15 results on '"Nomura, Hiroshi"'
Search Results
2. The 2015 activity report and prospects of the research team on spontaneous ignition of fuel droplet array near ignitable limit
- Author
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Moriue, Osamu, Nomura, Hiroshi, Kikuchi, Masao, Mikami, Masato, Tanabe, Mitsuaki, and Suganuma, Yusuke
- Subjects
Combustion ,Microgravity ,Cool flame ,Ignition ,Sounding rocket ,Droplet array - Abstract
第30回宇宙環境利用シンポジウム (2016年1月19日-20日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)), 相模原市, 神奈川県, Space Utilization Research (January 19-20, 2016. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)), Sagamihara, Kanagawa Japan, 資料番号: SA6000048014, レポート番号: G-10
- Published
- 2016
3. Interaction Effects on Combustion of Alcohol Droplet Pairs
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OKAI, Keiichi, ONO, Yutaka, MORIUE, Osamu, SHIBA, Seiji, ARAKI, Mikiya, NOMURA, Hiroshi, SHIGA, Seiichi, TSUE, Mitsuhiro, and KONO, Michikata
- Subjects
Physics::Fluid Dynamics ,endocrine system ,Liquid Fuel ,Interaction Effects ,technology, industry, and agriculture ,Physics::Atomic and Molecular Clusters ,Combustion ,Physics::Chemical Physics ,complex mixtures ,Disruptive Combustion ,eye diseases ,Astrophysics::Galaxy Astrophysics ,High Pressure Combustion - Abstract
Experimental investigation was conducted on two droplet-array combustion of methanol and methanol/dodecanol mixture fuels in microgravity. For methanol, effects of ambient pressure and droplet spacing were examined. Results show that the droplet lifetime decreases with increasing spacing at relatively low pressure and the droplet lifetime becomes independent of spacing at higher-subcritical and supercritical pressures. For methanol/dodecanol mixture, effects of pressure, fuel composition were investigated in terms of occurrence of disruption. Disruption of droplet during combustion was demonstrated both for single droplet and droplet pairs.
- Published
- 2001
4. 2014 Annual Report on activity of the working group on ignition and combustion at high pressures with a shared apparatus for microgravity experiments
- Author
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Nomura, Hiroshi, Mikami, Masato, Moriue, Osamu, Tsue, Mitsuhiro, Yamasaki, Hiroshi, Segawa, Daisuke, Tanabe, Mitshaki, Takahashi, Shuhei, Hashimoto, Nozomu, Imamura, Osamu, Okai, Keiichi, Hirota, Mitsutomo, Suganuma, Yusuke, and Kikuchi, Masao
- Subjects
Sounding rocket project ,Combustion ,Microgravity ,Cool flame ,Ignition ,Droplet array - Abstract
第29回宇宙環境利用シンポジウム (2015年1月24日-25日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)), 相模原市, 神奈川県, Space Utilization Research (January 24-25, 2015. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)), Sagamihara, Kanagawa Japan, 著者人数: 14名, 資料番号: SA6000035011, レポート番号: ISAS-SUR29-S06
- Published
- 2015
5. Activity Report of Research WG on Combustion Dynamics of Fuel Droplets
- Author
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Kikuchi, Masao, Yamamoto, Shin, Umemura, Akira, Kobayashi, Hideaki, Ogami, Yasuhiro, Nomura, Hiroshi, Mikami, Masato, Seo, Takehiko, Oshima, Nobuyuki, Moriue, Osamu, Shinjo, Junji, and Hisashi, Yasuyuki
- Subjects
Microgravity Experiments ,Combustion ,Fuel Droplets ,Numerical Simulations - Abstract
第28回宇宙利用シンポジウム (2012年1月23-24日. 日本学術会議), 港区, 東京都, Space Utilization Research (January 23-24, 2012. Science Council of Japan), Minato-ku, Tokyo Japan, 著者人数: 12名, 資料番号: SA6000032019, レポート番号: M19
