| 1. |
Elsayed Abdelhameed, Hiroshi Tashima, Experimental investigation on methane inert gas dilution effect on marine gas diesel engine performance and emissions
, Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 10.1080/15567036.2022.2067603, 44, 2, 3584-3596, 2022.04. |
| 2. |
Takuya Wakasugi, Daisuke Tsuru, Hiroshi Tashima , Influences of the pre-chamber orifices on the combustion behavior in a constant volume chamber simulating pre-chamber type medium-speed gas engines, Combustion Engines, https://doi.org/10.19206/CE-148171, 3-13, 2022.04. |
| 3. |
T. Thiripuvanam, H. Tashima, D. Tsuru, Air Entrainment and Combustion Process of High-Pressure Gas Jet in Gas Direct Injection Engines, Proc. the 8th International Symposium COMODIA 2017, C-304, 2017.07. |
| 4. |
H. Tashima, D. Tsuru, Y. Shintani, Air Entrainment of High Pressure Methane Gas and Effects of Nozzle Diameter and Injection Pressure, Proc. ILASS-Asia, Paper No. 143, 2016.11. |
| 5. |
H. Tashima, D. Tsuru, Methane Slip Reduction from Marine Gas Engines by Stratified Oxygen Concentration using Gas Permeation Membrane, Proc. CIMAC 2016 Helsinki, Paper No. 162, 2016.06. |
| 6. |
Hiroshi Tajima, Daisuke TSURU, Ryosuke Ishibashi, Study on Spray Developing Process under Pressurized Flow Field in Closed-Circuit Wind Tunnel, International Journal of Mechanical Engineering and Automation, 2, 2, 79-88, 2015.02, Interaction between a spray and the surrounding air is a key factor for the CFD codes simulating direct injection engines since spray penetration and droplet breakup have their source from the relative velocity between the droplets and the ambient flow. It applies especially to the sprays in large marine diesels which are often injected nearly parallel to a swirl flow to promote their penetration and distribution inside the large combustion chamber. Various sub-models in spray simulations, however, have been developed for smaller engines where the sprays are injected orthogonally into swirling in-cylinder gas. This may lead to obscurity in the spray prediction in large diesels. Practical and well-founded spray models are definitely needed in the field, but a lack of experimental information keeps it difficult to derive and validate such models. In this study, a diesel nozzle of a single injection hole was inserted into a channel of a closed-circuit wind tunnel, which has a cross-section of 50 mm ×50 mm and realizes maximum free stream velocity of 22 m/s under air pressure of 1.1 MPa. The spray was injected parallel to the tunnel stream windward or leeward, and its development was recorded by a high-speed camera. The measurement results showed the free stream velocity has significant effects both on the spray penetration and on the spray cone angle. Although the breakup process near the nozzle exit showed less dependency on the ambient flow, child droplets detached from an outer edge of the everted spray tip were observed to impinge on the liquid column of the spray body. Numerical reproduction of the spray developing process inside the ambient flow was tried via a KIVA-3V code based on the observation results.. |
| 7. |
K. Komada, H. Tajima, D. Tsuru, D. Sakaguchi, H. Ueki, Effect of Needle Lift on Atomization in Diesel Fuel Spray, Proc. THIESEL 2014, Paper A.2.2, 2014.09. |
| 8. |
H. Tashima, D. Tsuru, Methane Slip Reduction from Natural Gas Engines by Oxygen Stratification using Gas Permeation Membrane, Proc. THIESEL 2014, P-70, 2014.09. |
| 9. |
R. Ishibashi, D. Tsuru, H. Tashima, Effects of ambient pressure and temperature on penetration of a high compressed gas jet in high density conditions, Proc. the 26th European Conference on Liquid Atomization and Spray Systems, Paper No. 229, 2014.09. |
| 10. |
D. Tsuru, R. Ishibashi, H. Tashima, The investigation of air entrainment and development of diesel-like gas jet under engine condition, Proc. the 26th European Conference on Liquid Atomization and Spray Systems, Paper No. 296, 2014.09. |
| 11. |
