Polar region high-power double-propeller pod propelling device and design method

Abstract

The invention discloses a polar region high-power double-propeller pod propelling device which comprises a propelling component, a propelling shell, a steering base and a steering component. The propelling component comprises a propelling component shell, a radial ventilation permanent magnet propelling motor, a front propeller side bearing assembly, a front propeller side sealing assembly, a front propeller assembly, a rear propeller side bearing assembly, a rear propeller side sealing assembly, a rear propeller assembly and a cooling ventilation device. The steering component comprises a steering body, a hydraulic pump station, a steering driving device, a sliding ring, a rotary sealing assembly and a rotary bearing assembly. The invention further discloses a design method. The primary design is based on a single propeller, the detailed design is based on double propellers, and the final design is based on test verification; the power density of the propulsion motor is increased, so that the propulsion device is smaller in size and weight, smaller in borne ice impact load and higher in reliability.

Description

Technical Field

[0001] This invention belongs to the technical field of podded propulsion devices, and relates to a high-power polar twin-propeller podded propulsion device for ships with navigation requirements in polar ice-covered waters, as well as its design method. Background Technology

[0002] With the increasing interest in developing and utilizing polar resources, podded propulsion systems play an irreplaceable role in polar shipping routes due to their superior icebreaking capabilities. To improve the propulsion efficiency of podded propulsion systems, twin-propeller podded propulsion systems can be adopted. Existing twin-propeller podded propulsion systems mostly adopt a counter-rotating propeller configuration (such as CN115009489A, CN216154006U, CN213566416U), and mainly achieve dual-shaft counter-rotating output through two methods: dual-motor dual-shaft output and single-motor bevel gear transmission devices.

[0003] The dual-motor design increases the length of the propulsion device due to components such as end windings and end caps, thus increasing the assembly difficulty. Gear and other transmission devices significantly limit the size of the pod propulsion device. Furthermore, at high power levels (7MW and above), bevel gears, reduction gearboxes, and other transmission devices suffer from insufficient strength, low transmission efficiency, and high vibration and noise, thus limiting the power and performance of the pod propulsion device.

[0004] Therefore, current high-power pod propulsion devices are limited in terms of size, weight, and performance, while polar pod propulsion devices have even higher requirements in terms of size, weight, and performance. Summary of the Invention

[0005] To address the aforementioned technical problems, one objective of this invention is to provide a high-power polar twin-propeller pod propulsion device.

[0006] To achieve the above objectives, the technical solution adopted by the present invention to solve its technical problem is: a high-power polar twin-propeller pod propulsion device, comprising a propulsion component, a propulsion housing, and a rudder base connected in sequence, and a rudder component; the propulsion component includes a radially ventilated permanent magnet propulsion motor and a propulsion component housing connected to the front and rear ends of the permanent magnet propulsion motor; the front and rear ends of the permanent magnet propulsion motor shaft are respectively provided with a front propeller-side bearing assembly, a front propeller-side sealing assembly, a front propeller assembly, a rear propeller-side bearing assembly, a rear propeller-side sealing assembly, and a rear propeller assembly; the rudder component includes a rudder body mounted on the rudder base via a slewing sealing assembly and a slewing bearing assembly, and also includes a rudder drive device mounted on the rudder base and a hydraulic pump station connected to the rudder drive device; the rudder base is provided with a useful... The propulsion component includes a slip ring for electro-hydraulic transmission during rotation and a cooling ventilation device for cooling the propulsion component. The cooling ventilation device is equipped with a cooler and a fan, and is connected to the steering base via an inlet pipe and an outlet pipe. The propulsion housing contains a hot air duct and a cold air duct connecting the permanent magnet propulsion motor and the propulsion component housing. The steering base contains an outlet pipe and an inlet pipe. The outlet pipe connects the hot air duct, the slip ring, and the outlet pipe, while the inlet pipe connects the cold air duct and the inlet pipe. The propulsion component housing, permanent magnet propulsion motor, slip ring, propulsion housing, steering base, and cooling ventilation device achieve a forced air-cooling cycle: cooling ventilation device—inlet pipe—inlet pipe—cold air duct—propulsion housing—permanent magnet propulsion motor—hot air duct—outlet pipe—slip ring—outlet pipe—cooling ventilation device.

[0007] The aforementioned high-power polar twin-propeller pod propulsion device has an air guide device provided on the propulsion component housing and / or the end of the permanent magnet propulsion motor. The surface of the propulsion component housing is coated with anti-icing paint. The rotor core and stator core of the permanent magnet propulsion motor are provided with segmented and aligned radial ventilation slots in the axial direction. The rotor core has several axially penetrating ventilation holes.

[0008] The aforementioned high-power polar twin-propeller pod propulsion device has a cooling and ventilation system in which two sets of fans connected in parallel are combined into one path, and the two sets of fans can operate independently. At the same time, the cooling and ventilation system is also equipped with a baffle to prevent the cooling air from flowing back.

[0009] The aforementioned high-power polar twin-propeller pod propulsion device has a front propeller assembly and a rear propeller assembly with a split structure of hub and blades. The ratio of the diameter of the rear propeller to that of the front propeller is approximately 1 to 1.05. The pitch ratio of the rear propeller is greater than that of the front propeller, with a difference of approximately 0.05 to 0.1. Z represents the number of blades.

[0010] The aforementioned high-power polar twin-propeller pod propulsion device includes a radial bearing and a thrust bearing in both the front propeller side bearing assembly and the rear propeller side bearing assembly. The two thrust bearings are located on both sides and are used to bear the thrust in two directions, namely the radial force caused by ice impact load on both propellers. The two radial bearings are located on both sides and are used to bear the radial force caused by ice impact load on both propellers. The front propeller side sealing assembly and the rear propeller side sealing assembly are equipped with multiple sealing structures, mainly used to prevent seawater from entering the pod propulsion components and to prevent the lubricating fluid of the bearings from flowing out.

