1999 Fiscal Year Final Research Report Summary
A Study on the Flame Structure in Combustion Processes of an Emulsified Fuel Droplet under Microgravity
| Project/Area Number |
10650215
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Thermal engineering
|
|---|
| Research Institution | Ehime University |
|---|
Principal Investigator |
YAMASAKI Hiroshi Ehime University, Faculty of Education, Associate Professor, 教育学部, 助教授 (80182476)
|
|---|
| Project Period (FY) |
1998 – 1999
|
| Keywords | Emulsified Fuel / Droplet Combustion / Microgravity / Numerical Simulation / Flame Structure / Microexplosion |
|---|
| Research Abstract |
Numerical and experimental studies have been conducted to investigate on the flame structure in the combustion processes of an emulsified fuel droplet in a quiescent gaseous environment under microgravity condition. The attention was mainly paid to the secondary atomization and flame structures in the spherical flame. Experiment were carried out to clarify the transport processes of the liquid phase in the emulsified fuel droplet during the droplet combustion and flame structure. Numerical analyses were also carried out to obtain the detail information about the liquid phase transport processes, onset of microexplosion in the droplet and dispersion processes of the droplet under microgravity. Two dimensional numerical analysis has been carried out to clarify the flame structure. The temperature, fuel concentration and oxygen profiles were determined by using the same scheme of dispersion processes of the droplet. The results for the fuel in water emulsified fuel indicate that the secondary water droplet region was formed in the central portion of the droplet resulted in the liquid phase separation in the emulsified fuel droplet. This transport process might be mainly ruled by the temperature increase of the droplet. Microexplosion occurs resulted of the superheating of the secondary droplet. These dispersion processes of the emulsified fuel droplet are mainly ruled by the onset position of vapor bubble. The onset rate of microexplosion or puffing increases toward their peripheral portion of the droplet. Microexplosion occurs with high possibility in the case that the vapor bubble positioned at the surface portion of the secondary water droplet. These results also indicate that the flame structure was largely affected by the occurrence of secondary atomization.
|
