An online measuring device for deep water propellers

Abstract

The present invention provides a deep - water on - line measuring device for a propeller, which relates to the technical field of deep - water strain on - line measuring devices for propellers of ships or underwater vehicles. The device includes a sensing optical fiber, a data acquisition unit, and a hub cap tooling. The hub cap tooling is used for fixedly connecting with the hub of the propeller to be measured. The sensing optical fiber is used for being pasted on the blade of the propeller to be measured, acquiring the structural strain information of the blade and transmitting signals. The data acquisition unit is installed inside the hub cap tooling. The sensing optical fiber is introduced into the interior of the hub cap tooling through wall - penetrating sealing and is connected to the data acquisition unit. The data acquisition unit is used for detecting, processing the signals of the sensing optical fiber and storing data. The deep - water on - line measuring device for the propeller of the present invention is based on the OFDR distributed optical fiber measuring technology, with a large measuring capacity, high precision, simple layout, convenient installation, and wide application range. It is not only applicable to model test measurements but also can be used for measuring the propellers of ships and underwater vehicles during navigation.

Description

Technical Field

[0001] The present invention relates to the technical field of propeller structure monitoring devices, and more specifically to the technical field of an on-line deep-water strain measurement device for ship or underwater vehicle propellers. Background Art

[0002] The propeller is an important component of ships and underwater vehicles. As a propeller of a thruster, the propeller blades bear alternating forces and torques in an uneven flow field, as well as possible foreign object collisions or entanglements. The stress situation is complex and it is easy to be damaged. Therefore, it is very necessary to monitor the strength of underwater propellers. At the same time, the underwater measurement data also provides important reference and verification basis for the design of propellers.

[0003] For the strength measurement of underwater propellers, generally, electronic strain gauges are pasted on the blades and static loading is carried out on the ground for measurement, or an open water test is carried out in a ship model pool. The Chinese invention application with the application number CN202011456804.4 discloses a dynamic strain measurement device for marine propeller blades based on FBG. This measurement device pastes FBG sensors on the blades, and then leads out the FBG signals out of the water through a fiber optic slip ring and a bracket and accesses a fiber optic demodulator for data acquisition and analysis.

[0004] However, the above measurement technologies have the following deficiencies: 1. Using traditional resistance strain measurement, due to the difficulty of the sensor in overcoming the waterproof problem and the signal transmission problem of many measuring points and many cables, underwater measurement cannot be carried out. 2. Using the FBG measurement scheme, the FBG sensor is a fiber optic point sensor. When used in series, each sensor needs to be fused and then protected, with complex technology and great operation difficulty. In addition, limited by the demodulation light source, generally about 8-10 sensor signals can be demodulated for a single channel in engineering, resulting in very limited deployable measuring points. For the strength analysis of propeller blades, theoretically, the more measuring points for strain measurement, the better. 3. In signal transmission, the fiber optic slip ring is a rotating device, and its rotation speed is generally lower than 2000 revolutions per minute, which cannot meet the measurement requirements of higher propeller rotation speed conditions. In addition, the fiber optic slip ring is a non-waterproof device with a low protection level, and is only suitable for shallow water and short-term use. 4. In signal transmission, the fiber optic signal line should be avoided from being entangled by the propeller blades. Special brackets need to be installed for traction from underwater to the water surface. The added brackets will affect the flow field, thus affecting the measurement results. At the same time, the stator of the fiber optic slip ring installed in the cabin below the bracket should always be coaxial with the propeller, with great implementation difficulty. 5. The existing underwater propeller test devices are only applicable to the open water test in a ship model pool and cannot meet the needs of in-service ship deep-water measurement. The water depth of in-service ship or underwater vehicle propellers generally exceeds 3 meters and even reaches several hundred meters. Summary of the Invention

[0005] The present invention provides a deep - water online measurement device for a propeller, which solves the problems caused by the existing methods of measuring by pasting electronic strain gauges on the propeller blades and performing static loading on the ground, or conducting open - water tests in a ship model pool.