[0011] The aforementioned high-power polar twin-propeller pod propulsion device employs multiple hydraulic motors in its rudder drive unit, which is supplied with oil by a hydraulic pump station.

[0012] The second objective of this invention is to propose a design method for the aforementioned high-power polar twin-propeller pod propulsion device.

[0013] The technical solution adopted by this invention to solve its technical problem is: a design method for a high-power polar twin-propeller pod propulsion device, comprising the following steps:

[0014] S1, Preliminary design of a high-power polar pod propulsion device based on a single propeller;

[0015] S101 specifies the requirements for ice class, classification standards, and power of podded propulsion systems based on the overall requirements of the vessel.

[0016] S102 specifies the requirements for each operating condition of the podded propulsion system based on the overall needs of the ship. These generally include efficiency requirements for open water navigation, strength requirements for icebreaking navigation, and noise requirements for silent navigation.

[0017] S103. Based on the speed Vo and power Po requirements for open water navigation, the propeller is initially designed: the speed No and propeller diameter D for open water navigation are initially determined. Taking into account the efficiency requirements for open water navigation, the strength requirements for icebreaking navigation, and the quietness requirements for silent navigation, the distance L between the propeller center and the rudder centerline, the propeller pitch ratio P / D, the disk area ratio EAR, and the number of blades Z are selected. P / D is generally 0.7 to 1.0; EAR is generally 0.6 to 0.8; and Z is generally 3 to 5.

[0018] S104. Based on the relevant data in step S103, the ice thickness Hice entering the propeller is assumed according to the ship classification code requirements. The ice impact load is calculated and the data of the maximum rearward force Fb, the maximum forward force Ff, the shaft design thrust Tr, and the blade failure load Fex of the propeller blades in the front propeller assembly and the rear propeller assembly are obtained under the ice impact load.

[0019] S105, calculate the maximum response torque Qi (generally described as Qmax in the specification) of the ice impact load on the shaft system of the pod propulsion device according to the requirements of the ship classification code. Considering the maximum power Pi under the icebreaking navigation condition, calculate the rotational speed Ni under the icebreaking navigation condition.

[0020] S106, Design of motor under icebreaking navigation conditions: The electromagnetic field and temperature field of the motor are coupled based on the maximum power Pi and the rotational speed Ni under icebreaking navigation conditions. The motor envelope shape that conforms to the overall design is selected to obtain a permanent magnet motor with high power density.

[0021] S107, based on the above, complete the design of the main propulsion components: Design the shaft dimensions and material selection based on the blade failure load Fex and the maximum shaft response torque Qi; select and design the thrust bearing and radial bearing based on the bearing arrangement scheme and the shaft design thrust Tr; design the front rotor side sealing assembly, rear rotor side sealing assembly, and rotary sealing assembly based on the shaft diameter and rotational speed; design the cooling and ventilation device based on the requirements of the cooling gas inlet temperature, inlet flow rate, and inlet pressure head in the temperature field, mainly including the cooler's output power and the fan flow rate and pressure head design; design the slip ring based on the current in the electromagnetic field, bearing lubrication requirements (liquid), and sealing requirements.

[0022] S108, in combination with the overall requirements of the ship and the requirements of the propulsion components, complete the design of the main components of the steering body: based on the propeller diameter D of the podded propulsion device, the maximum response torque Qi of the shaft system and the distance L between the steering center and the propeller center in the preliminary design, calculate the steering torque Qsg of the podded propulsion device, and combine other load data to design the slewing bearing, steering drive device and hydraulic pump station.

[0023] S109, according to the ship classification code, shaft vibration verification calculation is performed, considering the vibration characteristics analysis under the ice impact load time domain mode, mainly including torsional vibration, longitudinal vibration and gyratory vibration.

[0024] S110, according to the ship classification code, calculate the shafting strength, shafting stiffness, and shafting fatigue: shafting strength includes minimum diameter calculation; finite element analysis of shafting static strength, displacement, and deflection under maximum combined load conditions; fatigue strength calculation of shafting components under ice impact load is performed using Weibull distribution theory and linear cumulative damage theory, and the shafting fatigue strength is checked in conjunction with the material SN curve;

[0025] S111, According to the ship classification regulations, the propeller strength is checked in conjunction with the data from step S104: The fatigue strength of the propeller under ice impact load is calculated using the Weibull distribution theory and the linear cumulative damage theory, and the fatigue strength of the propeller is checked in conjunction with the material SN curve.

[0026] S112, Calculate the ice impact force and ice ridge penetration force based on the geometric parameters of the pod propulsion device, check the strength of the propulsion device under multiple working conditions of ice impact and ice ridge penetration, and strengthen the corresponding structural areas of the propulsion component shell if the requirements are not met, determine the optimized pod propulsion device scheme, and check the propulsion component shell.

[0027] S113, based on the optimized pod propulsion device scheme in S112, performs hydrodynamic performance verification under open water navigation conditions, including speed, torque, thrust, etc. under various conditions;

[0028] S114, based on the optimized pod propulsion device scheme in S112, conduct noise performance verification for silent navigation conditions, mainly including surface vibration of the propulsion component housing and propeller noise.

[0029] S2, based on a detailed design of a twin propeller;

[0030] S201, based on S1, replaces the original propeller with two propellers scaled down by a smaller ratio. Calculate the propeller speed N and diameter D, where the power P is proportional to N. 3 D 5 To ensure that the advance coefficient remains constant (i.e., N×D remains constant) to guarantee similar propulsion efficiencies, the diameter D of the two propellers is... 双桨 =D / 1.412, N 双桨 =1.412×No;

[0031] S202, Perform load verification according to step 201, verifying the maximum backward force Fb, maximum forward force Ff, blade failure load Fex, and maximum shaft response torque Qi of the propeller blades; where Fb is proportional to N. 0.7 D 2.7 Ff is proportional to D 2 Fex is proportional to D 2 Qi is proportional to N 0.17 D 3.17 Therefore, Fb = 2 × Fb 双桨 Ff = 2 × Ff 双桨 Fex = 2 × Fex 双桨 Qi = (2 × Qi) 双桨 ) / 0.72;

[0032] S203, considering the recovery of wake energy from the front propeller by the rear propeller to improve efficiency, and taking into account the design optimization of the diameter, pitch ratio and blade misalignment angle of the front and rear propellers.

