Hydrodynamic analysis method of wave energy device based on arbitrary layout

Abstract

The present invention discloses a method for analyzing the hydrodynamic force of a wave energy device based on an arbitrary arrangement form, comprising: arbitrarily selecting a first floating body in a multi-floating body array; I and second floating body J ; Establish a fixed coordinate system according to the connection relationship between the first floating body and the second floating body; Establish a rotating coordinate system according to the positional relationship between the first floating body and the second floating body after rotation, and solve the new coordinates of the hinge point in the rotating coordinate system; Calculate the displacement limit constraint matrix according to the coordinates of the hinge point and the displacement continuity condition, and establish the frequency domain motion equation of the multi-floating body; Solve the relative pitch angle of the two objects according to the projection relationship of each degree of freedom vector; Solve the energy generation efficiency of the device according to the relative pitch angle. This application is not limited to any form of floating body, and can solve the constraint matrix of the float and platform of any complex arrangement of wave energy device and the relative pitch angle solution problem to improve the energy efficiency of the wave energy device.

Description

Technical Field

[0001] The invention relates to the technical field of hydrodynamic analysis, and in particular to a hydrodynamic analysis method for a wave energy device based on an arbitrary arrangement form. Background Art

[0002] In the context of the gradual consumption of fossil fuels and the deterioration of the ecological environment in the world today, wave energy has become an indispensable part of the development of global renewable energy with its advantages of no land occupation, wide distribution of resources, high mining prospects, sustainable use and green environmental protection. It is a hot research direction and frontier topic in the current international energy field. However, problems such as low wave energy conversion efficiency and equipment reliability have always been key obstacles to the upgrading of the scientific and technological system of wave energy devices and the high-quality development of wave energy development. At present, some scholars have proposed the concept and solution of dynamic compensation that integrates wave energy devices with carrier platforms to achieve cost sharing, space sharing and synergy between traditional marine structures and wave energy devices, and to improve the energy conversion efficiency of wave energy devices and the competitiveness of advanced marine equipment. At the same time, this has also brought new challenges and higher requirements to scientific and innovative research in the fields of wave energy development array and platform coupling. This requires the analysis of the hydrodynamic characteristics (motion response, energy capture efficiency) of floating platforms and array wave energy floats under wave action, and provides scientific guidance for the structural design and deployment of wave energy devices.

[0003] For wave energy devices in which floating platforms and array wave energy floats are hinged under arbitrary complex layout conditions, the structural form is novel and the multi-body hinge relationship is complex. The study of its hydrodynamic performance has always been a hot issue at the academic frontier. During the wave propagation process, the hinge relationship constraint matrix and relative angular displacement of the wave energy device under arbitrary layout conditions will undergo new changes, thereby affecting the energy efficiency of the device. Therefore, in view of the above status quo, it is urgent to develop a complete calculation method that can characterize the relative displacement calculation of the hinge between the floating platform and the array wave energy float under arbitrary complex layout conditions. It is particularly important to solve the analysis method of the hydrodynamic system of complex multi-body structures to overcome the shortcomings in current practical applications. Summary of the invention

[0004] Therefore, the purpose of the present invention is to provide a hydrodynamic analysis method for a wave energy device based on an arbitrary arrangement form, which can solve the analysis of the hydrodynamic system of a complex multi-body structure to improve the energy efficiency of the wave energy device.

[0005] In order to achieve the above object, a method for hydrodynamic analysis of a wave energy device based on any arrangement form of the present invention comprises the following steps:

[0006] S1. Randomly select the first float in the multi-float array I and second floating body J;

[0007] S2, establishing a fixed coordinate system according to the connection relationship between the first floating body and the second floating body; establishing a rotating coordinate system according to the positional relationship between the first floating body and the second floating body after rotation, and solving the new coordinates of the hinge point in the rotating coordinate system;

[0008] S3. According to the coordinates of the hinge points and the displacement continuity conditions, the displacement limit constraint matrix is ​​calculated and the frequency domain motion equation of the multi-floating body is established;

[0009] S4, solving the frequency domain motion equations of multiple floating bodies to obtain the motion response of each degree of freedom, and solving the relative pitch angle of the two objects according to the projection relationship of the degree of freedom vector;

[0010] S5. Calculate the energy generation efficiency of the device based on the relative pitch angle.

[0011] Further preferably, the first floating body is a floating platform, and the second floating body is a float arbitrarily selected from a multi-float array; the first floating body and the second floating body are hingedly or rigidly connected.

