The main data of the Cavitation Tunnel is as follows:
Pressure regulation from relatively high vacuum to above atmospheric pressure measured at the pressure regulation container 1 bar Approx
Cavitation number adjustable in wide range down to belows = 0.2
Total length including stiffening girder not including the length required for the impeller drive 20.4 m Approx.
Measuring section 850 mm x 850 mm
Length of measuring section 4000 mm
Contraction ratio of the nozzle 4.99:1 Approx.
Maximum velocity of the water in the measuring section 12 m/s
Total height from the floor at which the tunnel foundations are supported to the highest part of the cavitation tunnel, inclusive stiffening girders, not including additional height for the separate pressure regulation container and not including the height for setting in propeller dynamometers or other test equipment 12.9 m.
The cavitation tunnel installed at the Laboratory for Hydraulic Machines provides high speed visualization of various types of cavitation phenomena, including leading edge cavitation, wake cavitation, and tip vortex :
Cavitation nuclei control
Pressure transducers
High speed visualization
5 components load cell
Optical instrumentation: particle image velocimetry, Laser Doppler velocimetry.
The additional measuring sections Nos. 2, 3 and 4 are exchangeable against the standard measuring section so that the tunnel can be made suitable for a wide range of test work.
The main data of a Cavitation Tunnel with the standard measuring section are as follows:
Contraction ratio of the nozzle 5.96 : 1
Measuring section 60 cm x 60 cm
Cavitation number adjustable in a wide range down to below
Total length including stiffening girders, not including the length required for a propeller dynamometer and a wake rake 13.9m
Maximum velocity of the water in the measuring section 12m/s
Pressure regulation from relatively high vacuum to above atmospheric pressure measured at the pressure regulation container 1 bar Approx.
Total height from the floor at which the tunnel foundations are supported to the highest part of the cavitation tunnel, inclusive stiffening girders, not including some additional height for the separate pressure regulation container and not including the height required for setting in propeller * dynamometers or other test equipment 9.3m.
High Speed / Frame Rate Camera system for observing cavitation.
Window mounting hydrophone system for use in the educational cavitation tunnels.
Educational Wake Rake with integrated pressure transducers for measuring the wake profile within the tunnel.
Flat Plate and Cylinder Model Experiment for use in Tunnels.
Pitot Static tube for use in measuring section of Tunnel.
The dynamometers have been designed for low friction torque at the propeller shaft and for this reason shaft seals are not fitted. As a result, the dynamometers are not watertight. If watertight propeller dynamometers are required, alternative designs are available. All dynamometers have a similar appearance although vary in size / rating to suit the intended specification required. The Dynamometers are compact with low weight and small dimensions and as such are suitable for use with models over a wide range of sizes however also offer with suitable accessories the ability of mounting two dynamometers driven through a gear box to allow the testing of twin screw models. The self propulsion dynamometer measures thrust and torque of the propellers during propulsion tests with ship models on smooth water and in waves in towing tanks.
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