[0033] S204, Optimization of propeller speed, diameter, pitch ratio, and stator core outer diameter: Taking into account factors such as propulsion efficiency, propulsion unit weight, and ice impact load on the propulsion unit, the propeller speed N of the podded propulsion unit is optimized.双桨 and diameter D 后桨 D 前桨 The propeller pitch ratio P / D 前桨 P / D 后桨 The outer diameter Ds of the motor stator core is optimized.

[0034] S205, based on a twin-propeller scheme, optimizes the design of the podded propulsion device in terms of environmental adaptability, corrosion resistance, intelligentization, and maintainability, and completes the detailed design of the main components of the podded propulsion device;

[0035] S206, based on the detailed design scheme of the podded propulsion device, update the relevant calculations and verification of the dual propeller content in step S1 to ensure that the calculation design inputs are consistent in the final iteration;

[0036] S3, the final design of a high-power polar pod propulsion device based on experimental verification;

[0037] S301, through pool testing, tests the hydrodynamic characteristics of the podded propulsion system and the ship's self-propulsion performance;

[0038] S302, the noise characteristics of the podded propulsion device are verified by testing the sound of the propeller blades through a circulating water tank or a cavitation water tank.

[0039] S303, through ice pool tests, tests the ice-breaking performance of the podded propulsion device and the hydrodynamic and anti-icing performance of the podded propulsion device under ice impact loads, and verifies the ice zone performance of the design results;

[0040] S304, based on model test data, was optimized to form the final design scheme of polar high-power twin-propeller pod propulsion device.

[0041] Furthermore, step S1 also includes:

[0042] S115. In the above steps, if a component involves optimization, the optimization design of S104 to S108 and the update and verification of S109 to S114 also need to be iteratively updated to ensure that the input of each calculation design is consistent in the final iteration.

[0043] S116. If the relevant requirements cannot be met through component optimization in the above steps, it is necessary to return to step 103 to perform corresponding data optimization until a preliminary design based on a single propeller that meets the requirements is obtained.

[0044] Furthermore, in step S202, the maximum backward force Fb of the propeller blade is proportional to N. 0.7 D 2.7 The maximum forward force Ff is proportional to D 2 The blade failure load Fex is proportional to D 2The maximum response torque Qi of the shaft system is proportional to N. 0.17 D 3.17 Therefore, Fb = 2 × Fb 双桨 Ff = 2 × Ff 双桨 Fex = 2 × Fex 双桨 Qi = (2 × Qi) 双桨 ) / 0.72.

[0045] Furthermore, in step S202, while ensuring that the propulsion power and propulsion efficiency remain unchanged, when the single-propeller scheme is replaced with the twin-propeller scheme, the speed increases by 1.412 times and the torque decreases to 71% of the original in open water navigation conditions; in icebreaking navigation conditions, the axial force of the ice impact load remains unchanged, and the axial torque of the ice impact load decreases to 72% of the original.

[0046] The significant beneficial effects of this invention are as follows:

[0047] 1. When the ship is overloaded (ship sailing in ice-covered areas), using two coaxial propellers can improve propulsion efficiency, and the rear propeller can use the wake of the front propeller to improve efficiency.

[0048] 2. This invention eliminates the need for gears or other transmission devices, resulting in superior performance. Gears and other transmission devices suffer from insufficient strength, low transmission efficiency, and high vibration and noise at high power levels (7MW and above).

[0049] 3. Under the same power and propulsion efficiency, using two coaxial propellers can reduce the propeller diameter, increase the propulsion motor speed, and reduce the size and weight of the pod propulsion device, providing favorable support for the production, assembly, and testing of the pod propulsion device.

[0050] 4. The use of radial ventilation permanent magnet propulsion motors improves the thermal load of permanent magnet propulsion motors, increases power density, and reduces the size and weight of motors, providing favorable support for the production, assembly, and testing of pod propulsion devices.

[0051] 5. The power-speed curve of the podded propulsion system with two coaxial propellers is flatter, the adaptability to operating conditions is stronger, and the control of motor speed under ice impact load is more robust.

[0052] 6. This invention has passed the review of the classification society and provides a design reference for podded propulsion devices for polar vessels. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the structure of the pod propulsion device of the present invention;

[0054] Figure 2 This is a forced air cooling path diagram for the pod propulsion device of the present invention;

[0055] Figure 3This is a flowchart of the design method of the present invention;

[0056] Figure 4 The specific process of step S1 of the present invention;

[0057] Figure 5 The specific process of step S2 of the present invention;

[0058] Figure 6 The specific process of step S3 of the present invention is as follows.

[0059] The reference numerals in the attached figures are as follows: 1-1—propulsion component housing, 1-2—permanent magnet propulsion motor, 1-3—front propeller side bearing assembly, 1-4—front propeller side sealing assembly, 1-5—front propeller assembly, 1-6—rear propeller side bearing assembly, 1-7—rear propeller side sealing assembly, 1-8—rear propeller assembly, 1-9—cooling and ventilation device, 2-1—rudder body, 2-2—hydraulic pump station, 2-3—rudder drive device, 2-4—slip ring, 2-5—slewing sealing assembly, 2-6—slewing bearing assembly, 3-1—propulsion housing, 3-2—rudder base. Detailed Implementation

[0060] To more clearly illustrate the present invention, the following description, in conjunction with the accompanying drawings and examples, further explains the invention. It should be understood that the specific embodiments described herein are merely illustrative of the invention, and the scope of protection is not limited to the examples described.

