An adaptive method based on improved load simulation model of marine main engine

Abstract

The application provides a quick adaptation method based on an improved ship main engine load simulation model, comprising the following steps: constructing the improved ship main engine load simulation model; setting the structure parameters in the ship main engine load simulation model according to the ship and propeller data corresponding to the engine model; if it is a medium-speed engine or a high-speed engine, configuring a reduction gear box model according to the reduction ratio; setting the checking coefficient as a recommended value, and running the ship main engine load simulation model; calibrating the 75% load condition, taking the shaft torque under the condition as a checking target, iteratively modifying the checking coefficient, so that the simulation result is not deviated from the checking target; adjusting the checking target, completing the checking of the remaining checking targets, and ensuring that the error under each condition is within 5%; coupling the independently checked ship main engine load simulation model with the engine model, and performing joint operation test on the overall model, so that the ship main engine load simulation model is successfully adapted.

Description

Technical Field

[0001] This invention relates to the field of ship propulsion system simulation technology, and more particularly to an adaptation method based on an improved ship main engine load simulation model. Background Technology

[0002] The propulsion system is the primary power system of a ship, directly affecting its power, economy, reliability, and maneuverability, thus becoming a focus of ship research. The propulsion system mainly includes the main propulsion engine (main engine), the ship's shafting, transmission equipment, and the propeller. The main engine provides the power required for the ship's movement, while the shafting and transmission equipment transmit this power to the propeller (propeller). When the main engine drives the propeller to rotate, the propeller absorbs the power output from the main engine, overcomes the drag torque, generates thrust from the water flow, and thus propels the ship forward or backward.

[0003] To gain a deeper understanding of the performance of ship propulsion systems and ensure that the propulsion system is controlled or studied under near-realistic load conditions, thus avoiding malfunctions during actual operation, developing a load simulation device capable of simulating real-world operating conditions is crucial. Currently, simulations typically involve placing the propeller in a closed waterway, but this method is complex, requires large equipment, and incurs high costs. Establishing a propeller load simulation model can not only calculate the effective thrust and torque of the propeller but also consider the effects of different navigation conditions (such as wind, waves, current speed, and load), thereby replacing some sea trials. This facilitates in-depth research into ship propulsion systems and shortens the research and development and testing cycle.

[0004] Traditional load modeling methods suffer from low efficiency and high repetitiveness. Therefore, in fields such as engine research, marine engine simulation platform development, and ship-engine-propeller matching research, load models are typically simplified linearly. However, for more in-depth research on ship propulsion systems, establishing a rapidly adaptable load mechanism simulation model is essential. Furthermore, to expand the application scenarios of load simulation models, research into rapid adaptation methods has become a primary task in load simulation research. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides an adaptation method based on an improved ship main engine load simulation model. First, a modular modeling approach is adopted to establish a load model, including a propeller model, a navigation condition simulation model, a ship speed calculation model, and a reduction gearbox model. Further, the parameters of the main engine load model are extracted into structural parameters, verification coefficients, and calibration targets. Based on this, a specific adaptation process for the main engine load model is proposed. This adaptation method enables rapid adaptation of the ship's main engine load model to high-, medium-, and low-speed main engines.

[0006] The technical means employed in this invention are as follows:

[0007] A rapid adaptation method based on a ship main engine load simulation model includes:

[0008] S1. Construct an improved simulation model of ship main engine load;

[0009] S2. Based on the ship and propeller data corresponding to the engine model, set the structural parameters in the ship main engine load simulation model;

[0010] S3. If it is a medium-speed engine or a high-speed engine, calculate the appropriate reduction ratio based on the rated speed of the medium-speed engine or the high-speed engine, and set the reduction ratio in the reduction gearbox model.

[0011] S4. Set the verification coefficients to the recommended values ​​and run the ship's main engine load simulation model;

[0012] S5. Calibrate under 75% load condition, using the shaft torque under this condition as the verification target, and iteratively modify the verification coefficient to ensure that the simulation results are in line with the verification target.

[0013] S6. Adjust the verification targets and complete the verification of the remaining verification targets; run the model with the verification coefficients determined in step S5 under load conditions of 110%, 100%, 50% and 25% respectively, comprehensively compare the deviation between the simulation results and the verification targets under each load condition, further fine-tune the verification coefficients, and ensure that the error under each condition is within 5%.

[0014] S7. Couple the independently calibrated ship main engine load simulation model with the engine model, and further conduct joint operation tests of the overall model to determine that the ship main engine load simulation model is successfully adapted.

[0015] Furthermore, the structural parameters in step S2 include ship structural parameters and propeller structural parameters, specifically including:

[0016] Propeller diameter, propeller pitch, length between perpendiculars, beam, depth, design draft, gross weight, and deadweight.

[0017] Furthermore, the verification coefficients in step S4 include the thrust reduction coefficient t and the wake coefficient ω.

