CN103308289B - A kind of zigzag three multi pack shrouded blade damping behavior experimental provisions - Google Patents

Abstract

The invention discloses a sawtooth triple-installed shrouded vane vibration damping characteristic experiment device for studying the shrouded blade vibration damping characteristics under different contact angles, pre-twisted angles and contact positive pressures, including shrouded blades, clamping mechanisms and Loading mechanism; wherein, there are three shrouded blades, which are vertically arranged, and the blade shrouds are of the same height, and after being fixed by the clamping mechanism, three adjacent blade shrouds are in close contact. A loading mechanism is arranged above the clamping mechanism; the loading mechanism consists of a loading plate and a friction block; wherein, the loading plate is arranged horizontally, and there is a crown outlet on the loading plate, so that the crowns of the three crowned blades protrude from the crown exit ; There are two friction blocks, which are respectively located on the left and right sides of the outlet of the crown; the two friction blocks are fixed on the loading plate, and after fixing, one end of the two friction blocks is respectively in contact with the friction surface of the crown in the adjacent crowned blade . The invention has the advantages of reasonable structure, and can realize the measurement of the damping characteristics of shrouded blades under different key parameters.

Description

Experimental device for vibration reduction characteristics of sawtooth triple-mounted crowned blades

technical field

The invention relates to the field of aero-engines, in particular to an experimental device for vibration-damping characteristics of sawtooth triple-mounted shrouded blades in aero-engines, which is used to obtain the vibration-damping characteristics of shrouded blades.

Background technique

In an aero-engine, the turbine blade is one of the important components. In addition to bearing the impact of high-temperature and high-pressure gas during work, it will also cause high-cycle fatigue vibration of the blade due to cyclic loads such as centrifugal force and aerodynamic force. In order to reduce the vibration stress of engine blades, in addition to avoiding blade resonance and improving the fatigue resistance of blade materials, the damping of the blade system must also be increased. At present, the effect of dry friction damping is the most obvious, and its advantages are simple structure and strong environmental adaptability. Dry friction damping uses the friction between the contact surfaces when the objects in contact with each other vibrate to consume vibration energy for vibration reduction. At present, the most commonly used in the vibration reduction of turbine blades is the crowned structure of the blade, which is designed at the top of the blade. Crown, and through the tightness design of the damping surface of the zigzag blade crown, the resonant frequency of the blade is adjusted to achieve the purpose of vibration reduction and frequency modulation.

In order to obtain a better vibration reduction effect, it is necessary to understand the influence of the key parameters of the shroud (pre-twist angle, contact angle, and normal pressure, etc.) on vibration reduction. At present, scholars at home and abroad have carried out theoretical analysis and experimental verification on the vibration reduction law of shrouded blades, and have achieved certain results, but most of them are theoretical and mechanism studies. Due to the differences between theoretical assumptions and actual models, the results of theoretical analysis It is difficult to verify the engineering applicability.

Contents of the invention

In order to overcome the deficiencies of the background technology, the present invention proposes an experimental device for vibration reduction characteristics of shrouded blades with reasonable structure to study the vibration reduction characteristics of shrouded blades under different contact angles, pre-twist angles and contact positive pressures.

The vibration-reduction characteristic experiment device of the zigzag triple shrouded vane of the present invention comprises a shrouded vane, a clamping mechanism and a loading mechanism. Among them, there are three crowned blades, all of which are vertically arranged, and the crowns are of the same height, and adopt a zigzag structure; after the three crowned blades are fixed by the clamping mechanism, three adjacent leaf crowns are in close contact. A loading mechanism is arranged above the clamping mechanism; the loading mechanism includes a loading plate and a friction block; wherein, the loading plate is arranged horizontally, and a crown outlet is opened on the loading plate, so that the crowns of the three crowned blades protrude from the crown exit; There are two friction blocks, which are respectively located on the left and right sides of the outlet of the crown; the two friction blocks are fixed on the loading plate, and after being fixed, one end of the two friction blocks is respectively in contact with the friction surface of the crown in the adjacent crowned blade.

