations to predict the volumetric mass transfer coef- ficient have been presented. Many practical applications using ozone, oxygen and air microbubbles, some of which are currently at various stages of commercialization, have been presented. Other important uses of microbubbles for wastewater treatment, namely, removal of fine solid particulate matter and oil, have also been discussed. In addition, directions for future research of microbubble technology and their potential applications have been identified.

120 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the effects of different nozzle structures on the performance of a steam ejector with five different nozzles, namely, conical, elliptical, square, rectangular and cross-shaped.

119 citations

Journal ArticleDOI
TL;DR: In this paper, the mean velocities and turbulence characteristics of a turbulent plane offset jet with a small offset ratio of 2.125 have been studied using laser Doppler anemometry (LDA).
Abstract: Mean velocities and turbulence characteristics of a turbulent plane offset jet with a small offset ratio of 2.125 have been studied using laser Doppler anemometry (LDA). Static pressure measurements highlight the importance of side plates in enhancing two-dimensionality of the jet. The spatial distributions of turbulence intensities and Reynolds shear stress show a high turbulence recirculating flow region close to the nozzle plate between the jet and the offset plate. The LDA results have been used to examine the capability of three different turbulence models (i.e. k–ɛ, RNG and Reynolds stress) in predicting the velocity field of this jet. While all three models are able to predict qualitatively the recirculation, converging and reattachment regions observed experimentally, the standard k–ɛ turbulence model predicts a reattachment length that best agrees with the experimentally determined value.

103 citations