- Published
- 2012
6. 2011 Annual Report on Activity of the Research Team on Ignition and Combustion at High Pressures with a Shared Apparatus for Microgravity Experiments
- Author
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Moriue, Osamu, Nomura, Hiroshi, Mikami, Masato, Tsue, Mitsuhiro, Yamasaki, Hiroshi, Segawa, Daisuke, Tanabe, Mitsuaki, Takahashi, Syuhei, Hashimoto, Nozomu, and Imamura, Osamu
- Subjects
Microgravity Experiments ,Combustion ,High Pressure ,Shared Experimental Apparatus - Abstract
第28回宇宙利用シンポジウム (2012年1月23-24日. 日本学術会議), 港区, 東京都, Space Utilization Research (January 23-24, 2012. Science Council of Japan), Minato-ku, Tokyo Japan, 資料番号: SA6000032018, レポート番号: M18
- Published
- 2012
7. Activity Report of Research Team on Combustion Dynamics of Fuel Droplets
- Author
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Kikuchi, Masao, Yamamoto, Shin, Umemura, Akira, Kobayashi, Hideaki, Ogami, Yasuhiro, Nomura, Hiroshi, Mikami, Masato, Seo, Takehiko, Moriue, Osamu, and Shinjo, Junji
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Microgravity Experiments ,Combustion ,Flame Propagation ,Fuel Droplets - Abstract
第27回宇宙利用シンポジウム (2011年1月24日-25日, 宇宙航空研究開発機構宇宙科学研究所相模原キャンパス), 相模原市, 神奈川県, The Twenty-seventh Space Utilization Symposium (January 24-25, 2011. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan, This paper describes activity report of Research Team(WG) on Combustion Dynamics of Fuel Droplets. In accordance with the objectives of this WG, normal gravity and ground-based microgravity experiments have been performed as well as numerical simulation. Also, discussion on next-generation simulation technique for spray combustion has been discussed. It should be emphasized that a proposal on microgravity experiment for validation of the new atomization concept, which was prepared by Prof. Umemura, was newly selected as a candidate for KIBO experiment. The investigation is the 3rd space experiment, derived from our WG activities, following previous 2 space experiments., 著者人数: 11人, 形態: カラー図版あり, Number of authors: 11, Physical characteristics: Original contains color illustrations, 資料番号: AA0065129012
- Published
- 2011
8. 各種液体燃料の高温空気中における蒸発・自発点火特性に関する研究
- Author
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Moriue, Osamu, Nomura, Hiroshi, and Murase, Eiichi
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ignition delay ,liquid fuel ,点火遅れ ,液体燃料 ,点火 ,火炎温度 ,燃料燃焼 ,fuel droplet ,fuel combustion ,冷炎 ,evaporation ,Physics::Fluid Dynamics ,燃料液滴 ,flame temperature ,温度計測 ,Physics::Plasma Physics ,ignition ,自発燃焼 ,cool flame ,Physics::Chemical Physics ,蒸発 ,火炎 ,微小重力 ,spontaneous combustion ,microgravity ,燃焼 ,flame ,temperature measurement ,combustion - Abstract
Spontaneous ignition of isolated fuel droplets was experimentally studied as the simplest model of spray ignition. Experiments were performed in microgravity so that the results on large droplets may be compared to fine droplets in a spray in a practical use. Ignition delays and temperatures of cool flame were measured, and their dependence on ambient conditions and fuel kinds were examined., 資料番号: AA0063706040
- Published
- 2008
9. 高圧環境下における点火・燃焼現象解明のための共通微小重力実験装置試作および研究報告
- Author
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Nomura, Hiroshi, Mikami, Masato, Tsue, Mitsuhiro, Yamasaki, Hiroshi, Segawa, Daisuke, Tanabe, Mitsuaki, Takahashi, Shuhei, Moriue, Osamu, Nokura, Masaki, and Hashimoto, Nozomu
