Faculty Profiles - TSUBOI Nobuyuki

Papers - TSUBOI Nobuyuki

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Numerical simulation on ignition with shock tube - Effect of reflected shock wave - Boundary layer at adiabatic wall interaction on ignition Reviewed

75 ( 1-2 ) 50 - 58 2014.01

Numerical simulation on H<inf>2</inf>-O<inf>2</inf> detonation induced by direct initiation near detonation limits Reviewed

75 ( 3-4 ) 99 - 105 2014.01

An analysis of the quantum effect on the thermodynamic and transport properties of cryogenic hydrogen using molecular dynamics method Reviewed

490 ( 1 ) 2014.01

A molecular dynamics study of nuclear quantum effect on the diffusion of hydrogen in condensed phase Reviewed

1618 950 - 953 2014.01

Numerical Study of Real Gas Effects on Shock Tube Problems at Supercritical Conditions Reviewed

MUTO Daiki, TSUBOI Nobuyuki, TERASHIMA Hiroshi

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN 12 ( 29 ) Po_2_39 - Po_2_44 2014.01

J0550204 An Analysis of Quantum Effect on the Transport Properties of Liquid Hydrogen using Molecular Dynamics Method

NAGASHIMA Hiroki, TSUDA Shinichi, TSUBOI Nobuyuki, KOSHI Mitsuo, HAYASHI Koichi, TOKUMASU Takashi

The Proceedings of Mechanical Engineering Congress, Japan ( The Japan Society of Mechanical Engineers ) 2014 ( 0 ) _J0550204 - -_J0550204- 2014.01

Language：Japanese Publishing type：Research paper (conference, symposium, etc.)

In this study, we conducted analysis of quantum effect of hydrogen molecules on the energy transport of liquid hydrogen using classical Molecular Dynamics (MD) and path integral Centroid MD (CMD) method. We performed MD simulation across a wide temperature region in the constant density and compared the thermal conductivity of each method. The thermal conductivity was calculated using non-equilibrium MD method. As a result, it was confirmed that CMD shows lower thermal conductivity than classical MD and this tendency is consistent with experimental data. Moreover, it was clarified that because of the change of intermolecular potential due to the quantum effect, the potential energy transport by molecular motion and the energy transport by intermolecular interaction decrease.

DOI： 10.1299/jsmemecj.2014._J0550204-

CiNii Article

Other Link： https://ci.nii.ac.jp/naid/110009943927

J0550104 Evaluation of the Density Fluctuation against the Diatomic Fluids around the Critical Points using Molecular Dynamics Simulation

IKAWA Shohei, TOKUMASU Takashi, TSUBOI Nobuyuki, TSUDA Shin-ichi

The Proceedings of Mechanical Engineering Congress, Japan ( The Japan Society of Mechanical Engineers ) 2014 ( 0 ) _J0550104 - -_J0550104- 2014.01

Language：Japanese Publishing type：Research paper (conference, symposium, etc.)

In this study, we investigated the density fluctuation of diatomic fluids around the critical points for evaluation of the principle of corresponding state. We used Molecular Dynamics (MD) simulation against the 2-Center Lennard-Jones (2CLJ) fluids for extraction of structure of fluctuation around the critical points. We evaluated the density fluctuation by two methods. One is the dispersion of number of molecules at certain domain as time-averaged quantity. The other is the calculation of static structure factor. As the results, in 2CLJ fluids that have shorter molecular elongations comparatively, the principle of corresponding state is satisfied because of the small difference in the fluctuation structure extracted by the present two methods.

DOI： 10.1299/jsmemecj.2014._J0550104-

CiNii Article

Other Link： https://ci.nii.ac.jp/naid/110009943922

G0510306 Three-Dimensional Numerical Study on Clarification of Self-Ignition Mechanism of High-Pressure Hydrogen Jet in a Tube

YOKOYAMA Akinori, ASAHARA Makoto, TSUBOI Nobuyuki

The Proceedings of Mechanical Engineering Congress, Japan ( The Japan Society of Mechanical Engineers ) 2014 ( 0 ) _G0510306 - -_G0510306- 2014.01

Language：Japanese Publishing type：Research paper (conference, symposium, etc.)

One of self-ignition mechanisms of high-pressure hydrogen jet occurs by vortex caused from instability. Several studies about self-ignition of high-pressure hydrogen spouted from a tube attached with a tank are reported. In this analysis, the numerical study is performed to find out mechanism of self-ignition of hydrogen jet in a tube with a 10mm in diameter connected to a high pressure tank of 9.0MPa. Hydrogen and air are mixed at their contact surface to yield vortices, and the mixture ignites because the high temperature and high pressure regions are yielded behind the precursor shock wave.

