Nippon Steel and Sumikin Engineering

Engineering, Japan

Nippon Steel and Sumikin Engineering

Engineering, Japan
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Kishiki S.,Osaka Institute of Technology | Ene D.,Tokyo Institute of Technology | Yamada S.,Tokyo Institute of Technology | Terashima M.,Nippon Steel and Sumikin Engineering | And 2 more authors.
Journal of Structural and Construction Engineering | Year: 2014

Evaluation of bi-directional characteristics of base-isolation devices is a very important issue for base-isolated structures. The present paper focused on structural behavior and deformation capacity of U-shaped steel dampers under random bi-directional dynamic loadings. The major findings obtained from the test are summarized as follows: (1) the index J c proposed in the previous paper can evaluate the limitation of cumulative torsion until contact with connections under random bi-directional loadings; (2) damage evaluation with two indices D2 and J c leads to a conservative result under the random bi-directional loadings; (3) in addition to this, cumulative deformation due to the different orbits brings more conservative evaluation.


Handa T.,Kyushu University | Mii K.,Kyushu University | Sakurai T.,Kyushu University | Imamura K.,Nippon Steel and Sumikin Engineering | And 2 more authors.
Experiments in Fluids | Year: 2014

In the present study, the characteristics of supersonic rectangular microjets are investigated experimentally using molecular tagging velocimetry. The jets are discharged from a convergent-divergent rectangular nozzle whose exit height is 500 μm. The jet Mach number is set to 2.0 for all tested jets, and the Reynolds number Re is altered from 154 to 5,560 by changing the stagnation pressure. The experimental results reveal that jet velocity decays principally due to abrupt jet spreading caused by jet instability for relatively high Reynolds numbers (Re > ~450). The results also reveal that the jet rapidly decelerates to a subsonic speed near the nozzle exit for a low Reynolds number (Re = 154), although the jet does not spread abruptly; i.e., a transition in velocity decay processes occurs as the Reynolds number decreases. A supersonic core length is estimated from the streamwise distribution of the centerline velocity, and the length is then normalized by the nozzle exit height and plotted against the Reynolds number. As a result, it is found that the normalized supersonic core length attains a maximum value at a certain Reynolds number near which the transition in the velocity decay process occurs. © 2014 Springer-Verlag Berlin Heidelberg.


Nakamura Y.,Nippon Steel and Sumikin Engineering | Katsura T.,Hokkaido University | Nagano K.,Hokkaido University
Journal of Environmental Engineering (Japan) | Year: 2015

Field test of the Ground Source Heat Pump (GSHP) system applying variable water volume (VWV) control and multi-split heat pump has been carried out in order to demonstrate the effect of reduction of circulation pumps' electric power consumption. It was confirmed that the constant differential temperature control is practicable method as the VWV control method. As the result of field test, the GSHP system applying VWV control could reduce approximately 80% of circulation pumps' electric power consumption compared to the GSHP system applying constant water volume. Seasonal performance factor of the GSHP system was 4.51 and this result achieved the target value of more than 4.5. During the heating operation, seasonal performance factor of the GSHP system was 3.61 and the value was higher than the one of conventional system. In addition, it was shown that the decrease of system COP of GSHP system using antifreeze solution as heat carrier fluid is less than 15% compared to the one of GSHP system using water. © 2015, Architectural Institute of Japan. All rights reserved.


Suzuki H.,University of Tokyo | Shibata H.,University of Tokyo | Fujioka H.,Nippon Steel and Sumikin Engineering | Hirabayashi S.,University of Tokyo | And 2 more authors.
Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE | Year: 2013

Coupled rotor-floater response analysis is essentially important for the design of Rotor Nacelle Assembly (RNA) and floating support structure of Floating Offshore Wind Turbine (FOWT). The authors have developed an analysis code UTWind for analysis of the coupled structural response. Blades and floater are modeled as frame structure with beam elements. Lumped mass model is use for mooring. Aerodynamic load on blade is calculated by Blade Element Momentum Theory (BEM), and hydrodynamic load is calculated by Hooft's method, and Morison equation was modified to be applicable to cylindrical element with cross section with two axes of lines symmetry. The equations of motion of rotor, floater and mooring are solved in time domain by weak coupling algorithm. The numerical results by the code were compared with responses measured by experiment in wave and wind-and-wave coexistence field with/without blade pitch control and showed good agreement. Response by negative damping was reproduced by the code and showed good agreement with experiments. © 2013 by ASME.


Handa T.,Kyushu University | Miyachi H.,Mitsubishi Group | Kakuno H.,Nippon Steel and Sumikin Engineering | Ozaki T.,Kyushu University
Experiments in Fluids | Year: 2012

The mechanism behind cavity-induced pressure oscillations in supersonic flows past a deep rectangular cavity is not well understood despite several investigations having been carried out. In particular, the process by which the pressure wave is generated and the path of the pressure wave propagating inside the cavity remains unclear. In the present study, the pressure waves around a deep rectangular cavity over which nitrogen gas flows at a Mach number of 1.7 are visualized using the schlieren method. The length of the cavity is 14.0 mm. The depths of the cavity are selected as 20.0 and 11.7 mm, corresponding to length-to-depth ratios of 0.70 and 1.2, respectively. The pressure waves propagating inside as well as outside the cavity have been successfully visualized using a high-speed camera, and the propagation pattern of these waves is found to be different from that previously predicted by numerical simulation and from those expected in previous oscillation models. In addition, the pressure oscillation near the trailing edge of the cavity is also measured using semiconductor-type pressure transducers simultaneously with the capture of the schlieren images. As a result, the relationship between the shear-layer motion, pressure-wave generation, and pressure oscillation at the trailing edge of the cavity is clarified experimentally. © 2012 Springer-Verlag Berlin Heidelberg.


