Underwater turning and lifting method for marine propeller

Abstract

The application discloses a marine propeller underwater turning and hoisting method and relates to the technical field of ship equipment installation. The method comprises the following steps: S1, determining a ship body hoisting assembly: an asymmetric streamlined installation port is designed at the stern, a honeycomb damping structure is arranged at the installation port, and double-redundancy hydraulic rails and intelligent hoisting equipment are arranged; S2, underwater positioning and installation: after the propeller and the base flange are butt-jointed through the arranged laser centering assembly, multi-lifting-point cooperative lifting is performed; and S3, environmental protection emergency treatment: different hoisting treatment operations are determined according to the hoisting state. Through real-time calibration of the laser centering assembly, millimeter-level positioning accuracy is realized, the problem of misalignment of the sealing surface cooperation is solved, the flange can be accurately fixed through the adsorption force generated by the soft iron magnetic core, the displacement deviation under dynamic sea conditions is reduced, the sealing failure caused by vibration is avoided, and the sealing property can be further enhanced by filling silicone grease on the rubber strip.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ship equipment installation, in particular to a method for lifting a marine propeller by turning it over underwater. BACKGROUND

[0002] In the process of installation and maintenance of marine engineering equipment, the propeller, as a key component of the power system of the ship and offshore platform, directly affects the equipment operation performance and overall project progress in terms of installation accuracy and construction safety. Especially in deep water or complex sea conditions, the lifting operation of the propeller faces greater technical challenges.

[0003] Currently, the traditional propeller lifting usually adopts the mode of integral lowering after onshore assembly or underwater installation after water turning. However, such methods have many limitations: first, the water turning operation needs to rely on large lifting equipment, which is greatly affected by weather and waves; second, the propeller structure is complex and the center of gravity is obviously offset, which is prone to instability during turning, causing equipment damage or personnel safety accidents; third, the traditional lifting process has low control accuracy of installation angle, which is difficult to meet the high-precision docking requirements.

[0004] The Chinese invention patent with publication number CN117585099A discloses a water surface unmanned boat and a main-passive combined wave compensation method thereof. The water surface unmanned boat comprises a water surface unmanned boat body, multiple light standard module attachments on both sides, and a telescopic device and a control system. The water surface unmanned boat body is provided with a propelling device at the tail end to enable the water surface unmanned boat to sail on the water surface. Multiple light standard module attachments are arranged on both sides of the water surface unmanned boat body. One end of the telescopic device is linked to the light standard module attachments through a universal joint, and the other end of the telescopic device is connected to the water surface unmanned boat body. The control system is used for adjusting the telescopic device according to the sea wave data to balance the sailing state of the water surface unmanned boat. By adjusting the extension length of the light standard module attachments to adjust the virtual width of the unmanned boat, the technical problem of lacking a technology with various comprehensive advantages of wave compensation in the prior art is solved.

[0005] However, due to the influence of sea wave fluctuation and water flow disturbance, the existing lifting method is difficult to achieve millimeter-level positioning accuracy, which may cause misalignment between the sealing surface of the propeller and the base of the ship body, thereby causing leakage risk. The imbalance between the ship body sway in dynamic sea conditions and the lifting rigging load will cause local overload damage to the propeller structure. And the conventional sealing detection technology is limited by the micron-level defect recognition ability, so it cannot accurately capture the microscopic leakage hidden danger of the installation interface. SUMMARY

[0006] The purpose of the present application is to provide a method for lifting a marine propeller by turning it over underwater, to solve the problem of misalignment of the sealing surface.

[0007] To achieve the above object, the present application provides the following technical solutions: a method for lifting a marine propeller under water, comprising the following steps:

[0008] S1: determining a ship body lifting assembly: designing an asymmetric streamlined installation port at the stern, and setting a honeycomb shock-absorbing structure in the installation port, and setting double-redundancy hydraulic rails and intelligent lifting equipment;

[0009] S2: underwater positioning and installation: after the propeller and the base flange are connected through the set laser centering assembly, lifting is performed in coordination with multiple lifting points, comprising the following steps:

[0010] S2.1: underwater attitude adjustment: the propeller is clamped in water through a hydraulic clamp, and the water flow disturbance is reduced through a flow guide fin, so as to determine the underwater state of the propeller and the hydraulic clamp;

[0011] S2.2: underwater butt joint: a laser is set in the center of the base flange, a laser receiving target is installed on the flange surface of the propeller, a laser centering assembly is set, and the propeller and the base flange are temporarily fixed through magnetic adsorption through the laser centering assembly;

[0012] S2.3: lifting point lifting: the tension deviation between the main lifting cable and the auxiliary lifting cable is obtained through a tension sensor, the tension deviation is compared with a deviation threshold value, and the lifting cable tension is adjusted according to the comparison result, specifically as follows:

[0013] When the tension deviation is greater than the deviation threshold value, the adjusting lifting cable is determined from the main lifting cable and the auxiliary lifting cable, and the steel cable of the adjusting lifting cable is retracted according to the hydraulic winch corresponding to the adjusting lifting cable until the tension deviation is not greater than the deviation threshold value; otherwise, the lifting cable tension is not adjusted;

[0014] The formula for obtaining the adjusting speed of the steel cable is specifically as follows:

[0015]

[0016] Wherein: is the steel cable adjusting speed, is the displacement change, is the time interval;

[0017] S3: environmental protection emergency treatment: different lifting treatment operations are determined according to the lifting state.