DOI： 10.1299/jsmemecj.2014._G0510306-

CiNii Article

Other Link： https://ci.nii.ac.jp/naid/110009943304

G0510305 Numerical Simulation of Three-Dimensional Flow Behavior Induced by Reflected Shock Wave-Boundary Layer Interaction

WAKABAYASHI Ryo, ASAHARA Makoto, TSUBOI Nobuyuki

The Proceedings of Mechanical Engineering Congress, Japan ( The Japan Society of Mechanical Engineers ) 2014 ( 0 ) _G0510305 - -_G0510305- 2014.01

Language：Japanese Publishing type：Research paper (conference, symposium, etc.)

At the reflected shock rear, a chemical reaction starts at a temperature and pressure constant static premixed gas conditions by filling reactive premixed gas in the shock tube, and reflects the shock wave in the pipe ends. Meyer and Oppenheim were classified into ignition two forms Mild Ignition and Strong Ignition, the start of the H2/O2 detonation due to the reflected shock wave. In order to ignite instantly in the tube cross-section of the entire near-wall reflection, Strong Ignition is a form ignition reaction theory. Mild Ignition is a firing mode hydrodynamic, under the influence of lambda shock wave generated by the mutual interference between the boundary layer and are reaching the ignition shock wave backward flow becomes multidimensional. Mark was revealed from the experiment due to the mutual interference between the boundary layer and the reflected shock, lambda shock wave to be formed in connection with this phenomenon. Thus, experiments by the reflected shock ignition is performed, there are cases in which ignition occurs is unexpected due to the interference of the reflected shock wave and boundary layer. In this study, we focus on the flow field due to the interference of the boundary layer and reflected shock, it is an object of the present invention to elucidate the flow three-dimensional.

DOI： 10.1299/jsmemecj.2014._G0510305-

CiNii Article

Other Link： https://ci.nii.ac.jp/naid/110009943303

G0510304 Three-Dimensional Numerical Analysis on Multi-Head Structure of Detonation Wave Front Propagating in Rectangular Tube

ASAHARA Makoto, NAGAO Tsuyoshi, TSUBOI Nobuyuki, HAYASHI Koinch

The Proceedings of Mechanical Engineering Congress, Japan ( The Japan Society of Mechanical Engineers ) 2014 ( 0 ) _G0510304 - -_G0510304- 2014.01

Language：Japanese Publishing type：Research paper (conference, symposium, etc.)

Three-dimensional numerical analysis using practical scale of the experiment is performed to obtain cellular structure in rectangular tube. As a result, transverse wave in three-dimensions moves in different direction comparing with two-dimensional structure at the point of propagation structure. Furthermore, each transverse wave affects to accelerate the propagation velocity in circumferential direction and makes unreacted gas pockets after transverse wave goes through each other.

DOI： 10.1299/jsmemecj.2014._G0510304-

CiNii Article

Other Link： https://ci.nii.ac.jp/naid/110009943302

G0510303 Numerical Study on Thrust Performance of Rotating Detonation Engine

YOSHIDA Wataru, ASAHARA Makoto, TSUBOI Nobuyuki

The Proceedings of Mechanical Engineering Congress, Japan ( The Japan Society of Mechanical Engineers ) 2014 ( 0 ) _G0510303 - -_G0510303- 2014.01

Language：Japanese Publishing type：Research paper (conference, symposium, etc.)

Study of detonation engine has been actively carried out in order to improve the thrust performance and expected to apply rocket engine. Even among them, rotating detonation engine has attracted attention. Many experiments have been performed, but in the experiments, varying the combustion chamber size is difficult. In this study, the numerical study is carried out to find out thrust performance with changing combustion chamber size.

DOI： 10.1299/jsmemecj.2014._G0510303-

CiNii Article

Other Link： https://ci.nii.ac.jp/naid/110009943301

806 Thrust Performance Estimation on Rotating Detonation Engine Using Two-dimensional Numerical Simulations : Effect of Grid Resolution on I_<sp>

WATANABE Yusuke, TSUBOI Nobuyuki, HARANO Takaya, KOJIMA Takayuki, HAYASHI A. Koichi

The Proceedings of Conference of Kyushu Branch ( The Japan Society of Mechanical Engineers ) 2014 ( 0 ) _806 - 1_-_806-2_ 2014.01