Keisuke Komada, Hiroshi Tajima, Daisaku Sakaguchi, Hironobu Ueki, Masahiro Ishida, Study on Simulation of Diesel Fuel Spray Based on L2F Measurement, Proceedings of 16th Annual Conference of ILASS-Asia, 83-86, 2013.12. |
| 12. |
Hiroshi Tajima, Daisuke TSURU, Reduction of Methane Slip from Gas Engines by O2 Concentration Control using Gas Permeation Membrane, Proceedings of SAE/KSAE 2013 PFL Meeting, 1-8, 2013.10. |
| 13. |
Hiroshi Tajima, Daisuke TSURU, Ryosuke Ishibashi, Komada Keisuke, Investigation of Spray Combustion with Fuel-Water Emulsification under Exhaust Gas Recirculation using Detailed Visualization and Spray Modelling, Proceedings of 25th ILASS Europe 2013, 1-7, 2013.09. |
| 14. |
Keisuke Komada, Takashi Yamada, Hiroshi Tajima, Daisaku Sakaguchi, Hironobu Ueki, Masahiro Ishida, Study on Cyclic Variation in near-Nozzle Region of Diesel Spray by L2F, Proceedings of 25th ILASS Europe 2013, 1-10, 2013.09. |
| 15. |
Keisuke Komada, Hiroshi Tajima, Daisaku Sakaguchi, Hironobu Ueki, Masahiro Ishida, Relation between Tip Penetration and Droplet Size of Diesel Spray, COLL-TP-00351, 139-148, 2013.05. |
| 16. |
Hiroshi Tajima, Daisuke TSURU, Potential Investigation of PCCI Combustion as NOx Reduction Measure at Low-load Operation with Low-CN LCO Fuel, Proceedings of 27th CIMAC World Congress on Combustion Engines, 1-10, 2013.05. |
| 17. |
Dino Imhof, Daisuke TSURU, Hiroshi Tajima, Koji Takasaki, High-Pressure Natural Gas Injection (GI) Marine Engine Research with a Rapid Compression Expansion Machine, Proceedings of 27th CIMAC World Congress on Combustion Engines, 1-11, 2013.05. |
| 18. |
Hiroshi Tajima, 加藤 寿子, Daisuke TSURU, Ryosuke Ishibashi, Study on Spray Propagation under Pressurized Flow Field in Circuit Wind Tunnel, Proceedings of ICLASS 2012, Poster I-1-Poster I-8, 2012.09. |
| 19. |
Daisuke TSURU, 加藤 寿子, Hiroshi Tajima, Numerical and Experimental Study of Reduction of NOx on Diesel Combustion by Using Water Injection Systems, Proceedings of ICLASS 2012, Combustion II-1-Combustion II-8, 2012.09. |
| 20. |
Keisuke Komada, Daisuke Sakaguchi, Hiroshi Tajima, Hironobu Ueki, Masahiro Ishida, Effect of Ambient Pressure on Breakup of Droplets near Diesel Injector Nozzle , Proceedings of THIESEL 2012, Fuel Injection & Sprays (II)-3-1-Fuel Injection & Sprays (II)-3-11, 2012.09. |
| 21. |
Daisuke TSURU, Dino Imhof, Ryosuke Ishibashi, Hiroshi Tajima, PCCI Combustion as NOx Reduction Measure for Marine Engines by Spray Distribution Control and LCO Fuel, Proceedings of THIESEL 2012, Poster-1-Poster-3, 2012.09. |
| 22. |
Dino Imhof, 青柳 陽彦, Hiroshi Tajima, Koji Takasaki, Combustion and emission formation of gasoil and LCO (light cycle oil) water-in-fuel emulsions in nitrogen enriched air, Proceedings of 8th International Symposium COMODIA 2012, 188-193, 2012.07. |
| 23. |
Hiroshi Tajima, Daisuke TSURU, 川内 智詞, Ryosuke Ishibashi, Analysis of PCCI Combustion of Light Cycle Oil Reducing NOx Emission from Large Marine Engines, Proceedings of 8th International Symposium COMODIA 2012, 422-427, 2012.07. |
| 24. |
青柳 陽彦, 加藤 寿子, 川内 智詞, Daisuke TSURU, Hiroshi Tajima, Study on Spray Propagation in Pressured Following-wind Field of Circuit Wind Tunnel, Proceedings of ILASS-Asia 2011 15th Annual Conference on Liquid Atomization and Spray Systems-Asia, pp.355-360, 2011.10, Spray breakup has been one of the most obscure processes around practical CFD codes for diesel simulations because their breakup models are more calculative and adjustable tools in tuning the calculation results. Practical also well-founded breakup models are definitely needed, but a lack of experimental information keeps it difficult to derive such models and to validate them in objective basis. In this study, a diesel injection nozzle of a single hole was inserted into a channel of a circuit wind tunnel capable of wind speed up to 22m/s under 1.1MPa. The spray was injected parallel to the wind stream equivalent to swirling in-cylinder gas motion, and its propagation and breakup process near the nozzle exit was magnified and digitally recorded by a high-speed camera. Lower injection pressure was intentionally applied to control the relative speed between the spray and the ambient air. The measurement results showed the wind velocity had significant effects on surface breakup. Qualitative and quantitative comparisons with simulation results were also demonstrated using a KIVA-3V code. Although selected sub models were rather standard ones in large engine simulations, it proved to fail to predict the spray penetrations especially in the early stage of spray propagation.. |
