A method for calculating hydrodynamic parameters of dynamic steering of spoiler fins

Abstract

The invention provides a method for calculating the hydrodynamic parameters of a dynamic steering of a spoiler, and relates to the technical field of ship control. The invention comprises the following steps: step 1, constructing a geometric model; step 2, establishing a viscous flow CFD numerical calculation model; step 3, numerical calculation; step 4, calculating the local hydrodynamic parameters of the spoiler. The method for calculating the hydrodynamic parameters of the dynamic steering of a spoiler of the invention establishes a two-dimensional dynamic steering numerical model of the spoiler, obtains the global hydrodynamic parameters of the spoiler during the dynamic steering process, and converts and obtains the time-varying curve of the local hydrodynamic parameters of the spoiler by establishing a calculation method for the local hydrodynamic parameters of the spoiler, so as to realize the effective acquisition of the hydrodynamic parameters of the spoiler during the dynamic steering process.

Description

Technical Field

[0001] The invention relates to the technical field of ship control, in particular to a method for calculating hydrodynamic parameters of a dynamic steering spoiler. Background Art

[0002] The maneuverability of a ship is ensured by the rudder, and the performance of the rudder is crucial to the safety of the ship's navigation. The ship needs to steer during navigation to achieve steering or maintain heading stability. The hydrodynamic performance of the ship's rudder during dynamic steering has significant non-steady-state characteristics, which has a significant impact on the performance and safety of the rudder. The Chinese patent document with publication number CN113401327A discloses a cooperatively controlled ship spoiler rudder, which arranges two independent spoilers on both sides of the trailing edge of the rudder blade, and the opening and closing of the two spoilers are controlled by a drive device; the opening angle of the spoiler is adjusted based on the incoming flow speed and the rudder angle to significantly improve the rudder performance.

[0003] The existence of spoilers makes the overall structure of the rudder more complex. The existing potential flow theory method is not suitable for predicting the hydrodynamic performance of complex structures, and the viscous flow CFD method is difficult to directly capture the local force of the spoiler under dynamic steering. In summary, a method to accurately monitor the global force of the spoiler rudder under dynamic steering and the calculation method of the local force of the spoiler needs to be proposed. Summary of the invention

[0004] The invention provides a method for calculating hydrodynamic parameters of a spoiler rudder under dynamic steering, so as to solve the technical problem that the hydrodynamic parameters of the spoiler rudder under dynamic steering are difficult to monitor.

[0005] In order to achieve the above object, the technical solutions adopted by the present invention are as follows:

[0006] A method for calculating hydrodynamic parameters of a dynamic steering spoiler, the method comprising the following steps:

[0007] Step 1: Build the geometry model

[0008] Determine the spoiler rudder type value parameters according to the target task. The spoiler rudder includes a rudder blade, a rudder stock, a first spoiler and a second spoiler. The rudder stock is set at the leading edge of the rudder blade, and the left side of the trailing edge of the rudder blade is connected to the first spoiler by rotation, and the right side of the trailing edge of the rudder blade is connected to the second spoiler by rotation. When the spoiler rudder is dynamically steered, the spoiler on the upstream surface is opened, and the spoiler on the downstream surface is in a closed state. Considering the symmetry of the spoiler rudder steering to the left and right, only the opening of the first spoiler is considered. The opening angle of the first spoiler is determined according to the calculation conditions, and the rudder blade and the first spoiler are integrated into a model without considering the influence of the rudder stock.

[0009] Step 2: Establish a viscous flow CFD numerical calculation model

[0010] Use the geometric model constructed in step 1 to import the viscous flow CFD software to build the calculation domain, set the global coordinate system, motion conditions and boundary conditions, and determine the optimal grid division strategy and time step based on the selected turbulence model;

[0011] Step 3: Numerical calculation

[0012] Using the viscous flow CFD numerical calculation model established in step 2, obtain the time-varying results of the hydrodynamic parameters of the spoiler rudder and the first spoiler relative to the global coordinate system;

[0013] Step 4: Calculation of local hydrodynamic parameters of spoiler

[0014] A calculation method for the local hydrodynamic parameters of the spoiler is established based on the relative position of the spoiler and the global coordinate system, and the time-varying curve of the local hydrodynamic parameters of the spoiler is obtained.

