A detection platform and method for the mass moment of an aero-engine blade

Abstract

The present invention provides an aero-engine blade mass moment detection platform and detection method, the detection platform includes a scale bar, a main frame, a sub-frame, a frame shaft, a fixture, a bearing, a sleeve, a leveling system, a middle platform, a guide rail support, a measurement system and a base; wherein the fixture is fixed to one end of the scale bar, the scale bar is fixed to the main frame and the sub-frame through a bearing, a frame shaft and a sleeve, the main frame and the sub-frame are positioned and fixed to the middle platform through the guide rails on the guide rail support, and the guide rail support is fixed to the base; a leveling spring is installed at the front end of the base for initial leveling of the scale bar; a sensor upper bracket and a sensor lower bracket are fixed to the rear bottom of the scale bar and the rear end of the base respectively, and the sensor is connected to the sensor upper bracket and the sensor lower bracket. Based on the technical solution of the present invention, the mass moment of the blade in the service state is measured, and a single-stage rotor blade arrangement order optimization method is constructed with the blade arrangement order as the optimization variable.

Description

Technical Field

[0001] The present invention relates to the technical field of aero-engine assembly, and in particular to an aero-engine blade mass moment detection platform and a detection method. Background Art

[0002] When assembling engine rotors, it's difficult to ensure the complete consistency of blade mass moments during the processing process due to the complex blade shapes and the fact that some blades are hollow. Furthermore, the blade assembly posture also affects the blade mass moment, which in turn causes an initial imbalance in the rotor after assembly. Currently, dynamic balancing experiments are used to eliminate imbalance by removing material from a turntable, but this method has limited balancing capabilities and the balancing process can compromise structural strength. High-precision and high-efficiency measurement of rotor blade mass moments is an effective way to rationally arrange blades and reduce initial rotor imbalance. This can reduce the difficulty of the rotor balancing process and even replace the rotor dynamic balancing step. Currently, some foreign manufacturers have developed blade mass moment measurement equipment, but the equipment is expensive and the system lacks openness. There is a lack of dynamic balance prediction for the entire blade disk. Current domestic mass moment measurement equipment has a low level of integration and poor accuracy, making it difficult to meet the needs of efficient engine assembly.

[0003] Based on the principle of micro-moment balance, the present invention will design and build a set of mass moment measurement equipment using high-precision sensors and fixtures. It can accurately measure the mass moment of the blade in the assembled state, thereby guiding the optimization of the blade assembly layout, reducing the initial imbalance of the engine rotor after assembly, reducing the difficulty of dynamic balancing of the engine rotor, improving the assembly efficiency of the blade disk, and extending the service life of the engine blade disk. Summary of the Invention

[0004] In response to the problems in the above-mentioned prior art, the present application proposes an aircraft engine blade mass moment detection platform, which includes a weighing rod, a main frame, a sub-frame, a frame shaft, a clamp, a bearing, a sleeve, a leveling system, a middle platform, a guide rail support, a measuring system and a base; wherein, the clamp is fixed to one end of the weighing rod, and the weighing rod is fixed to the main frame and the sub-frame through bearings, a frame shaft and a sleeve, and the main frame and the sub-frame are positioned and fixed to the middle platform through the guide rails on the guide rail support, and the guide rail support is fixed to the base; a leveling spring is installed at the front end of the base for the initial leveling of the weighing rod; a sensor upper bracket and a sensor lower bracket are fixed to the rear end bottom of the weighing rod and the rear end of the base respectively, and the sensor is connected to the sensor upper bracket and the sensor lower bracket.

[0005] Preferably, the clamp includes a main clamp and a sub-clamp, the main clamp and the sub-clamp are connected by bearings and shafts, and the main clamp and the sub-clamp provide clamping force through springs to clamp the blades; the clamp is designed with clamping teeth inside according to a structure that matches the tenon groove at the fixed end of the blade.

