Field of invention
The present invention relates to a system and a method for determining erosion
of pipes carrying nanofluids by impingement of the nanofluids.
Background of the invention
The applicability of nanofluids as superior heat removal agents has been well
established. Nanofluids can be described as a colloidal solution containing
suspended nano particles (nanometer sized particles of metals, oxides or nano
tubes), dispersed in a homogenous way in a base fluid [1]. They exhibit
enhanced thermal properties like thermal conductivity and high heat transfer
coefficient compared to the base fluid. With the miniaturization of electronic
components and with ever- increasing demand for better heat extracting
coolants in steel and power sector, the nanofluids are expected to completely
replace the commonly used fluids for cooling purpose in the near future.
But it is anticipated that the nanofluids in contact with the material surface for a
longer duration of time may pose a threat due to the gradual erosion of the
material surface. In order to frame a preventive maintenance schedule, it is
always imperative to analyze in advance the wear that can be expected within a
vessel, a pipe or any other device, due to their constant contact with the
nanofluid. Currently there exists no appropriate device or procedure for
addressing this issue. Erosion of the impeller/ pipe lines during the coal
liquefaction process has been reported by prior art (US 2274541 and,
US2519323). US 4493206 describes various test procedures for determination of
material surface erosion in the presence of abrasive particles in a liquid medium
or slurries.

The test procedures described in the cited patents essentially involve, rotation of
a test specimen in an erosion/corrosive fluid, which generally simulate the
rotation of an impeller in an abrasive fluid medium. ASTM standard "Standard
Test Method for liquid Impingement Erosion using rotating Apparatus"
(Designation 73-10) provides further details on erosion tests in which the solid
specimens are eroded or damaged by repeated discrete impacts of liquid drops
or jets including systematic steps for determining the damage by mass loss
measurements.
Detailed literature review [2-5], reveals that the most significant parameters in
the erosion caused by slurries are the angels of impingements, velocity of
impingement and distance between the impinging source and the test surface.
Objects of the invention
It is therefore an object of the invention to propose a;system for determining an
erosion rate of nano-fluid carrying material caused by impingement of
nanofluids.
Another object of the invention is to propose a system for determining an
erosion rate of nano-fluid carrying material caused by impingement of
nanofluids, which is enabled to identify a co-relation amongst the impingements
angle, impingement velocity, and impingement distance on the determined
erosion rate.
A further object of the invention is to propose a method for measuring the
erosion rate of a material surface caused by nanofluid impingement.

SUMMARY OF THE INVENTION
Accordingly there is provided a system for determining material surface erosion
caused by impingement of nanofluids on pipes carrying nanofluids, comprising:
a nozzle device having atleast four nozzles disposed equidistantly on a test-
specimen surface; a device for holding the test specimen having atleast four
sample holders, and a metal rod; a first stand having a plurality of clamping
means, the nozzle assembly and the sample holders mounted on the first stand
being movable by means of said plurality of clamping means; and a dial attached
to said metal rod to measure the angular tilt of the nozzle; a second stand
holding a tank attached to a sump, the tank accommodating the assembly of the
nozzle device, specimen holders with test specimens, and the first stand, the
tank having an opening flowably connected via a triangular channel to the sump
for collecting the nano-fluid after being impinged by the nozzle device on the
surface of the test specimen; a nanofluid distribution device having at a first end
a plurality of second tee- joints, the second end being closed; and a plurality of
pumps controlling delivery of the nanofluid from the nozzles being measured
through corresponding number of flow-meters and a series of first plurality of
tee-joints, an electronic circuitory monitoring a plurality of solenoid valves to
prevent over-heating of the pumps to control flow from the pumps to the
nozzles.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The scope of the invention can be better understood by the description provided
here in below with reference to the accompanying drawings, in which:
Fig 1 represents an exploded view of a nozzle bank used for the impingements of
fluids on test specimens, hence referred to as a nozzle' unit.
Fig 2 represents an exploded view of means for holding test specimens,
henceforth referred to as a sample holder unit.
Fig 3 represents an assembly of the nozzle unit, the sample holder unit along
with a stand.
Fig 4 represents a sectional front view of an erosion test device of the invention
disposed inside a tank.
Fig 5 represents a front view of the erosion test device according to the
invention.
Fig 6 represents an isometric view of the system of fig-5.
Fig 7 represents a top view of the system of fig-5.