[0018] Further, the honeycomb shock-absorbing structure is set in the installation port, comprising the following steps:

[0019] S1.1.1: Set the stern opening: according to the diameter of the propeller, set the stern opening length, and set the honeycomb grid on the edge of the stern opening, while filling the inside of the honeycomb grid with polyurethane-silicon carbide composite material through the vacuum infusion process;

[0020] S1.1.2: Prepare the hull base: determine the installation reference point of the hull base according to the stern opening length, set the annular sealing groove on the flange end face of the hull base, and set the rubber strip inside the annular sealing groove, and fill the silicone lubricant between the inner wall of the annular sealing groove and the rubber strip.

[0021] Further, according to the diameter of the propeller, the stern opening length is determined, and the corresponding radius of curvature is obtained, specifically:

[0022]

[0023] Wherein: is the radius of curvature, is the curvature coefficient, is the opening design length.

[0024] Further, set up a double-redundant hydraulic rail and intelligent lifting equipment, including:

[0025] S1.2.1: Install double-redundant hydraulic rail: according to the local bearing capacity of the rail installation area, determine the single rail section size in the double-redundant hydraulic rail, and rigidly connect the rail base and deck of the double-redundant hydraulic rail through full penetration weld, while setting a polytetrafluoroethylene-tungsten carbide composite coating on the surface of the double-redundant hydraulic rail after rigid connection;

[0026] S1.2.2: Set up lifting equipment: according to the span and running speed of the double-redundant hydraulic rail, obtain the wheelbase and drive motor power of the lifting trolley, specifically:

[0027]

[0028] Wherein: is the wheelbase of the lifting trolley, is the rail span, is the safety factor, is the motor power, is the total traction, is the running speed, is the mechanical efficiency, is the acceleration of gravity, is the friction coefficient, is the total mass of the lifting system, is the acceleration.

[0029] Further, the double hydraulic motors are arranged on each side rail of the double-redundant hydraulic rail, the speed of each side rail is obtained, the running speed difference between the double-redundant hydraulic rails is determined, the running speed difference is compared with a preset speed difference threshold, and parameter adjustment is performed according to the comparison result, specifically:

[0030] When the running speed difference is greater than the preset speed difference threshold, the hydraulic valve flow distribution is adjusted or the rail levelness error is corrected until the running speed difference is not greater than the preset deviation threshold; otherwise, the double-redundant hydraulic rail operates normally.

[0031] Further, the underwater state of the thruster and the hydraulic clamp is determined, including:

[0032] S2.1.1: Hydraulic clamp clamping: through the laser projector, the clamping points on both sides of the center of gravity on the thruster surface are calibrated, the hydraulic clamp is moved to the clamping points through the double-redundant hydraulic rail, the clamping force of the hydraulic clamp is adjusted through the PLC controller and the preset target pressure value, and when the clamping force of the hydraulic clamp is the same as the preset target pressure value, the hydraulic pump is switched to the pressure maintaining mode, the electromagnetic reversing valve is switched to the middle position locking state, and the oil circuit is cut off.

[0033] S2.1.2: Set up the vortex suppression system: a plurality of guide vanes are uniformly arranged on the tail of the thruster in the circumferential direction, the roots of the guide vanes are connected with waterproof servo motors through flanges, and the range of the attack angle of the guide vanes is limited through mechanical limit blocks.

[0034] Further, the claw arm section of the hydraulic clamp is arranged in an I-shaped structure, the outer surface of the hydraulic clamp is provided with a polyurethane anti-skid layer through a vulcanization process, and the polyurethane anti-skid layer is provided with staggered grooves.

[0035] Further, the thruster and the base flange are temporarily fixed by magnetic attraction, including:

[0036] S2.2.1: Centering adjustment: the thruster flange is clamped and fixed by the mechanical arm gripper, and the thruster flange and the base flange are aligned according to the laser centering assembly;

[0037] S2.2.2: Magnetic temporary fixation: a soft iron magnetic core is arranged on the base of the thruster, the attraction force of the soft iron magnetic core is obtained through a direct current power supply, and the aligned thruster flange and base flange are magnetically connected through the attraction force of the soft iron magnetic core, and the attraction force of the soft iron magnetic core is obtained according to the following formula:

[0038]

[0039] wherein: is the adsorption force of the soft ferromagnetic core, is the magnetic induction, is the vacuum permeability, is the effective area of the magnetic pole.