The two friction blocks are of bar-shaped block structure, and there are two through-groove A and through-groove B with length along the long direction on the two friction blocks; Through holes, and an arc-shaped through-groove C is opened at the corresponding position of the through-groove B; through the through-groove A and the through-hole through the bolt, and through the through-groove B and the through-groove C through the bolt, connect the nut; when the nut is loosened Finally, the friction block moves along the arc-shaped groove C, so that the friction block adapts to the change of the crown contact angle of the shrouded blade; at the same time, the friction block moves along the long direction of the friction block, so that the friction block adapts to the change of the crown spacing ; The recessed side of the arc-shaped slot C faces the outlet of the blade crown, and the perpendicular bisector of the line connecting the two ends of the arc-shaped slot C is the axis of the friction block.

The advantages of the present invention are:

1. The present invention’s sawtooth-shaped triple-installed shrouded blade vibration-reduction characteristic experimental device can realize the measurement of the vibration-reduction characteristics of shrouded blades under different key parameters, so as to have an intuitive understanding of the influence of various parameters of the blade shroud structure on the vibration-reduction effect, And can provide a basis for verification and improvement of theoretical analysis results;

2. The vibration-reduction characteristic experimental device of the zigzag triple shrouded blades of the present invention has a reasonable structure, and the design of the triple shrouded blades can truly reflect the different key parameter requirements of the shrouded blades.

Description of drawings

Fig. 1 is a schematic diagram of the overall structure of the experimental device of the present invention;

Fig. 2 is the schematic diagram of friction block installation mode in the experimental device of the present invention;

Fig. 3 is the modal analysis that adopts the experimental device of the present invention to carry out triple-mounted shrouded blade, and adopts existing device to carry out the modal analysis contrast figure of single free shrouded blade;

Fig. 4 adopts experimental device of the present invention to the modal test result under different contact angles;

Fig. 5 is the modal result of different pre-twist angles under the crowned blade contact angle measured by the experimental device of the present invention at 30 degrees;

Figure 6 shows the effect of the normal pressure on the vibration reduction effect of the two friction blocks and the adjacent shroud friction surface obtained through numerical simulation on the basis of the modal experiment.

In the picture:

1-Blade with crown 2-Clamping mechanism 3-Loading mechanism 101-Crown

102-blade body 201-base 202-support frame 203-clamping assembly

203a-clamping body 203b-bolt and nut assembly A301-loading plate 302-friction block

303-through slot A304-through slot B305-through slot C

detailed description

The present invention will be further described below in conjunction with accompanying drawing.

The present invention is an experimental device for vibration reduction characteristics of sawtooth triple-mounted crowned blades, comprising a crowned blade 1 , a clamping mechanism 2 and a loading mechanism 3 , as shown in FIG. 1 .

Among them, the shroud 101 of the shrouded blade 1 adopts a zigzag structure, and the pre-twisted angle and contact angle of the shroud 101 are designed according to the needs of the experiment; ; In order to ensure the verticality and rigidity of the blade body 102 and the blade crown 101, the top of the blade body 102 is inserted through holes on the blade crown 101, and fixed by spot welding; three crowned blades 1 are vertically arranged, and are clamped The holding mechanism 2 is fixed, and after being fixed, three adjacent blade crowns 101 are in close contact. Thus, the real contact state of three adjacent shrouded blades in the entire circle of turbine shrouded blades is simulated by the above-mentioned three shrouded blades 1;

The clamping mechanism 2 is used to clamp the crowned blade 1, including a base 201, a support frame 202 and a clamping assembly 203; wherein, a plate-shaped support frame 202 is vertically fixed on the left and right sides of the base 201, and the support frame 202 Install the fixed loading mechanism 3. The clamping assembly 203 has three sets, and each set of clamping assembly 203 is composed of two clamping bodies 203a, which are fixedly installed between the support frames 202 on the left and right sides of the base 201; A bolt hole is opened at a symmetrical position on each clamping body 203a, and penetrates into the bolt and nut assembly 203b; thus the root of the airfoil 102 in the shrouded blade 1 is arranged between the two clamping bodies 203a, and by tightening the bolt and nut assembly 203b, Make the two clamping bodies 203a clamp the root of the blade body 102 in the crowned blade 1, realize the rigid fixation of the crowned blade 1, and then fix and clamp the entire crowned blade 1; the two clamps in each set of clamping assemblies 203 The holding body 203A can be installed on the base by sliding connection in the left and right directions, so that the distance between the two holding bodies 203A can be adjusted, so that the fixed shrouded blade 1 can move in a small range left and right in the horizontal direction, and the blade shroud can be adjusted. The spacing is such that three adjacent leaf crowns 101 are in close contact. In the present invention, the two clamping bodies 203a in each clamping assembly 203 can adopt an L-shaped plate structure, so that one side A of the two clamping bodies 203a is slidably installed on the upper surface of the base 201, and the other side B They are arranged oppositely, so that the root of the airfoil 102 in a shrouded blade 1 is clamped and fixed by the side surfaces B of the two clamping bodies 203a correspondingly.