[0012] Further preferably, in S2, establishing the fixed coordinate system and the rotating coordinate system includes:

[0013] Set the initial fixed coordinate system of the first floating body and the second floating body to o-xyz ;

[0014] The midpoint connecting the first floating body and the second floating body is used as the coordinate origin to establish a rotating coordinate system ; wherein the x′ axis completely coincides with the connecting axis of the first floating body and the second floating body, The ' plane is perpendicular to the connection axis and completely coincides with the cross section of the connection axis in the tangent direction of the connection point; the three coordinate axes x', y', and z' are arranged perpendicular to each other; the positive angle between the projection of the x' axis and the positive direction of the x axis is defined as θ; the x' axis and The plane angle is defined as ψ , Axis and plane The angle is 。

[0015] Further preferably, the step of solving the new coordinates of the hinge point in the rotating coordinate system in S2 includes:

[0016] The midpoint of the connection between the first floating body I and the second floating body J is set as the reference point P; the coordinates of the reference point in the fixed coordinate system are The new coordinates of the reference point P after the relative motion between the first floating body I and the second floating body J are ; The translation displacement of the first floating body I is set in the fixed coordinate system , the corner is , the translational displacement of the second floating body J is and the corner is ;

[0017] Then the approximate solution of the hinge point coordinates at a small rotation angle after the first floating body I moves is:

[0018]

[0019] Second floating body J Approximate solution of the hinge point coordinates under small rotation angle after movement:

[0020]

[0021] Further preferably, in S3, it also includes calculating the constraint matrix of the first floating body according to the hinge point coordinates and the displacement continuity condition. and the constraint matrix of the second floating body ;

[0022] According to the approximate solution of the hinge point coordinates under a small rotation angle after the movement of the first floating body I, and the approximate solution of the hinge point coordinates under a small rotation angle after the movement of the second floating body J; and at the hinge point, the displacements of the first floating body and the second floating body on both sides satisfy the linear displacement continuity and angular displacement continuity, it can be obtained:

[0023]

[0024] Further preferably, the matrix constructed in the multi-float array is also included and After integration, the complete constraint matrix of the multi-floating array is formed [D];

[0025]

[0026] Further preferably, the frequency domain motion equation of the multi-floating body is expressed by the following formula:

[0027]

[0028] Where [Fe] represents the global stiffness matrix of the floating system; is the displacement vector of each floating body in the floating system; F is the external force vector applied to the multi-floating system; [D] is the constraint matrix; [K] is the overall stiffness matrix of the floating system.

[0029] Further preferably, according to the relative rotation angle relationship in the frequency domain motion equation of the multi-floating body and the vector projection of the corresponding roll, pitch and yaw degrees of freedom in the pitch degree of freedom direction, the relative pitch rotation angle between the first floating body and the second floating body is calculated according to the following formula:

[0030]

[0031] Further preferably, in S5, according to the relative pitch angle, solving the energy generation efficiency of the device includes calculating the average wave energy capture efficiency according to the following formula;

[0032] The average wave energy capture efficiency in the floating system is

[0033] in, Pincident represents the incident power of a single-width wave; Ptotal In floating system m The total power generated by the wave energy device.

[0034] The hydrodynamic analysis method of a wave energy device based on an arbitrary arrangement form disclosed in the present application has at least the following advantages compared to the prior art:

[0035] 1. This application is not limited to any form of floating body, and can solve the problem of solving the constraint matrix of float and platform of wave energy device with any complex arrangement and relative pitch angle;

[0036] 2. It can realize the calculation of hydrodynamic parameters and optimization of energy capture efficiency of any complex arrangement of wave energy devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic flow chart of a hydrodynamic analysis method for a wave energy device based on any arrangement provided by the present invention.

[0038] Figure 2 A schematic diagram of the position distribution of the first floating body and the second floating body provided by the present invention.

[0039] Figure 3 This is a schematic diagram of the rotating coordinate system provided by the present invention. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below through the accompanying drawings and specific embodiments.

[0041] like Figure 1 As shown, an embodiment of one aspect of the present invention provides a method for analyzing hydrodynamic force of a wave energy device based on any arrangement form, comprising the following steps:

[0042] S1. Randomly select the first float in the multi-float array I and second floating body J ;

[0043] S2, establishing a fixed coordinate system according to the connection relationship between the first floating body and the second floating body; establishing a rotating coordinate system according to the positional relationship between the first floating body and the second floating body after rotation, and solving the new coordinates of the hinge point in the rotating coordinate system;

[0044] S3. According to the coordinates of the hinge points and the displacement continuity conditions, the displacement limit constraint matrix is ​​calculated and the frequency domain motion equation of the multi-floating body is established;

[0045] S4, solving the frequency domain motion equations of multiple floating bodies to obtain the motion response of each degree of freedom, and solving the relative pitch angle of the two objects according to the projection relationship of the degree of freedom vector;

[0046] S5. According to the relative pitch angle, solve the energy generation efficiency and motion state of the device.