[0040] Further, different hoisting processing operations are determined, including:

[0041] S3.1: Oil pollution prevention and control: A portable adsorption pad is arranged outside the hoisting area, and the leaked oil at the hydraulic pipeline joint is adsorbed through the portable adsorption pad, the adsorption amount of the portable adsorption pad is obtained, and at the same time, the oil leakage amount at the hydraulic pipeline joint is obtained through an oil-sensitive sensor, and the oil leakage amount and the adsorption amount are compared, and the portable adsorption pad is replaced according to the comparison result, specifically:

[0042] When the oil leakage amount is greater than the preset range of the adsorption amount, the portable adsorption pad is replaced; otherwise, the portable adsorption pad is not replaced;

[0043] S3.2: Emergency release: The main sling tension value of the main sling is obtained through a tension sensor, and the main sling tension value is compared with a preset tension overrun threshold value, and according to the comparison result, the sling connection is cut off, specifically:

[0044] When the main sling tension value is less than the preset tension overrun threshold value, the sling connection is continued; otherwise, the sling connection is cut off, and the compressed air tank is released, and the inflatable airbag is inflated to provide the thruster with an upward floating force;

[0045] S3.3: CO2 cleaning: CO2 cleaning is performed in the ship body weld and flange area through a heater and a booster pump.

[0046] Compared with the prior art, the beneficial effects of the present application are:

[0047] Firstly, the present application realizes millimeter-level positioning accuracy through real-time calibration of the center laser of the base flange and the laser receiving target of the thruster flange face, solves the problem of misalignment of the sealing surface cooperation, and can accurately fix the flange through the adsorption force generated by the soft ferromagnetic core, thereby reducing the displacement deviation under dynamic sea conditions, avoiding sealing failure caused by vibration, and further enhancing the sealing performance by filling silicone grease on the rubber strip, thereby effectively preventing microscopic leakage hazards;

[0048] Secondly, the present application can ensure load balance by monitoring the deviation between the main and auxiliary hoisting ropes in real time through the tension sensor and dynamically adjusting the hydraulic winch speed, can prevent local overload, and can reduce water flow disturbance by adjusting the attack angle of the circumferentially distributed flow guide fins by the waterproof servo motor, thereby stabilizing the underwater posture of the propeller; the double hydraulic motor synchronous drive track can correct the speed difference in real time, thereby ensuring the stable operation of the hoisting trolley and reducing the sway of the ship body.

[0049] Thirdly, the present application can not only disperse stress and absorb vibration energy, but also prolong the service life of the ship body by optimizing the curvature radius of the opening shape of the stern and filling the honeycomb grid with polyurethane-silicon carbide composite material, and can improve hoisting efficiency and reduce dependence on external large equipment by calculating the track and motor power according to the span and running speed.

[0050] Fourthly, the present application can ensure zero emission of oil pollution by using a portable adsorption pad and biodegradable hydraulic oil and monitoring the leakage amount in real time through the oil-sensitive sensor, can avoid propeller falling accidents by triggering the explosive bolt to cut off the connection and providing buoyancy through the inflatable airbag when the tension of the main hoisting rope exceeds the limit, and can further reduce the risk of leakage after installation by using supercritical CO2 to remove grease particles in the weld and flange area. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 The figure is a flowchart of underwater positioning and installation in the present application. DETAILED DESCRIPTION

[0052] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0053] Reference Figure 1 The present embodiment provides a marine propeller underwater turning and hoisting method, which specifically includes the following steps:

[0054] Step S1: Determine the ship body hoisting assembly. That is, design an asymmetric streamline installation port at the stern and integrate a honeycomb damping structure, and set double-redundancy hydraulic rails and intelligent hoisting equipment. Specifically as follows:

[0055] Step S1.1: Set the ship body structure. That is, according to the three-dimensional structure of the stern, set an asymmetric streamline installation port at the stern, and install a honeycomb damping structure at the set asymmetric streamline installation port. Specifically as follows:

[0056] Step S1.1.1: Set the opening of the stern. That is, according to the three-dimensional structure of the stern, such as the thickness of the steel plate, the spacing of the ribs, and the position of the bulkhead, a local three-dimensional model of the stern is established by ANSYS or ABAQUS finite element model, including the steel plate, the reinforcing rib and the surrounding structure. At the same time, an initial opening shape is cut out in the stern area of the local three-dimensional model of the stern, and water flow pressure load and ship inertia force are applied in the initial opening shape. It is worth noting that during the stress loading process in the finite element model, the curvature radius of the opening edge and the layout of the reinforcing rib are adjusted by iteration to reduce the maximum von Mises stress to below 120 MPa.

[0057] In this embodiment, according to the diameter size of the propeller, the corresponding opening length is determined, and the corresponding curvature radius is obtained, which is specifically:

[0058]

[0059] Wherein: is the curvature radius, is the curvature coefficient, is the opening design length.

[0060] In the process of specific implementation, the diameter of the propeller is set to 2.8m, so the opening length is 7m and the opening width is 3m, and the corresponding curvature radius is 1.125m.

[0061] Further, according to the wave height of the sea wave and the density of seawater, the corresponding wave pressure is determined, which is specifically:

[0062]

[0063] Wherein: is the wave pressure, is the safety factor, is the density of seawater, is the acceleration of gravity, is the wave height.