DETAILED DESCRIPTION OF THE INVENTION
Hereafter, the embodiments of the invention are illustrated with reference to the
accompanying figures. Fig 1 shows the nozzle assembly which consists of atleast
four nozzles 3, each having an outlet diameter between 1.0 to 2.0 mm, through
which the nanofluid is allowed to impinge on a test specimen surface 10 in Fig 2
as jets. The nozzles (3) are fixed equidistantly on a holder 2 having substantially
square shaped cross section and a tubular shape at the ends, on which the
nozzles 3 are fixed. All the nozzles 3 and the holder 2 are fabricated with high
grade stainless steel, to avoid the corrosion that may be caused by the base fluid
in which nano particles are suspended. The inlet and outlet diameters of the
nozzle 3 are between 8 to 16 mm, and 1.0 to 2.0 mm,respectively.The outlet
diameter is selected in such a way that the characterization of surfaces of the
test specimen (10) using instruments like SEM and AFM can be effectively carried
out.
The tubular ends of the nozzle holder 2 are connected to atleast two identical
first clamps 29. The first clamp 29 is made of a square tube welded at the end of
a metal rod. The square tube is drilled and taped at its center and a first bolt 30
is used to fix the first clamp (29) on the nozzle holder unit (3) on a first stand 1
in fig 3. The second clamp 4 is made of two square tubes, which are welded
together in such a way that their hollow ends are perpendicular to each other as
shown in fig 1. Each tube is drilled at its center and a first nut 7 is welded over
the drilled hole. One of the square tube of the second clamp 4 is inserted on the
first stand 1 as shown in Fig 3 and is fixed on it using a sixth bolt (5).

Fig 2 represents a device for holding the test specimens 10. A set of four sample
holders 9 made of stainless steel is used to fix the test specimen 10 each having
dimensions 25x25x6x mm, in such a way that the jet from the nozzle 3 impinges
on the test specimen 10. The test specimens 10 are kept in position by means of
a plurality of third bolts 17 which are attached to the specimen holder 9. Each of
the specimen holders 9 is attached to a stainless rod 8. The ends of the steel rod
are connected to two third identical clamps 12. The third clamp 12, similar to the
second clamp 4, is made of two square tubes which are welded together keeping
the hollow sections perpendicular to each other. Each tube is drilled at its center
and a second nut 15 is welded over the drilled hole. One of the square tubes of
the third clamp(12) is inserted to the steel rod 8 which holds the sample holders
9 and is fixed to the third clamp 12 as shown in Fig 3. The second square tube of
the third clamp 12 is inserted on the first stand 1 as shown in Fig 3 and is fixed
on it by means of a fifth bolt 14.
In Fig 3, the complete arrangement of the nozzle assembly (3) and the specimen
holders (9) attached to first stand (1) is shown. Both the bank of nozzle 3 and
the sample holders 9 can be moved over the common first stand 1 with the help
of the second and third clamps 4,12 respectively and the sixth and fifth bolts
5,14 respectively. This is provided to understand the effect of distance between
the nozzle 3 and the specimen 10, on erosion rate of the materials surface.
In addition to the distance adjustments, the angular adjustment of the specimen
holders 9 can also be done with the help of the third clamp 12. A dial 31 at the
end of the rod 8 is used to measure the angular tilts. The first stand 1 is of
substantially rectangular cross section and is made of stainless steel.

In Fig 4, the assembly shown in Fig 3 is placed inside a tank 16, which is
configured to allow collection of nanofluid after impinging the test specimen 10.
For collecting of nanofluid in a sump 19, a triangular channel with appropriate
inclination at the bottom of the tank 16 is provided.
An opening 28, provided at the corner of the tank 16, helps to drain the fluid out
of the tank 16.
Fig 5 represents the front view of the test system, in which connection of the
four nozzles 3 to corresponding number of flow meters 23, fixed on the side of
the tank 16, is shown. The flow meters 23 are used to measure the flow rate
through each nozzle 3 and are connected to the nozzle using same number of
flexible pipes 11. The flow meters 23 are capable of measuring flow rates up to
250 liters per hour. The flow meters 23 are connected to corresponding number
of flow control valves 25 which constitute a part of a nanofluid distribution
means 24 of Fig 6 using the flexible pipes 11, to adjust the speed of the
nanofluid jet impinging on the test specimen 10. A second stand 18 made of mild
steel is used to hold the tank 16 and assembly of Fig 3, above the ground level.
In Fig 6, the distribution of the nanofliud to each nozzle 9 via the flow meter 13
is achieved by means of a series of first tee joints 26 and said flow control valves
25. One end of the nanofluid distribution means 24 is closed and the other end is
connected to a second tee joint 27, which is a common output from a plurality of
pumps 21 as shown in Fig 7. To prevent over heating of the pumps due to
continuous operation, an electronic circuit 22, along with a plurality of solenoid
valves 20 is used for controlling the flow from the pumps 21 and also for
switching the operation from one pump 21 to another after a specified duration
of time. The pumps 21 are connected to the sump 19 by means of the flexible

