| Project/Area Number |
06555051
|
|---|
| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
Fluid engineering
|
|---|
| Research Institution | Tohoku University |
|---|
Principal Investigator |
IKOHAGI Toshiaki (1995) Tohoku University, Institute of Fluid Science, Professor, 流体科学研究所, 教授 (90091652)
大場 利三郎 (1994) 東北大学, 流体科学研究所, 教授 (40006169)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
SATO Kazunori Babcock Hitachi K.K., Kure Works, Researcher, 呉研究所, 研究員
SOYAMA Hitoshi Tohoku University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (90211995)
井小萩 利明 東北大学, 流体科学研究所, 助教授 (90091652)
|
|---|
| Project Period (FY) |
1994 – 1995
|
| Project Status |
Completed (Fiscal Year 1995)
|
| Budget Amount *help |
¥8,000,000 (Direct Cost: ¥8,000,000)
Fiscal Year 1995: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 1994: ¥5,400,000 (Direct Cost: ¥5,400,000)
|
|---|
| Keywords | Submerged Water Jet / Cavitation / Peening / Jet Erosion / lmpulsive Pressure / Cavitation Cloud / Residual Stress Improvement / Numerical Simulation / 気泡崩壊衝撃圧 |
|---|
| Research Abstract |
Our purpose is to establish a new peening technology using high-speed submerged water jets as an effective utilization of cavitation erosion energy. The structure and unsteady behavior of such water jets governing the processing ability have been investigated, and the peening effect has been verified experimentally. The research results are
1. The residual stresses of stainless steel specimens were measured by X-ray stress analizer. It is found that such peening effects as the stress improvement from pre-processing tensile conditions to compressible ones are realized definitely without any surface damage.
2. Cavitation noise and impulsive pressure were measured under a wide range of processing ambient pressure, and an exponential law between the acoustic power/the ambient pressure and the erosion rate is found to hold on the processing operation.
3. The breakup frequency of unsteady cavitation cloud which is related directly to the jet processing ability becomes maximum near the 1st peak of erosion curve, and an erosion mechanism is due to the intermittent impingement of water column. Also, the cylindrical nozzle provides a high breakup frequency and the most erosive action to the specimen surface.
4. Such a knowledge concerning jet processing is obtained that the impulsive pressures measured on various cylindrical surfaces distribute widely upto the back surface of the cylinder due to flow acceleration when the jet width is greater than the radius of curvature.
5. A computational code newly developed based on a model of compressible gas-liquid two-phase media can predict well the shock wave behavior in cavitation clouds and the cloud-breakup phenomenon.
|