[0064] In the process of specific implementation, the safety factor is set to 1.2, the wave height is set to 8m, and the density of seawater is 1025kg / m 3 , the acceleration of gravity is 9.81m / s 2 , so the corresponding wave pressure is 96.5kPa. At the same time, the obtained wave pressure is set as the boundary condition of the finite element model, and the material properties of the ship steel are set, including the elastic modulus, the Poisson's ratio and the yield strength. Specifically, full freedom constraints are applied at the ship bow section, and the obtained wave pressure is uniformly distributed on the inner surface of the stern opening, and the direction is perpendicular to the plate surface.

[0065] In the embodiment, a honeycomb grid is arranged on the opening edge of the hull steel plate by laser cutting or water jet cutting process, the depth of the honeycomb grid is the same as the thickness of the steel plate, and the wall thickness of the honeycomb grid is set to 2-3 mm to balance the structural stiffness and shock absorption performance.

[0066] Further, the honeycomb grid is filled with polyurethane-silicon carbide composite material by vacuum infusion process, and the polyurethane-silicon carbide composite material filled in the honeycomb grid is cured for 4 hours at a temperature of 80±5℃ for curing treatment. It is worth noting that the polyurethane-silicon carbide composite material in the embodiment is composed of a polyurethane matrix and silicon carbide particles, and the polyurethane matrix and silicon carbide particles are arranged in a ratio of 7:3.

[0067] Step S1.1.2: preparing the hull base. That is, according to the three-dimensional coordinates of the stern opening obtained in step S1.1, the installation reference point of the hull base is determined, that is, the hull base and the stern opening are matched. Further, the flange conical surface is processed by a five-axis numerical control machine tool, and the conical angle error and roundness of the processed flange conical surface are detected by a three-coordinate measuring machine, and a ring-shaped sealing groove is milled on the flange end face.

[0068] It is worth noting that the rubber strip cross section is set according to the size of the sealing groove, and the material of the rubber strip is composed of a ternary ethylene-propylene rubber matrix and a water-absorbing resin. Specifically, the rubber strip is uniformly embedded in the sealing groove by a pressing tool to ensure no distortion or gap. At the same time, after the rubber strip is installed, silicone grease lubricant is set on the rubber strip to avoid displacement of the rubber strip during subsequent propeller docking.

[0069] Step S1.2: setting the lifting system of the propeller. That is, by setting the wave parameters and deck steel parameters, a double-redundant hydraulic rail and intelligent lifting equipment are set, and a wave compensation hook and a plastic-coated composite cable are set. Specifically as follows:

[0070] Step S1.2.1: installing a double-redundant hydraulic rail. That is, according to the yield strength of the deck steel and the thickness of the deck, the local bearing capacity of the rail installation area is determined, specifically:

[0071]

[0072] Wherein: is the maximum compressive stress of the deck under the pressure of the rail, is the vertical load borne by a single bearing, is the effective contact area of the rail and the deck, is the yield strength of the deck steel, is the strength reduction factor.

[0073] Further, according to the span of the deck support structure and the vertical load borne by the single track, the maximum bending moment of the deck under the track load and the bending stress of the deck steel are determined, specifically:

[0074]

[0075] wherein: is the maximum bending moment of the deck under the track load, is the vertical load borne by the single track, is the span of the deck support structure, is the bending stress of the deck steel, is the sectional modulus of the deck section, is the allowable bending stress.

[0076] Further, according to the actual weight and the center of gravity position of the thruster, the load distribution of the track system and the spacing between the support points are determined, specifically:

[0077]

[0078] wherein: is the design load borne by the single track, is the weight of the thruster, is the acceleration of gravity, is the dynamic load coefficient, is the number of tracks, is the maximum allowable spacing of the track support points, is the vertical load borne by the single track, is the span of the deck support structure, is the maximum compressive stress of the deck under the track pressure, is the elastic modulus of the deck steel, is the moment of inertia of the deck section.

[0079] In the process of specific implementation, the deck width is set to 0.2 m, the deck thickness is set to 0.025 m, and the corresponding moment of inertia of the deck section is 2.6*10 -7 m 4 , and the maximum allowable spacing of the track support points is 1.48 m.

[0080] In this embodiment, by using high-strength alloy steel, a double-redundant hydraulic track is set, and according to the local bearing capacity of the track installation area, the single track section size in the double-redundant hydraulic track is obtained. At the same time, the track base is welded at the preset position of the deck, and the rigid connection between the track and the deck is ensured through the full penetration weld. It is worth noting that the surface of the double-redundant hydraulic track after welding is sprayed with a polytetrafluoroethylene-tungsten carbide composite coating, and the spraying thickness is not less than 0.5 mm.

[0081] Further, in the double-redundant hydraulic track, double hydraulic motors are arranged on each side of the track, and the double hydraulic motors are synchronously driven through a closed-loop hydraulic circuit. Notably, according to the obtained load distribution of the double-redundant hydraulic track, an equivalent load is loaded on the double-redundant hydraulic track to obtain a running speed difference between the double-redundant hydraulic tracks. Specifically, the obtained running speed difference is compared with a preset speed difference threshold, and according to the comparison result, parameter adjustment is performed, specifically:

[0082] When the obtained running speed difference is greater than the preset speed difference threshold, the double-redundant hydraulic track is running out of limits, at which time the hydraulic valve flow distribution needs to be adjusted or the track levelness error needs to be corrected until the obtained running speed difference is not greater than the preset deviation threshold. Conversely, the double-redundant hydraulic track is running normally.

