2006 Fiscal Year Final Research Report Summary
Flow characteristics of high speed water jet and effective nozzle shape for machining
| Project/Area Number |
16560160
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Fluid engineering
|
|---|
| Research Institution | Waseda University |
|---|
Principal Investigator |
YAMAMOTO Katsuhiro Waseda University, Faculty of Science and Engineering, Professor, 理工学術院, 教授 (10063752)
|
|---|
| Project Period (FY) |
2004 – 2006
|
| Keywords | Water Jet / Cavitation Jet / Mass Loss Curve / CIP Method / Impulse Water Jet / Impact Pressure / Flow Characeristics / Effective Nozzle Shape |
|---|
| Research Abstract |
Two types of high speed water jets are examined by experimental method and numerical analysis to find effective nozzle shape. One is submerged water jet with constant delivery pressure of 50-200MPa, and nozzle diameter of 0.155 mm, the other is impulse water jet issuing from a taper nozzle into the atmosphere with velocity of 500m/s and nozzle diameter of 2mm.
The main results are summarized as follows.
(1) The finite difference method of CIP is effective for the numerical analysis of gas-liquid two phase flows which include discontinuous interface in the flow field.
(2) In case of machining with high speed submerged water jet, the stand off distance of material from a nozzle should be taken as possible as short for piercing, drilling or cutting, because the momentum of jet plays an important role in removing material. On the other hand, the stand off distance depends on the delivery pressure for polishing or peening, because cavitation plays a main part the surface treatment. In both cases, outlet length of nozzle cap should be taken short and the diameter small.
(3) On the impulse water jet which is produced by piston impact, collision and break up of the jet with complicated shock waves are observed by colored Schlielen method and high speed video camera. The computational results show the same characteristics of the jet flow as observed one qualitatively. The effect of the nozzle shape, the initial position of water column in the nozzle and stand off distance on the impact pressure on a solid material can be examined by CIP difference method.
|
