Method for determining power required by sail lifting hydraulic cylinder

Abstract

A method for determining power required by a sail lifting hydraulic cylinder is characterized in that in order to calculate the lifting power requirement of a sail, the weight of a mast and a sail surface, the weight of a steel wire rope, a pulley block and the hydraulic cylinder, inertial load and friction force are used as load input; the time and the stroke of the hydraulic cylinder in the acceleration operation stage, the constant-speed operation stage, the deceleration operation stage and the whole-course constant-speed stage are considered, meanwhile, the pressure of the hydraulic cylinder is considered, the power requirements of all the stages are calculated, and a method for calculating the power needed by sail lifting is formed and used for designing a new ship generator or checking the power of a refitted ship generator. The operation of the hydraulic cylinder is divided into three stages, namely an acceleration operation stage, a constant-speed operation stage and a deceleration operation stage, and an assumed full-scale constant-speed operation stage is added; by calculating parameters such as the speed of the intermediate stationary stage and the time of each stage, the power demand of each stage can be quickly calculated and completed.

Description

Technical Field

[0001] The present invention belongs to the field of design and construction of ships with sails, and particularly relates to a method for determining the power required for a sail lifting hydraulic cylinder. Background Art

[0002] With the promulgation and implementation of new low-carbon emission reduction regulations globally, the global shipping and shipbuilding industries are developing towards a green direction. Marine sail devices use wind energy, a clean energy source, as the driving force. The shipbuilding group took the lead in carrying out the technical research on the world's first wing-type wind-assisted ocean-going cargo ship, breaking through a series of key technologies, including the calculation method for the power required for sail lifting.

[0003] Due to the economic requirements of the ship, generally under normal operating conditions, only one generator is operated, that is, the output power of one generator meets the power requirements of the equipment under normal operating conditions of the ship. However, with the use of sails, whether the driving power required by the sail hydraulic cylinder will exceed the output power of one generator requires accurate prediction of the power demand of the sail lifting hydraulic cylinder.

[0004] This patent aims to predict the power demand of the sail lifting hydraulic cylinder, takes the lifting weight, inertial load, friction force, etc. of the sail as the design input, calculates the power demand in each stage through the time and stroke of the hydraulic cylinder in the acceleration operation stage, the intermediate steady operation stage, and the deceleration operation stage, and at the same time considers the pressure of the hydraulic cylinder, takes the maximum value as the power required for lifting, and proposes a calculation method for the power required for sail lifting to determine whether the generator can meet the normal operating equipment and at the same time meet the lifting action of the sails. Summary of the Invention

[0005] To solve the above problems, the present invention provides a method for determining the power required for a sail lifting hydraulic cylinder, and the technical solution adopted is as follows:

[0006] A method for determining the power required for a sail lifting hydraulic cylinder, wherein the cylinder body of the hydraulic cylinder is fixed on the deck, and the sail is fixedly connected to the hydraulic rod of the hydraulic cylinder and rises and falls through the hydraulic rod.

[0007] During the lifting process of the hydraulic cylinder, driving the sail surface to rise is divided into three stages, namely the initial acceleration operation stage, the intermediate steady operation stage, and the subsequent deceleration operation stage. The friction forces in the three stages are different, and the situation with the maximum friction force is considered separately in each stage. Denote the friction force in the initial acceleration operation stage as F1, the friction force in the intermediate steady operation stage as F2, the friction force in the subsequent deceleration operation stage as F3, and at the same time denote the friction force for the whole journey at a constant speed as F4.

[0008] Let the total stroke of the hydraulic cylinder be L, the stroke of the hydraulic cylinder in the initial acceleration stage be La, and the stroke in the subsequent deceleration stage be Lb. Then the stroke of the hydraulic cylinder in the intermediate steady running stage is L - La - Lb. When the hydraulic cylinder runs from the starting position to the end point, according to the design requirements, the total running time is T, and the running time in the initial acceleration stage is t1. In the subsequent deceleration stage of the hydraulic cylinder, the running time is t2. Then the running time of the hydraulic cylinder in the intermediate steady running stage is T - t1 - t2, then

[0009]

[0010] Substituting Equation (2) into Equation (1) gives:

[0011]

[0012] In the initial acceleration stage of the hydraulic cylinder, the power of the hydraulic cylinder is equal to the product of the maximum speed and the maximum lifting force in this stage:

[0013]

[0014] In the uniform motion stage of the hydraulic cylinder, the power of the hydraulic cylinder is equal to the product of the average speed and the maximum lifting force in this stage:

[0015]

