Velocity Measurements of Dense Diesel Fuel Sprays in Dense Air

Chaves, H.; Kirmse, Clemens; Obermeier, F.

doi:10.1615/atomizspr.v14.i6.60

Cited by 27 publications

(16 citation statements)

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“…ディーゼル機関において，熱効率の向上と排気物質低減のためには，燃焼の適切な制御が不可欠である．これらの実現には，燃焼を支配する噴霧特性を詳細に把握することが必要となる．特に燃焼領域が噴霧の広がりにより決定されることから，噴孔近傍の噴霧幅と噴霧内部構造との関係を明らかにすることが必要である．噴射ノズル内部流動の研究として，例えば針弁リフトの変化に伴う燃料の過渡的な流れ場やキャビテーション特性を調査した結果や，ディーゼル噴霧構造に及ぼす針弁の影響を X 線で調査した結果が報告されている．噴射ノズル外部の噴霧特性の過渡的変化に及ぼす針弁リフトの影響はまず噴孔近傍に現れる．これまでに X 線による噴孔近傍の燃料質量分布の計測 (Im et al, 2009)や噴霧コア部計測 (Alan et al, 2007)，位相ドップラー流速計を用いた液滴計測に関する報告がなされている．しかしながら噴孔近傍の高数密度領域における噴霧液滴の計測は容易でないため，十分な知見は得られていない． 2 つの焦点の間を液滴が飛行する時間を計測して速度を求めるレーザー2 焦点流速計(L2F ; Laser 2-Focus velocimeter)は光学的 SN 比が高く，液滴数密度の高い噴霧計測において多重散乱の影響を受けにくいという特徴 *1 長崎大学大学院工学研究科(〒852-8521 長崎県長崎市文教町 1-14) *2 正員，長崎大学大学院工学研究科 E-mail of corresponding author: komada@nagasaki-u.ac.jp を有している．これまでに噴孔近傍での噴霧測定に適用することが検討された (Chaves et al, 2001) ．本研究では，L2F により計測されたディーゼル噴霧の液滴の速度，サイズおよび液滴数に基づいて噴霧画像の時間的，空間的変化と噴霧内部の微細非定常構造との関係を調査した． 2. 実験装置および実験方法 2・1 レーザー2 焦点流速計 Upstream Sig.…”

Section: 緒言unclassified

Study of unsteady structure inside near-nozzle diesel spray by L2F

Mori

Komada

Ueki

2017

Transactions of the JSME (In Japanese)

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A laser 2-focus velocimeter (L2F) was used for measurements of velocity and size of droplets in diesel fuel sprays. Diesel fuel was injected intermittently into the atmosphere by using a 8-hole injector nozzle. The diameter of the nozzle orifice was 0.112mm. The rail pressure was set at 65MPa by using a common rail system. The period of injector solenoid energizing was set at 2.3ms. The L2F had a micro-scale probe which consists of two foci. The focal diameter was about 3μm, and the distance between two foci was 20μm. The data sampling rate of the L2F system was markedly high as 15MHz. L2F measurement was conducted at 10mm downstream from the nozzle exit. Temporal and spatial changes in the velocity, size and number of droplets inside sprays were investigated. Spray images were taken by using a 180ns spark light source, and the scattered light intensity distribution and spray width were estimated. The scattered light intensity, the spray width and the number of droplets were oscillated several times in the injection period. The number of droplets at the inner region of the spray decreased and the one at the outer region of the spray increased, when the spray width increased. That is, many droplets fly to the outer region of the spray at the time when spray width is wide.

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Section: 緒言unclassified

Study of unsteady structure inside near-nozzle diesel spray by L2F

Mori

Komada

Ueki

2017

Transactions of the JSME (In Japanese)

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“…The RMS fluctuations u rms , v rms and w rms are set to fit the turbulence intensity of a gas jet in the self-similarity area according to [20,21]…”

Section: þ ð3þmentioning

confidence: 99%

Eulerian – Eulerian Large Eddy Simulations Applied to Non-Reactive Transient Diesel Sprays

Robert

Martinez

Tillou

et al. 2013

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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and available online here Cet article fait partie du dossier thématique ci-dessous publié dans la revue OGST, Vol. 69, n°1, et téléchargeable ici D o s s i e rDOSSIER Edited by/Sous la direction de : C. Angelberger IFP Energies nouvelles International Conference / Les Rencontres Scientifiques d'IFP Energies nouvelles LES4ICE 2012 -Large Eddy Simulation for Internal Combustion Engine FlowsLES4ICE 2012 -La simulation aux grandes échelles pour les écoulements dans les moteurs à combustion interne

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“…The L2F has a high optical signal-to-noise ratio, so an effect of multiple scattering of droplets on the spray measurement is small even in high number density sprays. The L2F methods were applied to measure droplets inside the breakup length (Schugger, et al, 2000, Chaves, et al, 2001. The authors showed that the velocity and the size of droplets can be simultaneously obtained by adding the measurement of time-of-scattering to the L2F (Ueki, et al, 1994).…”

Section: Introductionmentioning

confidence: 99%

Effects of injector valve movement on diesel spray characteristics under short full valve opening

Kawaharada

Sakaguchi

Ueki

et al. 2015

JTST

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A laser 2-focus velocimeter (L2F) was used for the measurement of diesel fuel sprays. Temporal and spatial changes in the number, velocity and size of droplets inside sprays were investigated near the nozzle orifice and were correlated with the needle valve lift of the injector nozzle. The L2F had a micro-scale probe which consists of two foci. The focal diameter was about 3µm, and the distance between two foci was 17µm. The data sampling rate of the L2F system was markedly high as 15MHz. Fuel sprays were injected intermittently into the atmosphere by using a common rail injector. The orifice diameter of the injector nozzle was 0.112mm and the rail pressure was 40MPa. The periods of solenoid energizing was set at 2.0ms. Measurement positions were located at 10mm downstream from the exit of the nozzle orifice. The results show that droplets mainly existed in the region off the spray center in the early injection period and concentrated at the spray center in the middle of injection period. Temporal changes in the number of droplets near the spray center were strongly affected by the needle lift and there in the relatively wide region were affected by the injection rate. Temporal changes in the droplet velocity near the spray center were strongly affected by the injection rate. The luminance distribution of the spray image was similar to the distribution of the number of droplets multiplied by the square of droplet size.

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Velocity Measurements of Dense Diesel Fuel Sprays in Dense Air

Cited by 27 publications

References 0 publications

Study of unsteady structure inside near-nozzle diesel spray by L2F

Study of unsteady structure inside near-nozzle diesel spray by L2F

Eulerian – Eulerian Large Eddy Simulations Applied to Non-Reactive Transient Diesel Sprays

Effects of injector valve movement on diesel spray characteristics under short full valve opening

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