[0006] Preferably, the measurement system includes a micro tension and pressure sensor, a signal amplifier, an interface converter and host computer software.

[0007] Preferably, the force measuring part of the miniature tension and pressure sensor is an internal thread-table.

[0008] Preferably, the leveling system includes a spring and a bolt that can be adjusted up and down. The bottom end of the spring is sleeved on the boss of the adjusting bolt, and the upper end is clamped in the slot below the scale beam. Both ends of the spring are free ends and the displacement in the Z-axis direction and the rotation around the Z-axis are not constrained.

[0009] This application relates to a detection method comprising the following steps:

[0010] Step 1: First, place the testing platform on a relatively open horizontal surface and perform initial leveling of the testing platform base and the scale bar;

[0011] Step 2: After the test bench is stable, place the scale bar freely without load and spring damping. After the value of the tension sensor stabilizes, record the data. This data is defined as the free gravity at one end of the fixture without load at this moment.

[0012] Step 3. Use the clamp at one end of the scale bar to clamp the standard blade. Note that the clamp teeth and the mortise and tenon on the blade must match. Then let the scale bar fall freely without adjusting the spring. The value of the sensor at this time is recorded as G. 标 ;

[0013] Step 4: Restore the spring action, observe the value of the tension sensor, and rotate the adjustment bolt until the value of the sensor is calibrated to "zero point". The reading of the sensor at "zero point" is recorded as G 零 ;

[0014] Step 5: Remove the standard blade, keep the experimental bench in its current state, measure the blades to be tested one by one, record the data, and arrange them in order.

[0015] Preferably, the distance from the blade centroid to the blade root is calculated:

[0016] m1g(X+L2)-F 拉 L4=F 弹 L3 (5.1)

[0017]

[0018]

[0019] m1 represents the mass of the blade to be measured;

[0020] X represents the distance from the centroid of the leaf to the root;

[0021] F 弹 Indicates the initial elastic force when the spring is leveled;

[0022] F 拉 Indicates the tension applied to the sensor during measurement;

[0023] L2 represents the distance from the blade root to the center support point;

[0024] L3 represents the distance from the center of the spring to the center fulcrum;

[0025] L4 represents the distance from the center of the sensor to the center support point;

[0026] G 标 Indicates the gravity acting on a standard blade;

[0027] G 零 Indicates the reading of the sensor when calibrating the "zero point".

[0028] Preferably, after determining the center of mass position of the blade, the mass moment M of the blade after assembly is calculated. z Where: L1 is the distance from the blade root to the center of the blade disk; the mass moment calculation formula after the blade is assembled is:

[0029] M z =m1·(X+L1)(5.4).

[0030] Preferably, the blades with calculated mass moments are sorted according to their numerical values; the two blades with the closest mass moment values are grouped together; the initial unbalance of the blade disk is measured; when assembling the blades, blades with similar mass moment values are installed relative to each other, blades with complementary values are installed adjacent to each other, and the initial unbalance of the blade disk is adjusted.

[0031] Preferably, the arranged blades are assembled onto the blade disk in sequence, and a dynamic balancing test is performed on a dynamic balancing machine, by comparing the dynamic balancing experimental data before and after optimization.

[0032] The above technical features can be combined in various suitable ways or replaced by equivalent technical features, as long as the purpose of the present invention can be achieved.

[0033] Compared with the prior art, the detection platform and detection method provided by the present invention have at least the following advantages:

[0034] Beneficial effects:

[0035] Based on actual assembly conditions, the principle of micro-torque balance, and combined with mechanical design and manufacturing technology, a high-precision, rapid measurement mechanism for blade mass moments can be designed. Furthermore, based on the blade root structure and actual assembly requirements, a measuring fixture can be designed to simulate the tightening state caused by centrifugal force during blade service. This, combined with the mass moment measurement mechanism, enables measurement of the blade mass moment during service. Based on the established single-blade mass moment model and single-stage rotor static imbalance model, an objective function is constructed with the blade arrangement sequence as the optimization variable and the single-stage rotor static imbalance as the optimization target, establishing a single-stage rotor blade arrangement sequence optimization method. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings, wherein:

