Kōbe-shi, Japan
Kōbe-shi, Japan
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Suzuki A.,IDAJ Co. | Ohnaka A.,Ube Industries | Tano T.,Ube Industries | Itokazu R.,IHI Corporation | And 2 more authors.
Energy and Fuels | Year: 2012

An advanced simulator is newly developed to predict desulfurization behavior by direct injection of Ca fine particles in coal combustion furnaces. The Ca fine particles, the main component of which is CaCO3, are a byproduct of cement manufacturing process. This simulator is built on the coal combustion/gasification module based on the commercial computational fluid dynamics (CFD) software of STAR-CD V3.26. Regarding the desulfurization reaction model, it is based on two physical models of thermal decomposition reaction of CaCO3 and of desulfurization reaction by CaO. We improve both models in order to simulate desulfurization behavior of Ca fine particles in coal combustion furnaces. A case study is carried out with a bench scale experimental furnace. According to the comparison between calculated result and experimental one, this simulator can predict the tendency of the increase of desulfurization ratio with an increase of feeding rate of Ca fine particles and the influence of the temperature at injection part of Ca fine particles. Moreover, the calculated result shows that the desulfurization reaction does not finish in the boiler and it continues at the exhaust pipe, since the Ca fine particle's temperature in the pipe is still higher than 1073 K. As a consequence, this simulator well predicts the tendency of the desulfurization process successfully and can be used for improvement of the operation condition of the furnaces. © 2012 American Chemical Society.

Ishikawa S.,IDAJ Co. | Nosaka N.,BBS Japan Co.
Constitutive Models for Rubber IX - Proceedings of the 9th European Conference on Constitutive Models for Rubbers, ECCMR | Year: 2015

Aluminum Wheel is one of the critical components in order to improve convenience and safety of automobile vehicles. Therefore impact tests have been required for a guarantee of safety condition. SAE regulates the 13 degree lateral impact test, furthermore, Automobile makers require more rigorous test which is 90 degree vertical impact test. To achieve a higher level of design, we constructed CAE models which were analyzed by FEM both Implicit and Explicit methods, and also improved the accuracy of analysis results by comparing with the experiments. In this paper, we discussed the application of impact analysis of aluminum wheel with inflated tire. In addition, we investigated incompressible effect of tire material with Poisson’s ratio. The Finite element model consisted of aluminum wheel and tire structure. The tire structure model was naturally inflated with pressure by implicit analysis, and the results were imported to explicit analysis for the dynamical impact analysis afterward. © 2015 Taylor and Francis Group.

Gotoh S.,Chiba University | Kuboyama T.,Chiba University | Moriyoshi Y.,Chiba University | Hatamura K.,Hatamura Engine Research Office | And 3 more authors.
SAE International Journal of Engines | Year: 2013

HCCI combustion can realize low NOx and particulate emissions and high thermal efficiency. Therefore, HCCI combustion has a possibility of many kinds of applications, such as an automotive powertrain, general-purpose engine, motorcycle engine and electric generator. However, the operational range using HCCI combustion in terms of speed and load is restricted because the onset of ignition and the heat release rate cannot be controlled directly. For the extension of the operational range using either an external supercharger or a turbocharger is promising. The objective of this research is to investigate the effect of the intake pressure on the HCCI high load limit and HCCI combustion characteristics with blowdown supercharging (BDSC) system. The intake pressure (Pin) and temperature (Tin) were varied as experimental parameters. The intake pressure was swept from 100 kPa (naturally aspirated) to 200 kPa using an external mechanical supercharger. The experimental results showed that the maximum load successfully increased with increasing the intake pressure. The highest load in this study was 935kPa in IMEPg at the condition of 200 kPa in Pin and 32 ŶC in Tin. The maximum load of boosted BDSC-HCCI engine can be achieved comparable to the full load of naturally aspirated SI engine. In addition, for conditions with above 200 kPa in Tin, A/F and G/F could be almost the same. The comparison of heat release rate between with and without BDSC showed that the peak value of heat release rate decreased and the combustion duration was prolonged with BDSC by thermal stratification. Not only the pressure rise rate but also the peak cylinder pressure could be reduced by BDSC system. Moreover, the intake temperature was decreased while maintaining the conditions of G/F and intake pressure to investigate the intake temperature on heat release. The results showed that the dP/dθ max is reduced with Tin less than 50 ŶC. © 2013 SAE Japan and © 2013 SAE International.