[0018] Furthermore, the verification targets in steps S5 and S6 include the shaft torque corresponding to typical engine loads (110%, 100%, 75%, 50%, and 25%).

[0019] Furthermore, the ship's main engine load simulation model includes: a propeller model, a navigation condition simulation model, a ship speed calculation model, and a reduction gearbox model, wherein:

[0020] The propeller model is used to calculate the effective thrust and torque of the propeller by collecting engine speed and ship speed in real time.

[0021] The navigation condition simulation model is used to simulate the resistance of ships under different marine environments, ship loading, and foul-bottom conditions.

[0022] The ship speed calculation model connects the propeller model and the navigation condition simulation model. It is used to receive the effective thrust of the propeller model and the resistance fed back by the navigation condition simulation model, calculate the real-time ship speed, and use the real-time ship speed as the input of the propeller model at the next moment.

[0023] The reduction gearbox model, connected to the propeller model, is used to calculate the output speed and torque after passing through the reduction gearbox, thereby reducing the real-time speed of the engine to the required range.

[0024] Furthermore, the propeller model includes a speed-to-weight ratio module, a thrust coefficient module, a torque coefficient module, a torque calculation module, and an effective thrust calculation module, wherein:

[0025] The advance ratio module is used to initially calculate the advance ratio under known propeller parameters and initialization conditions. The calculation formula is as follows:

[0026]

[0027] Where J represents the propeller advance ratio of the simulated ship; D P The value represents the diameter of the propeller of the simulated ship; n represents the rotational speed of the engine output in the simulation system; V P ω represents the propeller advance speed; V represents the wake coefficient; s Indicates the speed of the simulated ship;

[0028] The thrust coefficient module is used to calculate the thrust coefficient in the actual simulation. The calculation formula is as follows:

[0029] K P =αK p

[0030] Where α represents the conversion factor; K′ P This represents the thrust coefficient that needs to be calculated in the actual simulation.

[0031] The torque coefficient module is used to calculate the torque coefficient in the actual simulation. The calculation formula is as follows:

[0032] K′ M =αK M

[0033] Where α represents the conversion factor; K′ M This represents the torque coefficient that needs to be calculated in the actual simulation.

[0034] The torque calculation module is used to calculate the propeller torque based on the calculated bounded advance ratio and torque coefficient. The calculation formula is as follows:

[0035]

[0036] Where M is the propeller torque;

[0037] The effective thrust calculation module is used to calculate the accurate effective thrust by inputting the propeller speed and diameter, as well as the calculated thrust coefficient and corrected by the thrust deduction coefficient. The calculation formula is as follows:

[0038]

[0039] Among them, P e ρ represents the accurate effective thrust; ρ represents the density of seawater.

[0040] Furthermore, the navigation condition simulation model includes a drag module, a wind disturbance module, a wave disturbance module, a current disturbance module, a fouling bottom condition influence module, and a loading condition influence module, wherein:

[0041] The resistance module is used to calculate the total resistance of the hull in still water, and the calculation formula is as follows:

[0042]

[0043] Among them, R T C represents the total static resistance of a ship; T C represents the total drag coefficient; r Represents the residual drag coefficient; ΔC f V represents the frictional resistance compensation coefficient; s Indicates the ship's speed; S represents the ship's submerged area; C f C represents the coefficient of frictional resistance. f The calculation formula is as follows:

[0044]

[0045] Where Rn represents the Reynolds number;

[0046] The wind disturbance module is used to calculate the absolute wind speed U. T and the average wind pressure acting on the hull relative to the wind The calculation formula is as follows:

[0047] U T =U R +V

[0048]

[0049] Among them, absolute wind speed U T Let the ship speed V and the relative wind speed U be the given values. R The vector sum of ρ; a Air density at the current ship's position; A f C is the projected area of ​​the ship's above-water structure. wx The wind pressure coefficient in the X direction;

[0050] The wave disturbance module is used to establish an average wave resistance model, specifically including:

[0051] Calculate the mean wave height h and period T W The calculation formula is as follows:

[0052]

[0053]

[0054] The wave frequency ω of the calculation rule is calculated using the following formula:

[0055]

[0056] Calculate the meaningful wave height The calculation formula is as follows:

[0057]

[0058] Calculate the frequency ω of the waves encountered by the ship e The calculation formula is as follows:

[0059] ω e =ω-V·k

[0060] The formula for calculating the coefficient k is as follows:

[0061] Calculate wave disturbance force The calculation formula is as follows:

[0062]

[0063] in, s(t)=(k·h / 2)sin(ω e t);

[0064] The influence of blade exit conditions on propeller thrust and torque was considered, and corresponding influence factors were designed for the propeller thrust coefficient K′. P Torque coefficient K′ M The formula has been revised as follows:

[0065]

[0066] β M =(β) P ) m 0.8 <m<0.85

[0067] Where, β P The factor representing the influence of propeller thrust coefficient; β M The factor representing the influence of the propeller torque coefficient; h represents the propeller shaft immersion depth; R represents the propeller radius;