[0015] Furthermore, the specific steps of step 2 are as follows:

[0016] Step 21, construct a two-dimensional calculation domain based on the three-dimensional geometric model, set the global coordinate system O-XY, whose origin O is located on the rudder section chord line, the X-axis points to the downstream, and the Y-axis points to the right side of the upstream direction; the entire calculation domain rotates rightward around the origin O at a set rotation speed ω to simulate the dynamic steering effect, and the angle between the X-axis and the rudder section chord line is the instantaneous rudder angle α; during the right steering process, the front boundary and the left boundary of the calculation domain are upstream boundaries, and their boundary conditions are set as velocity inlets, while the rear boundary and the right boundary are backflow boundaries, and their boundary conditions are set as pressure outlets;

[0017] Step 22: Divide the computational domain into grids with a proportional By changing the grid size, three sets of grids are obtained. The three sets of grids have the same bottom layer thickness of the boundary layer. The total thickness of the boundary layer is adjusted only by changing the number of boundary layers, so that the total thickness of the boundary layer is equal to the grid size of the rudder section surface. The turbulence model is used to carry out static grid independence analysis to obtain the optimal grid division strategy, and the time step convergence analysis is carried out to determine the optimal unsteady time step at the maximum steering speed.

[0018] Further, in step 3, the hydrodynamic parameters of the spoiler relative to the global coordinate system include the resistance D along the X-axis direction, the lift L along the Y-axis direction, and the steering moment M around the origin O; the hydrodynamic parameters of the first spoiler relative to the global coordinate system include the moment M borne by the first spoiler relative to the origin O s0 And the force F along the X-axis and Y-axis respectively x and F y .

[0019] Furthermore, the specific steps of step 4 are as follows:

[0020] According to the component force F along the X-axis and Y-axis directions borne by the first spoiler x and F y , the resultant force F and the action direction angle ε of the resultant force F borne by the first spoiler are calculated, where the action direction angle ε of the resultant force F is the angle between the resultant force F and the X-axis. The expressions of the resultant force F and the action direction angle ε of the resultant force F are:

[0021]

[0022] ε=arctan(F y / F x );

[0023] According to the resultant force F and the moment M borne by the first spoiler s0 Calculate the force arm L of the resultant force F relative to the origin O. The calculation expression of the force arm L is:

[0024] L=M s0 / F;

[0025] According to the resultant force F and the arm l of the resultant force F relative to the front end point o of the first spoiler, the moment M of the first spoiler relative to its front end point o is calculated. s , the expression is:

[0026] M s =F×l;

[0027] In the formula,

[0028] The expression of the force arm l of the first spoiler relative to its front end point o is:

[0029] l=Ll Oo ×sin(α+ε+δ);

[0030] Among them, l Oo is the distance between the front end point o of the first spoiler and the origin O, δ is l Oo The angle between the straight line and the chord line of the rudder section.

[0031] The beneficial technical effects of the present invention are:

[0032] The method for calculating the hydrodynamic parameters of the dynamic steering of the spoiler of the present invention establishes a two-dimensional dynamic steering numerical model of the spoiler, obtains the global hydrodynamic parameters of the spoiler during the dynamic steering process, and establishes a method for calculating the local hydrodynamic parameters of the spoiler to convert and obtain the time-varying curve of the local hydrodynamic parameters of the spoiler, so as to achieve effective acquisition of the hydrodynamic parameters of the spoiler during the dynamic steering process. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the flow chart of the method for calculating hydrodynamic parameters of a dynamic steering spoiler according to an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the structure of a spoiler fin, which is a research object of an embodiment of the present invention;

[0035] Figure 3 A schematic diagram of the structure of a geometric model constructed for an embodiment of the present invention;