[0037] Figure 1 Shows a schematic structural diagram of the mass moment measurement experimental platform of the present invention;

[0038] Figure 2 Shows a schematic diagram of the fixture structure of the present invention;

[0039] Figure 3 Shows a schematic structural diagram of the micro tension and pressure sensor of the present invention;

[0040] Figure 4 shows a schematic diagram of a signal amplifier of the present invention;

[0041] Figure 5 Shows a schematic structural diagram of the leveling system of the present invention;

[0042] Figure 6 Shows a simplified force diagram of mass moment measurement of the present invention;

[0043] Figure 7 Shows a simplified diagram of the blade assembly of the present invention;

[0044] Figure 8 A physical diagram of a test piece of the present invention is shown;

[0045] Figure 9 Shows a schematic diagram of leveling the detection platform of the present invention;

[0046] Figure 10 Shows a schematic diagram of the beam leveling of the present invention;

[0047] Figure 11 The residual unbalance and vibration test diagram before optimization of the present invention are shown;

[0048] Figure 12 The diagram shows the residual unbalance after optimization and the vibration test diagram of the present invention. DETAILED DESCRIPTION

[0049] The present invention will be further described below with reference to the accompanying drawings.

[0050] The present invention provides a detection platform and detection method, the detection platform mainly includes a weighing beam, a main and auxiliary frames, a frame shaft, a clamp, a bearing, a sleeve, a leveling system, a middle platform, a guide rail support, a measuring system and a base. Among them, the clamp is fixed to one end of the weighing beam by a screw, the weighing beam is fixed to the main and auxiliary frames by a bearing, a frame shaft and a sleeve, the main and auxiliary frames are positioned and fixed to the middle platform by the guide rails on the guide rail platform, and finally the guide rail platform is fixed to the corresponding position of the base. A leveling spring is installed at the front end of the base for the initial leveling of the weighing beam; a group of sensor brackets are respectively fixed to the rear bottom of the weighing beam and the rear end of the base, and the sensors are connected to the upper and lower brackets by bolts. The main structure is as follows Figure 1 shown.

[0051] The fixture consists of two parts, the main fixture and the auxiliary fixture, which are connected by bearings and shafts. The main fixture and the auxiliary fixture provide clamping force through springs to clamp the blade. The clamping teeth inside the fixture are designed according to the structure that matches the tenon groove of the blade fixing end. It can accurately determine the initial clamping position of the blade while ensuring its consistency with the assembled state. The fixture structure is as follows: Figure 2 shown.

[0052] In one embodiment, the measurement system is constructed by a micro tension and pressure sensor, a signal amplifier, an interface converter, and host computer software.

[0053] The sensor has a measuring range of 0-50N, which is fully capable of measuring blades; the output sensitivity is 2.0±10% mV / V; the operating voltage is 2.5-5V, and the maximum operating voltage is 10V; the operating temperature range is -20~80℃, which meets the requirements of general working environments. The sensor is a tension and compression dual-purpose sensor (such as Figure 3 ), the force measuring part is internal thread-table.

[0054] The signal amplifier has an accuracy better than 0.01%; input signal -30 to 30mV; dynamic response 50 to 1600Hz; output signal ±10V, 4-20mA (adjustable), the signal amplifier is Figure 4 shown.

[0055] The sensor value can be read directly on the signal amplifier or using the host computer software, and the obtained data can also be output through the host computer software for secondary development.

