WATER JET CONFERENCE - Waterjet Technology Association

Again, not limited to Newtonian fluids. (Brown & Loper, 1961 and Forstal & Gaylord,
1955).
Bernouli's laws define the lower limits of "X/D". There appear to be no upper
limits to this relationship, other than those governed by economics.
Polymer
Subsequent experimentation by this author and others (Private Communication,
1980) demonstrated that by the addition of long chain high molecular weight polymers
(such as "SUPER WATER") to the fluid, the jet stream could be made to maintain its
departure cross section for a greater distance, as well as increase target impact (NPRA
1978 and Private Communication 1980).
With the addition of polymers a statement similar to Equation (10) was suggested
from preliminary test data as follows (see Chart No. 2):
Px = Po 2130/ X
3
⎛ ⎞
⎜ ⎟ and Px ≤ Po (11)
⎝ D⎠
Clean ng Energy
Combining Equations (6), (7) and (9),
where
CE = 14.1 D^2 P^.75 N/e^.5 Vt (12)
CE = Cleaning Energy Flux (Lb - Ft/in .)
Equation (11) (Zublin, 1982) represents the "CE" values developed at the jet. In
order to determine the value of "CE" at the target, power efficiencies must be considered.
Using Equations (10) or (11) and rewriting we have:
Where
Px/Po = C/ (X/D)^3 = E f (13)
C = a constant (213 or 2130).
Ef = system efficiency in %age.
Operating Speed
Now rewriting equation (12) to solve for Vt and combining with Equation (13)
yields:
Vt=14.1*D^2 P^3/2 N*Ef/e^.5 CE (14)
as the linear expression for jet cleaning travel rate in inches per second (Zublin, 1982).
DISCUSSION
While equation (14) relates all of the variables and is dimensionally correct, there
are some parameters that need to be explored.
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