[0068] The ocean current disturbance module is used to calculate ocean current disturbances, and the calculation formula is as follows:

[0069] V = V c +V s

[0070] Among them, V c Indicates the speed of the external seawater flow;

[0071] The fouling condition impact module considers the effect of ship fouling on ship resistance and designs corresponding impact factors on the friction drag coefficient C based on different degrees of fouling. f and residual drag coefficient C r The formula for calculating the impact factor has been revised and is as follows:

[0072] β f =f f (x)

[0073] β r =f r (x)

[0074] Where, β f The coefficient of frictional resistance C of the dirt bottom f Influence factor, β r The residual resistance coefficient C of the filth bottom r The influencing factor is x, where x represents the degree of soiling.

[0075] The loading condition influence module considers the impact of ship loading on ship resistance and designs corresponding influence factors for the total resistance coefficient C based on different loading volumes. T The formula for calculating the impact factor has been revised and is as follows:

[0076] β T =f T (y)

[0077] Where, β T The coefficient of frictional resistance C for the dirty bottom T The influencing factor is y, where y represents the loading status.

[0078] Furthermore, the ship speed calculation model is used to calculate the ship's speed at the next moment using the ship's hull mechanical equilibrium equations, which are as follows:

[0079]

[0080] Where m represents the mass of the ship, and Δm represents the mass added by the ship's motion; V s Indicates the ship's speed; P e This indicates the effective thrust generated by the propeller.

[0081] Furthermore, the reduction gearbox model is used to calculate the output speed and torque after passing through the reduction gearbox, and the calculation formula is as follows:

[0082]

[0083] M G =M·i·itas

[0084] Where i represents the reduction ratio; M G Indicates output torque; n s Itas indicates engine speed; itas indicates shaft transmission efficiency.

[0085] Compared with the prior art, the present invention has the following advantages:

[0086] 1. The rapid adaptation method based on an improved ship main engine load simulation model provided by this invention achieves a closed-loop system for ship main engine load simulation by modularly modeling and connecting various modules in series or parallel to form a closed-loop connection structure. This structure enables real-time prediction of ship main engine load and has strong real-time performance. Due to the adoption of modular modeling, the modeling work of complex large systems is decomposed into several simpler modules, thereby reducing modeling costs, workload, and shortening the model development cycle and expenses. Furthermore, the modular structure facilitates subsequent improvements, optimizations, and adaptations.

[0087] 2. The rapid adaptation method based on the improved ship main engine load simulation model provided by this invention fully considers the impact of various navigation scenarios on the ship's main engine load, including factors such as wind, waves, ocean currents, foul seabed, and loading. Furthermore, the impact of propeller discharge on main engine power under different sea states is analyzed. This enables the invention to comprehensively simulate the main engine load under various navigation conditions, and it features strong predictive capabilities and ease of operation.

[0088] 3. Based on the improved marine main engine load simulation model, this invention provides a standardized rapid adaptation process for the marine main engine load model, making the adaptation work more procedural, flexible, and easy to master. Adaptation of the load model to various engines can be completed through parameter configuration and minimal calibration.

[0089] Based on the above reasons, this invention can be widely applied in fields such as ship propulsion system simulation. Attached Figure Description

[0090] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0091] Figure 1 This is a flowchart illustrating the overall process of adapting the present invention to the improved ship main engine load simulation model.

[0092] Figure 2 The diagram shows the balance relationship between the hull, engine, and propeller provided for an embodiment of the present invention.

[0093] Figure 3 A schematic diagram of the structure of the improved ship main engine load simulation model provided in the embodiments of the present invention.

[0094] Figure 4 The encapsulated load simulation model provided for embodiments of the present invention.

[0095] Figure 5 This is a flowchart of the rapid adaptation scheme based on the improved ship main engine load simulation model of the present invention. Detailed Implementation

[0096] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0097] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0098] like Figure 1 As shown, this invention provides a ship main engine load simulation model and its adaptation method. The overall process is as follows: Establish a ship main engine load simulation model (including a propeller model, a navigation condition simulation model, a ship speed calculation model, and a reduction gearbox model); analyze the load simulation model (including sorting and calculating various data, classifying parameters, and selecting verification targets); design the adaptation process; and adapt the ship main engine load simulation model according to the process. The method is described in detail below.

[0099] This invention provides an improved simulation model for ship main engine load, such as... Figure 2 As shown, this model is based on the inherent characteristics of the hull, engine, and propeller: the rotational balance of the shaft system between engine torque and propeller torque, and the translational balance of the hull between ship resistance and propeller thrust. Specifically, the difference between the engine output torque and the torque absorbed by the load determines the real-time speeds of the engine and propeller, while the difference between ship resistance and propeller thrust determines the hull's acceleration, thus affecting the ship's speed. Simultaneously, the propeller speed and ship speed affect the propeller's torque and thrust; ship speed, as well as external environmental factors such as foul bottom, wind, waves, currents, and load, play a decisive role in ship resistance. The hull, engine, and propeller are interconnected and mutually influential.

