1989 Fiscal Year Final Research Report Summary
Large Eddy effect on Turbulent Heat Transfer Analyzed by Correlations between Heat flux and Velocity Fluctuations
| Project/Area Number |
63460096
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
Thermal engineering
|
|---|
| Research Institution | Tokyo Institute of Technology |
|---|
Principal Investigator |
HIJIKATA Kunio Tokyo Institute of Technology Mechanical Engineering Science, Professor, 工学部 (60016582)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
HIMENO Nobuhiro Tokyo Institute of Technology Mechanical Engineering Science, Associate Professo, 繊維学部, 助教授 (20114887)
NAGASAKI Takao Tokyo Institute of Technology Mechanical Engineering Science, Research Associate, 工学部, 助手 (30155923)
|
|---|
| Project Period (FY) |
1988 – 1989
|
| Keywords | Turbulent Heat Transfer / Corr elation between Heat Flux and Velocity Fluctuations / Impinging Jet |
|---|
| Research Abstract |
Many researches to clarify the mechanism of turbulent heat transfer performance have been carried out.
In the most of these researches, the relations between the turblent motions in space and the transported flux have not been studied. In this research, the structures of large eddy motion in the impinging jet, which strongly affect the heat transfer, the mass transfer and the shear stress on the impinged plate, were investigated by measuring the cross-correlations between the transported fluxes and the velocity fluctuation in the jet. The movement and collapse of the large eddies can be traced from the time and space distributions of the cross-correlation. In the case of heat transfer, the velocity field were measured by LDV, and the heat flux on the plate were measured by a hand-made heat flux sensor. To measure the shear stress and the mass transfer coefficient, electro-chemical method were used. The large eddies affecting on the heat flux moved in jet whose moving speed was quite same as the mean velocity of the jet. However, in the case of mass transfer, the auto-correlative structure was existed near the measuring point of the mass flux. This structure was caused by the existence of the diffusion boundary. In order to clarify the structure, the responses of the mass flux, the heat flux and the shear stress boundary layeto the velocity fluctuation outside of the boundary layer were numerically analyzed. The theoretical results showed that the existence of the auto-correlative structure only for the mass transfer. This tendency accurately agreed with the experunental results.
|