[0056] In one embodiment, the leveling system Figure 5As shown, the spring consists of a spring with a low spring constant and a bolt that can be adjusted up and down. The spring has a diameter of 17 mm and a length of 80 mm. The bottom end of the spring fits over the boss of the adjusting bolt, while the top end fits into a slot below the beam. Both ends of the spring are free and unconstrained in terms of displacement in the Z-axis and rotation about the Z-axis. The height of the boss can be increased by rotating the adjusting bolt, thereby applying pressure to the spring and leveling the beam above. Leveling is primarily intended to avoid large tilt angles during measurement. Directly measuring the blade without a leveling device could, firstly, exceed the sensor's measurement range; secondly, the large swing amplitude would require a long time for the beam to stabilize, consuming considerable time; and thirdly, the beam would tilt excessively, resulting in a significant error between the measured value and the actual weight acting on the blade. Therefore, after comprehensive considerations, this device was added to act as a damper in the entire system.

[0057] In one embodiment, based on the principle of micro-torque balance, a tension and pressure sensor and a beam test bench are used to indirectly convert the distance from the blade center of mass to the blade root. Then, a three-coordinate measuring machine is used to measure the distance from the blade root to the center of the blade disk. Finally, the torque formula is used to multiply the actual gravity on the blade by the total length of the lever arm (the length from the blade center of mass to the blade disk center) to obtain the magnitude of the mass moment of the blade in the assembled state. The steps are as follows:

[0058] 1. First, place the mass moment measurement platform on a relatively open horizontal surface, and use an electronic level to perform initial leveling on the experimental platform base and the scale beam.

[0059] 2. After the test bench is stable, place the scale bar freely without load and spring damping. After the value of the tension sensor stabilizes, record the data. This data is defined as the free gravity at one end of the fixture without load at this moment.

[0060] 3. Use the clamp at one end of the scale bar to clamp the standard blade. Note that the clamp teeth and the mortise and tenon on the blade must match to ensure accurate positioning. Then let the scale bar fall freely without adjusting the spring. The sensor value at this time is recorded as G 标 .

[0061] 4. Restore the action of the adjustment spring, while observing the value of the tension sensor, rotate the adjustment bolt until the value of the sensor is the calibration "zero point". (Here "zero point" does not refer to the point where the sensor reading is zero, but to maintain a pre-tension on the sensor. This is because if the measuring blade is lighter than the calibration blade, the force on the sensor will change from tension to pressure, and the tension-pressure conversion will cause an error. In order to avoid this error, a small amount of tension is reserved.) The reading of the sensor at "zero point" is recorded as G 零 .

[0062] 5. Remove the standard blade, keep the experimental bench in its current state, measure the blades to be tested one by one, record the data, and arrange them in order.

[0063] 6. Measure the center of mass position: Figure 6 The figure shows a simplified diagram of the forces acting on the entire test bench during the measurement process. Based on the moment balance principle, equations 5.1 and 5.2 are used to derive the distance from the blade's center of mass to the blade root. The length of the lever arm must be measured using a three-dimensional coordinate measuring machine.

[0064] The distance formula from the centroid of the leaf to the root is:

[0065] m1g(X+L2)-F 拉 L4=F 弹 L3 (5.1)

[0066]

[0067]

[0068] m1——the mass of the blade to be tested;

[0069] X - the distance from the centroid of the leaf to the root;

[0070] F 弹 ——The initial elastic force of the spring when it is leveled;

[0071] F 拉 ——The tensile force applied to the sensor during measurement (i.e. the value displayed by the sensor);

[0072] L2 - the distance from the blade root to the center support point;

[0073] L3 - the distance from the center of the spring to the center fulcrum;

[0074] L4 - the distance from the center of the sensor to the center fulcrum;

[0075] G 标 ——Gravity acting on a standard blade;

[0076] G 零 ——The reading of the sensor when calibrating the “zero point”;

[0077] Note: Since the secondary compression distance of the spring is extremely small when measuring the blade, the elastic force generated by the spring in this process can be ignored.

[0078] 7. Calculate the mass moment: Figure 7 As shown, after determining the center of mass of the blade, the mass moment M of the blade after assembly can be calculated according to formula 5.4: z Where: L1 is the distance from the blade root to the center of the blade disk, and the specific data is measured using a three-coordinate measuring machine.