[0061] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. For example, although the various components in the drawings are drawn to a specific scale, these proportional relationships are merely exemplary, and those skilled in the art can adjust them as needed to adapt to specific application scenarios.

[0062] It should be noted that in the description of this invention, the terms "center", "upper", "lower", "left", "right", "inner", "outer", etc., indicate the direction or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed or operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0063] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0064] To address the bottleneck of low power density in polar high-power podded propulsion devices, this invention proposes a polar high-power twin-propeller podded propulsion device for use on ships navigating in ice-covered areas. Its main feature is high power density, with a propulsion power typically ranging from 7MW to 20MW.

[0065] According to one embodiment of the present invention, reference is made to... Figure 1 The pod propulsion system mainly includes a propulsion component and a steering component. The propulsion component, propulsion shell 3-1, steering base 3-2 and steering component are connected in sequence.

[0066] The propulsion components mainly include: a propulsion component housing 1-1, a radially ventilated permanent magnet propulsion motor 1-2, a front propeller-side bearing assembly 1-3, a front propeller-side sealing assembly 1-4, a front propeller assembly 1-5, a rear propeller-side bearing assembly 1-6, a rear propeller-side sealing assembly 1-7, a rear propeller assembly 1-8, and a cooling and ventilation device 1-9. The shaft of the permanent magnet propulsion motor 1-2 is respectively equipped with the front propeller-side bearing assembly 1-3, the front propeller-side sealing assembly 1-4, the front propeller assembly 1-5, the rear propeller-side bearing assembly 1-6, the rear propeller-side sealing assembly 1-7, and the rear propeller assembly 1-8. The steering components mainly include: a steering body 2-1, a hydraulic pump station 2-2, a steering drive device 2-3, an electro-hydraulic slip ring 2-4, a slewing sealing assembly 2-5, and a slewing bearing assembly 2-6.

[0067] The propulsion casing 3-1 is equipped with a hot air duct and a cold air duct, respectively. The rudder base 3-2 is equipped with an air outlet duct and an air inlet duct, respectively. The cooling ventilation device 1-9 for cooling the propulsion components is equipped with a cooler and a fan. The cooling ventilation device 1-9 is connected to the rudder base 3-2 and the slip ring 2-4 through the air inlet pipe and the air outlet pipe, respectively. The rotary sealing assembly 2-5 is provided to prevent seawater from entering the rudder components and to prevent the lubricating fluid of the bearing in the rotary bearing assembly 2-6 from flowing out. The slip ring 2-4 is used for electro-hydraulic transmission when the propulsion components are rotating.

[0068] The propulsion component housing 1-1, permanent magnet propulsion motor 1-2, slip ring 2-4, propulsion housing 3-1, rudder base 3-2, and cooling ventilation device 1-9 achieve forced air cooling circulation, increasing the thermal load of the permanent magnet propulsion motor, increasing power density, and reducing the size and weight of the motor. The main path is: cold air outlet of cooling ventilation device 1-9 → air inlet pipe → air inlet duct → cold air duct → propulsion housing 3-1 → permanent magnet propulsion motor 1-2 → hot air duct → air outlet duct → slip ring 2-4 → air outlet pipe → hot air inlet of cooling ventilation device 1-9, such as... Figure 2 As shown.

[0069] This invention improves the power density of the propulsion device in two main ways: First, the propulsion component housing, radially ventilated permanent magnet motor, slip ring, and cooling ventilation device form a forced air-cooling cycle, which increases the thermal load of the permanent magnet propulsion motor and increases the power density of the propulsion motor. Second, the propulsion is achieved by the coaxial rotation of two propellers on each side, which can reduce the diameter of the propellers, increase the speed of the propulsion motor, and further increase the power density of the propulsion motor.

[0070] As a further embodiment of the present invention, an air guide device is provided at the end of the propulsion component housing 1-1 or the permanent magnet propulsion motor 1-2. Alternatively, air guide devices can be provided at both the ends of the propulsion component housing 1-1 and the permanent magnet propulsion motor 1-2. The surface of the propulsion component housing 1-1 is coated with anti-icing paint. The rotor core and stator core of the permanent magnet propulsion motor 1-2 are provided with segmented and aligned ventilation slots in the axial direction. The rotor core has several axially penetrating ventilation holes. The height of the ventilation slots is generally 6mm, 8mm, 10mm, or 12mm. The propulsion motor structure has sufficient strength to withstand ice impact loads. The propulsion component housing 1-1 has watertightness for the corresponding working water depth. The airflow route within the cooling ventilation device 1-9 combines two sets of parallel fans into one route. The two sets of fans can operate independently. A baffle to prevent backflow of cooling air is also provided within the cooling ventilation device 1-9.

[0071] The main path of the air-cooled circulation is: cooling ventilation device 1-9 → air inlet pipe → air inlet duct → cold air duct → propulsion housing 3-1 → permanent magnet propulsion motor 1-2 (stator end air guide device → rotor axial channel → stator radial channel) → hot air duct → air outlet duct → slip ring 2-4 → air outlet pipe → cooling ventilation device 1-9.

[0072] As a further embodiment of the present invention, the front propeller assembly 1-5 and the rear propeller assembly 1-8 are arranged on the same shaft, and the front and rear propeller assemblies rotate at the same speed. They have a split structure of hub and blades, which are connected by bolts. The material is stainless steel. The diameter ratio of the rear propeller to the front propeller is about 1 to 1.05. The pitch ratio of the rear propeller is greater than that of the front propeller, with a difference of about 0.05 to 0.1. When the number of front and rear propellers is the same, the rear propeller blades should lag behind the adjacent front propeller blades to avoid wake vortex interference. It is recommended that the blade misalignment angle of the front and rear propeller blades be 180° / Z, where Z is the number of blades.