The loading mechanism 3 is composed of a loading plate 301 and a friction block 302; wherein, the loading plate 301 is arranged horizontally, and the two ends are respectively fixed on the top of the support frames 202 on the left and right sides of the clamping mechanism 2; the loading plate 301 is provided with leaf crowns Outlet, so that the blade crown 101 of the crowned blade 1 can be stretched out from the blade crown outlet, as shown in Figure 2, there are two friction blocks 302, both of which are bar-shaped block structures, arranged on the top surface of the loading plate 301, respectively located on the blade The left and right sides of the crown outlet; the two friction blocks 302 are provided with two lengths of through grooves A303 and B304 along the long direction; at the same time, a through hole is opened at the corresponding position of the through groove A303 on the loading plate 301, and There is an arc-shaped through-slot C305 corresponding to the position of the through-slot B304, and the concave side of the arc-shaped through-slot C305 faces the outlet of the blade crown, and the perpendicular bisector of the line connecting the two ends of the arc-shaped through-slot C305 is the axis of the friction block 302 ;Thus pass through the through-slot A303 and the through-hole through the bolt, and pass through the through-slot B304 and the arc-shaped through-slot C305 through the bolt, and tighten the nut to realize the positioning between the friction block 302 and the loading plate 301; and when it is loose After the nut, the friction block 302 can be moved along the arc-shaped slot C, so that the friction block 302 can adapt to the change of the crown contact angle of the shrouded blade 1; at the same time, the friction block 302 can also be moved along the long direction of the friction block 302 , and then make the friction block 302 adapt to the change of the distance between the blade shrouds 101, and then realize the position adjustment of the friction block 302 on the loading plate 301, and finally adjust the positions of the friction block 302 and the loading plate 301 so that one end of the two friction blocks 302 They are respectively in contact with the friction surfaces 302 of adjacent shrouded blades, thereby simulating the normal pressure of the surrounding blade shrouds 101 on their contact surfaces, and the magnitude of the normal pressure can be measured by strain gauges.

Through the above-mentioned device, the roots of the three shrouded blades 1 are respectively fixed by three sets of clamping assemblies 203, so that the three shrouded blades 1 are all vertically arranged, and the blade crowns 101 of the three shrouded blades 1 are evenly arranged. It protrudes from the top opening of the loading disk 301, and the crowns 101 of the three crowned blades 1 are of the same height, and the three adjacent blade crowns 101 are in close contact; then adjust the positions of the two friction blocks 302 on the loading disk 301 so that the two One friction block 302 is adapted to the blade shroud 101 contact angle and spacing of its adjacent shrouded blade 1, so that one end of two friction blocks 302 fully contacts the contact surface of its adjacent blade shroud 101, that is, it is ensured that the blade shroud 101 has different The contact area between the friction blocks 302 and the blade shroud 101 under the contact angle remains unchanged, and then the nuts are tightened to fix the two friction blocks 302 and the loading plate 301, and the strain gauges are used to read the contact area between the two friction blocks 302 and the adjacent blade shroud 101. For the normal pressure on the friction surface, after adjusting the normal pressure on the friction surface of the two friction blocks 302 and the adjacent shroud 101 to be consistent, the vibration reduction characteristics of the triple shrouded blade can be completed through the modal test and the simple harmonic excitation experiment Analysis is carried out to realize the influence law of different parameters of the blade shroud on the shroud blade on the vibration reduction characteristics.

Because what simulated was the damping characteristic of the blade shroud under normal temperature, and the damping characteristic of No. 45 steel is similar to the aviation material DZ125 alloy under normal temperature, so the whole experimental device adopts No. 45 steel to make among the present invention; And the whole experimental device is carried out as a whole The bluing treatment can prevent corrosion and rust by rapidly oxidizing the surface of each part of the entire experimental device to form a dense oxide film protective layer, so as to prolong the service life.

