|
Abrasive Water suspension jets, namely water jets containing
abrasive particles, have a considerable niche in the material
processing industry. Like laser cutting instruments they
are accurate, easily managed and cause very little loss
of material. However, abrasive jet cutting does not involve
high temperatures, which is characteristic to laser cutting,
and as a result they are suitable for practically any material.
Furthermore, the instrumentation required for high-speed
jets is simpler and much cheaper. Consequently, jet cutting
can be implemented in a broad range of industries, ranging
from small machine shops and quarries, to large sheet metal,
composites or ceramic processing in the car and aircraft
industries.
The most troublesome
difficulty associated with high speed slurry jets, which
presently limits their usefulness, is wear of the nozzle
walls. Since the jet speed ranges between 100-500 m/sec,
and the particle size can be as high as 40% of the nozzle
diameter, it does not take long to destroy a nozzle. Consequently,
in current systems nozzles must be replaced frequently,
sometimes every 10-20 minutes requiring constant maintenance,
inspection, loss of accuracy and machine down time.
This project introduces a novel method for preventing nozzle
wear in high-speed slurry jets. The method consists of using
a nozzle with porous walls and lubricating the internal
walls of the nozzle with oil forced under pressure through
the porous walls. The resulting oil film protects the walls
from impact and shear caused by the abrasive particles.
We have constructed two facilities:
- Two-dimensional nozzle facility - to visualize
the flow and optimize the parameters
- Axisymmetric nozzle facility - to test the
extent of nozzle wear
Several techniques have been used during the experiments:
|
|
Anand,
U., Katz, J., 2003, "Prevention
of nozzle wear in Abrasive Water Suspension Jets (AWSJ)
using porous lubricated nozzles," ASME Journal
of Tribology, Vol. 125 (1), pp. 168-180.
Anand,
U., Katz, J., 2001, "Using
Porous Lubricated Nozzles to prevent Nozzle Wear in Abrasive
Water Suspension Jets (AWSJ)", Proceedings of the
American Water Jet Conference, Minneapolis, Minnesota,
USA, August 18-21.
Anand,
U., Katz, J., 2001, "Improving the Life Span of Nozzles
in Abrasive Water Suspension Jets using Porous Lubricated
Nozzles", Proceedings of the ASME Fluids Engineering
Division Summer Meeting, New Orleans, USA, May 27 -
June 1.
Anand,
U., Katz, J., 2000, "Prevention
of nozzle wear in high-speed slurry jets using porous lubricated
nozzles", Proceedings of the 6th Pacific Rim International
Conference on Water Jetting technology, Sydney, Australia,
October 8-11.
Anand,
U., Katz, J., 2000, "Lubricated nozzles for high-speed slurry
jets", Proceedings of the ASME Fluids Engineering Division
Summer Meeting, Boston, June 11-15.
|
