A device for testing the hydroelastic properties of an underwater rotating propeller-shaft system

Abstract

The present invention belongs to the technical field related to ship hydroelasticity or fluid-solid coupling mechanics test, and discloses an underwater rotating propeller-shaft system hydroelasticity performance test device, the device comprising: an open water tank is provided with a motor, a torque thrust speed test system and an electromagnetic exciter; one end of the rotating shaft is provided in the open water tank, the motor is provided at the end of the rotating shaft, and the torque thrust speed test system and the electromagnetic exciter are provided in the rotating shaft; the propeller is provided at the other end of the rotating shaft, and the propeller blades and the rotating shaft are provided with acceleration sensors, and the acceleration sensors are output to the data processing computer through the conductive slip ring at the end of the rotating shaft; the open water tank, the rotating shaft and the propeller are provided on a trailer. The present application avoids the limitation of the traditional propeller scale, and designs a test device that is more in line with the actual propeller operation state, and then the accurate test of the hydroelasticity performance of the propeller-shaft system can be achieved by installing sensors and exciters.

Description

Technical Field

[0001] The present invention belongs to the technical field related to ship hydroelasticity or fluid-solid coupling mechanics tests, and more specifically, relates to a hydroelasticity performance test device for an underwater rotating propeller-shaft system. Background Art

[0002] The propeller-shaft system is the core component of the ship's propulsion device. When the propeller vibrates in the non-uniform wake field at the stern due to the elasticity of the blades and the shaft, a complex bidirectional fluid-solid coupling phenomenon of fluid-elastic propeller-shaft is generated. With the widespread use of large side-skew propellers and composite propellers, the bidirectional fluid-solid coupling effect of the complex fluid-elastic propeller-shaft system has become more significant. Figure 1 As shown in the figure. The vibration of the elastic propeller-shaft system will not only damage various precision equipment on the ship, but also cause discomfort symptoms such as seasickness to the crew on board, which is not conducive to the safe operation of the ship. In addition, the vibration of the elastic propeller-shaft system is an important source of underwater low-frequency radiated noise of ships. The study of the bidirectional fluid-solid coupling / hydroelastic phenomenon of the fluid-elastic propeller-shaft complex system is of great significance to the propeller-induced propulsion system vibration and underwater radiated noise of the hull.

[0003] In the prior art, obtaining the steady-state force characteristics of ship propellers under uniform flow and the dynamic characteristics (such as dynamic strain, etc.) of rigid propellers under non-uniform flow can be achieved by setting corresponding sensors. However, it is difficult to test the dynamic mechanical characteristics caused by the interaction between fluid and blade solid (involving the elasticity of blades and rotating shaft) under non-uniform flow. The only relevant research on the hydroelasticity of propeller-shaft systems was carried out in the cavitation water cylinder experimental environment. Due to the size limitation of the cavitation water cylinder, the size of the test propeller is greatly constrained. On the one hand, it increases the scale effect of the test. On the other hand, the size and weight of the acceleration sensor used in the test will cause greater interference to the vibration characteristics and hydrodynamic characteristics of the propeller, which increases the signal-to-noise ratio of the test bench to a certain extent, which is not conducive to the study of the hydroelastic law of the propeller-shaft system. Summary of the invention

[0004] In view of the above defects or improvement needs of the prior art, the present invention provides a test device for the hydroelastic properties of an underwater rotating propeller-shaft system, which avoids the limitations of the traditional propeller scale and designs a test device that is more in line with the actual propeller operating state. Furthermore, accurate testing of the hydroelastic properties of the propeller-shaft system can be achieved by installing sensors and exciters.