[0016] In the deceleration stage of the hydraulic cylinder, the power of the hydraulic cylinder is equal to the product of the maximum speed and the maximum lifting force in this stage:

[0017]

[0018] Assume that the hydraulic cylinder runs at a constant speed throughout the process, and the running time is T. Then the average speed is L / T. The lifting force of the hydraulic cylinder can be calculated according to the average value of the aforementioned three stages, that is, F4 = (F1 + F2 + F3) / 3, and the power is equal to the product of the average speed and the average lifting force:

[0019]

[0020]

[0021] Through the above four stages, take the maximum value of the powers in the acceleration stage of the hydraulic cylinder, the uniform motion stage of the hydraulic cylinder, the deceleration stage of the hydraulic cylinder, and the stage of the hydraulic cylinder running at a constant speed throughout the process as the selection of the final power of the hydraulic cylinder:

[0022]

[0023] Among them, M is the total mass of the structures and components to be lifted by the hydraulic cylinder.

[0024] Mg is the gravity load.

[0025] Ma is the inertial load.

[0026] Finally, the required power is obtained.

[0027] For the above method of determining the required power of the sail lifting hydraulic cylinder, further, the sail is fixed on the main deck of the ship, and its fixed position is structurally strengthened to be higher or lower than the main deck.

[0028] For the above method of determining the required power of the sail lifting hydraulic cylinder, further, the mast is divided into three sections: upper, middle and lower, and adopts a polygonal nested structure. The size of the uppermost section of the mast is the smallest, and the size of the lowermost section is the largest.

[0029] For the above method of determining the required power of the sail lifting hydraulic cylinder, further, the sail surface is divided into three sections: upper, middle and lower, and is a polygonal nested structure. The size of the lowermost section is the smallest, and the size of the uppermost section is the largest.

[0030] For the above method of determining the required power of the sail lifting hydraulic cylinder, further, each section of the mast corresponds to the sail surface one by one. The mast and the sail surface are fixed on the slewing bearing, and the rotary motor drives the slewing bearing to rotate through the pinion, and the mast and the sail surface rotate together with it.

[0031] For the above method of determining the required power of the sail lifting hydraulic cylinder, further, the fixed position of the sail is within 3000 mm higher or lower than the main deck.

[0032] The present invention divides the operation of the hydraulic cylinder into three stages: the acceleration operation stage, the uniform speed operation stage and the deceleration operation stage, and adds a hypothetical full-uniform speed operation stage; by calculating parameters such as the speed and time of each stage in the intermediate steady stage, the power requirements for each stage can be quickly calculated. Brief Description of the Drawings

[0033] Figure 1 They are schematic diagrams of each stage of the hydraulic cylinder running from the starting point to the ending point. From left to right, they are the original state of the hydraulic cylinder, the acceleration operation stage of the hydraulic cylinder, the intermediate steady stage of the hydraulic cylinder, and the deceleration operation stage of the hydraulic cylinder. Detailed Embodiment

[0034] A method for determining the required power of a sail lifting hydraulic cylinder. The sail uses the pressure difference of the outer profile to boost the ship forward. Generally, the sail is installed on the main deck of the ship. According to the specific project requirements, its installation position can be slightly higher or slightly lower than the main deck through structural strengthening, and the specific value is about within 3000 mm.

[0035] The mechanical structure of the sail is divided into a mast, a sail surface, a base, a slewing mechanism, and a lifting mechanism. The mast and the sail surface each consist of three sections, all of which are polygonal nested structures. Among them, the uppermost section of the mast has the smallest size, and the lowermost section has the largest size; on the contrary, for the sail surface, the lowermost section has the smallest size, and the uppermost section has the largest size to meet the requirements of the lifting action.

[0036] The slewing mechanism consists of a slewing base, a slewing bearing, a rotating motor, and a pinion. The lifting structure is composed of a hydraulic cylinder and a pulley block.

[0037] The mast and the sail surface are fixed on the slewing bearing. The rotating motor drives the slewing bearing to rotate through the pinion, and the mast and the sail surface rotate together with it.

[0038] The mast is lifted and lowered by the drive of the hydraulic cylinder. Each section of the mast corresponds to the sail surface one by one. When the mast completes the lifting and lowering action, it drives the sail surface to complete the lifting and lowering action together.

[0039] The sail control system can adapt to the wind field where the ship is located. According to the relative wind direction and relative wind speed, it automatically controls the rotation of the sail to provide the maximum thrust for the ship. The control interface displays the main functions of the sail, including the performance, status of the equipment, and real-time energy-saving analysis, etc. The crew can complete the control of the sail on the control panel in the cab. When an emergency occurs, manual control panels are provided near the cab and the sail to complete the emergency lowering of the sail.

