MATSUI Jun

Affiliation

Faculty of Engineering, Division of Systems Research

Job Title

Professor

Research Fields, Keywords

Fluid Dynamics, Fluid Machinery

Mail Address

E-mail address



The Best Research Achievement in Research Career 【 display / non-display

  • 【Published Thesis】 Similarity on Occurrence Condition of Vortexes in Pump Sumps  2016.03

    【Published Thesis】 Numerical Study on the Internal Flow and Torque in Variable Capacity Type Fluid Coupling  2008.03

    【Published Thesis】 Study on Control of Axial Thrust in Centrifugal Pump by User of J-Groove  2008.02

The Best Research Achievement in the last 5 years 【 display / non-display

Graduating School 【 display / non-display

  •  
    -
    1988

    The University of Tokyo   Faculty of Engineering   Department of Mechanical Engineering   Graduated

Graduate School 【 display / non-display

  •  
    -
    1993

    The University of Tokyo  Graduate School, Division of Engineering  Doctor Course  Completed

Degree 【 display / non-display

  • Doctor of Engineering -  The University of Tokyo

Campus Career 【 display / non-display

  • 2009.01
    -
    Now

    Duty   Yokohama National UniversityFaculty of Engineering   Division of Systems Research   Professor  

  • 2007.04
    -
    2008.12

    Duty   Yokohama National UniversityFaculty of Engineering   Division of Systems Research   Associate Professor  

  • 2001.04
    -
    2007.03

    Duty   Yokohama National UniversityFaculty of Engineering   Division of Systems Research   Associate Professor  

  • 1996.04
    -
    2001.03

    Duty   Yokohama National UniversitySchool of Engineering   Associate Professor  

  • 1993.04
    -
    1996.03

    Duty   Yokohama National UniversitySchool of Engineering   Lecturer  

display all >>

Field of expertise (Grants-in-aid for Scientific Research classification) 【 display / non-display

  • Fluid engineering

 

Research Career 【 display / non-display

  • study on turbomachinery

    Project Year:  -   

Papers 【 display / non-display

  • Specific Internal Flow in Balancing Hole

    YAMASHITA Yosuke, MATSUI Jun, OKUBO Atsushi

    Turbomachinery ( Turbomachinery Society of Japan )  47 ( 12 )   723 - 729   2020.03  [Refereed]

    Joint Work

     View Summary

    <p>In order to research the discharge coefficient of a balancing hole <i>C<sub>d</sub></i> for a wide range of axial flow velocity <i>v</i> in the hole and rotational speed <i>u</i>, we carried out CFD simulations. Some of the results and the reported experimental data agree within the difference of about 5.3% on the pressure difference of the hole. Flow in a balancing hole is influenced by not only <i>v</i> but also <i>u</i>. Therefore the parameter <i>v</i>/<i>u</i> is considered as an important parameter of <i>C<sub>d</sub></i>. Furthermore, for very low range of <i>v</i>/<i>u</i>, we found a rare flow situation with S-shaped streamlines. Due to the strong pumping effect by rotating disk, <i>C<sub>d</sub></i> is greatly different in this region.</p>

    DOI CiNii

  • Suction Vortices in a Pump Sump-Their Origin, Formation, and Dynamics

    Yamade Yoshinobu, Kato Chisachi, Nagahara Takahide, Matsui Jun

    JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME   142 ( 3 )   031110-1 - 031110-26   2020.03  [Refereed]

    Joint Work

    Web of Science DOI

  • LARGE EDDY SIMULATION OF A SUBMERGED VORTEX IN A SIMPLIFIED COMPUTATIONAL MODEL

    Yamade Yoshinobu, Kato Chisachi, Nagahara Takahide, Matsui Jun

    PROCEEDINGS OF THE ASME/JSME/KSME JOINT FLUIDS ENGINEERING CONFERENCE, 2019, VOL 3B   3B   2019.11  [Refereed]

