Hydrodynamic stand

 

(57) Abstract:

The invention relates to hydrodynamic and magneto-hydrodynamic tests and can be used to study the dynamics of unsteady fluid flow around various objects and to create a flow of a given configuration, for example a screw, magnetohydrodynamic studies at high Reynolds numbers. Hydrodynamic test facility consists of a sealed closed channel having an axis of rotation with an electric drive and brake system. Tests are conducted by the sudden braking of the pre-hyped channel. This liquid inertia moves in the channel and flows around the analyzed model. The characteristic time of the braking fluid is of the order of 0.5 s, which is sufficient to conduct the necessary measurements, for example, in experiments on modeling the excitation of the magnetic field of a moving conducting medium (MHD Dynamo). At the initial moment of braking, it is possible to achieve a flow velocity of the liquid up to 200 m/s and more. The speed limit is determined by the strength characteristics of the materials of the channel. The acceleration of the channel may be low-power drive than can be achieved companyprovides and magnetohydrodynamic test and can be used to study the dynamics of unsteady fluid flows around various objects and to create a flow of a given configuration, for example, a screw, magnetohydrodynamic studies at high Reynolds numbers.

Known hydrodynamic stand by A. S. USSR N 1210079, MKI G 01 M 10/00 designed for hydrodynamic tests, consisting of pressure and drain tanks, pump and valves to control the flow of fluid. The disadvantage of the construction is the low speed of the liquid when the flow around the model under investigation, as the speed is determined by the pressure difference between the pressure and drain tanks, which in this stand may not exceed one atmosphere.

A device for studying the flow of bodies in a fluid flow by A. S. USSR N 473077, MKI G 01 M 10/00, consisting of a U-shaped pipe connected at the top by a pipe with the valve. The disadvantage of the design is the presence of two pipe bends. The fluid moving through these curves, turbulizers, and already turbulizing the fluid flow flows around the object under examination. This narrowed the possibilities of the experiment (for example, it is impossible to simulate the flow around the model, laminar flow). In addition, calculations show that to obtain high speeds of movement of liquid (more than 100 m/s) design will have a big envelope is ostoja, and the direct contact of the liquid with the gas environment leads to its aeration, which in some cases is undesirable.

The closest in design and the achieved technical result and chosen for the prototype is a device for hydrodynamic testing of models by A. S. USSR N 340926, MKI G 01 M 10/00, consisting of an annular hydrodynamic channel of the tool holder for fastening the tested models, the reverse drive of the tool holder and measuring equipment.

The disadvantage of the design is the presence of a free surface of a liquid that causes a wave generation, turbulence in the fluid flow and its saturation with air bubbles and consequent distortion of the pattern of the flow and the difficulty of the video stream. Moreover, these distortions depend on the frequency of rotation of the hydrodynamic channel, which makes it almost impossible to study in non-stationary modes. In addition, difficult, and in some cases impossible, to test models in the stream aggressive, volatile liquids, and also in the flow of liquid metals.

The aim of the invention is to eliminate above-mentioned disadvantages.

This goal is achieved by performing gidrodinamicheskoe movement about its axis, and then slow down. This stand has the drive and brake system. The analyzed model (one or more) installed within the channel and is stationary with respect to it. To create a fluid flow configuration within the channel set photocourtesy profiles, such as the divertor to create a screw thread.

The drawing shows an embodiment of the hydrodynamic stand.

Hydrodynamic test facility consists of a collapsible annular hydrodynamic channel 1, made for example of a transparent material, inside which is placed the analyzed model 2. Channel 1 has a reinforcing ring 3 and is mounted on the shaft 4. On the same shaft 4 is placed bearing unit 5 and the brake system 6. For the drive channel 1 set the motor 7. The channel has a drainage hole 8 with the cap 9.

Hydrodynamic stand works as follows.

Turns on the electric motor 7, and the annular hydrodynamic channel 1 together with the test model can accelerate to the desired speed. The fluid due to friction on the walls of the channel also comes into rotational motion and delay of a few seconds reaches custodial 7 is turned off, and activated brake system 6. Channel 1 is braked, and the fluid inertia continues to move and wrap around the model 2. The nature of the flow is recorded by the camera (in the drawing, the video camera is not shown). In the first moment, until the indignation from photocourses profile and the channel walls do not extend throughout the volume, the flow is laminar in nature with a turbulent boundary layer, the ow then becomes turbulent. Thus in the course of one experiment recorded the behavior of the model when different nature of the fluid flow and at various speeds of the fluid, so there is the whole cycle from the beginning, when the maximum speed to full attenuation of fluid flow. The intensity of the braking channel 1 or its angular acceleration is regulated brake system 6.

The acceleration can be supplied from a low-power motor, which reduces the installation, reduces its dimensions. This acceleration can be many times the braking time.

To study the flow model the flow of liquid of a given configuration, such as a screw (liquid simultaneously moves progressively along the channel and rotationally relative to the center of the channel "O"), in the channel ustawy flows of liquids, as well as the divertor necessary for other physics experiments, in particular, to study the conditions for the generation of magnetic fields in spiral flows of liquid metals.

To study the possibility of practical realization of such hydrodynamic stand was made a pilot plant with an outer diameter of 0.3 m Channel filled with water, was accelerated to 3000 rpm braking Time channel was regulated in the range of 0.02 to 0.2 C. the Characteristic decay time of the liquid stream (time, speed reduction in the e time) was about 0.5 s, which is sufficient to conduct the necessary measurements, for example, in experiments on modeling the excitation of the magnetic field of a moving conducting medium (MHD Dynamo).

Hydrodynamic stand containing ring rotating channel, the drive motor and the measuring apparatus, characterized in that it contains the brake system, and the analyzed model is stationary relative to the channel walls.

 

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