(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.
FIELD: mechanical engineering; testing facilities.
SUBSTANCE: invention can be used for stand tests of pumps of any application. According to proposed method full pressure at pump input is maintained constant by means of reservoir with free surface of liquid exposed to constant (atmospheric) pressure installed in intake pipeline. Working liquid saturated vapor pressure at pump input is changed by heating. Periodical measurement of required parameters in process of liquid heating makes it possible to calculate sought for cavitation margin Δh. Method is implemented by test stand containing pump to be tested, output throttle, flow meter, heat exchanger, service tank, pipe fittings, all arranged in closed hydraulic circuit, and reservoir with free surface of working liquid in combination with capsule made of heat conducting material connected to circuit at pump input. Space of capsule is divided into two parts, one of which is partly filled with working liquid and sealed, and other communicates with circuit.
EFFECT: improved accuracy of measurements and simplified determination of pump cavitation characteristics.
3 cl, 1 dwg
SUBSTANCE: in through portion of pipe with choking of through portion cavitation flow lock mode is set, and in zone of low density value of critical pressure of cavitation and liquid flow are determined, which flow is used to determined liquid speed in pipe neck. Received critical pressure value of cavitation is aligned with pressure of saturated steam of pumped liquid, after that to specially built calculation graph dependencies of relative value of critical pressure of critical speed of flow in channel neck are applied in the moment of setting of lock mode with different concentration of cores target concentration of cores of cavitation of pumped liquid is determined.
EFFECT: higher efficiency.
FIELD: aviation industry.
SUBSTANCE: device helps to get real pattern of liquid pressure distribution which flows about "blown-about" object in water tunnel. Device has driven frequency pulse oscillator, frequency divider, control pulse counter, longitudinal contact multiplexer which connect capacitors with shelves, lateral contact multiplexer which connect the other output of capacitors, matching unit, analog-to-digital converter, indication unit, water tunnel, blown-about object, grid with capacitive detector.
EFFECT: improved precision of measurement.
FIELD: experimental hydrodynamics.
SUBSTANCE: method comprises making a model dynamically similar to the marine engineering structure in mass, sizes, location of the center of gravity, and inertia moment and mounting the model in the experimental tank by means of anchor-type links provided with dynamometers. The device comprises experimental tank and model provided with anchor-type links for connecting with the frame. The anchor-type links are provided with dynamometers and devices for control of initial tension. The frame has flat horizontal base, vertical pillars , and blocks. The base is provided with the members for securing the vertical pillars at specified points of the base. The vertical pillars are provided with blocks and members that are mounted for permitting movement along the pillars and their locking at a given position. The model is provided with the pickups of angular and linear movements. The outputs of the dynamometers and pickups of angular and linear displacements of the model are connected with the input of the computer.
EFFECT: expanded functional capabilities.
2 cl, 3 dwg
FIELD: measuring techniques.
SUBSTANCE: method and device can be used for measurement of hydraulic-dynamic resistance of different surfaces moving in fluid. Time of load descending, which load is kinetically connected with disc rotating in water, is compared when surface of load is coated with different matters.
EFFECT: simplicity at use; reduced cost.
2 cl, 1 dwg
SUBSTANCE: method comprises modeling the process of interaction of water flow with a rough surface by changing the working member of the sloping chute for a precision member with the smooth surface, measuring the height of the water flow in the entrance and exit sections of the chute by means of micrometer with measuring needle, determining the flow rate, and measuring the width of the chute. The smooth member is changed for the working member provided with a rough surface, and the height of the water in the exit section of the chute is measured.
EFFECT: simplified method.
FIELD: experimental hydromechanics; designing of equipment for conducting hydrodynamic and ice searches of marine engineering facility models in model testing basins.