[0036] Figure 4 A schematic diagram of a calculation domain, motion conditions and boundary conditions according to an embodiment of the present invention;

[0037] Figure 5a , Figure 5b , Figure 5c and Figure 5d A schematic diagram of grid division according to an embodiment of the present invention;

[0038] Figure 6a , Figure 6b , Figure 6c , Figure 6d , Figure 6e and Figure 6f Schematic diagram of hydrodynamic parameters of a spoiler relative to a global coordinate system according to an embodiment of the present invention;

[0039] Figure 7 A schematic diagram of the definition of relevant variables for calculating the local hydrodynamic parameters of a spoiler according to an embodiment of the present invention;

[0040] Figure 8 Schematic diagram of the moment of the first spoiler relative to its front end point according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and beneficial effects of the present invention more clearly understood, the present invention is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings. Certain embodiments of the present invention will be described more comprehensively with reference to the accompanying drawings, in which some but not all embodiments will be shown. In fact, the various embodiments of the present invention can be implemented in many different forms and should not be construed as being limited to the embodiments described herein; rather, these embodiments are provided so that the present invention meets applicable legal requirements.

[0042] In the description of the present invention, it should be noted that the terms "inside", "outside", "upper", "lower", "front", "back" and the like indicate directions or positional relationships based on directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0043] Please refer to Figures 1 to 8 As shown, a method for calculating hydrodynamic parameters of a spoiler dynamic steering comprises the following steps:

[0044] Step 1: Build the geometry model

[0045] Determine the spoiler rudder type value parameters according to the target task, such as Figure 2 As shown, the spoiler comprises a rudder blade 1, a rudder stock 2, a first spoiler 3 and a second spoiler 4. The rudder stock 2 is arranged at the leading edge of the rudder blade 1, the left side of the trailing edge of the rudder blade 1 is connected to the first spoiler 3 by rotation, and the right side of the trailing edge of the rudder blade 1 is connected to the second spoiler 4 by rotation. When the spoiler is dynamically steered, the spoiler on the upstream surface is opened, and the spoiler on the downstream surface is in a closed state. Considering the symmetry of the spoiler steering to the left and right, only the opening of the first spoiler 3 is considered, and the opening angle of the first spoiler 3 is determined according to the calculation conditions. The rudder blade 1 and the first spoiler 3 are integrated and modeled, and the influence of the rudder stock 2 is not considered. The geometric model used for calculation is as follows: Figure 3 shown.

[0046] Step 2: Establish a viscous flow CFD numerical calculation model

[0047] Use the geometric model constructed in step 1 to import the viscous flow CFD software to build the calculation domain, set the global coordinate system, motion conditions and boundary conditions, and determine the optimal grid division strategy and time step based on the selected turbulence model.

[0048] The specific steps of step 2 are as follows:

[0049] Step 21: Construct a two-dimensional computational domain based on the three-dimensional geometric model, such as Figure 4 As shown in the figure, a global coordinate system O-XY is set, with its origin O located on the chord line of the rudder section, the X-axis pointing downstream, and the Y-axis pointing to the right of the upstream direction; the entire calculation domain rotates rightward around the origin O at a set rotation speed ω to simulate the dynamic steering effect, and the angle between the X-axis and the chord line of the rudder section is the instantaneous rudder angle α; during the right steering process, the front boundary and the left boundary of the calculation domain are upstream boundaries, and their boundary conditions are set as velocity inlet, while the rear boundary and the right boundary are backflow boundaries, and their boundary conditions are set as pressure outlet;

[0050] Step 22: Divide the computational domain into grids, such as Figure 5a As shown in d, the ratio The grid size is changed to obtain three sets of grids. Since the thickness of the first boundary layer is determined by the adopted turbulence model, the three sets of grids have the same thickness of the bottom layer of the boundary layer. The total thickness of the boundary layer is adjusted only by changing the number of boundary layers, so that the total thickness of the boundary layer is equal to the grid size of the rudder section surface. The SST k-ω turbulence model is used to carry out static grid independence analysis to obtain the optimal grid division strategy, and the time step convergence analysis is carried out to determine the optimal unsteady time step at the maximum steering speed.

