Dynamometer for measuring forces on a model propeller controllable pitch
(57) Abstract:Usage: to determine the hydrodynamic and ice efforts generated by the blades of a model propeller controllable pitch. The inventive dynamometer includes a housing with a radial cylindrical recesses in which are placed the butt with blades, one of which is measuring, the discrete mechanism of the reversal of the blades, heavy mechanism installed inside the housing, the sensing element with strain gauges and two flanges, one of which is rigidly connected with the housing, and the other, movable, with the measuring blade propeller. In the dynamometer elastic sensitive element is designed as platysternidae springs with Central and four peripheral rods in pairs arranged in orthogonal planes, which are oriented along the Central axis of the rod concluded between the flanges, while the Central and peripheral terminals with strain gauges that are included in the measuring bridges, form the sensors lateral, axial force, two bending moments and twisting moment of the blades. In the bottom of the radial cylindrical cavities for measuring the blades are made nests under the fixed flange of the panel is 2">The invention relates to measurement techniques, in particular to a device for determining the hydrodynamic and ice efforts generated by the blades of a model propeller controllable pitch.A device (ed.St. USSR N 1735725, CL G 01 L 1/04) for the experimental determination of the efforts generated by the blades of a model propeller controllable pitch, comprising a housing with a radial cylindrical recesses in which are placed the butt with blades, one of which is measuring, the discrete mechanism of the reversal of the blades, scoring mechanism and mounted inside the enclosure elastic sensitive element with strain gauges and two flanges, one of which is rigidly connected with the housing, and the other, movable, with the measuring blade propeller (prototype).A disadvantage of the known devices is the inability to measure lateral forces and bending the blade and the lack of reliability of the measurement results, twisting the blade and stop the blades, due to the significant impact on them unaccountable component dynamometer load (lateral force, bending moments). The latter is explained by the fact that the twisting moment and the rest of the blade op the e data about the magnitude of these affect the measurement component of the load it is impossible to obtain sufficiently reliable results of measurements of the torsional moment and stop the blade.In addition, at present all of the most urgent issues testing the forms of propulsion and marine engineering structures, protecting the propeller when sailing ship in the ice. The absence of experimental measurement data of the lateral force and the bending blade moments restricts the possibility of designing the most effective profile of the blades of the propeller and its means of protection.The objective of the invention is the possibility of experimental determination of the lateral component of force and a bending blade moments, as well as increasing the reliability of the measurement of torsional moment and stop the blade.This technical result is achieved by the fact that in the known dynamometer elastic sensitive element is designed as platysternidae springs with Central and four peripheral rods in pairs arranged in orthogonal planes, which are oriented along the Central axis of the rod concluded between the flanges, while the Central and peripheral terminals with strain gauges that are included in the measuring bridges, form the sensors lateral, axial force, two bending moments and twisting moment of the blades in the bottom of redelegating element, and the axis of the mentioned flange coincides with the axis of the Central rod.In Fig. 1 shows a dynamometer, section, side view; Fig. 2 - section a-a of Fig. 1 along the axes of the blades; Fig. 3 - dynamometer, a top view, in Fig. 4 - section b-B on the elastic element of Fig. 5, 6 - pictures of the dynamometer, the elastic element with the intermediate support and the measuring blade.The dynamometer includes (Fig. 1 - 3) case 1 with radially spaced cylindrical recesses 2 (the contour of the grooves in Fig. 1 shows a dashed line), blade 3, the measuring blade 4 with butt 5 and a movable index 6, the elastic sensitive element 7 measuring forces and moments on the individual blades in the form of platysternidae spring that is between the two flanges 8, 9, with a Central rod 10 and four peripheral rods 11, the mechanism of discrete rotation of the blades with the bushings 12 and combs-separately 13, fairing 14, the cap nut 15 and plug 16. The sensing element is fixed in the case of dynanometer screws 17. Central and peripheral terminals of the sensing element (Fig. 2 and 4) equipped with strain gages 18, 19, 20, 21, which form a measuring bridge sensors axial, lateral forces, two bending moments is Fixed to the flange 9 of the sensing element is designed in the shape of a square and connected to a cylindrical flange 23, underneath him. The axis of the fixed flange and flange coincide with the axis of the Central rod 10. In the bottom of the cylindrical recess of the housing for measuring the blades are made of the response of the socket 24 under the fixed flange of the elastic element, the axes of which coincide with the longitudinal and transverse axes of the body of the dynamometer.Combs-separately 13 are engaged with the toothed crowns made on the bushings 12, by means of screws 25. The blade 4 is fixed to the flange 8 through the intermediate support 26 by screws 27.The location of the strain gages of the corresponding sensor on the rods of the elastic sensing element is selected in the zone of maximum deformation on the surface of the rods from the corresponding measured force or moment, with immeasurable forces and moments created in these zones the minimum deformation. With this in mind, as well as the analytical properties of the bridge measuring circuit, which appear at the appropriate inclusion of the strain gages in the shoulders of this circuit is ensured almost independent measurement of the five component forces and moments. In the case of incomplete elimination of the mutual influence of individual components on the readings of the measuring sensor circuit time measurements automatically using a computer to perform the correction of the measurement result. This ensures a high accuracy of measurement of all five components of the load.The dynamometer operates as follows.Hydrodynamic and ice forces acting on the measuring blade 4 through the intermediate support 26 is transmitted to the elastic sensitive element 7, deforming its Central and peripheral terminals. These deformations using groups of strain gauges 18, 19, 20, 21, included in the measuring bridges are converted into electrical signals proportional to the current longitudinal and lateral forces, and two bending and twisting the blade moments, and transmitted through wires (not shown in Fig. 1) to the corresponding pins of the connector 16. Dynamometer for measuring forces on a model propeller controllable pitch, comprising a housing with a radial cylindrical recesses in which are placed the butt with blades, one of which is measuring, the discrete mechanism of the reversal of the blades, the scale mechanism installed inside the housing of the elastic sensing element with strain gauges and two flanges, one of which is rigidly connected with the housing, and the other movable with the measuring blade propeller, characterized in that the elastic customerno located in orthogonal planes, oriented along the axes of the Central core enclosed between the flanges, while the Central and peripheral terminals with strain gauges that are included in the measuring bridges, form the sensors lateral, axial force, two bending moments and twisting moment of the blades in the bottom of the radial cylindrical cavities for measuring the blades are made nests under the fixed flange of the elastic sensing element and the axis of the mentioned flange coincides with the axis of the Central rod.
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: measurement technology.
SUBSTANCE: detector can be used for testing transportation vehicles, control and alarm systems. Detector has shallow case, first and second elastic member and elastic members' relative displacement transducers. One end of first elastic member is tightly fastened to the case; the other end is made movable. Elastic member has shallow cavity inside which movable member is housed which is tightly connected with movable end of first elastic member. Second elastic member is made in form of membrane which has center to receive power action. Second elastic member is connected with movable end of first elastic member to form cavity between them. First to fourth relative displacement transducers are mounted pairwise in mutually perpendicular planes crossing central axis of first elastic member - between motionless end of first elastic member and free end of movable member. Fifth to eighth relative displacement transducers are mounted between case and movable end of first elastic member; the transducers are placed pairwise in mutually perpendicular planes crossing mentioned central axis. The ninth relative displacement transducer is mounted inside cavity between movable end of first elastic member and second elastic member at central part of membrane.
EFFECT: improved precision of measurement; reduced sizes; reduced number of detectors used for measurements.
3 cl, 4 dwg