Shock the camera to determine the hydrodynamic characteristics of the profile of the bottom of the studied body
(57) Abstract:Usage: in experimental hydrodynamics to study the processes of immersion of solids in the liquid through its free surface. The inventive wall of the first branch is equipped with attached plates with elastic strips at their upper ends, with the possibility of contact with a test body and mates with him when profiling, and the lower ends of these plates immersed in the liquid. 2 Il. The invention relates to experimental hydrodynamics and applied to the study of the processes of immersion of solids in the liquid through its free surface.Known shock the camera to determine the hydrodynamic characteristics of the profile of the bottom of the studied body containing a V-shaped partially fluid-filled vessel, the first of branches which are executed with the possibility of placing in her of the investigated body, and the upper part of the second branch through the valves communicated with a source of compressed air in the receiver and provided with a floating piston.A disadvantage of the known shock camera is the low accuracy of determination in her hydrodynamic characteristics of the models profiles dreamyh models profiles phone bottomsThe purpose of the invention to improve the accuracy of determination of the hydrodynamic characteristics of the models of the bottoms of the test bodies by eliminating the flow of fluid in the gaps between the ends of the tested model and the walls of the working parts of the camera.This objective is achieved in that the wall of the first branch is equipped with attached plates with elastic strips at their upper ends, with the possibility of contact with a test body and mates with him when profiling, and the lower ends of these plates are immersed in the said liquid.In Fig. 1 shows the described shock chamber, the cross-section of Fig. 2 is a view along arrow a in Fig. 1.The basis of the shock chamber is V-shaped vessel, partially filled with liquid. His broad knee 1 are connected by a pipe 2 with a knee 3 having smaller cross sectional area than the knee 1, and a transparent wall. Narrow knee 3 is the working part of the shock chamber for placing an experience of the body. It communicated with the upper tank 4. The pipe 2 is placed perforated plate 5, the role of hydraulic resistance, and the rotary stream directing vanes 6. In a wide knee 1 is the ha in the form of an air receiver 8 through the duct, equipped with a quick-acting valve 9. Draining the liquid from the upper tank 4 in a wide knee 1 is made through a pipeline with a valve 10. Fill the shock chamber fluid through the valve 11 and the discharge of fluid through the valve 12. In the working part of the shock chamber near its middle on the rigid base 13 is installed sensors 14 forces and moments at which a clearance to the walls can be fastened in the analyzed model of the bottom 15, which can be mounted on the plate 16 attached to the side walls of the test section of the shock chamber (narrow knee 3) through the elastic strip 17 having the ability to pair with a bottom 15 when profiling. To determine the flow velocity in the working section on the wall of the fixed high-speed sensor 18. A pressure gauge 19 is designed to control air pressure in the receiver 8. The piston 7 in a wide knee 1 is connected with a lever with release valve 20.The experiments proposed in shock camera are as follows.In the knee 1 through the valve 11 is poured to the desired level of the liquid. The air tank 8 when closed valve 9 is filled with compressed air, the pressure of which is controlled by a pressure gauge 19. Venue.The experiment begins with a fast opening valve 9 and the simultaneous operation of the recording equipment. Compressed air is supplied to the upper part of the wider tribe 1 and creates pressure on the piston 7. Under the action of the pressure piston 7 displaces the liquid from the wide knee 1 through pipe 2 to the knee 3.Due to the fact that the ends of the plates are lowered into the fluid perturbations of the free surface of the liquid in the working part of the camera (knee 3) does not occur.Initially the fluid is moving at a significant speed-UPS. As the growth speed of the flow increases dramatically retarding action of the plate 5. When the force acting on the liquid side of the compressed air, compared with the braking force flow rates, the liquid velocity in the shock chamber is set constant.The path traversed by the free liquid surface in the test section of the shock chamber from the beginning of the experiment to establish a constant flow rate depends on the initial excess pressure in the receiver 8 and the ratio of the perforation plate 5, but should not exceed the distance from the initial level of fluid in the knee 3 to the bottom part of the study model plate 15.Ptmodel bottom 15. The process of meeting model bottoms with a free surface and its further penetration into the liquid are captured by film or photography through the transparent wall of the knee 3. The signals from the sensors 14 are set by the DC amplifier and recorded on Daisy oscilloscope. The high-speed signals of the sensor 18 may also be recorded on the oscilloscope. Elastic strip 17 being deformed during the experiment (when the fluctuations of the studied models) prevent the penetration of liquid into the gaps between the ends of the model and the walls of the working parts of the camera.When the movement of the piston 7 selects the excess length of the rod, connected to a release valve 20, and after the fluid flow reaches the top of the knee 3, the valve 20 opens, venting to the atmosphere the compressed air from the upper part of the knee 1. Quick-acting valve 9 is closed. This experiment is terminated.The liquid caught during the experiment in the upper tank 4 is returned in a wide knee 1 after opening of the valve 10. After its closing the shock Luggage ready for the next experiment.Using the described shock of the camera by wrapping the tested models bottom only Dahmer audouze with constant velocity through the free liquid surface of the investigated model of the bottom, and get pictures and kilogramme flow model of the bottom, providing an assessment of the impact of the shape of the model plate and the flow velocity on the nature of the flow and intensity of Bryzgalova. When changing one of the model on another change and plates, repeating its shape. SHOCK the CAMERA TO determine the HYDRODYNAMIC CHARACTERISTICS of the PROFILE of the bottom of the STUDIED BODY containing a V-shaped partially fluid-filled vessel, the first of branches which are executed with the possibility of placing in her of the investigated body, and the upper part of the second branch through the valves communicated with a source of compressed air in the receiver and provided with a floating piston, characterized in that the wall of the first branch is equipped with attached plates with elastic strips at their upper ends, with the possibility of contact with a test body and mates with him when profiling, and the lower ends of these plates are immersed in the said liquid.