Fig. 3 is the modal analysis that adopts the experimental device of the present invention to carry out the modal analysis of the triple-mounted shrouded blade, and adopts existing experimental device to carry out the modal analysis comparison result figure of a single free shrouded blade, it can be seen that the triple-mounted shrouded blade is closer to The actual situation.

Fig. 4 adopts experimental device of the present invention to the modal test result under different contact angles; Fig. 5 adopts experimental device of the present invention to be the modal result of different pre-twisted angles under 30 degrees of crown blade 1 contact angles; Fig. 6 It is based on the modal experiment and obtained through numerical simulation how the normal pressure of the friction surface between the two friction blocks 302 and the adjacent shroud 101 affects the vibration damping effect. From the above experimental results, it can be seen that the experimental device of the present invention has a reasonable structure, and the vibration reduction characteristic experiment of triple-mounted shrouded blades can truly reflect the different key parameter requirements of the shrouded blades through the experimental device of the present invention. Therefore, by using the device of the present invention, it can be realized The natural modes of shrouded blades under different pre-twist angles and contact angles are studied, and the influence of different contact positive pressures on the vibration reduction effect of the shroud is analyzed by numerical simulation, so as to verify and further improve the corresponding theoretical calculation model.

Claims (5)

1. zigzag three multi pack shrouded blade damping behavior experimental provisions, is characterized in that: comprise shrouded blade, clamping machineStructure and load maintainer;

Wherein, shrouded blade is three, all vertically arranges, and integral shroud is contour, and adopts zigzag structure integral shroud; Three shrouded bladesAfter all fixing by clamping device, three adjacent integral shroud close contact; Clamping device top is provided with load maintainer; Load maintainer bagDraw together loading disc and brake pad; Wherein, loading disc is horizontally disposed with, and has integral shroud outlet on loading disc, makes the leaf of three shrouded bladesHat is stretched out by integral shroud outlet; Brake pad has two, lays respectively at the left and right sides of integral shroud outlet; Two brake pads are fixed on loadingOn dish, make after fixing two brake pad one end contact with the rubbing surface of integral shroud in adjacent separately shrouded blade respectively;

Described two brake pads are bar shaped block structure, and on two brake pads, have two along length direction and have the logical of lengthGroove A and groove B; On loading disc, groove A correspondence position has through hole simultaneously, and has arc-shaped slot at groove B correspondence positionC; Pass groove A and through hole by bolt, and pass after groove B and groove C attaching nut by bolt; When getting loose after nut,Brake pad moves along arc-shaped slot C, makes the variation of the integral shroud contact angle of brake pad adaptive zone shroud blade; Meanwhile, make brake pad edgeThe length direction of brake pad moves, and then makes brake pad adapt to the variation of integral shroud spacing; A recessed side of described arc-shaped slot C towardsIntegral shroud outlet, the axis that the perpendicular bisector of arc-shaped slot C two ends line is brake pad simultaneously.

2. a kind of zigzag three multi pack shrouded blade damping behavior experimental provisions as claimed in claim 1, is characterized in that: described inIn shrouded blade, integral shroud is vertical with blade, and on integral shroud, perforate and blade top are pegged graft fixing.

3. a kind of zigzag three multi pack shrouded blade damping behavior experimental provisions as claimed in claim 1, is characterized in that: described inClamping device comprises base, bracing frame and clamp assemblies; Wherein, the base left and right sides is vertically fixed with respectively a bracing frame, logicalCross bracing frame fixing load maintainer is installed; Described clamp assemblies has three covers, and every cover clamp assemblies forms by two cramping bodies,All be fixedly installed between the bracing frame of the base left and right sides; On two cramping bodies in every cover clamp assemblies, symmetric position has spiral shellKeyhole, and penetrate bolt and nut component; In shrouded blade, the root of blade is arranged between two cramping bodies, by the spiral shell that tights a boltFemale component, makes the root of blade in two cramping body clamping band shroud blades.

4. a kind of zigzag three multi pack shrouded blade damping behavior experimental provisions as claimed in claim 3, is characterized in that: described inTwo cramping bodies in clamp assemblies adopt on left and right directions and are slidably connected and are arranged on base.

5. a kind of zigzag three multi pack shrouded blade damping behavior experimental provisions as claimed in claim 3, is characterized in that: described inTwo cramping bodies in clamp assemblies all adopt L shaped platy structure, and a side A in two cramping bodies is fixed on base and showsFace, another side B is oppositely arranged.