[0006] The technical solution of the present invention is realized as follows:

[0007] A deep - water online measurement device for a propeller includes a sensing optical fiber, a data acquisition unit, and a hub cap tooling. The hub cap tooling is used for fixedly connecting with the hub of the propeller to be measured. The sensing optical fiber is used for pasting on the blades of the propeller to be measured, acquiring the structural strain information of the blades and transmitting signals. The data acquisition unit is installed inside the hub cap tooling. The sensing optical fiber is introduced into the interior of the hub cap tooling through wall - penetrating sealing and is connected to the data acquisition unit. The data acquisition unit is used for detecting, processing, and storing the signals of the sensing optical fiber.

[0008] Furthermore, the data acquisition unit includes a main control module, a power supply module, and a signal demodulation module. The main control module, the power supply module, and the signal demodulation module are respectively installed inside the hub cap tooling. The power supply module is electrically connected to the main control module and the signal demodulation module respectively. The signal demodulation module is communicatively connected to the main control module. The sensing optical fiber is connected to the signal demodulation module.

[0009] Furthermore, it further includes an optical fiber watertight connector. The optical fiber watertight connector is fixedly installed on the hub cap tooling through wall - penetrating sealing. The sensing optical fiber is introduced into the interior of the hub cap tooling through the optical fiber watertight connector by wall - penetrating sealing.

[0010] Furthermore, the optical fiber watertight connector includes a socket and a plug. A bracket is provided on the hub cap tooling. An optical fiber groove is provided on the outer side wall of the hub cap tooling. The sensing optical fiber is buried in the optical fiber groove. A through - hole is provided on the end face of the hub cap tooling. The socket is fixedly installed in a sealed manner at the through - hole of the hub cap tooling. The plug is fixedly inserted into the socket. A pigtail is provided on the plug. The pigtail is fixed on the bracket and is fusion - spliced with the sensing optical fiber in the optical fiber groove. The socket is connected to the optical fiber channel of the signal demodulation module.

[0011] Furthermore, it further includes a power switch. The power switch is fixedly installed on the hub cap tooling through wall - penetrating sealing. The power switch is electrically connected to the main control module and the signal demodulation module. The power switch is used to control the power - on or power - off of the main control module and the signal demodulation module with respect to the power supply module.

[0012] Furthermore, it further includes a nut. A stud is provided on the power switch. A switch hole is provided on the hub cap tooling. The stud on the power switch penetrates into the interior of the hub cap tooling through the switch hole. The nut is located inside the hub cap tooling and is threadedly connected to the stud of the hub cap tooling. The power switch is a push - type deep - water power switch.

[0013] Further, it further includes a bracket. A support bar is provided inside the hub cap tooling. The bracket is fixedly installed on the support bar, and the main control module, the power module, and the signal demodulation module are fixedly installed on the bracket.

[0014] Further, the hub cap tooling is in a cylindrical shape with one end open. A flange plate for fixedly connecting with the propeller hub of the propeller to be measured is provided at the open end of the hub cap tooling, and a sealing groove is provided on the end face of the flange plate.

[0015] The beneficial effects that can be achieved by the present invention adopting the above technical solution are as follows: The deep - water online measurement device for propellers of the present invention is based on the OFDR distributed optical fiber measurement technology, with a large measurement capacity, high precision, simple layout, convenient installation, and wide application range. It is not only applicable to model test measurements but also can be used for measuring propellers during the navigation of ships and underwater vehicles. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0017] Figure 1 It is a schematic diagram when the present invention conducts measurement;

[0018] Figure 2 It is a cross - sectional view of the present invention after omitting the sensing optical fiber;

[0019] Figure 3 It is an exploded schematic diagram of the optical fiber watertight connector and the power switch;

[0020] Figure 4 and Figure 5 It is a schematic diagram of the hub cap tooling.

