A method for optimizing the speed of a ship navigating in ice

Abstract

This invention discloses a method for optimizing ship speed in ice-covered areas, comprising the following steps: obtaining the total resistance of the ship when navigating in ice-covered areas based on the ship's resistance in ice-free environments and ice resistance; calculating the ship's speed relative to land based on the total resistance when navigating in ice-covered areas; calculating the fuel consumption of the ship's main engine based on the ship's speed relative to land; calculating the fuel cost consumed in one voyage based on the fuel consumption of the ship's main engine; calculating the time consumed in one voyage based on the ship's voyage distance; calculating the ship's operating revenue per unit time based on the ship's operating revenue per voyage, the ship's management costs, and the time consumed in one voyage; and optimizing the ship's speed based on the ship's operating revenue per unit time. This invention achieves speed optimization or energy efficiency management by reading various parameters of the ship through a computer, aiming to reduce fuel consumption and lower operating costs.

Description

Technical Field

[0001] This invention belongs to the field of ship energy efficiency management technology, and relates to a method for optimizing ship speed for navigation in ice-covered areas. Background Technology

[0002] Existing methods for optimizing ship speed are mostly based on fuel consumption per unit distance traveled. These methods do not adequately consider the cargo turnaround efficiency requirements of merchant ships. Therefore, while adjusting speed based on these analyses may reduce fuel consumption, the increased time spent on individual voyages could actually lead to a decrease in operational revenue over the ship's lifespan.

[0003] On the other hand, existing speed optimization methods do not consider the impact of sea ice on ship resistance using analytical calculation models. In conventional waters, ship resistance is mainly affected by factors such as speed and wind force. However, when navigating in ice-covered areas, because sea ice resistance accounts for a high proportion of the total ship resistance, these energy efficiency management methods cannot be effective. Summary of the Invention

[0004] To address the aforementioned problems, the technical solution adopted by this invention is: a method for optimizing ship speed for navigation in ice-covered areas, comprising the following steps:

[0005] Calculate the resistance of a ship in an ice-free environment when navigating in an ice-covered area, based on the ship's speed relative to the water. Calculate the ice resistance of a ship navigating in an ice-covered area based on the ship's speed relative to water. Based on the resistance of the ship in an ice-free environment and the resistance of ice, the total resistance of the ship when navigating in an ice-covered area is obtained; Calculate the ship's speed relative to the ground based on the total resistance of the ship when navigating in ice-covered areas; Calculate the fuel consumption of the ship's main engine based on the ship's speed over land; Calculate the fuel cost of a voyage based on the fuel consumption of the ship's main engine. Calculate the time consumed for a voyage based on the ship's sailing distance in a voyage; Based on the ship's operating revenue for a voyage, the ship's management costs, and the time consumed for a voyage, the ship's operating revenue per unit time is calculated. Based on the ship's operating revenue per unit time, the ship's speed is optimized by solving for the ship's speed at which the operating revenue is maximized.

[0006] Furthermore, the expression for the total resistance of the vessel when navigating in ice-covered areas is as follows:

[0007] Where: is the total resistance of the ship when navigating in ice-covered areas. The resistance of a ship navigating in an ice-free environment, Ice resistance; The resistance of the ship when navigating in an ice-free environment The expression is as follows:

[0008] in, The resistance of a ship navigating in an ice-free environment, For ship propulsion efficiency, For the shafting transmission efficiency of a ship; ice resistance The expression is as follows:

[0009] in, and The drag coefficient, This refers to the ship's speed relative to the water.

[0010] Furthermore: Based on the ship's speed above the ground, the expression for calculating the ship's main engine fuel consumption is as follows:

[0011] in: Fuel consumption The fuel consumption rate of the main unit. For the distance of the voyage, It is the ship's speed relative to the ground;

[0012] in: It is the ship's speed. It refers to the speed of the ocean current.

[0013] Furthermore, the expression for calculating the fuel cost of a voyage based on the fuel consumption of the ship's main engine is as follows:

[0014] in, Fuel cost for a ship on one voyage. fuel Consumption amount, fuel The price.

[0015] Furthermore: the operating revenue of the vessel per unit time The expression is as follows:

[0016] in: This refers to the operating revenue of a single voyage. These are the ship's management costs;

[0017] in, The time it takes for a ship to complete a voyage. For the ship's voyage segment, for The voyage distance of a ship under a given voyage segment. for The speed of the ship during the voyage.

[0018] Furthermore, it also includes the process of correcting for the ship's resistance, as follows: Obtain environmental parameter sets and ship status parameter sets; The environmental parameter set includes at least wind speed and surge height; the ship condition parameter set includes at least rudder angle, load condition parameters, and trim angle. Determine the reference resistance under still water conditions based on the ship's current speed v; Calculate the corrected ship resistance based on the aforementioned baseline resistance and the comprehensive correction factor; The comprehensive correction factor is determined based on the wind speed correction factor, surge height correction factor, rudder angle correction factor, load condition parameter correction factor, and pitch angle correction factor.