- Subjects
高圧 ,温度依存性 ,biomass burning ,evaporation rate ,蒸発速度 ,点火 ,正ヘキサデカン ,燃料燃焼 ,fuel droplet ,fuel combustion ,evaporation ,Physics::Fluid Dynamics ,燃料液滴 ,バイオマス燃焼 ,ignition ,n-hexadecane ,Physics::Chemical Physics ,PME ,temperature dependence ,Physics::Atmospheric and Oceanic Physics ,蒸発 ,微小重力 ,microgravity ,palm methyl ester ,燃焼 ,high pressure ,パームメチルエステル ,combustion - Abstract
In our working group, three projects have been carried out, namely, study on Reynolds stress originated flame behavior in standing sound wave, study on evaporation and ignition of a biomass fuel droplet, and study on bifuel droplet ignition. Prototypes of a high pressure combustion chamber and an inner experimental module for single droplet evaporation/ignition/combustion were fabricated. Experiments on biomass fuel droplet evaporation at high pressures and high temperature were performed. Temporal variations of droplet diameter were measured at pressures from 0.1 to 2.0 MPa successfully., 資料番号: AA0063706034
- Published
- 2008
10. 2次元燃料液滴群の群燃焼発現メカニズムの解明
- Author
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Mikami, Masato, Nomura, Hiroshi, Moriue, Osamu, Umemura, Akira, Kikuchi, Masao, and Yoda, Shinichi
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flame spread ,群燃焼 ,パーコレーションモデル ,燃料燃焼 ,fuel droplet ,fuel combustion ,Physics::Fluid Dynamics ,燃料液滴 ,液滴配列 ,Physics::Atomic and Molecular Clusters ,シミュレーション ,percolation model ,Physics::Chemical Physics ,火炎 ,droplet array ,微小重力 ,group combustion ,燃料 ,simulation ,microgravity ,燃焼 ,combustion control ,flame ,燃焼制御 ,燃え広がり ,fuel ,combustion - Abstract
The objective of the present research is to improve understanding of group combustion excitation in randomly-distributed droplets by applying the research results on flame spread of linear droplet arrays to randomly-distributed two-dimensional droplet cloud., 資料番号: AA0063706035
- Published
- 2008
11. 高圧環境下における点火・燃焼現象解明のための共通微小重力実験装置検討および研究報告
- Author
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Nomura, Hiroshi, Mikami, Masato, Tsue, Mitsuhiro, Yamasaki, Hiroshi, Segawa, Daisuke, Tanabe, Mitsuaki, Takahashi, Shuhei, Moriue, Osamu, Nokura, Masaki, and Hashimoto, Nozomu
- Subjects
高圧 ,biomass burning ,液滴直径 ,高圧燃焼容器 ,evaporation ,Physics::Fluid Dynamics ,flame behavior ,バイオマス燃焼 ,ignition ,Physics::Chemical Physics ,圧力容器 ,蒸発 ,火炎 ,high pressure combustion chamber ,着火 ,微小重力 ,microgravity ,燃焼 ,high pressure ,研究設備 ,flame ,droplet diameter ,火炎挙動 ,research facility ,pressure chamber ,combustion - Abstract
In our working group, two projects started. One is a study on Reynolds stress originated flame behavior in standing sound wave, and the other is a study on evaporation and ignition of a biomass fuel droplet. A high pressure combustion chamber of the shared experimental apparatus was designed, and its stress and displacement at high pressures were numerically analyzed. One experimental module, which was designed for the shared experimental apparatus, has been made. Experiments on droplet evaporation at high pressures and high temperature were performed. Temporal variations of droplet diameter were measured at pressure of 5.0 MPa successfully., 資料番号: AA0063349054
- Published
- 2007
12. Droplet ignition behavior in the vicinity of the leading edge of a flame spreading along a fuel droplet array in fuel-vapor/air mixture.