[0005] To achieve the above-mentioned purpose, according to one aspect of the present invention, there is provided an underwater rotating propeller-shaft system water elastic performance test device, the device comprising: an open water tank, in which a motor, a torque thrust speed test system and an electromagnetic exciter are arranged; a rotating shaft, one end of which passes through the wall of the open water tank and is arranged in the open water tank, the motor is arranged at the end of the rotating shaft, the torque thrust speed test system and the electromagnetic exciter are arranged in the rotating shaft, and the electromagnetic exciter is communicatively connected with a power amplifier and a signal generator; a propeller, the propeller is arranged at the other end of the rotating shaft, the blades of the propeller and the rotating shaft are provided with acceleration sensors, and the acceleration sensors are output to a data processing computer through a conductive slip ring at the end of the rotating shaft; a trailer moves in coordination with a guide rail in a water pool, and the open water tank is arranged on the trailer.

[0006] Preferably, the conductive slip ring comprises a stator and a rotor which are arranged closely together, the rotor is connected to the acceleration sensor via a cable, and the stator is connected to a data acquisition instrument via a cable, and further connected to a data processing computer.

[0007] Preferably, there are a plurality of acceleration sensors arranged on the blades, and the plurality of acceleration sensors are evenly arranged on the blades of the propeller.

[0008] Preferably, the acceleration sensor is arranged on the blade at a distance of 0.6-0.9r from the axis of the propeller, wherein r is the radius of the blade.

[0009] Preferably, the distance between the propeller and the open water tank is greater than 3 times the diameter of the propeller.

[0010] Preferably, a shaft sleeve is fixed on the open water box, and the rotating shaft passes through the shaft sleeve.

[0011] Preferably, a fairing cap is provided at the end of the propeller.

[0012] In general, compared with the prior art, the above technical solution conceived by the present invention provides an underwater rotating propeller-shaft system hydroelastic performance test device with the following beneficial effects:

[0013] 1. Use a trailer to move forward in the towing pool to simulate the incoming flow. Since the open water tank can be installed farther away from the water surface and the pool wall, the propeller size can be larger than that in the cavitation water cylinder, which is more suitable for installing various acceleration sensors for vibration signal measurement, and the scale effect is smaller.

[0014] 2. The electromagnetic exciter can provide longitudinal vibration. The excitation frequency and amplitude are easy to adjust, and it can output excitation of any frequency and amplitude, which is convenient for timely adjustment of the excitation output and significantly improves the test efficiency and accuracy.

[0015] 3. The conductive slip ring is designed as a combination of rotor and stator, which can overcome the difficulty of signal collection caused by the rotation of the propeller.

[0016] 4. The acceleration sensor is arranged on the blade at a distance of 0.6 to 0.9 r from the axis of the propeller, which can measure the acceleration of the blade without affecting the interaction between the blade and water due to the acceleration sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the deformation of the elastic propeller-shaft system when working under an unsteady flow field;

[0018] Figure 2 It is a schematic diagram of a test device for the hydroelastic properties of an underwater rotating propeller-shaft system;

[0019] Figure 3 is a top view of a test device for the hydroelastic properties of an underwater rotating propeller-shaft system;

[0020] Figure 4 It is the main view of the conductive slip ring;

[0021] Figure 5 It is the right side view of the conductive slip ring.

[0022] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0023] 1- open water tank, 2- trailer, 3- motor, 4- torque thrust speed test system, 5- electromagnetic exciter, 6- shaft sleeve, 7- rotating shaft, 8- propeller, 9- conductive slip ring, 10- acceleration sensor, 11- rectifier cap, 12- power amplifier, 13- signal generator, 14- data acquisition instrument, 15- data processing computer, 16- cable, 17- water tank, 18- guide rail, 19- stator, 20- rotor. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] like Figure 2 and Figure 3As shown, the present invention provides a device for testing the hydroelastic properties of an underwater rotating propeller-shaft system, the device comprising an open water tank 1, a trailer 2, a motor 3, a torque thrust speed test system 4, an electromagnetic exciter 5, a shaft sleeve 6, a rotating shaft 7, a propeller 8, a conductive slip ring 9, an acceleration sensor 10, a fairing cap 11, a power amplifier 12, a signal generator 13, a data processing computer 15, a cable 16, and a guide rail 18, as shown below.