[0019] Furthermore, it also includes real-time calculation of the ship's optimal speed by accessing the ship's control system and reading parameters such as ship speed, wind speed, sea state, and route length.

[0020] This invention provides a method for optimizing ship speed for navigation in ice-covered areas. It is a ship energy efficiency management method or a ship speed optimization method. By reading various parameters of the ship through a computer, the method achieves speed optimization or energy efficiency management in order to reduce fuel consumption and lower operating costs.

[0021] The method described in this application optimizes ship speed based on parameters such as the ship's own parameters, route, and climate, thereby reducing fuel consumption while taking into account the ship's operating cycle and improving the ship's operational efficiency.

[0022] 1) This method can calculate the resistance caused by sea ice to ships, and thus can be used to optimize the speed of ships navigating in ice-covered areas.

[0023] 2) This method does not simply optimize the ship's speed from the perspective of fuel consumption. Its calculation results take into account the time cost of commercial operation of the ship, thereby improving the ship's operating efficiency. Attached Figure Description

[0024] 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.

[0025] Figure 1 This is a flowchart of the method. Detailed Implementation

[0026] It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Figure 1 This is a flowchart of the method.

[0029] A method for optimizing ship speed in ice-covered areas requires obtaining, before use, a curve showing the relationship between main engine power and speed, without considering the effects of sea ice, based on actual ship speed tests.

[0030] in, For the ship's speed relative to the water, This refers to the power of the main unit.

[0031] Based on parameters such as the ship's main engine fuel consumption rate and transmission efficiency, the ship's resistance at this point can be calculated:

[0032] in, The resistance of a ship navigating in an ice-free environment, For ship propulsion efficiency, This refers to the shafting transmission efficiency of a ship.

[0033] In addition to the resistance mentioned above, ships navigating in icy conditions are also subject to ice resistance, hence the formula for calculating ice resistance:

[0034] in, and The drag coefficient is related to a series of parameters, including the coefficient of friction between the hull surface and sea ice, hull parameters, the physical properties of sea ice, and environmental factors such as temperature.

[0035] in, This represents the total resistance a ship encounters when navigating in ice-covered areas.

[0036] Therefore, when navigating in ice-covered areas, the relationship between ship speed and main engine power is as follows:

[0037] With this relationship, we can plot the curve relating speed and engine power, and then solve for the curve relating fuel consumption and speed. Considering the actual speed of the ship and the influence of ocean currents, the ship's speed relative to land is:

[0038] in: It refers to the speed of the ocean current; Meanwhile, the fuel consumption of the main unit is:

[0039] in, Fuel consumption The fuel consumption rate of the main unit. The distance traveled.

[0040] Therefore, the relationship between fuel consumption and speed when a ship is navigating in ice-covered areas can be calculated for a certain route.

[0041] Based on this, the fuel cost consumed by a ship to complete one voyage can be obtained as follows:

[0042] in, Fuel cost for a ship on one voyage. fuel Consumption amount, fuel The price.

[0043] Because a ship's speed and navigation conditions constantly change during its voyage, this invention divides a voyage into several segments. The time required for a ship to complete one voyage can then be expressed as:

[0044] in, The time it takes for a ship to complete a voyage. For the ship's voyage segment, for The voyage distance of a ship under a given voyage segment. for The speed of the ship during the voyage.

[0045] Since the revenue a ship earns in a voyage is related to the cargo it carries, the operating revenue for a voyage can be quantified as a constant. The costs of crew salaries, ship maintenance, and ship depreciation are linearly related to time, and can be expressed as follows: .

[0046] Therefore, the operating revenue of a ship per unit of time is:

[0047] The method optimizes ship speed by solving for the ship speed when r is maximized.

[0048] Furthermore, when calculating ice resistance, this method can obtain meteorological data of the navigation area through the network, and then calculate the ice resistance based on parameters such as sea ice concentration, ice thickness, and snow thickness on the ice surface.

[0049] Commonly used formulas for calculating ice drag include the Riska formula and the Lindqvist formula; the Lindqvist formula divides the drag into three components: Icebreaking resistance :

[0050]

[0051] In the formula, , coefficient of friction Bow inclination angle, Waterline approach angle; Furthermore, the method employed in this invention can correct the ship's resistance based on parameters including but not limited to wind speed, surge, rudder angle, and the ship's load and trim during navigation, thereby optimizing the ship's speed, as detailed below: Obtain environmental parameter sets and ship status parameter sets; The environmental parameter set includes at least wind speed and surge height; the ship condition parameter set includes at least rudder angle, load condition parameters, and trim angle. Determine the reference resistance under still water conditions based on the ship's current speed v; Calculate the corrected ship resistance based on the aforementioned baseline resistance and the comprehensive correction factor; The comprehensive correction factor is determined based on the wind speed correction factor, surge height correction factor, rudder angle correction factor, load condition parameter correction factor, and pitch angle correction factor.