[0100] like Figure 3 The diagram shown is a structural schematic of the improved ship main engine load simulation model constructed in this invention, including: a propeller model, a navigation condition simulation model, a ship speed calculation model, and a reduction gearbox model, wherein:

[0101] The propeller model is used to calculate the effective thrust and torque of the propeller by collecting engine speed and ship speed in real time.

[0102] The navigation condition simulation model is used to simulate the resistance of ships under different conditions (including different sea states, degrees of fouling, and loading conditions). In this embodiment, in order to study the complex changes in propeller conditions and hull resistance under the disturbance of external environmental factors, the present invention establishes different sea state modules, including wind disturbance mathematical models, wave disturbance mathematical models, and current disturbance mathematical models, as well as fouling and loading influence modules, to simulate the resistance of ships under navigation conditions.

[0103] The ship speed calculation model connects the propeller model and the navigation condition simulation model. It is used to receive the effective thrust of the propeller model and the resistance fed back by the navigation condition simulation model, calculate the real-time ship speed, and use the real-time ship speed as the input of the propeller model at the next moment.

[0104] The reduction gearbox model, connected to the propeller model, is used to calculate the output speed and torque after passing through the reduction gearbox, thereby reducing the real-time speed of the engine to the required range.

[0105] After encapsulating each model, the result is as follows: Figure 4 The overall load simulation model is shown.

[0106] In a specific implementation, as a preferred embodiment of the present invention, the propeller model includes a speed-to-weight ratio module, a thrust coefficient module, a torque coefficient module, a torque calculation module, and an effective thrust calculation module, wherein:

[0107] The advance ratio module is used to initially calculate the advance ratio under known propeller parameters and initialization conditions. As the simulation progresses, the input conditions continuously change, thereby obtaining the advance ratio value in real time. The calculation formula is as follows:

[0108]

[0109] Where J represents the propeller advance ratio of the simulated ship; D P The value represents the diameter of the propeller of the simulated ship; n represents the rotational speed of the engine output in the simulation system; V P ω represents the propeller advance speed; V represents the wake coefficient; S Indicates the speed of the simulated ship;

[0110] The thrust coefficient module is used to calculate the thrust coefficient in actual simulations. The thrust coefficient is a function of the advance ratio and pitch ratio. The mathematical model for the thrust coefficient is based on the Nordstrom series test patterns measured in the Gothenburg water tank. For the same type of propeller, its thrust coefficient K... P With the feed rate coefficient J, pitch ratio H / D, and disk area ratio A E / A0 related. For different plate ratios A E The propeller of / A0 is preferably modified using the following expression:

[0111] K′ P =αK P

[0112] Where α represents the conversion factor; K′ P This represents the thrust coefficient that needs to be calculated in the actual simulation.

[0113] The torque coefficient module is used to calculate the torque coefficient in the actual simulation. The torque coefficient is a function of the feed rate ratio and the pitch ratio. The mathematical model for the torque coefficient is based on the Noltström series test patterns measured in the Gothenburg water tank. For the same type of propeller, its thrust coefficient K... M With the feed rate coefficient J, pitch ratio H / D, and disk area ratio A E / A0 related. For different plate ratios A E The propeller of / A0 is preferably modified using the following expression:

[0114] K′ M =αK M

[0115] Where α represents the conversion factor; K′ M This represents the torque coefficient that needs to be calculated in the actual simulation.

[0116] The torque calculation module is used to calculate the propeller torque based on the calculated bounded advance ratio and torque coefficient. The calculation formula is as follows:

[0117]

[0118] Where M is the propeller torque;

[0119] The effective thrust calculation module is used to calculate the accurate effective thrust by inputting the propeller speed and diameter, as well as the calculated thrust coefficient and corrected by the thrust deduction coefficient. The calculation formula is as follows:

[0120]

[0121] Among them, P e ρ represents the accurate effective thrust; ρ represents the density of seawater.

[0122] In this embodiment, the propeller is not only the provider of ship power but also a significant load on the engine. In constructing the propeller model, in addition to accurately reflecting the effective thrust and torque of the propeller, the impact of different navigation conditions (such as wind, waves, currents, fouling, and loading) on ​​its performance must also be considered. Because there is a mutual influence between the ship and the propeller, a thrust reduction factor t and a wake factor ω need to be introduced to correct the propeller mathematical model during the model establishment process.