[0026] The open water tank 1 is provided with a motor 3, a torque-thrust-speed test system 4 and an electromagnetic exciter 5. The motor 3 is used to provide the speed and torque of the propeller rotation. The torque-thrust-speed test system 4 is used to measure the speed, thrust and torque of the propeller rotation. The electromagnetic exciter 5 is used to excite the longitudinal vibration of the propeller and provide its longitudinal vibration frequency and amplitude. The electromagnetic exciter 5 is connected in communication with the power amplifier 12 and the signal generator 13, and is used to excite the propeller-shaft system to vibrate according to the required signal.

[0027] One end of the rotating shaft 7 passes through the wall of the open water tank 1 and is arranged in the open water tank 1, the motor 3 is arranged at the end of the rotating shaft 7, and the torque thrust speed test system 4 and the electromagnetic exciter 5 are arranged in the rotating shaft 7. A shaft sleeve 6 is fixed on the open water tank, and the rotating shaft 7 passes through the shaft sleeve 6, and the shaft sleeve 6 is used to support the rotating shaft 7.

[0028] The propeller 8 is arranged at the other end of the rotating shaft 7. An acceleration sensor 10 is arranged on the blades of the propeller 8 and the rotating shaft 7. The acceleration sensor 10 is output to the data processing computer 15 through the conductive slip ring 9 at the end of the rotating shaft 7. The acceleration sensor 10 is used to measure the vibration signal of the elastic propeller-shaft system.

[0029] There are multiple acceleration sensors 10 arranged on the blades, and the multiple acceleration sensors 10 are preferably evenly arranged on the blades of the propeller 8. The distance between the position of the acceleration sensor 10 arranged on the blade and the axis of the propeller 8 is preferably 0.6-0.9r, where r is the radius of the blade.

[0030] like Figure 4 and Figure 5As shown, the conductive slip ring 9 includes a stator 19 and a rotor 20 which are arranged closely together. The rotor 20 is connected to the acceleration sensor 10 through a cable 16, and the stator 19 is connected to a data processing computer 15 through a cable 16. Since the acceleration sensor 10 arranged on the blade rotates with the propeller, it is necessary to use the conductive slip ring 9 to transmit the signal of the rotating cable 16 to the stator 19 of the conductive slip ring 9, and then input it to the data acquisition instrument 14 to complete the signal acquisition. Therefore, using the conductive slip ring 9 to collect the vibration signal of the rotating propeller can overcome the difficulty of signal acquisition caused by the rotation of the propeller. The outer surfaces of the acceleration sensor 10 and the cable 16 are arranged with waterproof silica gel to ensure normal operation underwater.

[0031] A fairing cap 11 is provided at the end of the propeller 8 .

[0032] In order to avoid the influence of the wake flow at the rear of the open water tank 1 on the water flow at the propeller during the forward movement, the distance between the propeller 8 and the open water tank 1 is greater than 3 times the diameter of the propeller 8.

[0033] The trailer 2 moves in coordination with the guide rails 18 in the water pool 17 , and the open water tank 1 is arranged on the trailer 2 .

[0034] In the ship towing tank, the signal generator 13 sends out a hammer pulse / periodic excitation signal to excite the elastic propeller-shaft system to generate vibration. Based on the conductive slip ring 9, the technical difficulty of winding the rotating cable 16 of the propeller-shaft system is overcome. The acceleration sensor 10 is connected to the data acquisition instrument 14 through the conductive slip ring to measure the acceleration signal of the focus point on the propeller 8 and the rotating shaft 7. In the experiment, the influence law of the wet mode and hydrodynamic damping parameters of the elastic propeller-shaft system in the static state and different navigation states is measured to characterize the hydroelastic characteristics of the elastic propeller-shaft system.