[0021] In the drawings, the components corresponding to each reference numeral are as follows:

[0022] 1 - Propeller, 2 - Propeller hub, 3 - Propeller blade, 4 - Hub cap tooling, 5 - Sensing optical fiber, 6 - Main control module, 7 - Power module, 8 - Signal demodulation module, 9 - Optical fiber watertight connector, 10 - Through hole, 11 - Bracket, 12 - Optical fiber groove, 13 - Power switch, 14 - Switch hole, 15 - Bracket, 16 - Support bar, 17 - Socket, 18 - Plug, 19 - Nut, 20 - Flange plate, 21 - Bolt, 22 - Stud, 23 - Sealing groove, 24 - Pigtail. Detailed Embodiments

[0023] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0024] Referring to Figures 1 to 5 , a propeller deep - water on - line measuring device includes a sensing optical fiber 5, a data acquisition unit, a hub cap tooling 4, an optical fiber watertight connector 9, a power switch 13, a nut 19 and a bracket 15. The hub cap tooling 4 is used for fixedly connecting with the hub 2 of the propeller 1 to be measured. The hub cap tooling 4 is made of metal material with a pressure resistance greater than 2 MPa, and is used for the installation and sealing protection of the data acquisition unit. The hub cap tooling 4 is a cylindrical shape with one end open. At the open end of the hub cap tooling 4, there is a flange plate 20 for fixedly connecting with the hub 2 of the propeller 1 to be measured. The flange plate 20 can be fixedly connected with the hub 2 through bolts 21. On the end face of the flange plate 20, there is a sealing groove 23, and the sealing groove 23 can be used in cooperation with a sealing ring for sealing between the hub cap tooling 4 and the hub 2.

[0025] The sensing optical fiber 5 is used for being pasted on the blade 3 of the propeller 1 to be measured and acquiring the structural strain information of the blade 3 and transmitting signals. The sensing optical fiber 5 is a bare optical fiber. The data acquisition unit is installed inside the hub cap tooling 4. The sensing optical fiber 5 penetrates through the wall and is hermetically introduced into the interior of the hub cap tooling 4 and is connected with the data acquisition unit. The data acquisition unit is used for detecting, processing and storing the signals of the sensing optical fiber 5. The data acquisition unit includes a main control module 6, a power supply module 7 and a signal demodulation module 8. The main control module 6, the power supply module 7 and the signal demodulation module 8 are respectively installed inside the hub cap tooling 4 and are installed in the following manner: There is a support bar 16 inside the hub cap tooling 4. The bracket 15 is fixedly installed on the support bar 16. The main control module 6, the power supply module 7 and the signal demodulation module 8 are fixedly installed on the bracket 15.

[0026] The power supply module 7 is electrically connected with the main control module 6 and the signal demodulation module 8 respectively. The signal demodulation module 8 is communicatively connected with the main control module 6. The sensing optical fiber 5 is connected with the signal demodulation module 8. Inside the main control module 6, there are a high - performance CPU processing chip and a large - capacity solid - state hard disk, and it is communicatively connected with the signal demodulation module 8 through a network cable for data parsing and data storage. The power supply module 7 provides DC12V power for the signal demodulation module 8 and the main control module 6. The signal demodulation module 8 is designed based on the distributed optical fiber principle of OFDR (Optical Frequency Domain Reflectometry), and can achieve distributed strain measurement with a spatial resolution less than 1 cm and an accuracy of ±1 με.