[0123] In a specific implementation, as a preferred embodiment of the present invention, the navigation condition simulation model includes a drag module, a wind disturbance module, a wave disturbance module, a current disturbance module, a fouling condition influence module, and a loading condition influence module, wherein:

[0124] The resistance module is used to calculate the total resistance of the hull in still water, and the calculation formula is as follows:

[0125]

[0126] Among them, R T C represents the total static resistance of a ship; T C represents the total drag coefficient; r Represents the residual drag coefficient; ΔC f V represents the frictional resistance compensation coefficient; s Indicates the ship's speed; S represents the ship's submerged area; C f C represents the coefficient of frictional resistance. f The calculation formula is as follows:

[0127]

[0128] Where Rn represents the Reynolds number; then, the remaining drag is estimated based on the corresponding graph, and the friction drag subsidy coefficient ΔC is used. f It is related to the size of the ship;

[0129] In this embodiment, ship resistance is mainly divided into basic resistance and additional resistance. Basic resistance refers to the resistance experienced by a bare ship under ideal conditions, i.e., still water resistance, which is the main component of ship resistance. Additional resistance considers the influence of external factors, including the resistance increased by wind, waves, currents, ship fouling, and ship loading. Still water resistance is the resistance experienced by a ship when sailing in ideal sea conditions with no wind or waves. It is further divided into frictional resistance R... f Vortex drag R e Hexing wave resistance R w Vortex drag and wave-making drag are collectively referred to as residual drag. In addition to frictional drag and residual drag, drag compensation is also performed based on the ship's dimensions during actual calculations.

[0130] The wind disturbance module is used to calculate the absolute wind speed U. T and the average wind pressure acting on the hull relative to the wind The calculation formula is as follows:

[0131] U T =U R +V

[0132]

[0133] Among them, absolute wind speed U T Let the ship speed V and the relative wind speed U be the given values. R The vector sum of ρ; a Air density at the current ship's position; A f C is the projected area of ​​the ship's above-water structure. wx The wind pressure coefficient in the X direction;

[0134] In this embodiment, due to the influence of ship speed, the wind speed perceived on the ship differs from the actual wind speed. In this invention, the actual wind speed is referred to as absolute wind speed, while the wind speed perceived by a person on the ship is called relative wind speed. Absolute wind speed is the wind speed observed in the o-xo-yo coordinate system, denoted by U. T This is indicated. For ease of calculation, this invention only studies the wind in the direction of ship motion.

[0135] The wave disturbance module is used to establish an average wave drag model. In this embodiment, waves cause changes in the vertical distribution of pressure in the fluid, resulting in complex and random wave disturbance forces on the surface of the object. Wave disturbance forces are among the most complex of various environmental disturbances. Referring to the average wind drag model described above and considering the potential for blade ejection caused by waves, this invention establishes an average wave drag model, specifically including:

[0136] Ocean waves are closely related to wind; calculate the average wave height h and period T. W The calculation formula is as follows:

[0137]

[0138]

[0139] The wave frequency ω of the calculation rule is calculated using the following formula:

[0140]

[0141] Calculate the meaningful wave height The calculation formula is as follows:

[0142]

[0143] In this embodiment, ocean waves are actually irregular, composed of various wavelengths and wave heights. Observations show that one-third of the waves have a wave height 1.6 times the average wave height; these are referred to as significant wave heights. The wave height observed by people at sea is very close to the meaningful wave height;

[0144] The wave encounter angle is the angle between the direction of the ship's bow forward and the direction of the wave's forward movement. For simplicity, this invention only considers the case where the direction of the wave is the same as the ship's direction of motion. The frequency ω of the waves encountered by the ship is calculated.e Its value is affected by wave frequency, encounter angle, and ship speed, and the calculation formula is as follows:

[0145] ω e =ω-V·k

[0146] The formula for calculating the coefficient k is as follows:

[0147] Calculate wave disturbance force The calculation formula is as follows:

[0148]

[0149] in, s(t)=(k·h / 2)sin(ω e t);

[0150] The pitching and heave of a ship when facing waves can cause the propeller to emerge from the water. This embodiment takes into account the propeller blade emergence situation and adjusts the propeller thrust coefficient K′. p Torque coefficient K′ M The formula has been revised as follows:

[0151]

[0152] β M =(β) P ) m 0.8 <m<0.85

[0153] Where, β P The factor representing the influence of propeller thrust coefficient; β M The factor representing the influence of the propeller torque coefficient; h represents the propeller shaft immersion depth; R represents the propeller radius;

[0154] The ocean current disturbance module is used to calculate ocean current disturbances, and the calculation formula is as follows:

[0155] V = V c +V s

[0156] Among them, V c Indicates the speed of the external seawater flow;

[0157] In this embodiment, ocean current disturbance refers to the impact of seawater flow on the ship. For ease of calculation, this invention uses a velocity vector synthesis method to model ocean current disturbance. This method simplifies the ocean current as a uniform flow, reduces the influence of seawater velocity on ship motion to changes in ocean current displacement and velocity relative to the ship, and only considers flow disturbances in the direction of ship motion.