802 Numerical Study of Injector Geometry Effects on Cryogenic Coaxial Jet under Supercritical Conditions

MUTO Daiki, TSUBOI Nobuyuki, TERASHIMA Hiroshi

The Proceedings of Conference of Kyushu Branch ( The Japan Society of Mechanical Engineers ) 2014 ( 0 ) _802 - 1_-_802-2_ 2014.01

B213 A Study of the Density Fluctuation of Diatomic Fluids around the Critical Point by Molecular Dynamics Simulation

Ikawa Shohei, Tokumasu Takashi, Nobuyuki Tsuboi, Nagashima Hiroki, Tsuda Sin-ichi

The Proceedings of the Thermal Engineering Conference ( The Japan Society of Mechanical Engineers ) 2014 ( 0 ) _B213 - 1_-_B213-2_ 2014.01

Language：Japanese Publishing type：Research paper (conference, symposium, etc.)

In this study, we evaluated the density fluctuation of diatomic fluids around the critical point. We performed Molecular Dynamics (MD) simulation against 2-Center-Lenard-Jones (2CLJ) fluids that have molecular elongation as a parameter. We compared the density fluctuation of each fluid to evaluate the principle of corresponding state of density fluctuation. We evaluated the density fluctuation by dispersion of number of molecules, static structure factor, and intermediate scattering function. As the results, in 2CLJ fluids that have shorter molecular elongation comparatively, the principle of corresponding state of static fluctuation structure was satisfied.

DOI： 10.1299/jsmeted.2014._B213-1_

CiNii Article

Other Link： https://ci.nii.ac.jp/naid/110009938965

811 Three-dimensional Numerical Simulation on Unsteady Compressible Flow in Hybrid Rocket Engine : Effect of Turbulence Model

SAKAMOTO Mai, MUTO Daiki, TSUBOI Nobuyuki

The Proceedings of Conference of Kyushu Branch ( The Japan Society of Mechanical Engineers ) 2014 ( 0 ) _811 - 1_-_811-2_ 2014.01

808 Numerical Analysis of the Aerospike Nozzle for the Evaluation of Performance : Effect of Inner Nozzle Configuration

SHIBAO Masafumi, TSUBOI Nobuyuki, ITO Takashi

The Proceedings of Conference of Kyushu Branch ( The Japan Society of Mechanical Engineers ) 2014 ( 0 ) _808 - 1_-_808-2_ 2014.01

804 Numerical Simulation on Waveriders for Thermal Effects

URA Yusuke, ETOU Haruka, TSUBOI Nobuyuki, MARU Yusuke, FUJITA Kazuhisa

The Proceedings of Conference of Kyushu Branch ( The Japan Society of Mechanical Engineers ) 2014 ( 0 ) _804 - 1_-_804-2_ 2014.01

523 Molecular Dynamics Study for the Transport Phenomena of Oxygen in Primary Pores of Catalyst Layer in Polymer Electrolyte Fuel Cell

Deguchi Masashi, Fukushima Akinori, Tuboi Nobuyuki, Tokumasu Takashi

The Proceedings of Conference of Kyushu Branch ( The Japan Society of Mechanical Engineers ) 2014 ( 0 ) _523 - 1_-_523-2_ 2014.01

219 Numerical Study of the Flow Field over Compression Corner in Hypersonic Flow : Effect of Ramp Angle

KUROKAWA Kunihiko, TSUBOI Nobuyuki, KURAMOTO Takeshi

The Proceedings of Conference of Kyushu Branch ( The Japan Society of Mechanical Engineers ) 2014 ( 0 ) _219 - 1_-_219-2_ 2014.01

1404 Numerical Simulation of Ignition Mechanism by Shock Focusing into H_2-O_2 mixture

ASAHARA Makoto, MITANI Nana, TUBOI Nobuyuki

The Proceedings of the Fluids engineering conference ( The Japan Society of Mechanical Engineers ) 2014 ( 0 ) _1404 - 1_-_1404-2_ 2014.01

Language：Japanese Publishing type：Research paper (conference, symposium, etc.)

A reflected shock wave by focusing reflector is simulated using the Navier-Stokes equations with the detailed oxy-hydrogen reaction mechanism. Into the tube which has focusing end wall, ignition successes around focal point under the no-ignition condition at the flat wall. The shock focusing is one of effective way of detonation initiation. However, the ignition mechanism from shock focusing is not clear. In this study, we aim to indicate the ignition phenomena induced by shock focusing.

DOI： 10.1299/jsmefed.2014._1404-1_

CiNii Article

Other Link： https://ci.nii.ac.jp/naid/110009938781

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Papers - TSUBOI Nobuyuki