    Joint Work

    Web of Science DOI

  • Flow structure of a submerged vortex in a pump sump

    YAMADE Yoshinobu, KATO Chisachi, NAGAHARA Takahide, MATSUI Jun

    Transactions of the JSME (in Japanese) ( The Japan Society of Mechanical Engineers )  85 ( 878 )   19 - 00294-19-00294   2019.10  [Refereed]

    Joint Work

     View Summary

    <p>The flow structures of a submerged vortex that appears in a model pump sump have been fully clarified by performing large eddy simulation (LES) of a model vortex in a simplified computational model. The computational model had a sufficiently fine grid that could resolve the vortex core. The model sump is composed of a 2,500 mm-long water channel of rectangular cross section with a width of 300 mm and a water height of 150 mm and a vertical suction pipe with a 100 mm diameter installed at its downstream end. Our previous large eddy simulations (LES), which used approximately 2 billion grids and were applied to the whole pump sump, has fully clarified the origin and formation mechanism of a submerged vortex and an air-entrained vortex. In these computations, however, the static pressure in the vortex core decreased by only 5 kPa at a channel velocity of 0.37 m/s. The decrease in the static pressure was far smaller than the one for which one can expect initiation of cavitation in the vortex core. In the corresponding experiment, however, appearance of a submerged vortex was confirmed by the occurrence of cavitation in the vortex core. Therefore, the decrease in the static pressure is most likely to be underpredicted in our previous LES. Insufficient grid resolution was assumed to be one of the reasons for this underprediction. In the present study, LES with a sufficiently fine grid was applied to a simplified computational model that represents the stretch of a submerged vortex under a constant acceleration of the vertical velocity. Vertical and tangential velocities obtained by averaging those profiles of a submerged vortex computed in the previous LES were prescribed at the bottom wall of the computational domain as the inflow boundary conditions. In the present LES, the static pressure has decreased by more than 100 kPa. In addition, parametric studies with different initial swirl numbers varied from 0.08 to 10.9 have fully clarified the behavior of a submerged vortex. It is found that a strong submerged vortex appears only at a relatively small range of the swirl-number from 0.8 to 2.</p>

    DOI CiNii

  • Formation mechanism of suction vortices in a pump sump

    YAMADE Yoshinobu, KATO Chisachi, NAGAHARA Takahide, MATSUI Jun

    Transactions of the JSME (in Japanese) ( The Japan Society of Mechanical Engineers )  85 ( 875 )   19 - 00072-19-00072   2019.07

    Joint Work

     View Summary

    <p>The origin and formation mechanism of a submerged vortex and an air-entraining vortex have been fully clarified by large-eddy simulation (LES) that used approximately 2 billion hexahedral elements with maximum resolution of 0.255 mm and was applied to the internal flows of a model pump sump. The model pump sump is composed of a 2,500 mm-long water channel of rectangular cross section with a width of 300 mm and a water depth of 100 mm and a vertical suction pipe with a 100 mm diameter installed at its downstream end with an offset of 10 mm from the centerline of the rectangular channel. At the upstream end of the channel, a uniform velocity of 0.37 m/s is given. LES with different wall boundary conditions have revealed that the origin of a submerged vortex is the mean shear of the approaching boundary layers that develop on the bottom and side walls of the pump sump. From detailed investigations of LES computed for a long time period of 16 seconds have revealed that deviation of the mean flow that approaches the suction pipe triggers conversion of the axis of the vorticity that was originally aligned to the lateral direction in the approaching boundary layers to that aligned to the vertical direction. The local acceleration of the vertical flow stretches the afore-mentioned vertical vortex, which results in formation of a submerged vortex. The separated flows downstream of the suction pipe generate vertical vorticity, and forms an air-entraining vortex when such a vortex is sucked into the suction pipe. Computations with a different bellmouth height and a different water-surface height have supported the above mentioned origin and formation mechanism of these vortices.</p>

    DOI CiNii

display all >>