Yamaguchi T.,Nikken Sekkei Ltd. | Katsura T.,Hokkaido University | Nakamura Y.,Nippon Steel and Sumikin Engineering
Journal of Environmental Engineering (Japan) | Year: 2015

The authors established a technique for measuring calorie output from a variable refrigerant flow air conditioning system by applying the refrigerant enthalpy method. In this paper, the advantages of the measuring technique and its detailed estimation process of the calorie output are introduced. In addition, the measurement with water cooled variable refrigerant flow air conditioning system was carried out in order to confirm the accuracy of technique. In this actual measurement, it was shown that measuring the appropriate pressure of refrigerant in the heat pump is important to achieve the measurement accuracy. As the another results of actual measurement, the error of estimation values of heat quantity between the established technique and the conventional one is less than 20 % for cooling and heating, respectively. Therefore, the technique for measuring calorie output that the authors established has the high measurement accuracy. In addition, the authors suggested operation improvement method by analyzing measured values such as pressure, calorie output, electric power consumption and so on. As the results, it was confirmed that COPs is improved in the cooling period by lowering the high side pressure of refrigerant in the heat pump depending on the inlet water temperature in the primary side of the pump.


Fujishita K.,Tokyo Institute of Technology | Bal A.,University of Tokyo | Sutcu F.,Namik Kemal University | Matsui R.,Tokyo Institute of Technology | And 3 more authors.
Journal of Structural and Construction Engineering | Year: 2016

Strength and stiffness of panel and joint in non-diaphragm CHS-column to H-beam connection were experimentally investigated Herein, the panel means the cylindrical stub circumscribed by outer planes of the beam and the column, and the joint means the butt seam between the column wall and the beam end. Two types of specimen were tested: one is an X-shaped frame whose panel is subjected to shear, and the other is a 3-point bending specimen whose panel is free from shear. In result, the joint strength and stiffness are well predicted by the previously proposed formulae irrespective of the existence of shear in the panel, and the panel strength and stiffness are also well predicted by the well known formulae given for diaphragm connections. This suggests that the interaction between panel and joint of the non-diaphragm connection can be ignored in structural design.


Yamaguchl T.,University of Kitakyushu | Katsura T.,Hokkaido University | Nakamura Y.,Nippon Steel and Sumikin Engineering
Journal of Environmental Engineering (Japan) | Year: 2014

The authors established a technique for measuring heating or cooling output from a heat pump air conditioning system by applying the refrigerant enthalpy method. In this paper, advantages of the technique and estimation process of the heating or cooling output are introduced. In addition, field experiment with a water source heat pump unit was carried out to validate the established technique. In the experiment, the refrigerant saturation temperatures at inlet and outlet of compressor and compressor frequency, which are estimated in the technique, are firstly verified by comparing to measured values. As the result of experiments, it is confirmed that the established technique have possibility of omitting foundation of the pressure sensors and the measurement of compressor's frequency in the technique. As the another results of experiments, the error of estimation values of heat quantity between the established technique and the conventional one is less than 5 % for cooling and 7 % for heating. Therefore, the technique for heat quantity measuring that the authors established has the potential to become the new measuring method for the heat pump air conditioning system.


Jiao Y.,Tokyo University of Science | Yamada S.,Tokyo Institute of Technology | Ene D.,Tokyo Institute of Technology | Kobayashi R.,Tokyo University of Science | And 4 more authors.
AIJ Journal of Technology and Design | Year: 2015

U-shaped steel damper is a type of commonly-used damping device for seismically isolated structures. After earthquakes, it is necessary to quickly evaluate the damage of U-dampers to find out if they need to be replaced. However, current evaluation method can only be used when the deformation history of the U-damper is known. In this paper, a damage evaluation method based on the area covered by the recorded orbits of the base-isolated stories is proposed. The damage of the damper during aftershocks is proved to be small enough to be ignored. The conclusions of this paper are checked against experimental data.


Handa T.,Kyushu University | Miyachi H.,Mitsubishi Group | Kakuno H.,Nippon Steel and Sumikin Engineering | Ozaki T.,Nippon Steel and Sumikin Engineering | Maruyama S.,Kyushu University
AIAA Journal | Year: 2015

In this study, a feedback mechanism for supersonic deep-cavity flows is modeled. The model is developed on the basis of previous flow visualization results. In this model, two pressure waves play an important role in the feedback mechanism; one wave is generated at the trailing edge of the cavity owing to the motion of the shear layer, and the other wave is generated as a result of the third reflection of the former wave at the cavity bottom. The constants in the model are determined using the flow visualization results. The frequencies calculated in the model agree well with the dominant frequencies observed in experiments; in particular, the feedback mechanism responsible for deep-cavityinduced pressure oscillation is successfully clarified.

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