[0073] Both the front propeller-side bearing assembly 1-3 and the rear propeller-side bearing assembly 1-6 include one radial bearing and one thrust bearing. The two thrust bearings are located on both sides and are used to withstand thrust in two directions, namely the radial force caused by ice impact loads on both propellers. The two radial bearings are located on both sides and are used to withstand the radial force caused by ice impact loads on both propellers. The front propeller-side sealing assembly 1-4 and the rear propeller-side sealing assembly 1-7 are equipped with multiple sealing structures, mainly used to prevent seawater from entering the pod propulsion components and to prevent the lubricating fluid from leaking out of the bearings.

[0074] The two propeller assemblies, two propulsion seal assemblies, and two propulsion bearing assemblies are approximately symmetrical about the rudder centerline to reduce the turning radius of the pod propulsion system. Considering the robustness of the rudder under ice impact loads, the rudder drive device 2-3 employs multiple hydraulic motors, supplied with oil by hydraulic pump station 2-2. A slewing bearing assembly 2-6 is provided to withstand the forces under open water and ice impact loads.

[0075] This invention discloses a design method for a high-power polar twin-propeller pod propulsion device, the steps of which are as follows: Figure 3 As shown, the designs are as follows: S1, preliminary design of a high-power polar pod propulsion device based on a single propeller; S2, detailed design of a high-power polar pod propulsion device based on a dual propeller; and S3, final design of a high-power polar pod propulsion device based on experimental verification.

[0076] S1, This step applies to the design of single-propeller polar high-power podded propulsion devices. The specific steps are as follows: Figure 4 As shown.

[0077] S101 specifies the requirements for ice class, classification standards, and power of podded propulsion systems based on the overall needs of the vessel.

[0078] S102 specifies the requirements for each operating condition of the podded propulsion system based on the overall needs of the ship. These generally include efficiency requirements for open water navigation, strength requirements for icebreaking navigation, and noise requirements for silent navigation.

[0079] S103, based on the speed Vo and power Po requirements for open water navigation, the propeller is initially designed: the speed No and propeller diameter D for open water navigation are initially determined. Taking into account the efficiency requirements for open water navigation, the strength requirements for icebreaking navigation, and the quietness requirements for quiet navigation, the distance L between the propeller center and the rudder centerline, the propeller pitch ratio P / D, the disk area ratio EAR, and the number of blades Z are selected.

[0080] P / D is generally 0.7 to 1.0; EAR is generally 0.6 to 0.8; Z is generally 3 to 5.

[0081] S104. Based on the relevant data in step S103, select the assumed ice thickness Hice entering the propeller according to the ship classification regulations, perform ice impact load calculation, and analyze and obtain the data of the maximum rearward force Fb, maximum forward force Ff, shaft design thrust Tr, and blade failure load Fex of the propeller blades in the front propeller assembly 1-5 and the rear propeller assembly 1-8 under ice impact load.

[0082] S105, calculate the maximum response torque Qi (generally described as Qmax in the specification) of the ice impact load on the shaft system of the pod propulsion device according to the requirements of the ship classification code. Considering the maximum power Pi under the icebreaking navigation condition, calculate the rotational speed Ni under the icebreaking navigation condition.

[0083] S106, the design conditions of the motor under icebreaking navigation conditions are more stringent. The electromagnetic field and temperature field of the motor are coupled based on the maximum power Pi and the speed Ni under icebreaking navigation conditions. The motor envelope shape that conforms to the overall design is selected to obtain a permanent magnet motor with high power density.

[0084] The electromagnetic design should take into account the influence of the ventilation slots of the stator and rotor. The height of the ventilation slots is generally 6mm, 8mm, 10mm, or 12mm.

[0085] S107. Based on the above, complete the design of the main components of the propulsion system. The specific steps are: design the shaft dimensions and select the materials according to the blade failure load Fex and the maximum response torque Qi of the shaft system.

[0086] Based on the bearing arrangement scheme, the thrust bearings and radial bearings are selected and designed according to the shaft system design thrust Tr. It should be noted that the thrust bearings are arranged at both ends separately for forward and rearward forces, and one radial bearing is placed at each end, consistent with the arrangement shown in the attached diagram. The front rotor side sealing assembly 1-4, rear rotor side sealing assembly 1-7, and rotary sealing assembly 2-5 are designed based on the shaft diameter and rotational speed. The cooling ventilation device 1-9 is designed based on the requirements of the cooling gas inlet temperature, inlet flow rate, and inlet pressure head in the temperature field, mainly including the cooler's output power and the fan flow rate and pressure head design. The electro-hydraulic slip ring 2-4 is designed based on the current (electric), bearing lubrication requirements (hydraulic), and sealing requirements in the electromagnetic field.

[0087] S108, in accordance with the overall requirements of the ship, complete the design of the main components of the steering body 2-1. The specific steps are as follows: based on the propeller diameter D of the podded propulsion device, the maximum response torque Qi of the shaft system, and the distance L between the steering center and the propeller center in the preliminary design, calculate the steering torque Qsg of the podded propulsion device, and design the slewing bearing, steering drive device, and hydraulic pump station in conjunction with other load data.

[0088] S109, according to the ship classification code, shaft vibration verification calculation is performed, considering the vibration characteristics analysis under the ice impact load time domain mode, mainly including torsional vibration, longitudinal vibration and gyratory vibration.

[0089] S110, according to the ship classification code, perform shafting strength calculation, shafting stiffness calculation, and shafting fatigue calculation. The specific steps are as follows: shafting strength includes minimum diameter calculation; finite element analysis of shafting static strength, displacement, and deflection under maximum combined load conditions; fatigue strength calculation of shafting components under ice impact load is performed using Weibull distribution theory and linear cumulative damage theory, and the shafting fatigue strength is verified by combining the material SN curve.

[0090] S111, according to the ship classification regulations, and combined with the data from step S104, the propeller strength is checked: the fatigue strength of the propeller under ice impact load is calculated using the Weibull distribution theory and the linear cumulative damage theory, and the fatigue strength of the propeller is checked by combining the material SN curve.