- Author
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Nomura, Hiroshi, Takahashi, Hiromu, Suganuma, Yusuke, and Kikuchi, Masao
- Subjects
DROPLETS ,LEADING edges (Aerodynamics) ,COMBUSTION ,FLAME ,GAS mixtures ,FUEL ,VAPORS - Abstract
Abstract: Combustion experiments of fuel droplet array in fuel-vapor/air mixture were performed at normal and microgravities to investigate mechanism of flame spread. A 10-droplet array was inserted into the test section filled with a saturated fuel-vapor/air mixture as a simple model of prevaporized sprays. Gas equivalence ratio of the fuel-vapor/air mixture was controlled by the test section temperature. n-Decane droplets of 0.8mm in the initial diameter were employed. The first droplet was ignited by a hot wire to initiate flame spread along a fuel droplet array. Sequential magnified backlit-images of the target droplets in the droplet array were taken during flame spread. From those images, ignition behavior of droplets at the vicinity of the leading edge of a spreading flame was observed. The onset of droplet-heating was obtained from the history of droplet diameter. The ignition of the target droplet was detected by the glowing of the suspenders. Ignition delay time was defined as the time difference between the onset of droplet-heating and the ignition of the droplet. Flame spread induction time was defined as the time difference between the ignitions of the neighboring droplets. Effects of droplet spacing and gas equivalence ratio on the ignition delay time were examined. Nondimensional droplet spacing S/d
0 and gas equivalence ratio were varied from 2 to 12.75 and from 0 to 0.5, respectively. The ignition delay time slightly decreased as the increase in the gas equivalence ratio at all normalized droplet spacings. In the range of S/d0 <5, a spreading flame heated two unburnt droplets simultaneously. Around 6.25 in S/d0 , the time required for expansion of the thermal-effect zone of a flame occupied certain amount of the flame spread induction time. At 12.75 in S/d0 , the ignition delay time was a dominant factor for the flame spread induction time. [Copyright &y& Elsevier]- Published
- 2013
- Full Text
- View/download PDF
13. Microgravity experiments of flame spreading along a fuel droplet array in fuel vapor-air mixture.
- Author
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Nomura, Hiroshi, Iwasaki, Hiroshi, Suganuma, Yusuke, Mikami, Masato, and Kikuchi, Masao
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REDUCED gravity environments ,FLAME ,TEMPERATURE effect ,COMBUSTION ,FLAME spread ,THERMOCHEMISTRY ,SPRAY combustion ,EXPERIMENTS - Abstract
Abstract: Combustion experiments of fuel droplet array in fuel vapor-air mixture were performed at microgravities to investigate growth mechanism of group combustion of fuel droplets. A 10-droplet array was inserted into the test section filled with a saturated fuel vapor-air mixture as a simple model of prevaporized sprays. Gas equivalence ratio of the fuel vapor-air mixture was regulated by the test section temperature. n-Decane droplets of 0.8mm in the initial diameter were suspended at the crossing points of 10 sets of X-shaped suspenders. The first droplet was ignited by a hot wire to initiate flame spread along a fuel droplet array. Flame spread speed was obtained from the history of the leading edge position of a spreading flame. Effects of droplet spacing and gas equivalence ratio on the flame spreading behavior and the flame spread speed were examined. The droplet spacing and the gas equivalence ratio were varied from 1.6 to 10.2mm and from 0.2 to 0.7, respectively. The gas equivalence ratio has little effect on the relationship between the flame spreading behavior and the droplet spacing. The flame spread speed increases as the increase in the gas equivalence ratio at all droplet spacings. The influence of the gas equivalence ratio on the flame spread speed becomes strong as the increase in the droplet spacings. The flame spread speed increases as the increase in the droplet spacing, and then decreases. The maximum flame spread speed appears in the range from 2.4 to 3mm at all gas equivalence ratios. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