| 25. |
Dino Imhof, Hiroshi Tajima, Koji Takasaki, Yudai Kawafuchi, Experimental Study of Abnormal Combustion and Ignition Delay in Dual Fuel Type Gas Engine Combustion, Proceedings of ISME KOBE 2011 9th International Symposium on Marine Engineering, pp.A3-4_1-6, 2011.10, Dual fuel and gas burning engines are emerging solutions to decrease C02 and NOx and to eliminate SOx emissions simultaneously. However, the thermal efficiency is seriously restricted by the occurrence of abnormal combustion with excessive in-cylinder pressure rise.
A Rapid Compression-Expansion Machine (RCEM), built on the basis of a single cylinder gas engine, enabled precise visualization of combustion processes through its large observation view.
The negative effect of lubrication oil vapor, causing abnormal combustion, was visualized, and the correlation between flame kernels and growth rate of burning area are shown. In addition, the mixture temperature was identified as a key element.
Moreover, ignition delay of diesel fuel pilot injection in gas-air mixture was visualized and the significant longer ignition delay in dual fuel type combustion, compared to fuel spray in air, was studied. Finally, the correlation between ignition delay and gas-air mixture ratio was analyzed.. |
| 26. |
Hiroshi Tajima, Satoshi Kawauchi, Haruhiko Aoyagi, Norihiko Kimura, Effects of Oxygen Dilution of Charged Air on Combustion and NOx Emission of Low-Speed Diesel Engines, Proceedings of ISME KOBE 2011 9th International Symposium on Marine Engineering, pp.C7-2_1-6, 2011.10, IMO tier III NOx regulations prove to be a tough goal for marine diesels while several in-engine NOx reducing measures like EGR, SAM or NHM (Nitrogen Enrichment / Humidification) are earnestly being investigated. It has become clear that there consistently exists a positive correlation between oxygen concentration in charged gas into cylinders and NOx emission from engines. Effects of such charged air dilution on combustion process should be clarified to get the limit of any single reduction measure or any combination of other wet technologies. In this study, a visual Rapid Compression-Expansion Machine (RCEM) was introduced to capture the effects of oxygen dilution on combustion temperature combined with water-emulsified fuel injection. By supplying artificial air of reduced oxygen and increased nitrogen, the grounds of NOx emission reduction were successfully and qualitatively evaluated. Simulation results by an engine performance simulator and KIVA-3V code also gave corroborative support to those measurement results.. |
| 27. |
Daisuke Tsuru, Hisako Kato, Satoshi Kawauchi, Hiroshi Tajima, Experimental Study on Combustion Characteristics of Direct Water Injection with Double-Needle Type Injector, Proceedings of ISME KOBE 2011 9th International Symposium on Marine Engineering, pp.C7-2_1-6, 2011.10, Direct water injection (DWI) has been recognized as an effective measure reducing NOx emissions from medium-speed marine diesels. Since a double-needle type injector is favorably used in the DWI system thanks to its easier installation compatible with normal injection system, numerous and immiscible droplet collisions should happen inside the merging sprays from closely-located injection holes for water and fuel. Authors had developed the new collision models for simulating the complicated colliding behavior of these immiscible droplets, but the model validation is yet to be done especially in the spray combustion phase because of lack of parametric engine experiments using an actual DWI system. In this study, spray propagation and combustion process of a DWI system with a double-needle type injector was observed in detail using a Rapid Compression and Expansion Machine (RCEM). The effective strategy of water addition in DWI systems was successfu11y derived from the analysis of combustion results.. |