[0083] Step S1.2.2: setting the hoisting device. That is, according to the span and running speed of the double-redundant hydraulic track obtained in step S1.2.1, the wheelbase of the hoisting trolley and the power of the driving motor are obtained, specifically:

[0084]

[0085] wherein: is the wheelbase of the hoisting trolley, is the track span, is the safety factor, is the motor power, is the total traction force, is the running speed, is the mechanical efficiency, is the gravitational acceleration, is the friction coefficient, is the total mass of the hoisting system, is the acceleration.

[0086] In the process of specific implementation, the track span is 3m, and the safety factor is set to 0.93, so the corresponding wheelbase of the hoisting trolley is 2.8m. Further, the friction coefficient is set to 0.15, the total mass of the hoisting system is set to 120000kg, and the acceleration is set to 0.00083m / s 2 , so the corresponding total traction force is 176680N, and the motor power is 2kW.

[0087] Further, according to the obtained wave height and period, the vertical displacement range that needs to be compensated by the hoisting hook is obtained, and the response frequency of the wave compensation system is determined, specifically:

[0088]

[0089] wherein: is a vertical displacement range of the hook to be compensated, is a wave height, is a hull response coefficient, is a minimum response frequency of the wave compensation system, is a wave period, is a frequency redundancy coefficient.

[0090] In the process of implementation, the wave height is 3m, and the hull response coefficient is set to 0.67, so the corresponding vertical displacement range of the hook to be compensated is 2m. Further, the wave period is 8s, and the frequency redundancy coefficient is set to 4, so the corresponding minimum response frequency of the wave compensation system is 0.5Hz.

[0091] In this embodiment, the six-degree-of-freedom wave compensation hook is combined by hydraulic cylinders, servo motors and spherical hinges to realize six-degree-of-freedom motion. At the same time, through the hull attitude sensor, such as a gyroscope and an accelerometer, the hull heave and roll / pitch data are obtained in real time. Specifically, according to the obtained vertical displacement range of the hook to be compensated, the spherical hinge is controlled by the hydraulic cylinder and the servo motor to move the hook vertically.

[0092] Further, in the process of hoisting, the hoisting cable of the hook is set as a double-layer braided steel wire rope, and the braiding directions of the inner layer and the outer layer are set as reverse braiding. At the same time, a not less than 5mm thick ultra-high molecular weight polyethylene protective sleeve is arranged on the outer layer of the double-layer braided steel wire rope, and the double-layer braided steel wire rope and the ultra-high molecular weight polyethylene protective sleeve are bonded by an extrusion molding process.

[0093] Step S2: underwater positioning and installation. That is, through the set laser centering assembly, the thruster and the base flange are docked through the mechanical arm and the magnetic adsorption base, and the multi-lifting-point cooperative lifting is performed. Specifically as follows:

[0094] Step S2.1: underwater attitude adjustment. That is, after the thruster enters the water, it is clamped by the hydraulic clamp, and the water flow disturbance is reduced by the set multiple guide vanes to determine the state of the thruster and the hydraulic clamp under water. Specifically as follows:

[0095] Step S2.1.1: hydraulic clamp clamping. According to the track parameters of the double-redundant hydraulic track, the thruster center coordinates and the water flow velocity data obtained in step S1, the hydraulic clamp and the eddy current suppression system are set. Specifically, the clamping points on both sides of the center of gravity on the surface of the thruster are marked by a laser projector, and the hydraulic clamp is moved to the marked clamping point by the double-redundant hydraulic track.

[0096] In the embodiment, a double-axis digital tilt angle instrument is installed on the top and bottom of the propeller, and the angles of the top and bottom of the hydraulic clamp during installation are obtained through the double-axis digital tilt angle instrument, that is, the stability of the hydraulic clamp during installation is ensured through the angles of the top and bottom of the hydraulic clamp. Specifically, during clamping, after preheating the oil temperature through the hydraulic pump, the PLC controller sends a running instruction to the hydraulic pump, the hydraulic cylinder is extended, the hydraulic clamp is closed, and the clamping force of the hydraulic clamp is monitored through the pressure sensor to obtain the corresponding pressure data. At the same time, according to the preset target pressure value, the clamping force of the hydraulic clamp is adjusted to increase the clamping force of the hydraulic clamp on the propeller. Further, when the clamping force of the hydraulic clamp is the same as the preset target pressure value, the hydraulic pump is switched to the pressure maintaining mode, the electromagnetic reversing valve is switched to the middle locking state, and the oil circuit is cut off to prevent accidental pressure relief.

