The
Emerson Cavitation Tunnel is a propeller testing facility based at Newcastle University,
UKThe United Kingdom of Great Britain and Northern Ireland is a sovereign state located off the northwestern coast of continental Europe. It is an island country, spanning an archipelago including Great Britain, the northeastern part of Ireland, and many small islands...
. The tunnel is based in the department of Marine Science and Technology, and is currently the second largest cavitation tunnel in the UK, the largest being that owned by the
Ministry of DefenceThe Ministry of Defence is the United Kingdom government department responsible for implementation of government defence policy and is the headquarters of the British Armed Forces....
at
HaslarHaslar is the name of a place in the United Kingdom. It is found at the southern tip of Gosport, Hampshire and takes its name from two Anglo-Saxon words: haesel, meaning hazel, and ora, meaning bank...
.
The Emerson Cavitation Tunnel consists of a water circuit which flows in the vertical plane, within which propellers and other propulsion devices can be tested.
The
Emerson Cavitation Tunnel is a propeller testing facility based at Newcastle University,
UKThe United Kingdom of Great Britain and Northern Ireland is a sovereign state located off the northwestern coast of continental Europe. It is an island country, spanning an archipelago including Great Britain, the northeastern part of Ireland, and many small islands...
. The tunnel is based in the department of Marine Science and Technology, and is currently the second largest cavitation tunnel in the UK, the largest being that owned by the
Ministry of DefenceThe Ministry of Defence is the United Kingdom government department responsible for implementation of government defence policy and is the headquarters of the British Armed Forces....
at
HaslarHaslar is the name of a place in the United Kingdom. It is found at the southern tip of Gosport, Hampshire and takes its name from two Anglo-Saxon words: haesel, meaning hazel, and ora, meaning bank...
.
Capabilities
The Emerson Cavitation Tunnel consists of a water circuit which flows in the vertical plane, within which propellers and other propulsion devices can be tested. The system is powered by a pump, with a four-bladed
impellerAn impeller is a rotor inside a tube or conduit to increase the pressure and flow of a fluid.- Impellers in pumps :An impeller is a rotating component of a centrifugal pump, usually made of iron, steel, bronze, brass, aluminum or plastic, which transfers energy from the motor that drives the pump...
and can produce a maximum water velocity of . The test area has a cross sectional area of allowing model propellers of up to in diameter to be tested. The pressure range of the tunnel can vary from a minimum of 7.6kN/m
2 to a maximum of 106kN/m
2.
Cavitation numbersThe Euler number is a dimensionless number used in fluid flow calculations. It expresses the relationship between a local pressure drop e.g. over a restriction and the kinetic energy per volume, and is used to characterize losses in the flow, where a perfect frictionless flow corresponds to an...
of 0.5 (minimum) to 23 (maximum) can be accommodated for. Measurements can be taken using a 3 Watt, water-cooled,
ArgonArgon is a chemical element designated by the symbol Ar. Argon has atomic number 18 and is the third element in group 18 of the periodic table . Argon is present in the Earth's atmosphere at 0.94%. Terrestrially, it is the most abundant and most frequently used of the noble gases...
-ion laser, a hydrophone, and two
dynamometerA dynamometer or "dyno" for short, is a device for measuring force or power. For example, the power produced by an engine, motor or other rotating prime mover can be calculated by simultaneously measuring torque and rotational speed ....
s. A high-speed video camera is also attached with an imaging frequency of 0–50 frames per second.
Funding for the tunnel's equipment is raised by numerous organisations, including the
Engineering and Physical Sciences Research Council (EPSRC)The Engineering and Physical Sciences Research Council is a British Research Council that provides government funding for grants to undertake research and postgraduate degrees in engineering and the physical sciences , mainly to universities in the United Kingdom...
and the Scottish Universities of Glasgow and
StrathclydeThe University of Strathclyde , Glasgow, Scotland, is Glasgow's second university by age, founded in 1796, and receiving its Royal Charter in 1964 as the UK's first technological university. It takes its name from the historic Kingdom of Strathclyde...
.
History
- A full history of the Emerson Cavitation Tunnel is available at www.ncl.ac.uk/cavitation
The tunnel was first established at the University in 1949 after being disassembled and transported from Pelzerhaken,
GermanyGermany , officially the Federal Republic of Germany , is a country in Central Europe. It is bordered to the north by the North Sea, Denmark, and the Baltic Sea; to the east by Poland and the Czech Republic; to the south by Austria and Switzerland; and to the west by France, Luxembourg, Belgium,...
after the Second World War. The tunnel arrived at the University in 1947 and over the following few years the tunnel was heavily modified. The tunnel - which was originally designed to operated in the horizontal plane - was converted into a vertical loop tunnel and the length was reduced by half. The original observation window was modified and two more added. Because of damage, a new impeller was constructed and numerous pieces of measuring equipment were added. This equipment included
pitot tubeA pitot tube is a pressure measurement instrument used to measure fluid flow velocity. The pitot tube was invented by the French engineer Henri Pitot in the early 1700s and was modified to its modern form in the mid 1800s by French scientist Henry Darcy...
s, a
tachometerA tachometer is an instrument that measures the rotation speed of a shaft or disk, as in a motor or other machine. The device usually displays the revolutions per minute on a calibrated analogue dial, but digital displays are increasingly common...
,
stroboscopicA stroboscope, also known as a strobe, is an instrument used to make a cyclically moving object appear to be slow-moving, or stationary. The principle is used for the study of rotating, reciprocating, oscillating or vibrating objects...
lighting equipment, contact meters and a vacuum pump. The tunnel was connected to an electrical supply in 1949 and entered service late in 1950, after technical problems called for recalibration of some of the instruments. The Cavitation Tunnel is still housed in Newcastle University's old boiler house, where it was originally reconstructed.
The first research grant of £8,000 was awarded in 1950 for the testing of a new series of
propellerA propeller is a type of fan which transmits power by converting rotational motion into thrust. A pressure difference is produced between the forward and rear surfaces of the airfoil-shaped blade, and air or water is accelerated behind the blade...
s, and was awarded by the Department of Scientific and Industrial Research (DSIR).
In the 1970s and 1980s, the tunnel was extensively modified and upgraded in order to improve the range of propellers that could be tested. The tunnel was also renamed to its current name, the
Emerson Cavitation Tunnel after Dr Arnold Emerson, who was the tunnel superintendent and the driving force behind the upgrades.
Since the upgrades of the 1980s, few other modifications have been made to the tunnel itself. New computer-based data collection, interpretation and analysis technology has been added to aid with
computational fluid dynamicsComputational fluid dynamics is one of the branches of fluid mechanics that uses numerical methods and algorithms to solve and analyze problems that involve fluid flows. Computers are used to perform the millions of calculations required to simulate the interaction of liquids and gases with...
. Data is also collected with the help of
laser doppler anemometry (LDA)Laser Doppler Velocimetry is a technique for measuring the direction and speed of fluids like air and water. In its simplest form, LDV crosses two beams of collimated, monochromatic, and coherent laser light in the flow of the fluid being measured...
and phase doppler anemometry (PDA).
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