Bota J.,OGINO KOGYO Co. | Kumagai T.,IDAJ Co. | Kuboyama T.,Chiba University | Hatamura K.,Hatamura Engine Research Office Ltd.
SAE International Journal of Engines | Year: 2013

The variable valve lift and duration (in the following: VVLD) devices, some have been mass-produced already in the world, are necessary to be assembled with the variable cam phaser (in the following: VCP) to optimize open and close valve timing. On the other hand, with the variable valve phase and lift (in the following: VVPL) mechanism, the valve event is advanced with decreasing the valve lift and duration. Hence, no additional VCP is required when using the VVPL for throttle-less operation. A new VVPL has been developed as a mechanical, swing-cam actuation mechanism. The mechanisms of the conventional production VVLD devices are investigated and the functional analysis of the possible mechanisms is carried out to identify and design a simple mechanism for the new VVPL. The designed VVPL system is capable of continuously varying the valve lift from 0 mm to 10 mm, with the higher valve lift for any of the given duration. CAE oriented study, conducted before the production of the prototype, predicted the unexpected problems of the system at the design stage. By the multi-body dynamic simulation, predicting the dynamic behavior of the system, the requirement for the design to obtain the stable operation in the entire operation range was clarified. The trial manufactured VVPL was tested on the 4-cylinder test bench after the single cylinder test, and successfully operated up to 7000rpm of engine speed. The accuracy of the multi-body dynamic simulation was evaluated with the measured dynamic behavior. It was found that the high speed limitation of the system was sufficiently predicted by the multi-body simulation. Following the functional test, the newly designed VVPL system was installed into the 4-cylider gasoline engine and its effect on fuel efficiency was evaluated on the firing test bench. As a result, a large improvement in fuel efficiency was obtained with the developed VVPL system, as expected. Copyright © 2013 SAE International.

Sato M.,Japan Aerospace Exploration Agency | Aono H.,Japan Aerospace Exploration Agency | Yakeno A.,Japan Aerospace Exploration Agency | Nonomura T.,Japan Aerospace Exploration Agency | And 5 more authors.
AIAA Journal | Year: 2015

A substantial number of large-eddy simulations are conducted on separated flow controlled by a dielectric barrier discharge plasma actuator at a Reynolds number of 63,000. In the present paper, the separated flow over a NACA 0015 airfoil at an angle of attack of 12 deg, which is just poststall, is used as the base flow for separation control. The effects of the location and operating conditions of the plasma actuator on the separation control are investigated by a parametric study. The control effect is evaluated based on the improvement of not only the lift coefficient but also the drag coefficient over an airfoil. The most effective location of the plasma actuator for both lift and drag improvement is precisely confirmed to be upstream of the natural separation point. Even a low burst ratio is found to be sufficient to obtain the same improvements as the cases with a high burst ratio. The effective nondimensional burst frequency F+ is observed at 4 ≤ F+ ≤ 6 for the improvement in the lift coefficient and at 6 ≤ F+ ≤ 20 for that in the drag coefficient. The lift/drag ratio shows a clear peak at 6 ≤ F+ ≤ 10. To clarify the mechanism of the laminar-separation control, the effect of a turbulent transition is investigated. There is a clear relationship between the separation control effect and the turbulent transition at the shear layer. An earlier and smoother transition case shows greater improvements in the lift and drag coefficients. Flow analyses show that the cases with early and smooth turbulent transition can attach the separated flow further upstream, resulting in a higher suction peak of the pressure coefficient. In addition, another mechanism of the separation control is observed in which the lift coefficient is improved, not by the reattachment through the turbulent transition but by the large-scale vortex shedding induced by the actuation. It is possible to separate these two dominant mechanisms based on the effect of the turbulent transition on the separation control. Copyright © 2014 by Makoto Sato, Koichi Okada, Kengo Asada, Hikaru Aono, Aiko Yakeno, Taku Nonomura, and Kozo Fujii. Published by the American Institute of Aeronautics and Astronautics, Inc.

Sato M.,Japan Aerospace Exploration Agency | Nonomura T.,Japan Aerospace Exploration Agency | Okada K.,Ryoyu Systems Co. | Okada K.,IDAJ Co. | And 8 more authors.
Physics of Fluids | Year: 2015