[0158] The fouling condition impact module considers the effect of ship fouling on ship resistance and designs corresponding impact factors on the friction drag coefficient C based on different degrees of fouling. f and residual drag coefficient C r Corrections were made. In this invention, the degree of fouling is described by the area covered by the attached organisms. Coverage area (%) is a commonly used unit when macroscopically calculating fouling on ships and marine facilities; it refers to the percentage of the surface below the waterline of the hull or the test surface covered by attached organisms, expressed as %. The value of its influencing factor was determined by fitting the frictional drag coefficient C of fouling with different coverage areas (10%, 20%, 40%, 60%, 80%, and 90%, respectively) at the design speed. f and residual drag coefficient C R The influence function is calculated as follows:

[0159] β f =f f (x)

[0160] β r =f r (x)

[0161] Where, β f The coefficient of frictional resistance C for the dirty bottom f Influence factor, β r The residual resistance coefficient C of the filth bottom r The influencing factor, x, represents the degree of contamination (0–100%, where 0% is smooth, 25% is lightly contaminated, 50% is moderately contaminated, 75% is heavily contaminated, and 100% is severely contaminated).

[0162] The loading condition influence module considers the impact of ship loading on ship resistance and designs corresponding influence factors for the total resistance coefficient C based on different loading volumes. T Corrections are made. In this invention, the impact of loading on ship resistance can be divided into two aspects: first, the impact of the loaded weight on the total ship weight; and second, the impact of different drafts after loading on resistance. The value of its influencing factor can be obtained by fitting the effect of different loading amounts (0%, 47%, 74%, and 100%, respectively) on the total ship resistance coefficient C at the design speed. T The influence function is calculated as follows:

[0163] β T =f r (y)

[0164] Where, β T The coefficient of frictional resistance C for the dirty bottom T The influencing factor is y, which represents the loading condition (0-100%, where 0% is unloaded, 47% is ballasted, 50% is half-loaded, and 100% is fully loaded).

[0165] In a specific implementation, as a preferred embodiment of the present invention, the ship speed calculation model is used to calculate the ship's speed at the next moment through the ship's hull mechanical equilibrium equations, which are as follows:

[0166]

[0167] Where m represents the mass of the ship, and the loading conditions in this invention will affect this value; Δm represents the added mass due to the ship's motion; V s Indicates the ship's speed; P e This indicates the effective thrust generated by the propeller.

[0168] In this embodiment, when the system starts up, the propeller has an initial velocity, which corresponds to a resistance value. Under the action of thrust, the ship's velocity will change. The ship's velocity at the next moment can be calculated using the ship's mechanical equilibrium equations.

[0169] In a specific implementation, as a preferred embodiment of the present invention, the reduction gearbox model is used to calculate the output speed and torque after passing through the reduction gearbox, and the calculation formula is as follows:

[0170]

[0171] M G =M·i·itas

[0172] Where i represents the reduction ratio; M G Indicates output torque; n s Itas indicates engine speed; itas indicates shaft transmission efficiency.

[0173] In this embodiment, to ensure the load model has a certain degree of versatility, i.e., it can be adapted to low-speed, medium-speed, and high-speed engines, the engine speed needs to be reduced to a range suitable for the load model via a reduction gearbox before adaptation. The mathematical model of the reduction gearbox is relatively simple, and the output speed and torque after passing through the reduction gearbox can be calculated using this model.

[0174] This invention also provides a rapid adaptation method based on the above-mentioned ship main engine load simulation model. The following uses a load model configured with a two-stroke low-speed engine as an example to explain in detail the rapid adaptation method for the load simulation model proposed in this invention. Figure 5 The adaptation process shown includes:

[0175] S1. Organize and classify the data required for adaptation, including reduction ratio, structural parameters, verification targets, and verification coefficients, and find and calculate each data item;

[0176] S2. Based on the ship and propeller data, set the structural parameters in the load model;

[0177] S3. If it is a medium-speed or high-speed engine, calculate the appropriate reduction ratio based on its rated speed and set it in the reduction gearbox model (skip this step if it is a low-speed engine).

[0178] S4. Set the verification coefficients to the recommended values ​​and run the load simulation model;

[0179] S5. First, calibrate under a 75% load condition. Using the shaft torque under this condition as the verification target, iteratively modify the verification coefficients to ensure that the simulation results are consistent with the verification target.

[0180] S6. Adjust the verification targets and complete the verification of the remaining targets. Run the model under load conditions of 110%, 100%, 50%, and 25% using the verification coefficients determined in step S5. Compare the deviations between the simulation results and the verification targets under each load condition, further fine-tune the verification coefficients, and ensure that the error under each condition is within 5%.

[0181] S7. Couple the independently verified main engine load model with the engine model, and further conduct joint operation tests of the overall model to determine that the ship's main engine load simulation model is successfully adapted.

[0182] In a preferred embodiment of this invention, the structural parameters in step S2 include: parameters related to the ship structure, propeller structure, and environment corresponding to the two-stroke low-speed engine, and initial parameters required for model building (including propeller diameter, propeller pitch, length between perpendiculars, beam, depth, design draft, gross weight, and deadweight). These structural parameters are obtained from the engine manual, test report, and relevant ship and propeller data after the simulation object is determined. Specific parameters are detailed in Table 1. The parameters in the table are easy to obtain and can be used to make relatively accurate estimates of other ship parameters, thus making the method of this invention more versatile.