[0097] Further, the material of the hydraulic clamp is selected from 42CrMo alloy steel, and the claw arm section of the hydraulic clamp is provided in a I-shaped structure to improve the bending stiffness. Specifically, the claw arm section of the hydraulic clamp is provided in a height of 200 mm, a width of 80 mm, and a web thickness of 15 mm. Meanwhile, the outer surface of the hydraulic clamp is provided with a polyurethane anti-skid layer with a thickness of not less than 5 mm, and the polyurethane anti-skid layer and the outer surface of the hydraulic clamp are bonded by vulcanization process. It is worth noting that the surface of the polyurethane anti-skid layer is provided with staggered grooves to increase the biting effect of the contact surface between the hydraulic clamp and the propeller. Specifically, the depth of the grooves is set to 2 mm, and the spacing is set to 10 mm.

[0098] Step S2.1.2: Set up the vortex suppression system. That is, a plurality of guide vanes are provided on the tail of the propeller in the circumferential direction to ensure that the flow field disturbance can be uniformly suppressed. Meanwhile, a waterproof servo motor is installed at the root of each guide vane, and the waterproof servo motor is connected to the guide vane through the flange. Further, the attack angle range of the guide vane is limited by adjusting the mechanical limit block.

[0099] Step S2.2: underwater butt joint. That is, according to the center point coordinates of the base flange, the target position in the mechanical arm coordinate system is converted through the digital twin model, and the mechanical arm coordinate system and the ship body global coordinate system are calibrated and aligned underwater through the acoustic positioning system. Meanwhile, a laser is arranged at the center of the base flange, and a laser receiving target is installed on the flange surface of the propeller, and a laser centering assembly is arranged through the projection and reception of the laser. Specifically, the propeller and the base flange are temporarily fixed by magnetic adsorption through the laser centering assembly. Specifically as follows:

[0100] Step S2.2.1: centering adjustment. That is, the thruster flange is fixed by the mechanical arm clamp, and the thruster is pushed to the preset range of the base flange by the mechanical arm. At the same time, the laser emitter arranged at the center of the base flange emits laser, and the laser receiving target at the thruster flange receives the laser emitted by the laser emitter, and the thruster flange and the base flange are aligned through the laser alignment between the laser emitter and the laser receiving target.

[0101] In the process of specific implementation, the diver fixes the thruster flange by the mechanical arm clamp with a clamping force of 10kN, and moves the thruster to the range of 0.5m of the base flange at a speed of 0.1m / s.

[0102] Step S2.2.2: temporary fixation by magnetic force. That is, the oxygen-free copper wire is wound on the soft iron magnetic core, and the soft iron magnetic core wound with the oxygen-free copper wire is connected with the direct current power supply, and the magnetic field strength of the soft iron magnetic core wound with the oxygen-free copper wire is determined, which is specifically:

[0103]

[0104] Among them: is the magnetic induction intensity, is the vacuum permeability, is the relative permeability, is the number of turns, is the current intensity, is the magnetic path length.

[0105] Specifically, the soft iron magnetic core wound with the oxygen-free copper wire is arranged on the base of the thruster, and after being powered by the direct current power supply, the adsorption force of the soft iron magnetic core is determined, which is specifically:

[0106]

[0107] Among them: is the adsorption force of the soft iron magnetic core, is the magnetic induction intensity, is the vacuum permeability, is the effective area of the magnetic pole.

[0108] Further, the adsorption force of the soft iron magnetic core is adjusted by adjusting the cross-sectional area of the magnetic core, that is, the aligned thruster flange and base flange are temporarily fixed by the magnetic force through the adjusted soft iron magnetic core.

[0109] Step S2.3: lifting of the lifting point. That is, the tension values of the main hoist rope and the auxiliary hoist rope are respectively obtained by the tension sensor, and the tension deviation between the main hoist rope and the auxiliary hoist rope is determined. At the same time, the determined tension deviation is compared with the deviation threshold value, and the hoist rope tension is adjusted according to the comparison result. Specifically:

[0110] When the determined tension deviation is greater than the deviation threshold, the sling tension is adjusted, that is, the sling with smaller tension is determined from the main sling and the auxiliary sling, and the determined sling is set as the adjustment sling. Specifically, the steel cable of the adjustment sling is retracted by the hydraulic winch corresponding to the adjustment sling until the determined tension deviation is not greater than the deviation threshold. Otherwise, the sling tension is not adjusted.

[0111] Further, according to the determined steel cable to be retracted, the adjustment speed of the steel cable is determined by the heave displacement size of the ship body and the change time of the heave displacement of the ship body, specifically:

[0112]

[0113] Wherein: is the adjustment speed of the steel cable, is the displacement change amount, is the time interval.

[0114] Step S3: Environmental emergency treatment. That is, the biodegradable hydraulic oil is adsorbed by the portable adsorption pad to realize zero leakage of oil pollution in the whole process of lifting operation, and the breaking state of the sling is determined according to the breaking strength of the single sling tension, and the sling is cleaned by CO2 after installation. Specifically as follows:

[0115] Step S3.1: Oil pollution prevention and control. That is, a graphene aerogel adsorption floating row is laid outside the lifting area, and is fixed to the seabed by anchor chain, and a portable adsorption pad is arranged on the laid graphene aerogel adsorption floating row, and the oil pollution at the hydraulic oil tank of the lifting system is adsorbed by the arranged portable adsorption pad.