[0052] When sailing upwind, a ship's resistance is corrected upwards, while when sailing downwind, it is corrected downwards. Large waves correct resistance upwards, while small waves correct resistance downwards.

[0053] Furthermore, by connecting to the ship's control system, parameters such as ship speed, wind speed, sea state, and route length can be read from the ship to achieve real-time calculation of the ship's optimal speed.

[0054] The real-time speed and resistance of a ship can be calculated by taking into account the effects of parameters such as wind speed and sea state on ship speed and resistance. Then, the average speed and average resistance over a 10-minute period can be taken as the current speed and resistance.

[0055] Simultaneously, the changes in ship resistance and speed over 30 minutes are analyzed. A linear fitting method is used to predict the subsequent ship resistance value. Then, according to the formula in the instruction manual, the optimal speed for the next 10 minutes is calculated using the predicted resistance value. Furthermore, the difference between the current speed and the subsequent optimal speed is dynamically determined, allowing for advance adjustment of the main engine power.

[0056] 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 method for optimizing ship speed for navigation in ice-covered areas, characterized in that: Includes the following steps: Calculate the resistance of a ship in an ice-free environment when navigating in an ice-covered area, based on the ship's speed relative to the water. Calculate the ice resistance of a ship navigating in an ice-covered area based on the ship's speed relative to water. Based on the resistance of the ship in an ice-free environment and the resistance of ice, the total resistance of the ship when navigating in an ice-covered area is obtained; Calculate the ship's speed relative to the ground based on the total resistance of the ship when navigating in ice-covered areas; Calculate the fuel consumption of the ship's main engine based on the ship's speed relative to the ground. Calculate the fuel cost of a voyage based on the fuel consumption of the ship's main engine. Calculate the time consumed for a voyage based on the distance traveled by the ship in a voyage. Based on the ship's operating revenue for a voyage, the ship's management costs, and the time consumed for a voyage, the ship's operating revenue per unit time is calculated. Based on the ship's operating revenue per unit time, the ship's speed is optimized by solving for the ship's speed at which the operating revenue is maximized.

2. The method for optimizing ship speed for navigation in ice-covered areas according to claim 1, characterized in that: The expression for the total resistance of the ship when navigating in ice-covered areas is as follows: Where: represents the total resistance of a ship navigating in ice-covered areas. The resistance of a ship navigating in an ice-free environment. Ice resistance; The resistance of the ship when navigating in an ice-free environment The expression is as follows: in, The resistance of a ship navigating in an ice-free environment. For ship propulsion efficiency, For the shafting transmission efficiency of a ship; ice resistance The expression is as follows: in, and The drag coefficient, This refers to the ship's speed relative to the water.

3. The method for optimizing ship speed for navigation in ice-covered areas according to claim 1, characterized in that: The expression for calculating the fuel consumption of a ship's main engine based on the ship's speed above the ground is as follows: in: Fuel consumption The fuel consumption rate of the main unit. For the distance of the voyage, It is the ship's speed relative to the ground; in: It is the ship's speed. It refers to the speed of the ocean current.

4. The method for optimizing ship speed for navigation in ice-covered areas according to claim 1, characterized in that: The expression for calculating the fuel cost of a voyage based on the fuel consumption of the ship's main engine is as follows: in, Fuel cost for a ship on one voyage. fuel Consumption amount, fuel The price.

5. The method for optimizing ship speed for navigation in ice-covered areas according to claim 1, characterized in that: The ship's operating revenue per unit time The expression is as follows: in: This refers to the operating revenue of a single voyage. These are the ship's management costs; in, The time it takes for a ship to complete a voyage. For the ship's voyage segment, for The voyage distance of a ship under a given voyage segment. for The speed of the ship during the voyage.

6. The method for optimizing ship speed for navigation in ice-covered areas according to claim 1, characterized in that: This also includes the process of correcting for the ship's resistance, as follows: Obtain environmental parameter sets and ship status parameter sets; The environmental parameter set includes at least wind speed and surge height; the ship condition parameter set includes at least rudder angle, load condition parameters, and trim angle. Determine the reference resistance under still water conditions based on the ship's current speed v; Calculate the corrected ship resistance based on the aforementioned baseline resistance and the comprehensive correction factor; The comprehensive correction factor is determined based on the wind speed correction factor, surge height correction factor, rudder angle correction factor, load condition parameter correction factor, and pitch angle correction factor.

7. The method for optimizing ship speed for navigation in ice-covered areas according to claim 1, characterized in that: It also includes the ability to read parameters such as ship speed, wind speed, sea state, and route length from the ship's control system in real time to calculate the ship's optimal speed.

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