[0091] S112, Calculate the ice impact force and ice ridge penetration force based on the geometric parameters of the pod propulsion device, check the strength of the propulsion device under multiple working conditions of ice impact and ice ridge penetration, and strengthen the corresponding structural area of ​​the propulsion component shell 1-1 if the requirements are not met, determine the optimized pod propulsion device scheme, and check the propulsion component shell 1-1.

[0092] S113, based on the optimized podded propulsion device scheme in S112, performs hydrodynamic performance verification under open water navigation conditions, including speed, torque, thrust, etc. under various conditions.

[0093] S114, based on the optimized pod propulsion device scheme in S112, performs noise performance verification under silent navigation conditions, mainly including surface vibration of the propulsion component casing and propeller noise.

[0094] S115. In the above steps, if a component involves optimization, the related optimization design steps S104 to S108 and the update verification steps S109 to S114 also need to be iteratively updated to ensure that the input of each calculation design is consistent in the final iteration.

[0095] S116, If the requirements cannot be met through component optimization in the above steps, it is necessary to return to step 103 for corresponding data optimization until a preliminary design of a single-propeller-based high-power polar pod propulsion device that meets the requirements is obtained. Generally, in step S103, an increase in the speed No during open-water navigation and a decrease in the propeller diameter D are detrimental to propulsion efficiency but beneficial to the weight of the propulsion device and ice impact load; a decrease in the speed No during open-water navigation and an increase in the propeller diameter D are beneficial to propulsion efficiency but detrimental to the weight of the propulsion device and ice impact load.

[0096] S2, This step is based on the detailed design of the twin propellers, and the specific steps are as follows: Figure 5 As shown.

[0097] S201, based on S1, replaces the original propeller with two propellers scaled down by a smaller ratio, where the power P is proportional to N. 3 D 5 To ensure that the advance coefficient remains constant (i.e., N×D remains constant) to guarantee similar propulsion efficiencies, the diameter D of the two propellers is... 双桨 =D / 1.412, N 双桨 =1.412×No.

[0098] S202, Perform load verification according to step 201, where the maximum rearward force Fb of the propeller blade is proportional to N. 0.7 D 2.7 The maximum forward force Ff is proportional to D 2 The blade failure load Fex is proportional to D 2 The maximum response torque Qi of the shaft system is proportional to N. 0.17 D 3.17 Therefore, Fb = 2 × Fb 双桨 Ff = 2 × Ff 双桨 Fex = 2 × Fex 双桨 Qi = (2 × Qi) 双桨) / 0.72. That is, while maintaining the same propulsion power and efficiency, when replacing the single-propeller configuration with a twin-propeller configuration, in open water navigation: the speed increases by 1.412 times, and the torque decreases to 71% of the original; in icebreaking navigation: the axial force of the ice impact load remains unchanged, but the axial torque of the ice impact load decreases to 72% of the original. A significant benefit is that the motor's volume (weight) is proportional to its torque, and the motor weight can be reduced to 72% of the original; the propeller weight is proportional to D... 3 The propeller weight was also reduced to 72% of its original weight.

[0099] S203, considering the recovery of wake energy from the front propeller by the rear propeller to improve efficiency, involves design optimization of the diameters, pitch ratio, and blade misalignment angles of both propellers. The specific steps are: Rear propeller diameter D... 后桨 It should be no less than the diameter D of the front propeller. 前桨 Generally, D 后桨 =D 前桨 =D 双桨 I suggest D 后桨 / D 前桨 Take a value of 1.0 to 1.05; the incoming velocity of the rear propeller increases due to the acceleration of the front propeller, so the rear propeller should have a higher pitch ratio to obtain higher propulsion efficiency. Refer to the single propeller in step S1 for optimization. The recommended rear propeller pitch ratio (P / D) is as follows. 后桨 = (P / D) 单桨 +a, Recommended front propeller pitch ratio (P / D) 前桨 = (P / D) 单桨 -a, where a is suggested to be 0.02 to 0.05, taking into account the distance L between the front and rear propellers. 前后桨 In addition, appropriate optimization should be performed using CFD simulation. When the number of blades Z is the same for the front and rear propellers, the phase angle of the rear propeller blade should lag behind that of the adjacent front propeller blade to avoid wake vortex interference. It is recommended that the blade misalignment angle between the front and rear propeller blades be 180° / Z.

[0100] S204, Optimization of propeller speed, diameter, pitch ratio, and stator core outer diameter: Taking into account factors such as propulsion efficiency, propulsion unit weight, and ice impact load on the propulsion unit, the propeller speed N of the podded propulsion unit is optimized. 双桨 and diameter D 后桨 D 前桨 The propeller pitch ratio P / D 前桨 P / D 后桨 The outer diameter Ds of the motor stator core is optimized. Generally, this step mainly considers optimizing the outer diameter Ds of the stator core. If the relevant requirements cannot be met, N is considered. 双桨 Optimization. N 双桨 Increasing the N value is detrimental to propulsion efficiency but beneficial to the weight of the propulsion device and ice impact load. 双桨 Reducing the weight of the propulsion device is beneficial to the propulsion efficiency, but detrimental to the weight of the propulsion device and ice impact load.

[0101] S205, based on a twin-propeller design, optimizes the pod propulsion device in terms of environmental adaptability, corrosion resistance, intelligent features, and maintainability, and completes the detailed design of the main components of the pod propulsion device.

[0102] S206, based on the detailed design scheme of the pod propulsion device, update the relevant calculation and verification content in S1 to ensure that the calculation design inputs are consistent in the final iteration.

[0103] It should be noted that the design thrust Tr of the shaft is the sum of the thrust generated by the front propeller assembly 1-5 and the rear propeller assembly 1-8, Tr1+Tr2, and the maximum response torque Qi of the two propeller assemblies is calculated according to Qi1+Qi2, etc.

[0104] S3, This step is based on the final design verified by experiments. The specific steps are as follows: Figure 6 As shown.

[0105] S301 tests the hydrodynamic characteristics of the podded propulsion system and the ship's self-propulsion performance through a water tank test.