[0040] As Figure 1 shown, the power of the sail lifting hydraulic cylinder needs to be considered from the following two aspects. First, when the hydraulic cylinder runs from the starting position to the end position, it is divided into three stages, namely the acceleration running stage, the uniform speed running stage, and the deceleration running stage. Calculate the power requirements for the three stages respectively; second, assume that the hydraulic cylinder runs at a uniform speed from the starting position to the end position, and calculate the power requirements during this process. Take the maximum value of the two aspects as the input for the design or verification of the generator.

[0041] In the above two aspects, the hydraulic cylinder is subject to the following loads: the gravitational load Mg of the structure and components to be lifted by the hydraulic cylinder, the inertial load Ma formed due to the ship's motion acceleration a, and the frictional force between components.

[0042] The total mass of the structure and components to be lifted by the hydraulic cylinder is M. Generally, the mass of each structural member and equipment will be given in the design drawings of the sail. By counting the total mass of these structural members and equipment, the parameter M can be obtained, and then the gravitational load is Mg. The acceleration a formed due to the ship's motion can be calculated through the formula involving information such as ship type, ship length, ship width, molded depth, draft, etc. in the specifications given by the classification society association, and then the inertial load is Ma.

[0043] The frictional force is related to the lateral force formed by the sail due to the wind. During the lifting process of the hydraulic cylinder, the sail surface of the sail is driven to rise, and the windward area increases. Therefore, the frictional forces in the aforementioned three stages are also different. Due to the three stages, the maximum frictional force is considered separately for each stage. Then, the frictional force in the initial stage is denoted as F1, the frictional force in the intermediate steady stage is denoted as F2, and the frictional force in the subsequent stage is denoted as F3. At the same time, the frictional force for the whole process at a constant speed is denoted as F4.

[0044] The sail completes the lifting action through the drive of the hydraulic cylinder. The total time requirement for the sail to lift will be clearly specified in the technical requirements, and the design party will carry out the design according to this requirement. After the design is completed, the total operating time T of the hydraulic cylinder, the time t1 in the acceleration operating stage, and the time t2 in the deceleration operating stage will be given in the design drawings.

[0045] When the hydraulic cylinder runs from the starting position to the end point, the total operating time is T. Among them, in the acceleration operating stage, the operating time is t1; in the deceleration operating stage of the hydraulic cylinder, the operating time is t2; then the operating time of the hydraulic cylinder in the constant speed operating stage is T - t1 - t2.

[0046] In the acceleration operating stage, the hydraulic cylinder gradually accelerates from a speed of 0 to the maximum speed V in this stage, and then enters the steady stage, and then always completes the operation in this stage at a speed of V. After that, it enters the deceleration stage, and the speed gradually decreases from the maximum value V to 0. That is to say, the maximum speed in the three stages is all V. By dividing the distance in the intermediate steady stage by the operating time of the hydraulic cylinder during this operation, V can be obtained.

[0047] Through the above description, the power requirements of the hydraulic cylinder in the acceleration operating stage, the constant speed operating stage, the deceleration operating stage, and the whole process at a constant speed are calculated respectively.

[0048] Obtaining V:

[0049] Let the total stroke of the hydraulic cylinder be L, the stroke of the hydraulic cylinder in the acceleration operating stage be La, and the stroke of the hydraulic cylinder in the deceleration operating stage be Lb. Then the stroke of the hydraulic cylinder in the constant speed operating stage is L - La - Lb; when the hydraulic cylinder runs from the starting position to the end point, according to the design requirements, the total operating time is T. Among them, in the acceleration operating stage, the operating time is t1; in the deceleration operating stage of the hydraulic cylinder, the operating time is t2; then the operating time of the hydraulic cylinder in the constant speed operating stage is T - t1 - t2. Then

[0050]

[0051] Among them

[0052] Substituting Equation (2) into Equation (1) gives:

[0053]

[0054] Accelerating operation stage of the hydraulic cylinder

[0055] In this stage, the power of the hydraulic cylinder is equal to the product of the maximum speed and the maximum lifting force in this stage.

[0056]

[0057] Constant-speed operation stage of the hydraulic cylinder

[0058] In this stage, the power of the hydraulic cylinder is equal to the product of the average speed and the maximum lifting force in this stage.

[0059]

[0060] Decelerating operation stage of the hydraulic cylinder

[0061] In this stage, the power of the hydraulic cylinder is equal to the product of the maximum speed and the maximum lifting force in this stage.

