Grant-in-Aid for Co-operative Research (A).
|Research Institution||Osaka University|
MIZUTANI Yukio Osaka University, Professor, 工学部, 教授 (80028993)
TOMIYAMA Akio Kobe University, Associate Professor, 工学部, 助教授 (30211402)
IKEDA Yuji Kobe University, Associate Professor, 機器分析センター, 助教授 (10212789)
NAKAJIMA Tsuyoshi Kobe University, Professor, 工学部, 教授 (30031090)
AKAMATSU Fumiteru Osaka University, Research Assocciate, 工学部, 助手 (10231812)
KATSUKI Masashi Osaka University, Professor, 工学部, 教授 (20029292)
|Project Fiscal Year
1994 – 1995
Completed(Fiscal Year 1995)
|Budget Amount *help
¥33,600,000 (Direct Cost : ¥33,600,000)
Fiscal Year 1995 : ¥6,200,000 (Direct Cost : ¥6,200,000)
Fiscal Year 1994 : ¥27,400,000 (Direct Cost : ¥27,400,000)
|Keywords||Spray Combustion / Muti-phase Flow / Group Combustion / Phase Doppler Anemometer / Particle Tracking Method / Error Estimation / High Data-rate measurement / Size-classified Data / 噴霧燃焼 / 混相流 / 油滴群燃焼 / フェーズドップラー流速計(PDA) / 粒子追跡法 / 誤差評価 / 高データレート測定 / 粒径別データ / 混和流 / 二相流 / 光学計測 / 火炎計測 / 計測法 / 噴霧モデル / 数値シミュレーション|
Mizutani and Akamatsu : Quantitative Verification of Group Combustion Hypothesis for Spray Droplets
The optimized design of phase Doppler anemometer optics enabled us to discuss instantaneous characteristics of droplet clusters and to estimate the modified group combustion number G_C for each droplet cluster burning in various group combustion modes. It was found that the G_C-value averaged over all droplet clusters in the flame fell within the range of the external or internal group combustion modes so defined by Chiu et al., which was in good accordance with the previous experimental observations.
Katsuki : Statistical Modeling of Droplet Behavior for Spray Combustion
We have developed a model of droplet behavior in turbulent flows for numerical prediction of spray combustion in practical combustors. In the proposed model, the trajectory of a computational parcel representing a group of droplets is determined by Lagrangian tracking method through the predetermined gas-phase field by sol
ving Eularian equations as in PSI-Cell Model, Velocity fluctuation and turbulent dispersion of droplets are statistically characterized and calculated using a probability density function. This model does not required so many parcels in providing adequate local size distribution of droplets and in estimating the interaction between gas-phase and droplets. Therefore, the computational efficiency is significantly improved in comparison with the conventional stochastic methods.
Nakajima and Ikeda : Error Estimations on Phase Doppler Technique for spray research.
The purpose of this study is to investigate additional factors in such as slit location effect, measurement volume size effect and flame-front induced data bias. Three kinds of experiment were curried out using two sets of PDA.The results show that the slit location shift effect causes a significant measurement uncertainty, especially in high data rate. The optical alignment of the slit location at the initial stage is the most important factors, and this slit location shift effect can be improved dramatically using two PDA receiving optics. The measurement uncertainty of the mass flux at low data rate yields large value. The measurement volume size effect can be seen in detection rate of small droplet at high data rate.
Hosokawa : Cycle-Resolved PDA Measurement of Size-Classified Spray Structure
Cycle-resolved PDA measurement was performed and measured data was classified into droplet size groups in order to investigate detail and time-dependent droplet dynamics of spray by an air-assist injector, those are cyclic resolved flow and droplet dynamics variation, size-classified droplet characteristics and its fluctuation. Large cyclic variation of velocity was observed by the cycle-resolved PDA measurement. Flow oscillation due to shear induced vortex structure is also observed.
担当細川 茂雄 課題:非定常噴霧流における高データレートPDA計測とそのデータ解析
非定常噴霧における液滴と気流の相関作用を解明するため,エア-アシストインジェクターにより形成される非定常噴霧流において,高データレート条件下でPDA計測を行うとともに,その時系列データの解析法を検討し,流速の高いサイクルと低いサイクルが存在し,流速が速い条件ほど流れの変動周波数が高いことが明らかになった.また,この変動流れに追従する液滴の径は,高周波数ほど小さいことが明らかにされた.さらに,非定常噴霧における高データレート計測(Cycle-resolved PDA)および液滴径によるデータの分類(Size-Classified Data Analysis)の必要性を示した. Less