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.

 

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