[0027] The fiber optic watertight connector 9 is fixedly installed through the wall and sealed on the hub cap tooling 4, and the sensing optical fiber 5 is introduced into the interior of the hub cap tooling 4 through the wall and sealed by the fiber optic watertight connector 9. The specific connection relationship between the fiber optic watertight connector 9 and the hub cap tooling 4 is as follows: The fiber optic watertight connector 9 includes a socket 17 and a plug 18. A bracket 11 is provided on the hub cap tooling 4, a fiber optic groove 12 is provided on the outer side wall of the hub cap tooling 4, the sensing optical fiber 5 is buried in the fiber optic groove 12, a through hole 10 is provided on the end face of the hub cap tooling 4, the socket 17 is fixedly installed and sealed at the through hole 10 of the hub cap tooling 4, the plug 18 is fixedly inserted into the socket 17, a pigtail 24 is provided on the plug 18, the pigtail 24 is fixed on the bracket 11 and is fusion spliced with the sensing optical fiber 5 in the fiber optic groove 12, and the socket 17 is connected to the signal demodulation module 8 through an optical fiber channel. The fiber optic watertight connector 9 is made of stainless steel, is an optical signal transmission device, and has a pressure resistance greater than 2 MPa; the bracket 11 is used to guide the pigtail 24 to smoothly enter the fiber optic groove 12 without being bent at a small angle, which affects the signal strength; the fiber optic groove 12 is used to bury the sensing optical fiber 5 and the fusion splicing joint of the sensing optical fiber 5 and the pigtail 24, so that the sensing optical fiber 5 will not bulge and be damaged during construction.

[0028] The power switch 13 is fixedly installed through the wall and sealed on the hub cap tooling 4. The specific connection relationship between the power switch 13 and the hub cap tooling 4 is as follows: A stud 22 is provided on the power switch 13, a switch hole 14 is provided on the hub cap tooling 4, the stud 22 on the power switch 13 passes through the switch hole 14 and enters the hub cap tooling 4, and the nut 19 is located inside the hub cap tooling 4 and is threadedly connected to the stud 22 of the hub cap tooling 4. The power switch 13 is electrically connected to the main control module 6 and the signal demodulation module 8, and the power switch 13 is used to control the power on or off of the main control module 6 and the signal demodulation module 8 with the power module 7. The power switch 13 is made of stainless steel, is a push-type deep-water power switch, has a pressure resistance greater than 2 MPa, and is used for the power supply control of the data acquisition unit. After the power switch 13 is turned on, the software of the data acquisition unit automatically runs and saves data.

[0029] The propeller deep-water on-line measuring device of the present invention adopts OFDR distributed optical fiber technology and the sealing structure design of the hub cap tooling 4. Compared with the traditional measurement scheme, it has the following advantages:

[0030] a), The number of sensor measurement points is large and the installation is simple. Based on the OFDR-based distributed optical fiber sensing technology, only one sensing optical fiber 5 needs to be pasted on the blade 3 to achieve distributed strain measurement with a high spatial resolution <1 cm. It can be understood that each point on the sensing optical fiber 5 is a sensor, and at least 100 measurement points can be measured on 1 meter of the sensing optical fiber 5.

[0031] b), The signal does not need to be led out of the water surface, and there is no need to install a lead support facility, which reduces the construction difficulty and avoids measurement interference at the same time. The sensing optical fiber 5 is fixed in the optical fiber groove 12 and then enters the hub cap tooling 4 through the optical fiber watertight connector 9, without the need to be led out of the water surface, and also avoids the influence of the installed facilities on the measured flow field.

[0032] c), It can perform dynamic measurement at high rotational speeds and cover all working conditions. The data acquisition unit is installed in the hub cap tooling 4, and the hub cap tooling 4 rotates together with the hub 2 of the propeller 1. The signal transmission does not require rotating devices and there is no rotational speed limit.

[0033] d), It can perform long-term automatic measurement. The data acquisition unit of this device is equipped with a built-in power module 7, which uses a large-capacity lithium battery. The full-load endurance reaches more than 10 hours. After power-on, the system software of the main control module 6 automatically acquires data and stores the data. The storage space is much larger than the data volume for 10 hours.