Large-eddy simulations have been conducted to investigate the mechanisms of separated-flow control using a dielectric barrier discharge plasma actuator at a low Reynolds number. In the present study, the mechanisms are classified according to the means of momentum injection to the boundary layer. The separated flow around the NACA 0015 airfoil at a Reynolds number of 63 000 is used as the base flow for separation control. Both normal and burst mode actuations are adopted in separation control. The burst frequency non-dimensionalized by the freestream velocity and the chord length (F+) is varied from 0.25 to 25, and we discuss the control mechanism through the comparison of the aerodynamic performance and controlled flow-fields in each normal and burst case. Lift and drag coefficients are significantly improved for the cases of F+ = 1, 5, and 15 due to flow reattachment associated with a laminarseparation bubble. Frequency and linear stability analyses indicate that the F+ = 5 and 15 cases effectively excite the natural unstable frequency at the separated shear layer, which is caused by the Kelvin-Helmholtz instability. This excitation results in earlier flow reattachment due to earlier turbulent transition. Furthermore, the Reynolds stress decomposition is conducted in order to identify the means of momentum entrainment resulted from large-scale spanwise vortical structure or small-scale turbulent vortices. For the cases with flow reattachment, the large-scale spanwise vortices, which shed from the separated shear layer through plasma actuation, significantly increase the periodic component of the Reynolds stress near the leading edge. These large-scale vortices collapse to small-scale turbulent vortices, and the turbulent component of the Reynolds stress increases around the large-scale vortices. In these cases, although the combination of momentum entrainment by both Reynolds stress components results in flow reattachment, the dominant component is identified as the turbulent component. This indicates that one of the effective control mechanisms for laminar separation is momentum entrainment by turbulent vortices through turbulent transition. © 2015 AIP Publishing LLC.

Atsushi K.,IDAJ Co. | Kentaro Y.,Kyoto University | Takayuki Y.,Kyoto University | Kazuhiro I.,Kyoto University | Shinji N.,Kyoto University
Transactions of the Japan Society for Computational Engineering and Science | Year: 2015

This paper proposes a topology optimization method for steady state incompressible viscous flow problems, based on the finite volume method incorporating level set boundary expressions. The optimization problem is formulated to minimize the power dissipation under a volume constraint. The optimization algorithm is developed based on this formulation, using the adjoint variable method for the sensitivity analysis. The update scheme for design variables uses a reaction-diffusion equation derived from the concept of the topological derivative. Here, the finite volume method is applied to solve the governing, adjoint, and reaction-diffusion equations because it is more suitable than the finite element method for solving relatively large-scale problems that include higher Reynolds numbers. Several numerical examples are provided to confirm the utility of the proposed method. © 2015, Japan Society for Computational Engineering and Science. All rights reserved.

Itoh A.,Mitsubishi Motors | Wang Z.,Mitsubishi Motors | Nosaka T.,IDAJ Co. | Wada K.,IDAJ Co.
SAE Technical Papers | Year: 2016

Without engine noise, the cabin of an electric vehicle is quiet, but on the other hand, it becomes easy to perceive refrigerant-induced noise in the automotive air-conditioning (A/C) system. When determining the A/C system at the design stage, it is crucial to verify whether refrigerant-induced noise occurs in the system or not before the real A/C systems are made. If refrigerant-induced noise almost never occurs during the design stage, it is difficult to evaluate by vehicle testing at the development stage. This paper presents a 1D modeling methodology for the assessment of refrigerant-induced noise such as self-excitation noise generated by pressure pulsation through the thermal expansion valve (TXV). The GT-SUITE commercial code was used to develop a refrigerant cycle model consisting of a compressor, condenser, evaporator, TXV and the connecting pipe network. In order to simulate the vertical motion of the valve by the refrigerant fluid force, every component such as ball valve, spring and friction of TXV was modeled in detail. A spring-mass-damper model was used to calculate the balance of forces acting on the valve. A ball valve model was also used to calculate fluid forces passing through the valve in the detailed model. Finally, flow rate, thermal and hysteresis characteristics of TXV were calibrated to match the TXV performance data. Using this model, the 1D Navier-Stokes equations were solved by an explicit solver with a small time step to predict the behavior of refrigerant pressure pulsations. This paper discusses the correlation of the simulation results with measured data at vehicle level and also compares calculated pressure pulsations in the refrigerant cycle with different TXVs. © Copyright 2016 SAE International.

Ishikawa S.,IDAJ Co. | Aihara H.,IDAJ Co.
Constitutive Models for Rubber VIII - Proceedings of the 8th European Conference on Constitutive Models for Rubbers, ECCMR 2013 | Year: 2013

Boundary value problems involving contact are of great importance in industry related to mechanical and civil engineering, but also in environmental and medical applications. While the rubber materials so called elastomer admit to deform large deformation in a practical manner, and its deformation behavior is usually caused under the contact condition. In order to analyze the strict contact phenomenon by using FE-simulation, it is important to select the precise computational contact mechanics procedure. This paper refers typical contact numerical models, and illustrates the FE-simulation result of the hollow rubber ball which has enormous difficulty of contact condition. © 2013 Taylor & Francis Group.

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