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
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. Source
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
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. Source
Suzuki A.,IDAJ Co. |
Ohnaka A.,Ube Industries |
Tano T.,Ube Industries |
Itokazu R.,IHI Corporation |
And 2 more authors.
Energy and Fuels
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. Source
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
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. Source
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
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. Source