[0079] The calculation formula of the mass moment after the blade is assembled is:

[0080] M z =m1·(X+L1)(5.4)

[0081] In one embodiment, the present invention relates to a mass moment staggered arrangement method, and the specific steps are as follows.

[0082] (1) Sort the blades whose mass moments have been calculated according to their numerical values;

[0083] (2) The two blades with the closest mass moment values are grouped together;

[0084] (3) Measure the initial imbalance of the blade disk;

[0085] (4) The following three points should be met during blade assembly: blades with similar mass moment values should be installed relative to each other, blades with complementary values should be installed adjacent to each other, and attention should be paid to adjusting the initial imbalance of the blade disk.

[0086] Arrangement optimization verification: Assemble the arranged blades onto the blisk in sequence, and perform a dynamic balancing test on a dynamic balancing machine. By comparing the dynamic balancing test data before and after optimization, the feasibility of this optimization method can be verified.

[0087] In one embodiment, the detection method comprises the following steps:

[0088] 1. Preparation

[0089] Record the 12 blades and the corresponding blade slot numbers, such as Figure 8 Then remove the leaves and place them in order, waiting for measurement.

[0090] 2. Initial leveling

[0091] Place two electronic levels on both sides of the laboratory table base, such as Figure 9 . While adjusting the height of the four corners of the base, observe the level reading. When the reading is zero, it means the base is in a horizontal state. Place the electronic level on both ends of the scale bar. Figure 10 By adding counterweights or rotating the adjusting bolts, the beam is brought to its initial equilibrium position, i.e. the level indicator reads zero.

[0092] 3. Blade calibration

[0093] Blade No. 9 is randomly selected as the standard part and is clamped in the middle position of the fixture. At this time, the spring of the leveling bolt is removed, and one end of the fixture is allowed to fall freely. The sensor reads the reading (the negative sign here only indicates that the force applied to the sensor at this time is tension).

[0094] Reset the spring and adjust the bolt to make the sensor value reach -0.1000N. Mark the position at this time as the "zero point" and calculate F 弹 After calibrating the "zero point", remove the standard blade No. 9 and the preparations before measurement are completed.

[0095] The blades to be measured are placed on the fixture in order and measured. Each time, the data should be recorded after the sensor value is stable. (Note: Do not touch any place other than the fixture during each measurement to avoid affecting the original calibration state and causing large errors). Then use a three-sensor weighing platform to weigh each blade and obtain the mass of 12 blades. Finally, the three-coordinate measuring machine is used to measure the Figure 6 The length of each lever arm.

[0096] By combining the above measured data and substituting them into Formulas 5.3 and 5.4, the mass moment of the blade when assembled on the blisks can be calculated.

[0097] After obtaining the mass moment of each blade when assembled on the blade disk, the blades are reordered and assembled according to the blade arrangement optimization method, and then the dynamic balance test is carried out on the dynamic balance test machine. Comparing the experimental figures before and after optimization, it can be seen that ( Figure 11-12 ), after optimization, the imbalance of the overall blade disk is reduced and the vibration is significantly improved. Therefore, the detection platform designed by this patent and the optimization method proposed are helpful to achieve the dynamic balance of the rotor.

[0098] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. It should be understood that many modifications may be made to the illustrative embodiments, and that other arrangements may be devised, without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in ways other than those described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be employed in conjunction with other described embodiments.