[0034] e), It has good sealing performance and can perform deep-water measurement. The hub cap tooling 4 is sealed with the hub 2, the optical fiber watertight connector 9, and the power switch 13 respectively, and all are designed to withstand a pressure greater than 2 Mpa, which means it can be used normally at least in water depths of up to 100 meters.

[0035] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. An on-line measuring device for a propeller in deep water, characterized in that, It includes a sensing optical fiber (5), a data acquisition unit, and a hub cap tooling (4). The hub cap tooling (4) is used for fixedly connecting with the hub (2) of the propeller (1) to be measured. The sensing optical fiber (5) is used for being pasted on the blade (3) of the propeller (1) to be measured, acquiring the structural strain information of the blade (3) and transmitting signals. The data acquisition unit is installed inside the hub cap tooling (4). The sensing optical fiber (5) is introduced into the inside of the hub cap tooling (4) through wall sealing and is connected to the data acquisition unit. The data acquisition unit is used for detecting, processing the signals of the sensing optical fiber (5), and storing data; It further includes an optical fiber watertight connector (9). The optical fiber watertight connector (9) is fixedly installed on the hub cap tooling (4) through wall sealing. The sensing optical fiber (5) is introduced into the inside of the hub cap tooling (4) through wall sealing by the optical fiber watertight connector (9). The optical fiber watertight connector (9) includes a socket (17) and a plug (18). A bracket (11) is provided on the hub cap tooling (4). An optical fiber groove (12) is provided on the outer side wall of the hub cap tooling (4). The sensing optical fiber (5) is buried in the optical fiber groove (12). A through hole (10) is provided on the end face of the hub cap tooling (4). The socket (17) is fixedly installed in a sealed manner at the through hole (10) of the hub cap tooling (4). The plug (18) is fixedly inserted into the socket (17). A pigtail (24) is provided on the plug (18). The pigtail (24) is fixed on the bracket (11) and is fusion spliced with the sensing optical fiber (5) in the optical fiber groove (12). The socket (17) is connected to the signal demodulation module (8) through an optical fiber channel; It further includes a power switch (13). The power switch (13) is fixedly installed on the hub cap tooling (4) through wall sealing. The power switch (13) is electrically connected to the main control module (6) and the signal demodulation module (8). The power switch (13) is used for controlling the power on or off of the main control module (6) and the signal demodulation module (8) with the power supply module (7). It further includes a bracket (15). A support bar (16) is provided inside the hub cap tooling (4). The bracket (15) is fixedly installed on the support bar (16). The main control module (6), the power supply module (7), and the signal demodulation module (8) are fixedly installed on the bracket (15).

2. The online deep-water measuring device for a propeller according to claim 1, wherein, The data acquisition unit includes a main control module (6), a power supply module (7), and a signal demodulation module (8). The main control module (6), the power supply module (7), and the signal demodulation module (8) are respectively installed inside the hub cap tooling (4). The power supply module (7) is electrically connected to the main control module (6) and the signal demodulation module (8) respectively. The signal demodulation module (8) is communicatively connected to the main control module (6). The sensing optical fiber (5) is connected to the signal demodulation module (8).

3. The online deep-water measuring device for a propeller according to claim 1, characterized in that, It further includes a nut (19). A stud (22) is provided on the power switch (13), and a switch hole (14) is provided on the hub cap tooling (4). The stud (22) on the power switch (13) penetrates into the hub cap tooling (4) through the switch hole (14). The nut (19) is located inside the hub cap tooling (4) and is threadedly connected to the stud (22) of the hub cap tooling (4). The power switch (13) is a push-type deep-water power switch.

4. The online deep-water measuring device for a propeller according to claim 1, wherein The hub cap tooling (4) is in the shape of a cylinder with one end open. A flange plate (20) for fixedly connecting with the hub (2) of the propeller (1) to be measured is provided at the open end of the hub cap tooling (4), and a sealing groove (23) is provided on the end face of the flange plate (20).

Images