Simulation of C
and Corin Segal
University of Florida, Gainesville, Florida, 32611, USA
Cavitation in turbopumps is a major concern to the performance
and longevity of this equipment
since it leads to v
eady flow and
conventional substances such as water, cryogenics undergo a large temperature deficit that occurs
and therefore cavitation in water is
different than in cryogeni
simulation in water is limited. Hence, the study
detailed below employs a thermosensitive fluid to
simulate cryogenic cavitation.
The onset and formation of vapor b
ubbles and cloud cavitation
NACA 0015 hydrofoil as a generic surface.
conditions include changes in fluid velocity and cavitation number.
with perfluorinated ketone 2
1, 1, 1, 2, 4, 4, 5, 5,
pentanone as the working fluid at temperatures
25 and 70 degrees C.
The angle of attack of the airfoil
from 0 to 7 degrees
and the freestream fluid velocity
in the range of
to 10 m/s.
Strouhal numbers vary between 0.07 to 0.5 and Reynolds numbers of
the flow occur between
,000 and 2
The hydrofoil has a chord length of 50.8mm and
Graduate Research Assistant, MAE University of Florida, Gainesville FL 32611.
Associate Professor, MAE University of Florida, Gainesville FL 32611, Associate Fellow AIAA.
the flow has a dynamic viscosity ranging from 3.53 x10
achieved in these experiments
2.11 at 6 m/s and 25 degrees C
to almost zero
at 10 m/s and 48 degrees C
, thus a broad range of cavitation conditions
The fluid was chosen for its
large temperature change during evaporation
local effect on the cavitation characteristics is significant
. It appears
which is found from
* 0.7 0.2
The flow being studied has
a thermodynamic effect on the
same order of magnitude as
, whereas water ranges on the order of magnitude of 0.01
This thermodynamic effect is defined
, which has a 10
test section capable of 10
flow and has optical access from the top and front via glass windows and laser access
through the hydrofoil. It is equipped with stagnation and settling chambers
and a 7.5kW
heater. The hydrofoil can be pos
itioned with an angle of attack from
10 to 10
Figure 1b shows
selected results of
cavitation on the hydrofoil. At the bottom of the
image filaments of incipient cavitation appear on the hydrofoil and at the top there appears the
onset of cloud ca
Figure 2 shows
selected results of well
cloud cavitation over the entire span of
e hydrofoil when the
was set to
0.7. This type of cavitation is
heat transfer to the surface
loss in flow rate
for a pump,
and an increase in vibration and
fluctuations across the suction and
is a top view with the leading and trailing edge identified in the image.
is a side view with the hydrofoil suction side evident.
can be seen
cavitation extends beyond the trailing edge of the hydrofoil
and although the initial conditions
and geometry are 2
These two images were taken in
different experiments and indicate a large degree of unsteadiness is present.
a) layout of the
used in the experiments
This facility has a test section measuring 102x 102 mm
9.6 m/s with optical access from the top and side via glass windows and via laser sheet from the rear.
Top view of
under incipient cavitation
louroketone at ambient pressure and temperatures
of 1atm and 25°C, respectively. Flow is
from left to right at 6.7 m/s., angle of attack is 5.1 degrees.
a) Top view of cavitation at 35 degrees C and 8.64 m/s. This corresponds to a cavitation number of 0.7. Flow
from left to right. Superimposed vertical lines i
ndicate leading and trailing edge of the hydrofoil. b) Side view of
at 40 degrees C and 7,16 m/s
. Flow is from left to right. Vertical lines indicate leading and trailing edge of the
Cervone, A., Bramanti, C., Rapposelli, E., d’Agostino, L., “Thermal Cavitation Experiments on a
NACA 0015 Hydrofoil”.
Transactions of the ASME
(3), p. 326
Gustavsson, J. P. R., Denning, K., Segal, C.,
Experimental study of Cryogenic Cavita
, AIAA 2008
AIAA Aerospace Sciences Meeting and Exhibit
, Reno, NV,