[0035] The test method using the above underwater rotating propeller-shaft system hydroelastic performance test device is as follows:

[0036] S1: Test at different water depths and distances from shore to establish a range of water depths and distances from shore that can approximate infinite waters, in order to eliminate the influence of wall and water surface effects on the test results.

[0037] S2: For wet modal characteristics, the acceleration frequency response functions of the blades and the shaft are obtained by loading a periodic sweep signal stronger than the motor excitation through the exciter. The wet modal frequency and modal vibration shape of the propeller-shaft system under different working conditions are identified through the peak characteristics and phase relationship.

[0038] S3: Damping determination in static state, the motor does not rotate, a pulse signal is applied through the electromagnetic exciter, and the mechanical damping and viscous damping factors are obtained based on the free vibration decay method.

[0039] S4: Obtain the damping factor in the motion state, drag the trailer, rotate the motor, and apply a pulse signal much stronger than the motor excitation within the intensity range to obtain the total damping factor including the hydrodynamic damping.

[0040] S5: The hydrodynamic damping can be obtained by subtracting the static damping obtained in step S1 from the damping in the moving state obtained in step S4, and then the variation law of the hydrodynamic damping with the parameters can be obtained.

[0041] In summary, the present application provides a test device for the hydroelastic properties of an underwater rotating propeller-shaft system, which avoids the limitations of traditional propeller scales and designs a test device that is more in line with the actual propeller operating state. Furthermore, accurate testing of the hydroelastic properties of the propeller-shaft system can be achieved by installing sensors and exciters.

[0042] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An underwater rotating propeller-shaft system hydroelastic performance test device, characterized in that: The device comprises: An open water tank (1), wherein a motor (3), a torque thrust speed test system (4) and an electromagnetic exciter (5) are arranged in the open water tank (1); A rotating shaft (7), one end of the rotating shaft (7) passes through the wall of the open water tank (1) and is arranged in the open water tank (1), the motor (3) is arranged at the end of the rotating shaft (7), the torque thrust speed test system (4) and the electromagnetic exciter (5) are arranged in the rotating shaft (7), and the electromagnetic exciter (5) is communicatively connected with the power amplifier (12) and the signal generator (13); A propeller (8), the propeller (8) being arranged at the other end of the rotating shaft (7), the blades of the propeller (8) and the rotating shaft (7) being provided with an acceleration sensor (10), the acceleration sensor (10) being output to a data processing computer (15) through a conductive slip ring (9) at the end of the rotating shaft (7); The trailer (2) moves in coordination with the guide rail (18) in the water pool, and the open water tank (1) is arranged on the trailer (2); In the water pool, a signal generator (13) sends a hammer pulse / periodic excitation signal to excite the elastic propeller-shaft system to generate vibration; in the test, the influence of the wet mode and hydrodynamic damping parameters of the elastic propeller-shaft system in a static state and under different navigation states is measured to characterize the hydroelastic characteristics of the elastic propeller-shaft system.

2. The device according to claim 1, characterized in that The conductive slip ring (9) comprises a stator (19) and a rotor (20) which are arranged closely together. The rotor (20) is connected to the acceleration sensor (10) via a cable (16). The stator (19) is connected to a data acquisition device (14) via a cable (16), and is further connected to a data processing computer (15).

3. The device according to claim 1, characterized in that There are a plurality of acceleration sensors (10) arranged on the blades, and the plurality of acceleration sensors (10) are evenly arranged on the blades of the propeller (8).

4. The device according to claim 3, characterized in that The acceleration sensor (10) is arranged on the blade at a distance of 0.6 to 0.9r from the axis of the propeller (8), wherein r is the radius of the blade.

5. The device according to claim 1, characterized in that The distance between the propeller (8) and the open water tank (1) is greater than 3 times the diameter of the propeller (8).

6. The device according to claim 1, characterized in that A shaft sleeve (6) is fixed on the open water box (1), and the rotating shaft (7) passes through the shaft sleeve (6).

7. The device according to claim 1, characterized in that The end of the propeller (8) is provided with a fairing cap (11).

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