14. Effects of fine fuel droplets on a laminar flame stabilized in a partially prevaporized spray stream.
- Author
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Nomura, Hiroshi, Hayasaki, Masashi, and Ujiie, Yasushige
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LAMINAR flow ,FUEL ,COMBUSTION ,THERMOCHEMISTRY - Abstract
Abstract: A partially prevaporized spray burner was developed to investigate the interaction between fuel droplets and a flame. Monodispersed partially prevaporized ethanol sprays with narrow diameter distribution were generated by the condensation method using rapid pressure reduction of a saturated ethanol vapor–air mixture. A tilted flat flame was stabilized at the nozzle exit using a hot wire. Particle tracking velocimetry (PTV) was applied to measurements of the droplet velocity; the laminar burning velocity was obtained from gas velocity derived from the droplet velocity. Observations were made of flames in partially prevaporized spray streams with mean droplet diameters of 7μm and the liquid equivalence ratios of 0.2; the total equivalence ratio was varied. In all cases, a sharp vaporization plane was observed in front of the blue flame. Flame oscillation was observed on the fuel-rich side. At strain rates under 50s
−1 , the change in the burning velocity with the strain rate is small in fuel-lean spray streams. In spray streams of 0.7 and 0.8 in the total equivalence ratio, burning velocity increases with strain rates of greater than 50s−1 . However, in spray streams with 0.9 and 1.0 in the total equivalence ratio, burning velocity decreases as the strain rate increases. At strain rates greater than 80s−1 , burning velocity decreases with an increased gas equivalence ratio. The effect of mean droplet diameter, and the entry length of droplets into a flame on the laminar burning velocity, were also investigated to interpret the effect of the strain rate on the laminar burning velocity of partially prevaporized sprays. [Copyright &y& Elsevier]- Published
- 2007
- Full Text
- View/download PDF
15. Effects of pressure on flame propagation in a premixture containing fine fuel droplets.
- Author
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Nomura, Hiroshi, Kawasumi, Ikue, Ujiie, Yasushige, and Sato, Jun’ichi
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FUEL ,COMBUSTION ,FLAMMABILITY ,THERMOCHEMISTRY - Abstract
Abstract: Combustion experiments on fuel droplet–vapor–air mixtures have been performed with a rapid expansion apparatus which generates monodispersed droplet clouds with narrow diameter distribution using the condensation method. The effects of fine fuel droplets on flame propagation were investigated for ethanol droplet–vapor–air mixtures at various pressures from 0.2 to 1.0MPa. A stagnant fuel droplet–vapor–air mixture, generated in a rapid expansion chamber, was ignited at the center of the chamber using an ignition wire. Spherical flame propagation under constant-pressure conditions was observed with a high-speed video camera and flame speed was measured. Total equivalence ratio, and the ratio of liquid fuel mass to total fuel mass, was varied from 0.6 to 1.4 and from zero to 56%, respectively. The mean droplet diameter of fuel droplet–vapor–air mixtures was set at 8.5 and 11μm. It was found that the flame speed of droplet–vapor–air mixtures less than 0.9 in the total equivalence ratio exceeds that of premixed gases of the same total equivalence ratio at all pressures. The flame speed of fuel droplet–vapor–air mixtures decreases as the pressure increases in all total equivalence ratios. At large ratios of liquid fuel mass to total fuel mass, the normalized flame speed (the flame speed of droplet–vapor–air mixtures divided by the flame speed of the premixed gas with the same total equivalence ratio), increases with the increase in pressure for fuel-lean mixtures, and it decreases for fuel-rich mixtures. The outcome is reversed at small ratios of liquid fuel mass to total fuel mass; the normalized flame speed decreases with the increase in pressure for fuel-lean mixtures, and increases for fuel-rich mixtures. The results suggest that the increase in pressure promotes droplet evaporation in the preheat zone. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
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