[0047] like Figure 2 As shown, the first floating body is a floating platform, and the second floating body is a float randomly selected from a multi-float array; the first floating body and the second floating body are hinged or rigidly connected.

[0048] The multi-floating array layout system was studied in the global coordinate system, and a unified rotation center was adopted. First, select any of the multiple float arrays I and J Two objects are numbered 1 and 2 respectively. First, any two objects in the array are processed, and then any two objects on the array are matrix constructed. and ,Finally, all the matrix blocks are integrated into a total matrix to form a complete ,constraint matrix.

[0049] In S2, establishing a fixed coordinate system and a rotating coordinate system includes:

[0050] Set the initial fixed coordinate system of the first floating body and the second floating body to o-xyz ;

[0051] like Figure 3 As shown, the midpoint connecting the first floating body and the second floating body is taken as the coordinate origin to establish a rotating coordinate system ;in, x′ The axis completely coincides with the connecting axis of the first floating body and the second floating body. The plane is perpendicular to the connection axis and completely coincides with the cross section of the connection axis in the tangent direction at the connection point; x′,y′,z′ The three coordinate axes are arranged perpendicular to each other. x′ Axis projection and x The positive angle of the axis positive angle is defined as θ ; x′ Axis and The angle between the two planes is defined as ψ, Axis and plane The angle is ;

[0052] Solve the new coordinates of the hinge point in the rotating coordinate system, including:

[0053] The midpoint of the connection between the first floating body I and the second floating body J is set as the reference point P; the coordinates of the reference point in the fixed coordinate system are The new coordinates of the reference point P after the relative motion between the first floating body I and the second floating body J are ; The translation displacement of the first floating body I is set in the fixed coordinate system , the corner is , the translational displacement of the second floating body J is and the corner is ;

[0054] Then the approximate solution of the hinge point coordinates at a small rotation angle after the first floating body I moves is:

[0055] Formula (1)

[0056] Second floating body J Approximate solution of the hinge point coordinates under small rotation angle after movement:

[0057] Formula (2)

[0058] In S3, it also includes calculating the constraint matrix of the first floating body according to the coordinates of the hinge point and the displacement continuity condition. and the constraint matrix of the second floating body ;

[0059] According to the approximate solution of the hinge point coordinates under a small rotation angle after the movement of the first floating body I, and the approximate solution of the hinge point coordinates under a small rotation angle after the movement of the second floating body J; and at the hinge point, the displacements of the first floating body and the second floating body on both sides satisfy the linear displacement continuity and the angular displacement continuity,

[0060] The displacements on both sides should satisfy the linear displacement continuity and angular displacement continuity:

[0061] Formula (3)

[0062] We can get:

[0063] Formula (4)

[0064] Displacement Constraint Matrix Depend on and composition. express I Object acts on the floating J On the object, it can be expressed as:

[0065] Formula (5)

[0066] Indicates that the Jth object of the floating platform acts on the Ith On an object, it can be expressed as:

[0067] Formula (6)

[0068] After integration, the complete constraint matrix of the multi-floating array is formed [D]

[0069] Formula (7)

[0070] According to the frequency domain motion equations of articulated multi-floating bodies;

[0071] Formula (8)

[0072] Where [Fe] represents the global stiffness matrix of the floating system; is the displacement vector of each floating body in the floating system; F is the external force vector applied to the multi-floating system; [D] is the constraint matrix; [K] is the overall stiffness matrix of the floating system;

[0073] No. i The power generation capacity of a wave energy device is:

[0074] Formula (9)

[0075] Where: For the i The relative rotation angle of each buoy in the pitch direction with respect to the floating breakwater to which it is hinged; is the wave frequency; For the i A float in The power generated at the frequency.

[0076] According to the relative rotation angle relationship in the frequency domain motion equation of multiple floating bodies and the vector projection of the roll, pitch and bow freedom motion in the pitch freedom direction, the specific formula for the relative pitch of the floating platform and the float is as follows:

[0077]

[0078] Due to this Formula = 0

[0079] Formula (10)

[0080] The incident power of a single-width wave is:

[0081] Formula (11)

[0082] Where: Ais the amplitude of the incident wave, which is taken as 1m in this paper.

[0083] The wave energy capture efficiency of a single wave energy device is:

[0084] Formula (12)

[0085] Where: B It is the width of the wave energy device facing the waves.