[0116] Specifically, an oil-sensitive sensor is installed at the joint of the hydraulic pipeline, and the oil leakage amount at the joint of the hydraulic pipeline is obtained in real time by the oil-sensitive sensor. At the same time, the obtained oil leakage amount and the adsorption amount of the portable adsorption pad are compared, and the portable adsorption pad is replaced according to the comparison result, specifically:

[0117] When the obtained oil leakage amount is greater than the preset range of the adsorption amount of the portable adsorption pad, the portable adsorption pad is replaced. Otherwise, the portable adsorption pad is not replaced.

[0118] It is worth noting that the biodegradable hydraulic oil is used to replace the traditional mineral oil in this embodiment, such as rapeseed oil.

[0119] Step S3.2: Emergency release. That is, through the tension sensor installed on the main sling, the tension of the main sling is obtained, and the obtained main sling tension value is compared with the preset tension overrun threshold value (that is, set according to the breaking strength of the main sling), and according to the comparison result, the sling connection is cut off. Specifically:

[0120] When the obtained main sling tension value is less than the preset tension overrun threshold value, the sling connection is continued. Otherwise, the explosive bolt is triggered, and the sling connection is cut off. At the same time, the compressed air tank is released, and the inflatable air bag is inflated to provide the thruster with buoyancy.

[0121] In the process of specific implementation, 85% of the breaking strength of the main sling is set as the preset tension overrun threshold value. Specifically, the breaking strength of the main sling in the embodiment is set to 800kN, and the corresponding preset tension overrun threshold value is set to 722.5kN. At the same time, the thruster displacement is 100m 3 , and 15% of the additional buoyancy is required.

[0122] Step S3.3: CO2 cleaning. That is, through the heater and booster pump, the critical state of CO2 is maintained. Specifically, the liquid CO2 tank is vaporized by the heater, and the vaporized liquid CO2 is pressurized by the booster pump. Specifically, through the handheld supercritical CO2 spray gun, the CO2 is cleaned in the area of the ship body weld and the flange, so as to separate the oil and particles through the penetration of CO2.

[0123] Although the embodiments of the present application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended embodiments and their equivalents.

Claims

1. A method of underwater roll-on lifting of a marine propeller, c h a r a c t e r i s e d in that The application relates to a ship hull hoisting assembly method. S1: determining a ship hull hoisting assembly: designing an asymmetric streamlined installation opening at the stern, arranging a honeycomb damping structure at the installation opening, and arranging double-redundancy hydraulic rails and intelligent hoisting equipment; S2: underwater positioning and installation: after the propeller and the base flange are connected through the arranged laser centering assembly, the propeller is lifted through multiple lifting points, including: S2.1: underwater posture adjustment: the propeller is clamped in water through a hydraulic clamp, water flow disturbance is reduced through a flow guide fin, and the underwater state of the propeller and the hydraulic clamp is determined; S2.2: underwater connection: a laser is arranged at the center of the base flange, a laser receiving target is arranged on the flange surface of the propeller, a laser centering assembly is arranged, and the propeller and the base flange are temporarily fixed through magnetic adsorption through the laser centering assembly; S2.3: lifting point lifting: the tension deviation between the main hoisting cable and the auxiliary hoisting cable is obtained through a tension sensor, the tension deviation is compared with a deviation threshold value, and the hoisting cable tension is adjusted according to the comparison result, specifically: when the tension deviation is greater than the deviation threshold value, an adjusting hoisting cable is determined from the main hoisting cable and the auxiliary hoisting cable, and the steel cable of the adjusting hoisting cable is retracted according to the corresponding hydraulic winch of the adjusting hoisting cable until the tension deviation is not greater than the deviation threshold value; otherwise, the hoisting cable tension is not adjusted; the adjustment speed of the steel cable is obtained through the following formula: ； wherein: is the speed of the steel cable, is the displacement change, is the time interval; S3: environmental protection emergency treatment: different hoisting treatment operations are determined according to the hoisting state.

2. A method of underwater roll-on lifting of a marine propeller according to claim 1, characterized in that The honeycomb damping structure arranged at the installation opening includes: S1.1.1: setting a stern opening: according to the diameter of the propeller, the length of the stern opening is set, the honeycomb grid is arranged at the edge of the stern opening, and the inside of the honeycomb grid is filled with polyurethane-silicon carbide composite material through a vacuum pouring process; S1.1.2: preparing a ship hull base: according to the length of the stern opening, the installation reference point of the ship hull base is determined, an annular sealing groove is arranged on the flange end surface of the ship hull base, a rubber strip is arranged in the annular sealing groove, and a silicone lubricant is filled between the inner wall of the annular sealing groove and the rubber strip.

3. A method of underwater roll-on lifting of a marine propeller according to claim 2, characterized in that According to the diameter of the propeller, the length of the stern opening is determined, and the corresponding curvature radius is obtained, specifically: ； wherein: is the radius of curvature, is the curvature coefficient, is the open design length.