[0106] S302 uses a circulating water tank or cavitation water tank to test the sound of the propeller blades and verify the noise characteristics of the pod propulsion device.

[0107] S303 uses ice pool tests to test the ice-breaking performance of the pod propulsion device and its hydrodynamic and anti-icing performance under ice impact loads, thus verifying the ice-zone performance of the design results.

[0108] S304, based on model test data, was optimized to form the final design scheme of polar high-power twin-propeller pod propulsion device.

[0109] Taking a 10MW-class podded propulsion system for ice-covered areas as an example, the single-propeller podded propulsion system has the following characteristics: rotational speed N0, propeller diameter D0, stator core outer diameter DS0, and weight approximately W0.

[0110] Under the premise of ensuring that the propulsion power and propulsion efficiency of the propulsion device remain unchanged, this method is used to design a high-power polar pod propulsion device with two propellers. Its main parameters are as follows: rotational speed is 1.41×N0, propeller diameter is 0.71×D0, stator core outer diameter is 0.695×DS0, and weight is approximately 0.733×W0.

[0111] It can be seen that by adopting the scheme and design method proposed in this invention, the size and weight of the pod propulsion device are significantly reduced, providing favorable support for the production, assembly and testing of the pod propulsion device; at the same time, the corresponding ice impact loads are reduced, improving the reliability of the pod propulsion device.

[0112] The above embodiments are merely illustrative of the principles and effects of the present invention, as well as some examples of its application. For those skilled in the art, various modifications and improvements can be made without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A high-power polar twin-propeller pod propulsion device, characterized in that: The system includes a propulsion component, a propulsion housing (3-1), and a rudder base (3-2) connected in sequence, as well as a rudder component. The propulsion component includes a permanent magnet propulsion motor (1-2) and a propulsion component housing (1-1) connected to both ends of the permanent magnet propulsion motor (1-2). The permanent magnet propulsion motor (1-2) has a front propeller-side bearing assembly (1-3), a front propeller-side sealing assembly (1-4), a front propeller assembly (1-5), a rear propeller-side bearing assembly (1-6), a rear propeller-side sealing assembly (1-7), and a rear propeller assembly (1-8) respectively at both ends of its shaft. The rudder component includes a rudder body (2-1) mounted on the rudder base (3-2) via a rotary sealing assembly (2-5) and a rotary bearing assembly (2-6), a rudder drive device (2-3) mounted on the rudder base (3-2), and a hydraulic pump station (2-2) connected to the rudder drive device (2-3). The rudder base (3-2) is equipped with a slip ring (2-4) and a cooling ventilation device (1-9). The cooling ventilation device (1-9) is equipped with a cooler and a fan. The cooling ventilation device (1-9) is connected to the rudder base (3-2) through an air inlet pipe and to the slip ring (2-4) and the rudder base (3-2) in sequence through an air outlet pipe. The propulsion housing (3-1) is equipped with a hot air duct and a cold air duct that connect the permanent magnet propulsion motor (1-2) and the propulsion component housing (1-1). The rudder base (3-2) is equipped with an air outlet pipe and an air inlet pipe. The air outlet pipe connects the hot air duct and the slip ring (2-4), and the air inlet pipe connects the cold air duct and the air inlet pipe. The propulsion component housing (1-1), the permanent magnet propulsion motor (1-2), the slip ring (2-4), the propulsion housing (3-1), the rudder base (3-2), and the cooling ventilation device (1-9) achieve forced air cooling circulation.

2. The polar high-power twin-propeller pod propulsion device according to claim 1, characterized in that, The propulsion component housing (1-1) and / or the permanent magnet propulsion motor (1-2) are provided with air guide devices. The surface of the propulsion component housing (1-1) is coated with anti-icing paint. The rotor core and stator core of the permanent magnet propulsion motor (1-2) are axially provided with segmented and aligned ventilation slots. The rotor core has several axially penetrating ventilation holes.

3. The polar high-power twin-propeller pod propulsion device according to claim 1, characterized in that, The airflow path in the cooling ventilation device (1-9) is composed of two sets of fans connected in parallel, and the two sets of fans operate independently. The cooling ventilation device (1-9) is also equipped with a baffle to prevent the cooling air from flowing back.

4. A polar high-power twin-propeller pod propulsion device according to claim 1, 2, or 3, characterized in that, The front propeller assembly (1-5) and the rear propeller assembly (1-8) have a split structure of hub and blades. The diameter ratio of the rear propeller to the front propeller is 1 to 1.05, the pitch ratio of the rear propeller is greater than that of the front propeller, and the blade misalignment angle between the front and rear blades is 180° / Z, where Z is the number of blades.

5. A polar high-power twin-propeller pod propulsion device according to claim 4, characterized in that, The front propeller-side bearing assembly (1-3) and the rear propeller-side bearing assembly (1-6) each include a radial bearing and a thrust bearing. The front propeller-side sealing assembly (1-4) and the rear propeller-side sealing assembly (1-7) are both equipped with multiple sealing structures to prevent seawater from entering and lubricating liquid from flowing out.

6. A polar high-power twin-propeller pod propulsion device according to claim 5, characterized in that, The steering drive device (2-3) uses multiple hydraulic motors, which are supplied with oil by a hydraulic pump station (2-2).