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: transport, auxiliary ship equipment.
SUBSTANCE: proposed test pool comprises the bottom simulation plant including submerged suspended support made up of assemblage of identical support sections arranged across the channel and distributed over its length. Aforesaid sections are suspended with adjusting tie-rods jointed to their length adjustment devices arranged on the channel walls sides. False bottom is mounted and rigidly attached to the said suspended support. The bottom simulation plant can vary the false bottom inclination towards horizontal plane in both the channel lengthwise direction α° till , and crosswise direction β° till , where L is the length of assembled bottom simulator, B is the bottom simulator width, HB is channel water depth, HD is the deepest bottom point, α° and β° are the angles of inclination of false bottom in lengthwise and crosswise directions, respectively. The total area of sections across the channel of support sections of the bottom simulator makes, at least, 0.05 of false bottom area in plan, while the false bottom width does not exceed 0.75 of the channel width. The false bottom is arranged in the channel symmetrically relative to the channel lengthwise axis.
EFFECT: higher efficiency of using ice test pool.
3 cl, 2 dwg
FIELD: testing equipment.
SUBSTANCE: invention is related to the field of shipbuilding, namely to technical means of experimental hydromechanics, and may be used for hydrodynamic tests of surface vessel model. Device comprises area of water with free surface, model of surface vessel towed by rope, motion of which is carried out through falling liquid weight that fills metering reservoir, which has holes both for reception and drain of liquid weight. Reservoir is fixed to axis of movable unit. Water to reservoir is sent through nozzle, which, together with elbow, crossbeam and bar creating bearing structure, and water pump, develop continuous water flow for reservoir filling. Fixed unit is attached to crossbeam, which produces polyspast together with unit. In process of tests performance, vessel model is positioned in the end of metering section of water area, and at the same time empty reservoir is lifted upwards. After contact with hole, reservoir after filling with liquid weight till rated level starts evenly lowering vertically down, providing for even horizontal motion of vessel model. The main result of experiment is time of weight lowering from unit down to support plate.
EFFECT: reduced cost of pool equipment, increased accuracy of performed measurements, reduced labour intensity of experiments performance.
3 cl, 1 dwg
SUBSTANCE: in trial tank, model, for instance platform is rigidly joined to dynamometre, which is fixed to base on tank board on the other side. Bottom imitator is installed under model and is rigidly suspended to base with the help of stands, which are located in stern part beyond model borders, ice field is frozen, which is then pushed up to model by means of towing trolley, and parametres of experiment are registered. Bottom imitator in its front part is fixed to base by means of stands, which pass through tested model. With the help of all these stands, clearance is adjusted and established between imitator and model, and tests are carried out. Device for realisation of such method in trial tank comprises towing trolley with bulldoser for ice pushing up to model, for instance platform, and rigid base fixed on tank board. Tested model is connected to it via dynamometre, as well as bottom imitator with the help of stands arranged in stern extreme end behind model. Imitator in front part has stands, which are joined to rigid base and pass through tested model of platform. It has wells arranged for specified stands. Stands have facilities for adjustment and installation of clearance between imitator of bottom and model, preferably lanyards, in process of tests performance.
EFFECT: invention makes it possible to improve reliability and accuracy of experiment results by provision of accurate positioning of imitator versus model.
2 cl, 1 dwg
FIELD: test engineering.
SUBSTANCE: invention refers to experimental studies in ice test pools and can be implemented for designing screw-steering complexes of vessels and facilities for their protection from ice by means of model experiment in pool under created conditions similar to natural. The procedure consists in preparing a field of model ice and in testing a model with operating propellers by means of towing the model or at its free motion at specified speed and at specified frequency of propeller rotation; testing consists in recording frequency of submerged ice cakes meeting a propeller-steering complex and other facilities external relative to the case of the model when ice protection of the model case is present or absent. Also density of model ice is measured. Further, the vessel model is towed in not destructed ice cover with turned off propellers and at speed determined by model-prototype relationship. There is measured average dimension of ice-cakes and width of channel behind the model formed at model passing through ice cover. Ice cover in not destructed ice field strip before the model, the width of which is equal to width of channel after the model, is cut into separate tightly adjoining blocks of ice. Dimensions of blocks are equal to measured average dimensions of ice cakes. The test is carried out in such made channel by means of towing the model with operating propellers. Notably, speed of model towing during the said test is less in comparison to model-prototype relationship speed determined with consideration of water and ice density. Frequency of propellers rotation is set to facilitate correspondence of speed of liquid in the stream behind the propeller to a value determined considering speed in the stream behind the propeller under natural conditions. During testing model under mode of free self-propelling rotation frequency of propellers is specified to ensure correspondence of speed of liquid in the stream behind the propellers under dockside mode to value determined with consideration of speed in the stream behind the propeller at dockside mode under natural conditions.