Claims

1. A method for detecting the mass moment of an aero-engine blade, characterized in that: Step 1: First, place the testing platform on a relatively open horizontal surface and perform initial leveling of the testing platform base and the scale bar; Step 2: After the test bench is stable, place the scale bar freely without load and spring damping. After the value of the tension sensor stabilizes, record the data. This data is defined as the free gravity at one end of the fixture without load at this moment. Step 3. Use the clamp at one end of the scale bar to clamp the standard blade. Note that the clamp teeth and the tenon groove on the blade must match. Then let the scale bar fall freely without adjusting the spring. The value of the sensor at this time is recorded as G mark. Step 4: Restore the action of the adjustment spring, observe the value of the tension sensor, and rotate the adjustment bolt until the value of the sensor reaches the calibrated "zero point". The reading of the sensor at "zero point" is recorded as G zero. Step 5: Remove the standard blade, keep the test bench in its current state, measure the blades to be tested one by one, record the data, and arrange them in order; Step 6: Measure the center of mass position and calculate the distance from the blade center of mass to the blade root based on the moment balance principle; Step 7: After determining the center of mass position of the blade, calculate the mass moment of the blade after assembly.

2. The detection method according to claim 1, characterized in that Calculate the distance from the centroid of the leaf to the root: （5.1） （5.2） (5.3) m1 represents the mass of the blade to be measured; X represents the distance from the centroid of the leaf to the root; F 弹 Indicates the initial elastic force when the spring is leveled; F 拉 Indicates the tension applied to the sensor during measurement; L2 represents the distance from the blade root to the center support point; L3 represents the distance from the center of the spring to the center fulcrum; L4 represents the distance from the center of the sensor to the center support point; G 标 Indicates the gravity acting on a standard blade; G 零 Indicates the reading of the sensor when calibrating the "zero point".

3. The detection method according to claim 2, characterized in that After determining the center of mass of the blade, calculate the mass moment M of the blade after assembly. z Where: L1 is the distance from the blade root to the center of the blade disk; the mass moment calculation formula after the blade is assembled is: (5.4)。 4. The detection method according to claim 3, characterized in that Sort the blades with calculated mass moments according to their numerical values; group the two blades with the closest mass moment values; and measure the initial imbalance of the blade disk. When assembling the blades, blades with similar mass moment values are installed opposite each other, blades with complementary values are installed adjacent to each other, and the initial imbalance of the blade disk is adjusted.

5. The detection method according to claim 4, characterized in that Assemble the arranged blades onto the blisk in sequence, perform a dynamic balancing test on a dynamic balancing machine, and compare the dynamic balancing experimental data before and after optimization.

6. An aircraft engine blade mass moment detection platform, characterized in that: Used to perform any one of the detection methods of claims 1-5, the detection platform includes a weighing beam, a main frame, a sub-frame, a frame shaft, a clamp, a bearing, a sleeve, a leveling system, a middle platform, a guide rail support, a measuring system and a base; wherein, the clamp is fixed to one end of the weighing beam, the weighing beam is fixed to the main frame and the sub-frame through the bearing, the frame shaft and the sleeve, the main frame and the sub-frame are positioned and fixed to the middle platform through the guide rails on the guide rail support, and the guide rail support is fixed to the base; a leveling spring is installed at the front end of the base for initial leveling of the weighing beam; a sensor upper bracket and a sensor lower bracket are fixed to the rear end bottom of the weighing beam and the rear end of the base respectively, and the sensor is connected to the sensor upper bracket and the sensor lower bracket.

7. The detection platform according to claim 6, characterized in that: The clamp includes a main clamp and a sub-clamp. The main clamp and the sub-clamp are connected by bearings and shafts. The main clamp and the sub-clamp provide clamping force through springs to clamp the blades. The clamping teeth are designed inside the clamp according to the structure that matches the tenon groove at the fixed end of the blade.

8. The detection platform according to claim 6, characterized in that: The measuring system includes a micro tension and pressure sensor, a signal amplifier, an interface converter and a host computer software.

9. The detection platform according to claim 6, characterized in that: The leveling system includes a spring and a bolt that can be adjusted up and down. The bottom end of the spring is sleeved on the boss of the adjusting bolt, and the upper end is clamped in the slot below the scale beam. Both ends of the spring are free ends and the displacement in the Z-axis direction and the rotation around the Z-axis are not constrained.

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