4. A method of lifting a marine propeller in accordance with claim 1, wherein The double-redundancy hydraulic rails and the intelligent hoisting equipment are arranged, including: S1.2.1: installing double-redundancy hydraulic rails: according to the local bearing capacity of the rail installation area, the single rail section size in the double-redundancy hydraulic rails is determined, the rail base of the double-redundancy hydraulic rails and the deck are rigidly connected through full penetration welding, and a polytetrafluoroethylene-tungsten carbide composite coating is arranged on the surface of the double-redundancy hydraulic rails after rigid connection; S1.2.2: arranging hoisting equipment: according to the span and running speed of the double-redundancy hydraulic rails, the wheel track and driving motor power of the hoisting trolley are obtained, specifically: ； wherein: is the wheel span of the lifting trolley, is the track span, is the safety factor, is the motor power, is the total traction force, is the running speed, is the mechanical efficiency, is the gravitational acceleration, is the friction coefficient, is the total mass of the lifting system, is the acceleration.

5. A method of underwater roll-on lifting of a marine propeller according to claim 4, characterised in that, The double hydraulic motors are arranged on each side rail of the double-redundant hydraulic rail, the speed of each side rail is obtained, the running speed difference between the double-redundant hydraulic rails is determined, the running speed difference is compared with a preset speed difference threshold, and parameter adjustment is performed according to the comparison result, specifically as follows: When the running speed difference is greater than the preset speed difference threshold, the hydraulic valve flow distribution is adjusted or the rail levelness error is corrected until the running speed difference is not greater than the preset deviation threshold; otherwise, the double-redundant hydraulic rail operates normally.

6. A method of lifting a marine propeller in accordance with claim 1, wherein The underwater state of the thruster and the hydraulic clamp is determined, including: S2.1.1: Hydraulic clamp clamping: through the laser projector, the clamping points on both sides of the center of gravity on the surface of the thruster are calibrated, the hydraulic clamp is moved to the clamping points through the double-redundant hydraulic rail, the clamping force of the hydraulic clamp is adjusted through the PLC controller and the preset target pressure value, and when the clamping force of the hydraulic clamp is equal to the preset target pressure value, the hydraulic pump is switched to the pressure maintaining mode, the electromagnetic reversing valve is switched to the middle position locking state, and the oil circuit is cut off; S2.1.2: Set up the vortex suppression system: a plurality of guide vanes are uniformly arranged on the tail of the thruster in the circumferential direction, the roots of the guide vanes are connected with waterproof servo motors through flanges, and the range of attack angle of the guide vanes is limited through mechanical limit blocks.

7. A method of underwater roll-on lifting of a marine propeller according to claim 6, characterised in that, The claw arm section of the hydraulic clamp is arranged in an I-shaped structure, the outer surface of the hydraulic clamp is provided with a polyurethane anti-skid layer through a vulcanization process, and the polyurethane anti-skid layer is provided with staggered grooves.

8. A method of lifting a marine propeller in accordance with claim 6, wherein, The thruster and the base flange are temporarily fixed by magnetic attraction, including: S2.2.1: Centering adjustment: the thruster flange is clamped and fixed by the mechanical arm gripper, and the thruster flange and the base flange are aligned according to the laser centering assembly; S2.2.2: Magnetic temporary fixation: a soft iron core is arranged on the base of the thruster, the attraction force of the soft iron core is obtained through a direct current power supply, and the aligned thruster flange and base flange are magnetically connected through the attraction force of the soft iron core, and the attraction force of the soft iron core is obtained according to the following formula: ； where: is the attractive force of the soft ferromagnetic core, is the magnetic induction, is the vacuum permeability, is the effective area of the magnetic pole.

9. A method of lifting a marine propeller in accordance with claim 1, wherein, Different hoisting processing operations are determined, including: S3.1: Oil pollution prevention and control: a portable adsorption pad is arranged outside the hoisting area, and the leaked oil at the hydraulic pipeline joint is adsorbed through the portable adsorption pad, the adsorption amount of the portable adsorption pad is obtained, the oil leakage amount of the hydraulic pipeline joint is obtained through an oil-sensitive sensor, the oil leakage amount and the adsorption amount are compared, and the portable adsorption pad is replaced according to the comparison result, specifically as follows: When the oil leakage amount is greater than the preset range of the adsorption amount, the portable adsorption pad is replaced; otherwise, the portable adsorption pad is not replaced; S3.2: Emergency release: the main sling tension value of the main sling is obtained through a tension sensor, the main sling tension value is compared with a preset tension overrun threshold, and the sling connection is cut off according to the comparison result, specifically as follows: When the main sling tension value is less than the preset tension overrun threshold value, the sling connection is continued; otherwise, the sling connection is cut off, the compressed air tank is released, and the inflatable air bag is inflated to provide upward floating force for the thruster; S3.3: CO2 cleaning: CO2 cleaning is performed in the area of the hull weld and the flange by a heater and a booster pump.

Images