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|Title: ||The study of high pressure water jet assisted cutting of coal samples in the laboratory|
|Authors: ||Martin, John Andrew Peter|
|Issue Date: ||1991 |
|Publisher: ||Newcastle University|
|Abstract: ||A series of experiments were conducted to invesdgate high pressure water jet assisted
coal cutting. The research was sponsored by British Coal and carried out in the Department
of Mining Engineering at the University of Newcastle upon Tyne.
Two coals were tested: a black, coherent, anthracite; and a heavily cleated, friable, dull
coloured bituminous coal. The tests modelled as closely as possible a vane pick on a two
start shearer drum.
The experiment was performed on a modified 50 tonne linear cutting rig at a speed of
I. Im/s, using jet pressures of 35MPa, 70MPa, and 105MPa at different flow rates. A
75kW double acting intensifier type pump supplied the high pressure water for the jet. A
relieved cutting mode was adopted with a line spacing of 70mm, and a 30mm nominal
depth of cut. An actual production cutting tool (heavy duty 75mm radial with a HW tip)
cut the coal in both the sharp and blunt states. Additional tests were also performed by
pre-slotting the coal with a water jet before cutting it and by examining the effect of varying
the lead and offset distances on the parameters measured below.
Parameters measured were the cutting forces in three orthogonal directions; the breakout
patterns; and the coal size distribution. The coal yields and specific energies were calculated
from the experimental data.
Both coals achieved benefit from jet assistance but at different pressures depending upon
the coal type and tool wear. The breakout pattern differed between the two coals but generally
fracture occurred along the major cleat planes. Both coals were easier to cut when
the major cleat was orientated in the horizontal plane rather than in the vertical plane.
Specific energy increased linearly with jet power. In most cases the quantity of fine coal
(-0.5mm) produced decreased with jet assistance.|
|Description: ||PhD Thesis|
|Appears in Collections:||School of Mechanical and Systems Engineering|
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