444
P. Liu
of Hydrology and Shipbuilding in Berlin, Germany. It has a free surface;
the section size of the test section is 5 m by 3 m, and the length is 1 m.
The center of the cave is 10.5 m high; the maximum speed of water is
12 m/s. High-velocity water flow (such as cavitation mechanism studies
require that the water velocity is greater than 40 m/s) requires a lot of
power, so the test section of the high-velocity water tunnel is small, with a
diameter of 30−40 mm. The pressure reducing box of the test hydraulic
dam, gate, and other buildings is also a kind of circulating pipe, and the
test section is box-shaped. The test section of the water tunnel used in
hydraulic machineries such as water pumps and water turbines is mostly
vertical, which is suitable for installing the wing wheel model. This type
of water tunnel is often called a cavitation test bed.
2. Water tunnel test
During the cavitation test, groups of bubbles will be generated in the test
section. In order to prevent these bubbles from circulating into the test
section, the water tunnel must have a certain height so that the bubbles
can flow through a longer loop and a higher pressure zone to eliminate.
Special dissolvers can also be installed to eliminate bubbles in the water.
Some objects are in the wake of other objects, for example, the propeller
is in the wake after the ship. A special grid can be installed in the front of
the contraction section to simulate the wake. In recent years, stern models
have been installed in the test section to generate wake. In the propeller
test, a shaft connected with the external motor of the cave body should
be installed upstream or downstream of the test section, and the propeller
model should be installed on the shaft end of the test section. Torsimeter,
thrust meter, and tachometer can be installed on the shaft outside the
cave body, and pressure sensor, balance, and cavitation acoustic observation instrument can be installed in the test section to measure steady
pressure, pulsation pressure, various forces, and torques, and determine
cavitation initial conditions and various development forms.
P. Liu
of Hydrology and Shipbuilding in Berlin, Germany. It has a free surface;
the section size of the test section is 5 m by 3 m, and the length is 1 m.
The center of the cave is 10.5 m high; the maximum speed of water is
12 m/s. High-velocity water flow (such as cavitation mechanism studies
require that the water velocity is greater than 40 m/s) requires a lot of
power, so the test section of the high-velocity water tunnel is small, with a
diameter of 30−40 mm. The pressure reducing box of the test hydraulic
dam, gate, and other buildings is also a kind of circulating pipe, and the
test section is box-shaped. The test section of the water tunnel used in
hydraulic machineries such as water pumps and water turbines is mostly
vertical, which is suitable for installing the wing wheel model. This type
of water tunnel is often called a cavitation test bed.
2. Water tunnel test
During the cavitation test, groups of bubbles will be generated in the test
section. In order to prevent these bubbles from circulating into the test
section, the water tunnel must have a certain height so that the bubbles
can flow through a longer loop and a higher pressure zone to eliminate.
Special dissolvers can also be installed to eliminate bubbles in the water.
Some objects are in the wake of other objects, for example, the propeller
is in the wake after the ship. A special grid can be installed in the front of
the contraction section to simulate the wake. In recent years, stern models
have been installed in the test section to generate wake. In the propeller
test, a shaft connected with the external motor of the cave body should
be installed upstream or downstream of the test section, and the propeller
model should be installed on the shaft end of the test section. Torsimeter,
thrust meter, and tachometer can be installed on the shaft outside the
cave body, and pressure sensor, balance, and cavitation acoustic observation instrument can be installed in the test section to measure steady
pressure, pulsation pressure, various forces, and torques, and determine
cavitation initial conditions and various development forms.