SUBSTANCE: proposed device includes towing trolley with frame rigidly secured on it; this frame is provided with bar which is connected with model through dynamometers and bearing plate. Dynamometers form three-support force-measuring system; they are provided in each support in form of two interconnected elastic members; one elastic member is made in form of five-rod member provided with longitudinal and lateral force sensors; it is located between two flanges. Second elastic member of dynamometer is made in form of membrane-type elastic member whose membrane is located between rigid rim and rigid central part of this member provided with threaded rod with elastic hinge mounted over vertical axis perpendicularly relative to membrane. Membrane, rim and rigid central part with threaded rod and elastic hinge are made integral. Rim of membrane elastic members is rigidly connected with one of flanges of five-rod elastic member in such way that threaded rod is located along vertical axis of support and is rigidly connected via elastic hinge with bearing plate secured on model. Membrane is provided with resistance strain gages forming vertical force measuring bridge. Second flange of each five-rod member is connected with additional bearing plate secured on bar.
EFFECT: enhanced accuracy of measuring forces and moments.
FIELD: the invention refers to experimental hydrodynamics and may be used for definition of the resistance of small objects to a running flow at tests.
SUBSTANCE: the arrangement is fulfilled in the shape of a grate with the width Bt. and the height ht, deepened at the height T formed by rods with a step ▵ fixed in the supporting contour and is located at a certain distance in front of the tested object. At that it is installed with possibility of independent displacement relatively to the tested object and is fastened on the object and/or the body or probably on the bodies moving together with the tested object relatively to the test gondola. It is also may be formed by a system of private turbulators fulfilled in the shape of grates with a different size of cells, with possibility of their independent displacement relatively to each other including the fastening on different bodies and located primary in-series. The private turbulators may be fulfilled in the shape of grates particularly with different main direction of the rods of the grate. The mode is in locating the turbulator in front of the tested object with possibility of independent displacement relatively to the tested object and fastening on the object and/or on the body probably on the bodies moving together with the tested object particularly to test gondola. At that the position of the turbulator relatively to the tested object particularly the distance and displacement relatively to the tested object and also deepening and probably dimensions are chosen on the basis of comparison of results of the trial run of tarring of objects of different scales.
EFFECT: possibility of investigating of small models and revelation of the influence of resistance of the surface of the model.
6 cl, 3 dwg
SUBSTANCE: invention refers to experimental hydrodynamics, hydrodynamics and aerodynamics of airscrew and can be used in shipbuilding and aircraft building. Method includes force field created by airscrew rotation and carrier moving, use of visualising facilities and field structure registration by optical equipment. Thus airscrew rotary speed is established assuming production and stream maintenance of visualising facilities. Field is registered by scanning in two transversely-spaced planes, i.e. horizontal and vertical, in front of, and behind, the airscrew. Thus boundary layer, turbulence areas, increased and decreased pressure areas, airscrew expansion angles, and whole flow structure are showed.
EFFECT: high-accuracy picture of airscrew propeller environment flow.
5 cl, 16 dwg
SUBSTANCE: test stand for amphibious vehicles has basin with entrance and exit ramp, side walls, road, ramp and basin borders. From both sides of exit ramp pits are made in which ends of tubular shaft are embedded. Parallel arms-brackets of sheet metal are attached to the shaft equally spaced from axis. Between attached arms-brackets, spacer pipe is preliminary embedded on shaft which pipe has rectangular pawl with holes on both sides. By means of these holes the pipe is attached to captivating sheet located on symmetry axis of exit ramp. At the end of arms-brackets with lugs, cylinder is attached on axis. This cylinder is made along generator of curve corresponding to curve of vehicle front bumper. Tube rings with pawls are put on shaft ends. The pawls are fixed on pit floors. Spheroidal flanges are fixed on shaft ends to which flanges arms are attached, with brought-out from pits ends having lugs, and pneumatic cylinders are attached to arms from two sides.
EFFECT: reduction of scope of work during test stand construction and provides getting true data about capability of vehicle to move over water surface on tired wheels.