[0086] The average wave energy capture efficiency in the floating system is:

[0087] Formula (13)

[0088] In floating system m The total power generation of the wave energy device is:

[0089] Formula (14)

[0090] Obviously, the above embodiments are only examples for clear explanation, and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from them are still within the protection scope of the invention.

Claims

1. A method for hydrodynamic analysis of wave energy devices based on arbitrary arrangement forms, characterized in that: S1. Randomly select the first float in the multi-float array I and second floating body J ; S2, establishing a fixed coordinate system according to the connection relationship between the first floating body and the second floating body; establishing a rotating coordinate system according to the positional relationship between the first floating body and the second floating body after rotation, and solving the new coordinates of the hinge point in the rotating coordinate system; Set the initial fixed coordinate system of the first floating body and the second floating body to o-xyz ; The midpoint connecting the first floating body and the second floating body is used as the coordinate origin to establish a rotating coordinate system ;in, x′ The axis completely coincides with the connecting axis of the first floating body and the second floating body. The plane is perpendicular to the connection axis and completely coincides with the cross section of the connection axis in the tangent direction at the connection point; x′,y′,z′ The three coordinate axes are arranged perpendicular to each other. x′ Axis projection and x The positive angle of the axis positive angle is defined as θ ; x′ Axis and o-xy The plane angle is defined as ψ , y′ Axis and plane o-xy The angle is ； The step of solving the new coordinates of the hinge point in the rotating coordinate system includes: The midpoint of the connection between the first floating body I and the second floating body J is set as the reference point P; the coordinates of the reference point in the fixed coordinate system are The new coordinates of the reference point P after the relative motion between the first floating body I and the second floating body J are ; The translation displacement of the first floating body I is set in the fixed coordinate system , the corner is , the translational displacement of the second floating body J is and the corner is ; Then the approximate solution of the hinge point coordinates at a small rotation angle after the first floating body I moves is: Second floating body J Approximate solution of the hinge point coordinates under small rotation angle after movement: ； S3. According to the coordinates of the hinge points and the displacement continuity conditions, the displacement limit constraint matrix is ​​calculated and the frequency domain motion equation of the multi-floating body is established; S4, solving the frequency domain motion equations of multiple floating bodies to obtain the motion response of each degree of freedom, and solving the relative pitch angle of the two objects according to the projection relationship of the degree of freedom vector; S5. Calculate the energy generation efficiency of the device based on the relative pitch angle.

2. The hydrodynamic analysis method of a wave energy device based on any arrangement according to claim 1, characterized in that: The first floating body is a floating platform, and the second floating body is a float randomly selected from a multi-float array; the first floating body and the second floating body are hinged or rigidly connected.

3. The hydrodynamic analysis method of a wave energy device based on any arrangement according to claim 1, characterized in that: In S3, it also includes calculating the constraint matrix of the first floating body according to the coordinates of the hinge point and the displacement continuity condition. and the constraint matrix of the second floating body ; According to the approximate solution of the hinge point coordinates under a small rotation angle after the movement of the first floating body I, and the approximate solution of the hinge point coordinates under a small rotation angle after the movement of the second floating body J; and at the hinge point, the displacements of the first floating body and the second floating body on both sides satisfy the linear displacement continuity and angular displacement continuity, it can be obtained: 。 4. The hydrodynamic analysis method of a wave energy device based on any arrangement according to claim 3 is characterized in that , including the matrix constructed from the multi-float array and After integration, the complete constraint matrix of the multi-floating array is formed [D]; 。 5. The hydrodynamic analysis method of a wave energy device based on any arrangement according to claim 4, characterized in that: The frequency domain motion equation of the multi-floating body is expressed by the following formula: Where, [Fe] represents the overall stiffness matrix of the floating system; { } is the displacement vector of each floating body in the floating system; F is the external force vector applied to the multi-floating system; [D] is the constraint matrix; [K] is the overall stiffness matrix of the floating system.

6. The method for hydrodynamic analysis of wave energy devices based on arbitrary arrangement forms according to claim 5, characterized in that: According to the relative rotation angle relationship in the frequency domain motion equation of multiple floating bodies and the vector projection of the corresponding roll, pitch and bow freedom motion in the pitch freedom direction, the relative pitch rotation angle between the first floating body and the second floating body is calculated according to the following formula: 。 7. The method for hydrodynamic analysis of wave energy devices based on arbitrary arrangement forms according to claim 1, characterized in that: In S5, according to the relative pitch angle, solving the energy generation efficiency of the device, including calculating the average wave energy capture efficiency according to the following formula; The average wave energy capture efficiency in the floating system is ; in, Pincident represents the incident power of a single-width wave; Ptotal In floating system m The total power generated by the wave energy device.

Images