[0183] Table 1 Structural Parameters

[0184] 1 propeller diameter D m 2 propeller pitch P m 3 Length between perpendiculars <![CDATA[L PP ]]> m 4 Width B m 5 Deep D m 6 Design draft d m 7 gross weight of the ship W t 8 Load capacity <![CDATA[DW S ]]> t

[0185] In specific implementation, as a preferred embodiment of the present invention, the verification coefficients in step S4 include the influence factors used when establishing the model. In this embodiment, the rapid adaptation of the ship's main engine load model is mainly achieved by adjusting these coefficients. The present invention selects the thrust deduction coefficient t and the wake coefficient ω as verification coefficients, as shown in Table 2. When the propeller blades rotate, eddies and turbulence are generated, resulting in a certain thrust loss. The thrust deduction coefficient t describes the degree of influence of this thrust loss. In the simulation, the thrust deduction coefficient t is positively correlated with the verification target. The wake coefficient ω refers to the ratio of the actual resistance experienced by the propeller in the wake region of the ship to the resistance without a wake. The wake coefficient is used to describe the efficiency of the propeller and the performance of the propulsion system. In the simulation, it is also positively correlated with the verification target, and its influence is greater than that of the thrust deduction coefficient t. According to EEDI, the recommended values ​​for the thrust deduction coefficient t and the wake coefficient ω of the present invention are 0.1 and 0.15, respectively.

[0186] Table 2 Verification Coefficients

[0187]

[0188] In a specific implementation, as a preferred embodiment of the present invention, the verification targets in steps S5 and S6 include:

[0189] The shaft torque corresponding to various typical loads of the engine. The calibration target is the shaft torque of the two-stroke engine under various loads, as shown in Table 3. First, the shaft torque at 75% load was used as the calibration target and calibrated separately. Since there is no influence from other targets, the accuracy can approach 100%, and this accuracy is most relevant to the fit accuracy. Subsequently, the shaft torque at 110%, 100%, 50%, and 25% loads was used as the calibration targets for further calibration.

[0190] Table 3 Shaft torque corresponding to various engine loads.

[0191]

[0192] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A rapid adaptation method based on an improved ship main engine load simulation model, characterized in that, include: S1. Construct an improved simulation model of the ship's main engine load, including: a propeller model, a navigation condition simulation model, a ship speed calculation model, and a reduction gearbox model, wherein: The propeller model is used to calculate the effective thrust and torque of the propeller by collecting engine speed and ship speed in real time. The navigation condition simulation model is used to simulate the resistance of ships under different marine environments, ship loading, and foul-bottom conditions. The ship speed calculation model connects the propeller model and the navigation condition simulation model. It is used to receive the effective thrust of the propeller model and the resistance fed back by the navigation condition simulation model, calculate the real-time ship speed, and use the real-time ship speed as the input of the propeller model at the next moment. The reduction gearbox model, connected to the propeller model, is used to calculate the output speed and torque after passing through the reduction gearbox, and to reduce the real-time speed of the engine to the required range. S2. Based on the ship and propeller data corresponding to the engine model, set the structural parameters in the ship main engine load simulation model; S3. If it is a medium-speed engine or a high-speed engine, calculate the appropriate reduction ratio based on the rated speed of the medium-speed engine or the high-speed engine, and set the reduction ratio in the reduction gearbox model. S4. Set the verification coefficients to the recommended values ​​and run the ship's main engine load simulation model; S5. Calibrate under 75% load condition, using the shaft torque under this condition as the verification target, and iteratively modify the verification coefficient to ensure that the simulation results are in line with the verification target. S6. Adjust the verification targets and complete the verification of the remaining verification targets; run the model with the verification coefficients determined in step S5 under load conditions of 110%, 100%, 50% and 25% respectively, comprehensively compare the deviation between the simulation results and the verification targets under each load condition, further fine-tune the verification coefficients, and ensure that the error under each condition is within 5%. S7. Couple the independently calibrated ship main engine load simulation model with the engine model, and further conduct joint operation tests of the overall model to determine that the ship main engine load simulation model is successfully adapted.

2. The rapid adaptation method based on an improved ship main engine load simulation model according to claim 1, characterized in that, The structural parameters in step S2 include ship structural parameters and propeller structural parameters, specifically including: Propeller diameter, propeller pitch, length between perpendiculars, beam, depth, design draft, gross weight, and deadweight.

3. The rapid adaptation method based on an improved ship main engine load simulation model according to claim 1, characterized in that, The verification coefficients in step S4 include the thrust reduction coefficient. Flow coefficient .