[0051] Step 3: Numerical calculation

[0052] The viscous flow CFD numerical calculation model established in step 2 is used to obtain the time-varying results of the hydrodynamic parameters of the spoiler rudder and the first spoiler 3 relative to the global coordinate system.

[0053] In step 3, the hydrodynamic parameters of the spoiler relative to the global coordinate system include the resistance D along the X-axis direction, the lift L along the Y-axis direction, and the steering moment M around the origin O; the hydrodynamic parameters of the first spoiler 3 relative to the global coordinate system include the moment M borne by the first spoiler 3 relative to the origin O s0 And the force F along the X-axis and Y-axis respectively x and F y During dynamic steering, L, D, M, M s0 、F x 、F y The results of the time-varying changes are as follows Figure 6a As shown in f, Figure 6a To f in C L , C D , C M CM s0 CF x and CF y L, D, M, M respectively s0 、F x 、F y The dimensionless form of .

[0054] Step 4: Calculation of local hydrodynamic parameters of spoiler

[0055] Based on the relative position of the spoiler and the global coordinate system, a calculation method for the local hydrodynamic parameters of the spoiler is established, and the time-varying curve of the local hydrodynamic parameters of the corresponding spoiler is obtained. The relevant variables are defined as follows: Figure 7 shown.

[0056] The specific steps of step 4 are as follows:

[0057] According to the component force F along the X-axis and Y-axis directions borne by the first spoiler 3 x and F y , the resultant force F borne by the first spoiler 3 and the action direction angle ε of the resultant force F are calculated, wherein the action direction angle ε of the resultant force F is the angle between the resultant force F and the X-axis. The expressions of the resultant force F and the action direction angle ε of the resultant force F are:

[0058]

[0059] ε=arctan(F y / F x );

[0060] According to the resultant force F and the moment M borne by the first spoiler 3 s0 Calculate the force arm L of the resultant force F relative to the origin O. The calculation expression of the force arm L is:

[0061] L=M s0 / F;

[0062] According to the resultant force F and the arm l of the resultant force F relative to the front end point o of the first spoiler 3, the moment M of the first spoiler 3 relative to its front end point o is calculated. s , the expression is:

[0063] M s =F×l;

[0064] In the formula,

[0065] The expression of the force arm l of the first spoiler 3 relative to its front end point o is:

[0066] l=Ll Oo ×sin(α+ε+δ);

[0067] Among them, l Oo is the distance between the front end point o of the first spoiler 3 and the origin O, δ is l Oo The angle between the straight line and the chord line of the rudder section.

[0068] based on Figure 6a The result can be directly obtained by calculating the time history of the moment Ms of the first spoiler 3 relative to its front end point o, as shown in Figure 8 .

[0069] So far, the present embodiment has been described in detail in conjunction with the accompanying drawings. Based on the above description, those skilled in the art should have a clear understanding of the method for calculating the hydrodynamic parameters of the dynamic steering of the spoiler of the present invention. The method for calculating the hydrodynamic parameters of the dynamic steering of the spoiler of the present invention establishes a two-dimensional dynamic steering numerical model of the spoiler, obtains the global hydrodynamic parameters of the spoiler during the dynamic steering process, and converts and obtains the time-varying curve of the corresponding local hydrodynamic parameters of the spoiler by establishing a calculation method for the local hydrodynamic parameters of the spoiler, so as to achieve effective acquisition of the hydrodynamic parameters of the spoiler during the dynamic steering process.