pipes 11. AC power is used to start a switch over circuit 22, from which the
power required by the pumps 21 as well as the solenoids valves 20 is taken.
METHOD FOR THE ESTIMATION OF EROSION RATE
The test specimen surfaces are finished using polishing paper of 600 grit size.
The polished specimen is kept inside a beaker containing distilled water and the
beaker is then placed in an ultrasonic shaker for about 30 minutes to remove the
unnecessary particles sticking on the sample surface. The cleaned sample is kept
in an oven for drying. The dried sample is weighed in an electronic balance
having a least count of O.Olmg. For measuring the erosion rate, the sample is
fixed on the sample holder of the tester and the nanofluid is made to impinge on
it for a specified time, and the weight of the sample is again measured after
cleaning and drying using ultrasonic shaker and oven respectively. The weight
loss is noted down and variation of the weight loss with respect to time gives the
erosion rate. The inventive system can be used to estimate the nanofluid
impinged material surface erosion, of up to four different test specimens at a
time. The system can also be used to analyze the effect of the impingement
angle, impingement velocity of the nanofluid and impingement distance on the
material surface erosion rate. The method for estimating the damage by mass
loss measurement has also been provided.
REFERENCES
1. Choi SUS, Enhancing thermal conductivity of fluids with nonoparticles, ASME
Fluids Eng div (publ) FED 231:99-105,1995.

2. Levy Alan V and Paul Yau, Erosion of steels in liquid slurries, Wear, 98,pp 163-
182,1984.
3. Fuyan Lin and Hesheng shao, the effect of impingement angle on Slurry
erosion, wear, 141, pp 279-289-1991.
4. Al-Bukhaiti M A, Ahmed S M, Badran F M F NAD Emara K M, Effect of
impingement angle on slurry erosion behavior and mechanisms of 1017 steel and
high chromium white cast iron, Wear, 262,pp 1187-1198,2007.
5. Yuan zhong and kiyoshi Minemura, Measurement of erosion due to particle
impingement and numerical prediction of wear in pump casing, Wear.199.pp 36-
44,1996.

We claim:
1. A system for determining material surface erosibn caused by impingement
of nanofluids on pipes carrying nanofluids, comprising:
a nozzle device having atleast four nozzles disposed equidistantly on a
test-specimen surface; a device for holding the test specimen having
atleast four sample holders, and a metal rod; a first stand having a
plurality of clamping means, the nozzle assembly and the sample holders
mounted on the first stand being movable by means of said plurality of
clamping means; and a dial attached to said metal rod to measure the
angular tilt of the nozzle; a second stand holding a tank attached to a
sump, the tank accommodating the assembly of the nozzle device,
specimen holders with test specimens, and the first stand, the tank
having an opening flowably connected via a triangular channel to the
sump for collecting the nano-fluid after being impinged by the nozzle
device on the surface of the test specimen; a nanofluid distribution device
having at a first end a plurality of second tee- joints, the second end being
closed; and a plurality of pumps controlling delivery of nanofluid from the
nozzles being measured through corresponding number of flow-meters
and a series of first plurality of tee-joints, an electronic circuitory
monitoring a plurality of solenoid valves to prevent over-heating of the
pumps to control flow from the pumps to the nozzles.

2. A system for determining material surface erosion caused by
impingement of nanofluids on pipes carrying nanofluids, as
substantially described and illustrated herein with reference to the
accompanying drawings.

The invention relates to a system for determining material surface erosion
caused by impingement of nanofluids on pipes carrying nanofluids, comprisinga
nozzle device having atleast four nozzles disposed equidistantly on a test-
specimen surface; a device for holding the test specimen having atleast four
sample holders, and a metal rod; a first stand having a plurality of clamping
means, the nozzle assembly and the sample holders mounted on the first stand
being movable by means of said plurality of clamping means; and a dial attached
to said metal rod to measure the angular tilt of the nozzle; a second stand
holding a tank attached to a sump, the tank accommodating the assembly of the
nozzle device, specimen holders with test specimens, and the first stand, the
tank having an opening flowably connected via a triangular channel to the sump
for collecting the nano-fluid after being impinged by the nozzle device on the
surface of the test specimen; a nanofluid distribution device having at a first end
a plurality of second tee- joints, the second end being closed; and a plurality of
pumps controlling delivery of the nanofluid from the nozzles being measured
through corresponding number of flow-meters and a series of first plurality of
tee-joints, an electronic circuitory monitoring a plurality of solenoid valves to
prevent over-heating of the pumps to control flow from the pumps to the
nozzles.