4. The rapid adaptation method based on an improved ship main engine load simulation model according to claim 1, characterized in that, The verification targets in steps S5 and S6 include the shaft torque corresponding to typical engine loads of 110%, 100%, 75%, 50%, and 25%.

5. The rapid adaptation method based on an improved ship main engine load simulation model according to claim 1, characterized in that, The propeller model includes a speed-to-weight ratio module, a thrust coefficient module, a torque coefficient module, a torque calculation module, and an effective thrust calculation module, wherein: The advance ratio module is used to initially calculate the advance ratio under known propeller parameters and initialization conditions. The calculation formula is as follows: in, This indicates the propeller advance rate ratio of the simulated ship; Indicates the diameter of the propeller of the simulated ship; This represents the engine speed output in the simulation system; Indicates the propeller advance speed; Indicates the wake coefficient; Indicates the speed of the simulated ship; The thrust coefficient module is used to calculate the thrust coefficient in the actual simulation. The calculation formula is as follows: in, Indicates the conversion factor; This represents the thrust coefficient that needs to be calculated in the actual simulation. The torque coefficient module is used to calculate the torque coefficient in the actual simulation. The calculation formula is as follows: in, Indicates the conversion factor; This represents the torque coefficient that needs to be calculated in the actual simulation. The torque calculation module is used to calculate the propeller torque based on the calculated bounded advance ratio and torque coefficient. The calculation formula is as follows: in, It is the propeller torque; The effective thrust calculation module is used to calculate the accurate effective thrust by inputting the propeller speed and diameter, as well as the calculated thrust coefficient and corrected by the thrust deduction coefficient. The calculation formula is as follows: in, Indicates accurate effective thrust; This indicates the density of seawater.

6. The rapid adaptation method based on an improved ship main engine load simulation model according to claim 1, characterized in that, The navigation condition simulation model includes a drag module, a wind disturbance module, a wave disturbance module, an ocean current disturbance module, a fouling bottom influence module, and a loading condition influence module, wherein: The resistance module is used to calculate the total resistance of the hull in still water, and the calculation formula is as follows: in, This indicates the total static resistance of the ship; Indicates the total drag coefficient; Indicates the residual drag coefficient; This represents the friction resistance compensation coefficient; Indicates the ship's speed; Indicates the area of ​​the ship submerged in water; Indicates the coefficient of frictional resistance. The calculation formula is as follows: in, Represents the Reynolds number; The wind disturbance module is used to calculate the absolute wind speed. and the average wind pressure acting on the hull relative to the wind The calculation formula is as follows: Among them, absolute wind speed For ship speed relative wind speed The vector sum; Air density at the current ship's position; The projected area of ​​the ship's above-water structure; for Wind pressure coefficient in the direction; The wave disturbance module is used to establish an average wave resistance model, specifically including: Calculate the mean wave height and cycle The calculation formula is as follows: Calculation rules for wave frequency The calculation formula is as follows: Calculate the meaningful wave height The calculation formula is as follows: Calculate the frequency of waves encountered by a ship The calculation formula is as follows: Among them, coefficient The calculation formula is ; Calculate wave disturbance force The calculation formula is as follows: in, ; ; ; The influence of blade exit conditions on propeller thrust and torque was considered, and corresponding influencing factors were designed for the propeller thrust coefficient. Torque coefficient The formula has been revised as follows: in, The influencing factor representing the propeller thrust coefficient; The influencing factor representing the propeller torque coefficient; Indicates the depth of the propeller shaft in the water; Indicates the radius of the paddle; The ocean current disturbance module is used to calculate ocean current disturbances, and the calculation formula is as follows: in, Indicates the speed of the external seawater flow; The fouling condition impact module considers the influence of ship fouling on ship resistance and designs corresponding impact factors on the friction drag coefficient according to different degrees of fouling. and residual drag coefficient The formula for calculating the impact factor has been revised and is as follows: in, The coefficient of frictional resistance of the dirt bottom Influence factors The residual resistance coefficient of the dirty bottom Influence factors The degree of soiling; The loading condition influence module considers the impact of ship loading on ship resistance and designs corresponding influence factors for the total resistance coefficient based on different loading volumes. The formula for calculating the impact factor has been revised and is as follows: in, The coefficient of frictional resistance of the dirt bottom Influence factors For loading status.

7. The rapid adaptation method based on an improved ship main engine load simulation model according to claim 1, characterized in that, The ship speed calculation model is used to calculate the ship's speed at the next moment using the ship's hull mechanical equilibrium equations, which are as follows: in, Indicates the mass of the ship. Indicates the added mass of a ship due to its motion; Indicates the ship's speed; This indicates the effective thrust generated by the propeller.

8. The rapid adaptation method based on an improved ship main engine load simulation model according to claim 1, characterized in that, The reduction gearbox model is used to calculate the output speed and torque after passing through the reduction gearbox. The calculation formula is as follows: in, Indicates the reduction ratio; Indicates the output torque; Indicates engine speed; This indicates the transmission efficiency of the shaft system.

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