EFFECT: upgraded validity of test results by means of approaching them to natural conditions.
FIELD: testing equipment.
SUBSTANCE: invention is related to the field of experimental tests performance on models of ice breakers and ice ships in ice experimental pools. Method includes preparation of modeled ice field. Performance of model tests by means of its towing with a specified speed of vm. Registration of frequency of submerged ice debris ingress into propelling-steering complex, to ice boxes of ship model and to other external devices on model body with availability or absence of ice protection on model body. Density of modeled ice is identified as . In non-damaged ice cover they tow model of ship with a speed detected by ratio , where: νm and νf - speeds of model and full-sized vessels accordingly, λ is model scale. Average size of produced ice debris and channel width are measured behind model. In non-damaged ice field in front of vessel in width equal to width of channel behind model, ice cover is cut into separate adjacent ice floes. Size of ice floes equals measured average size of ice debris. Model towing in process of specified tests is carried out with speed ν'm, which is reduced in comparison with νm, which is identified by ratio ,
where: ρw - water density, - ice density required by technical task for performance of experiments.
EFFECT: provides for valid test results.
SUBSTANCE: method involves mounting a floating object model to the bottom of a tank through anchor connections and exposing the model to external wave effects and recording experiment parametres. The model under test is mounted to the bottom of the tank using two-branched flexible connection lines with which the model is movably joined through rollers freely hung to its housing. The paired branches of the flexible connection lines have different rigidity and the ends of the branches are attached to the base of the tank in points which are spaced apart. The device has truncated anchor connections through which the model under test is attached to the base of the tank. The anchor connections are in form of two-branched flexible connection lines between branches of which there are rollers mounted on the model, which are attached to its housing mainly on a flexible connection. The second branches of the flexible lines are also fitted with an elastic element, where the elastic elements of the paired branches of the flexible connection lines have different rigidity, and the other end of the branches of the said flexible lines is attached to the base of the tank at the corresponding point at a distance from the point of attachment of the first end.
EFFECT: approximation of simulated load in anchor connections to natural conditions.
3 cl, 2 dwg
SUBSTANCE: invention relates to ship building, namely, to safe operation of, mainly, gliding ships in shallow waters. Proposed method consists in optimising hydrodynamic characteristics of small-scale towed dynamically similar ship model in test pool in shallow depth prepared by using submerged screen and measuring model motion parameters. When model moves from deep water to shallow water, variations in draft and pitch angle are measured. This allows using experimental and computation procedures to define character of variations in position model hull bottom point at speed and at known tolerable depth for ship in shallow water and to evaluate ranges of safe speeds that make one of the basic elements in instructions for ships control in coastal navigation at water edges and in shallow waters.
EFFECT: possibility to define safe speed of ship model in move from deep water to shallow water.
FIELD: test equipment.
SUBSTANCE: invention refers to experimental flow dynamics of sea transport and deals with creation of laboratories for investigations of ice properties of ships. Ice experimental tank includes bowl with boards, handling dolly with equipment for water jets spraying at freezing of simulated ice cover. Outside the tank bowl parallel to one of its longitudinal boards there routed is a channel with the depth of not less than 0.5 m, which is interconnected with the bowl cavity via a pipeline. Perforated air supply tube to the channel is located at the channel bottom. Handling dolly is equipped with suction hydraulic pump for water supply to water jets spraying equipment, which is equipped with a connection pipe the receiving end of which is lowered into the above channel to the depth of not less than the half of its depth. Connection pipe of hydraulic pump is equipped with a rigid protective casing enclosing its housing and located so that it crosses free water surface in the channel and deepened with its lower end to the value of not less than 0.5 of the channel depth.
EFFECT: providing uninterrupted preparation of simulated ice for conducting the tests of ships models and engineering structures.
2 cl, 2 dwg
SUBSTANCE: invention relates to ship repair, particularly, to straightening of ship hull knuckle. Proposed method comprises measuring ship draught by all deadweight scales for ship fully loaded and empty. Results obtained allow calculating residual knuckle of the ship. Ship upper element cutting line is traced. Ship is placed in dock on dock floor to measure hull knuckle. Not here that hull center gives under gravity to reduce knuckle and eliminate clearances in supports pressed loosely to hull. Ship upper elements are cut along traced line. Cut edges at compressive stress converge. After convergence said edges are fitted in and welded together. Ship is launched and residual knuckle is measured to be eliminated, is required, by repetition of above jobs.
EFFECT: increased dead weight.
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