[0062]

[0063] Full-course constant-speed section of the hydraulic cylinder

[0064] If it is assumed that the hydraulic cylinder runs at a constant speed throughout the whole process and the running time is T, then the average speed is L / T; and the lifting force of the hydraulic cylinder can be calculated according to the average value of the aforementioned three stages, that is, F4 = (F1 + F2 + F3) / 3, and the power is equal to the product of the average speed and the average lifting force.

[0065]

[0066] Obtaining the final power of the hydraulic cylinder

[0067] Through the above four stages, take the maximum value of the powers in the accelerating operation stage, constant-speed operation stage, decelerating operation stage and full-course constant-speed section of the hydraulic cylinder as the selection of the final power of the hydraulic cylinder.

[0068]

[0069] In summary, the requirements of each stage of the sail hydraulic cylinder during lifting can be determined, and the calculation of the required power can be completed.

Claims

1. A method for determining the power required by a sail raising and lowering hydraulic cylinder, characterized in that: The cylinder body of the hydraulic cylinder is fixed on the deck, and the sail is fixedly connected to the hydraulic rod of the hydraulic cylinder and is raised and lowered by the hydraulic rod; During the lifting process of the hydraulic cylinder, the lifting of the sail surface is divided into three stages, namely the initial acceleration stage, the intermediate stable operation stage and the subsequent deceleration stage. The friction forces in the three stages are different. The maximum friction force is considered in each stage. The friction force in the initial acceleration stage is F1, the friction force in the intermediate stable operation stage is F2, and the friction force in the subsequent deceleration stage is F3. At the same time, the friction force at a uniform speed throughout the whole process is F4. Assume that the total stroke of the hydraulic cylinder is L, the stroke of the hydraulic cylinder in the initial acceleration stage is La, and the stroke in the subsequent deceleration stage is Lb, then the stroke of the hydraulic cylinder in the intermediate stable operation stage is L-La-Lb; when the hydraulic cylinder runs from the starting position to the end point, according to the design requirements, the total running time is T, of which the running time from the initial acceleration stage is t1; in the subsequent deceleration stage of the hydraulic cylinder, its running time is t2; then the running time of the hydraulic cylinder in the intermediate stable operation stage is T-t1-t2, then Substituting formula (2) into formula (1), we can obtain: During the initial acceleration phase of the hydraulic cylinder, the power of the hydraulic cylinder is equal to the product of the maximum speed and the maximum lifting force during this phase: During the uniform speed operation stage of the hydraulic cylinder, the power of the hydraulic cylinder is equal to the product of the average speed and the maximum lifting force in this stage: During the hydraulic cylinder deceleration operation stage, the power of the hydraulic cylinder is equal to the product of the maximum speed and the maximum lifting force in this stage: Assuming that the hydraulic cylinder has a uniform speed throughout the entire process and the running time is T, the average speed is L / T; and the lifting force of the hydraulic cylinder can be calculated according to the average value of the above three stages, that is, F4 = (F1 + F2 + F3) / 3, and the power is equal to the product of the average speed and the average lifting force: Through the above four stages, the maximum values ​​of the power of the hydraulic cylinder acceleration stage, the hydraulic cylinder uniform speed stage, the hydraulic cylinder deceleration stage and the hydraulic cylinder uniform speed stage throughout the hydraulic cylinder are taken as the final hydraulic cylinder power selection: Where M is the total mass of the structure and components to be lifted by the hydraulic cylinder; Mg is the gravity load; Ma is the inertia load; Finally the required power is obtained.

2. A method for determining the power required by a sail lifting cylinder according to claim 1, characterized in that: The sail is fixed to the main deck of the ship, and its fixed position is above or below the main deck through structural reinforcement.

3. A method for determining the power required by a sail lifting hydraulic cylinder according to claim 1, characterized in that: The mast is divided into three sections: upper, middle and lower, and adopts a polygonal nested structure. The top section of the mast is the smallest and the bottom section is the largest.

4. A method for determining the power required by a sail lifting cylinder according to claim 1, characterized in that: The sail surface is divided into three sections: upper, middle and lower. It is a polygonal nested structure, with the bottom section being the smallest and the top section being the largest.

5. A method for determining the power required by a sail lifting hydraulic cylinder according to claim 1, characterized in that: Each section of the mast corresponds to the sail surface one by one. The mast and the sail surface are fixed on a slewing bearing. The rotary motor drives the slewing bearing to rotate through a pinion, and the mast and the sail surface rotate together with it.

6. A method for determining the power required by a sail lifting hydraulic cylinder according to claim 2, characterized in that: The sail fixing position is within 3000mm above or below the main deck.

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