7. A design method for a high-power polar twin-propeller pod propulsion device as described in claim 1, characterized in that, Includes the following steps: S1, preliminary design based on a single propeller; S101 clarifies the ice class requirements, class acceptance specifications, and power requirements for podded propulsion systems; S102 clarifies the efficiency requirements for open-water navigation of podded propulsion devices, the strength requirements for icebreaking navigation, and the noise requirements for silent navigation. S103. Based on the speed and power requirements for open water navigation, the propeller speed and diameter for open water navigation are initially determined. Considering efficiency requirements, strength requirements and quietness requirements, the distance between the propeller center and the rudder centerline, the propeller pitch ratio, the disk ratio and the number of blades are selected. S104. Based on the classification specifications, select the ice thickness to calculate the ice impact load and obtain the data of the maximum rearward force, maximum forward force, shaft design thrust, and blade failure load of the propeller blades in the front propeller assembly (1-5) and the rear propeller assembly (1-8) under the ice impact load. S105, calculate the maximum response torque of the ice impact load on the shaft system of the pod propulsion device according to the classification specifications, and calculate the rotational speed under the icebreaking navigation condition based on the maximum power under the icebreaking navigation condition. S106, based on the maximum power and rotational speed under icebreaking navigation conditions, the electromagnetic field and temperature field of the motor are coupled to obtain a permanent magnet motor with high power density, thus completing the motor design under icebreaking navigation conditions. S107, Complete the design of the main components of the propulsion system: Design the shaft dimensions and material selection based on the blade failure load and the maximum response torque of the shaft system; Based on the bearing arrangement scheme, select and design the thrust bearing and radial bearing according to the shaft system design thrust; Design the front blade side sealing assembly (1-4), rear blade side sealing assembly (1-7), and rotary sealing assembly (2-5) based on the shaft diameter and rotational speed; Design the cooling ventilation device (1-9) based on the temperature field; Design the slip ring (2-4) based on the electromagnetic field. S108, Complete the design of the main components of the steering body (2-1): Calculate the steering torque of the pod propulsion device based on the propeller diameter, the maximum response torque of the shaft system and the distance between the steering center and the propeller center, and design the slewing bearing assembly (2-6), the steering drive device (2-3), and the hydraulic pump station (2-2). S109, according to the ship classification code, shaft vibration verification calculations including torsional vibration, longitudinal vibration, and gyratory vibration are performed; S110, according to the ship classification code, the shaft system strength calculation, shaft system stiffness calculation, and shaft system fatigue calculation are carried out. The Weibull distribution theory and linear cumulative damage theory are used to calculate the fatigue strength of the shaft system components under ice impact load. Combined with the material SN curve, the shaft system fatigue strength is checked. S111: The fatigue strength of the propeller under ice impact load is calculated using Weibull distribution theory and linear cumulative damage theory. The fatigue strength of the propeller is verified by combining the material SN curve. S112, calculate the ice impact force and ice ridge penetration force based on the geometric parameters of the pod propulsion device, verify the strength of the propulsion device under multiple working conditions of ice impact and ice ridge penetration, and verify the propulsion component shell (1-1). S113, to perform hydrodynamic performance verification under open water navigation conditions, including speed, torque and thrust; S114, conduct noise performance verification under quiet navigation conditions, including vibration of the propulsion component housing surface and propeller noise; S2, based on a detailed design of a twin propeller; S201, using two scaled-down propellers to replace the original propeller, calculate the propeller speed N and diameter D, where the power P is proportional to N. 3 D 5 We keep N×D constant to ensure similar propulsion efficiency; S202, perform load verification: verify the maximum backward force Fb, maximum forward force Ff, blade failure load Fex, and maximum shaft response torque Qi of the propeller blades; S203, considering the rear propeller to recover the wake energy of the front propeller to improve efficiency, takes into account the design of the diameter, pitch ratio and blade misalignment angle of the front and rear propellers. S204, optimization of propeller speed, diameter, pitch ratio, and stator core outer diameter: Taking into account propulsion efficiency, propulsion unit weight, and ice impact load on the propulsion unit, the propeller speed N of the podded propulsion unit is optimized. 双桨 and diameter D 后桨 D 前桨 The propeller pitch ratio P / D 前桨 P / D 后桨 The outer diameter Ds of the stator core is optimized. S205, based on the twin-propeller scheme, optimizes the environmental adaptability design, corrosion protection design, intelligent design and maintainability design of the pod propulsion device, and completes the detailed design of the main components of the pod propulsion device; S206, based on the detailed design scheme of the podded propulsion device, update the relevant calculations and verification of the twin propellers in step S1 to ensure that the calculation and design inputs are consistent; S3, the final design based on experimental verification; S301, through pool testing, tests the hydrodynamic characteristics of the podded propulsion system and the ship's self-propulsion performance; S302, the noise characteristics of the podded propulsion device are verified by testing the sound of the propeller blades through a circulating water tank or a cavitation water tank. S303, through ice pool tests, tests the ice-breaking performance of the podded propulsion device and the hydrodynamic and anti-icing performance of the podded propulsion device under ice impact loads, and verifies the ice zone performance of the design results; S304, based on the model test data, optimize the design to complete the final design.

8. The design method of a high-power polar twin-propeller pod propulsion device according to claim 7, characterized in that, Step S1 further includes: S115, when component optimization is involved, update the optimization design in steps S104 to S108 and the verification in steps S109 to S114 to ensure consistent input; S116 If the relevant requirements cannot be met through component optimization, return to step 103 for data optimization until a preliminary design that meets the requirements is obtained.

9. The design method of a high-power polar twin-propeller pod propulsion device according to claim 8, characterized in that, In step S202, the maximum backward force Fb of the propeller blade is proportional to N. 0.7 D 2.7 The maximum forward force Ff is proportional to D 2 The blade failure load Fex is proportional to D 2 The maximum response torque Qi of the shaft system is proportional to N. 0.17 D 3.17 Therefore, Fb = 2 × Fb 双桨 Ff = 2 × Ff 双桨 Fex = 2 × Fex 双桨 Qi = (2 × Qi) 双桨 ) / 0.

72.

10. A design method for a high-power polar twin-propeller pod propulsion device according to claim 7, 8, or 9, characterized in that, In step S202, while ensuring that the propulsion power and propulsion efficiency remain unchanged, when the single-propeller scheme is replaced with the twin-propeller scheme, the speed increases by 1.412 times and the torque decreases to 71% of the original in open water navigation conditions; in icebreaking navigation conditions, the axial force of the ice impact load remains unchanged, and the axial torque of the ice impact load decreases to 72% of the original.

Images