Emerson Cavitation Tunnel
Encyclopedia
The Emerson Cavitation Tunnel is a propeller testing facility based at Newcastle University, UK
. 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 Defence
at Haslar
.
and can produce a maximum water velocity of 15.5 knots (8.4 m/s). The test area has a cross sectional area of 0.99 m² (1.2 sq yd) allowing model propellers of up to 40 cm (15.7 in) in diameter to be tested. The pressure range of the tunnel can vary from a minimum of 7.6 kN/m2 to a maximum of 106 kN/m2. Cavitation numbers
of 0.5 (minimum) to 23 (maximum) can be accommodated for. Measurements can be taken using a 3 Watt, water-cooled, Argon
-ion laser, a hydrophone, and two dynamometer
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)
and the Scottish Universities of Glasgow
and Strathclyde
.
The tunnel was first established at the University in 1949 after being disassembled and transported from Pelzerhaken, Germany
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 tube
s, a tachometer
, stroboscopic
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 propeller
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 dynamics
. Data is also collected with the help of laser doppler anemometry (LDA)
and phase doppler anemometry (PDA).
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
. 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 Defence
Ministry of Defence (United Kingdom)
The 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 Haslar
Haslar
Haslar is place in England, at the southern tip of Alverstoke, on the Gosport peninsula, Hampshire. It takes its name from Anglo-Saxon hæsel-ōra = "hazel - landing place"...
.
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 300 kW pump, with a four-bladed impellerImpeller
An impeller is a rotor inside a tube or conduit used to increase the pressure and flow of a fluid.- Impellers in pumps :...
and can produce a maximum water velocity of 15.5 knots (8.4 m/s). The test area has a cross sectional area of 0.99 m² (1.2 sq yd) allowing model propellers of up to 40 cm (15.7 in) in diameter to be tested. The pressure range of the tunnel can vary from a minimum of 7.6 kN/m2 to a maximum of 106 kN/m2. Cavitation numbers
Euler number (physics)
The 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, Argon
Argon
Argon is a chemical element represented by the symbol Ar. Argon has atomic number 18 and is the third element in group 18 of the periodic table . Argon is the third most common gas in the Earth's atmosphere, at 0.93%, making it more common than carbon dioxide...
-ion laser, a hydrophone, and two dynamometer
Dynamometer
A dynamometer or "dyno" for short, is a device for measuring force, moment of 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 .A dynamometer can also be used to determine...
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)
Engineering and Physical Sciences Research Council
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
University of Glasgow
The University of Glasgow is the fourth-oldest university in the English-speaking world and one of Scotland's four ancient universities. Located in Glasgow, the university was founded in 1451 and is presently one of seventeen British higher education institutions ranked amongst the top 100 of the...
and Strathclyde
University of Strathclyde
The 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...
.
History
- A full history of the Emerson Cavitation Tunnel is available at research.ncl.ac.uk/cavitation
The tunnel was first established at the University in 1949 after being disassembled and transported from Pelzerhaken, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
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 tube
Pitot tube
A pitot tube is a pressure measurement instrument used to measure fluid flow velocity. The pitot tube was invented by the French engineer Henri Pitot Ulo in the early 18th century and was modified to its modern form in the mid-19th century by French scientist Henry Darcy...
s, a tachometer
Tachometer
A tachometer is an instrument measuring 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...
, stroboscopic
Stroboscope
A 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 propeller
Propeller
A propeller is a type of fan that 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 a fluid is accelerated behind the blade. Propeller dynamics can be modeled by both Bernoulli's...
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 dynamics
Computational fluid dynamics
Computational fluid dynamics, usually abbreviated as CFD, is a branch of fluid mechanics that uses numerical methods and algorithms to solve and analyze problems that involve fluid flows. Computers are used to perform the 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
Laser Doppler Velocimetry , also known as Laser Doppler Anemometry , is the technique of using the Doppler shift in a laser beam to measure the velocity in transparent or semi-transparent fluid flows, or the linear or vibratory motion of opaque, reflecting, surfaces.-Technology origin:With the...
and phase doppler anemometry (PDA).
External links
- Emerson Cavitation Tunnel website at Newcastle University
- Department of Marine Science and Technology at Newcastle University