[0070] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for calculating hydrodynamic parameters of a dynamic steering spoiler, characterized in that: The method comprises the following steps: Step 1: Build the geometry model Determine the spoiler rudder type value parameters according to the target task. The spoiler rudder includes a rudder blade, a rudder stock, a first spoiler and a second spoiler. The rudder stock is set at the leading edge of the rudder blade, and the left side of the trailing edge of the rudder blade is connected to the first spoiler by rotation, and the right side of the trailing edge of the rudder blade is connected to the second spoiler by rotation. When the spoiler rudder is dynamically steered, the spoiler on the upstream surface is opened, and the spoiler on the downstream surface is in a closed state. Considering the symmetry of the spoiler rudder steering to the left and right, only the opening of the first spoiler is considered. The opening angle of the first spoiler is determined according to the calculation conditions, and the rudder blade and the first spoiler are integrated into a model without considering the influence of the rudder stock. Step 2: Establish a viscous flow CFD numerical calculation model Use the geometric model constructed in step 1 to import the viscous flow CFD software to build the calculation domain, set the global coordinate system, motion conditions and boundary conditions, and determine the optimal grid division strategy and time step based on the selected turbulence model; The specific steps of step 2 are as follows: Step 21, construct a two-dimensional calculation domain based on the three-dimensional geometric model, set the global coordinate system O-XY, whose origin O is located on the rudder section chord line, the X-axis points to the downstream, and the Y-axis points to the right side of the upstream direction; the entire calculation domain rotates rightward around the origin O at a set rotation speed ω to simulate the dynamic steering effect, and the angle between the X-axis and the rudder section chord line is the instantaneous rudder angle α; during the right steering process, the front boundary and the left boundary of the calculation domain are upstream boundaries, and their boundary conditions are set as velocity inlets, while the rear boundary and the right boundary are backflow boundaries, and their boundary conditions are set as pressure outlets; Step 22: Divide the computational domain into grids with a proportional The grid size was changed to obtain three sets of grids, which had the same bottom thickness of the boundary layer. The total thickness of the boundary layer was adjusted only by changing the number of boundary layers, so that the total thickness of the boundary layer was equal to the grid size of the rudder profile surface. The turbulence model was used to carry out static grid independence analysis to obtain the optimal grid division strategy, and the time step convergence analysis was carried out to determine the optimal unsteady time step at the maximum steering speed. Step 3: Numerical calculation Using the viscous flow CFD numerical calculation model established in step 2, obtain the time-varying results of the hydrodynamic parameters of the spoiler rudder and the first spoiler relative to the global coordinate system; In step 3, the hydrodynamic parameters of the spoiler relative to the global coordinate system include the resistance D along the X-axis, the lift L along the Y-axis, and the steering moment M around the origin O; the hydrodynamic parameters of the first spoiler relative to the global coordinate system include the moment M borne by the first spoiler relative to the origin O s0 And the force F along the X-axis and Y-axis respectively x and F y ; Step 4: Calculation of local hydrodynamic parameters of spoiler A calculation method for the local hydrodynamic parameters of the spoiler is established based on the relative position of the spoiler and the global coordinate system, and a time-varying curve of the local hydrodynamic parameters of the spoiler is obtained; The specific steps of step 4 are as follows: According to the component force F along the X-axis and Y-axis directions borne by the first spoiler x and F y , the resultant force F and the action direction angle ε of the resultant force F borne by the first spoiler are calculated, where the action direction angle ε of the resultant force F is the angle between the resultant force F and the X-axis. The expressions of the resultant force F and the action direction angle ε of the resultant force F are: ε=arctan(F y / F x ); According to the resultant force F and the moment M borne by the first spoiler s0 Calculate the force arm L of the resultant force F relative to the origin O. The calculation expression of the force arm L is: L=M s0 / F; According to the resultant force F and the arm l of the resultant force F relative to the front end point o of the first spoiler, the moment M of the first spoiler relative to its front end point o is calculated. s , the expression is: M s =F×l; In the formula, The expression of the force arm l of the first spoiler relative to its front end point o is: l=Ll Oo ×sin(α+ε+δ); Among them, l Oo is the distance between the front end point o of the first spoiler and the origin O, δ is l Oo The angle between the straight line and the chord line of the rudder section.

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