| 28. |
Satoshi KAWAUCHI, Daisuke TSURU, Haruhiko AOYAGI, Hiroshi TAJIMA, Injection Strategy with Merged Spray Characteristics for PCCI Combustion in Large Bore Diesel Engines, Proceedings of ISME KOBE 2011 9th International Symposium on Marine Engineering, pp.A1-2_1-6, 2011.10. |
| 29. |
Shinji Yasueda, Koji Takasaki, Hiroshi Tajima, The Abnormal Combustion caused by Lubricating oil on High BMEP Gas Engines, Proceedings of 13th Conference, The Working Process of the Internal Combustion Engine, pp.324-327, 2011.09, Abnormal combustion with high peak firing pressure can be seen on high BMEP engines in recent years. This abnormal combustion is detected not as pre-ignition but as knocking on engines using a knock detection system with an acceleration sensor. Therefore the ignition timing is retarded and it makes combustion worse because this abnormal combustion grows by retarded spark timing. As the results of researches including the visualization tests on the single cylinder engine, this combustion was confirmed to be the kind of pre-ignition caused by the auto ignition of in-cylinder lubricating oil and one of the causes of the cyclic variation of peak firing pressure on premixed combustion gas engine.
In this paper, the characteristics of this abnormal combustion on production engines and the visualization data of combustions measured on a test engine are introduced and then the consideration about the reasons and the countermeasures are described in detail.. |
| 30. |
Hisako Kato, Hiroshi Tajima, Satoshi Kawauchi, Daisuke Tsuru, Approach of spray distribution control using two merging sprays of different injection rate for PCCI combustion, Proceedings of ILASS Europa 2011 24th European Conference on Liquid Atomization and Spray Systems, pp.1193_1-10, 2011.09, A new injection strategy was proposed to realize PCCI combustion for marine diesels of large-bore and yet longer-stroke dimensions. This strategy utilizes a set of sprays from closely aligned holes having injection directions intersecting one another. Mutual interaction and merger of the sprays happen by overlapping injection periods like some of the Direct Water Injection (DWI) systems. In addition, it is feasible to control the propagation direction of the merged spray body, or the mixture stratification in a combustion chamber, by applying a different shape of injection rate separately. The direction is supposed to change according to the vector sum of the two merging sprays. The potential of the novel injection system for PCCI combustion was successfully examined through the observation of the merging spray propagation in a constant volume vessel and in a rapid compression-expansion machine, although a conventional CFD code failed to reproduce the propagation behaviour.. |
| 31. |
H. Tajima,Y. Tominaga,A. Stroem,K. Takasaki,S. Yasueda,Y. Hirayama, Combustion with Water Injection- High-Speed Visualization and CFDs, Proc. 5th International Colloquium Fuels, pp83-92, 2005.01. |
| 32. |
K. Takasaki,A. Stroem,H. Tajima,T. Kitahara,T. Katafuchi, Characteristics of Trouble-making Bunker Fuel Oil, Proc. 5th International Colloquium Fuels, pp43-52, 2005.01. |
| 33. |
H. Tajima, K. Takasaki, A. Stroem, R. Masuda, Diagnosis of combustion with water injection using high-speed visualization and CFDs, Proc. Thermo- and Fluid Dynamic processes in Diesel Engines, THIESEL 2004, 2004.09. |
| 34. |
H. Tajima, A. Stroem, K. Uno, Y. Tominaga, Flame Temperature Measurement in Diesel Engine on Two Color Method utilizing CMOS Camera, Proc. 6th International Symposium COMODIA 2004, A1-1-7-12, 2004.08. |
| 35. |
K. Takasaki, K. Tayama, H. Tanaka, S. Baba, H. Tajima, A. Stroem, NOx Emissions from Bunker Fuel Combustion, Proc. 24th CIMAC (International Congress on Combustion Engine Technology), No.87-0-9, 2004.06. |
