Real ship testing method for aerodynamic characteristics of marine wind power boosting device

Abstract

The invention relates to a real ship test method for aerodynamic characteristics of a marine wind power boosting device, and the method comprises the following steps: 1, carrying out a variable-load ship model self-propulsion test on a target ship through employing a forced self-propulsion method, and obtaining a relation graph of the load change and the influence of the water navigational speed on the rotating speed of a propeller shaft; 2, carrying out actual ship trial voyage first speed measurement on the target ship; thirdly, the target ship carries out second-time speed measurement of actual ship trial voyage; 4, calculating a lift coefficient and a resistance coefficient of the wind power boosting rotor based on the results of the two times of speed measurement; and step five, repeating the step two, the step three and the step four, obtaining the lift coefficient and the resistance coefficient of the wind power boosting rotor under other rotating speed ratio working conditions, and establishing an aerodynamic characteristic model. According to the method, the rapidity characteristic and the wind field environment of the ship are used as input, the non-dimensionalized mathematical relationship among the thrust coefficient, the resistance coefficient and the lift coefficient is established, the measurement environment better fits the real environment of the wind power boosting device for the ship, and the test result is more reasonable.

Description

Technical Field

[0001] This application relates to the field of ship energy conservation and emission reduction technology, and in particular to a real-ship testing method for the aerodynamic characteristics of a marine wind-powered propulsion device. Background Technology

[0002] Wind-powered propulsion technology is an effective means for the shipbuilding industry to further enhance energy conservation and emission reduction. Among them, wind-powered propulsion rotors and airfoil sails are two mainstream wind-powered propulsion devices with broad market potential. However, the current evaluation methods for the energy-saving effects of these two types of wind-powered propulsion devices are not yet perfect.

[0003] The contribution of wind-powered propulsion devices to the Energy Efficiency Design Index (EEDI) of ships is used to evaluate the energy-saving effect of wind-powered propulsion devices. Calculating the contribution requires inputting the available effective power f of the device. eff ·P eff The calculation formula is as follows:

[0004]

[0005] Among them, V ref It refers to the speed of a ship in deep water with the wind booster turned off, under the assumption of calm weather conditions and the propulsion power and carrying capacity of the main engine used in EEDI calculations. The unit is knot.

[0006] η D This is the total efficiency of each main drive propulsion system at 75% of the main unit's rated installed power (MCR). Unless otherwise verified, η D It should be set to 0.7.

[0007] F(V ref ) K Given a reference speed V ref The thrust matrix generated by the downwind booster is shown. Each element in the matrix represents the thrust at different wind speeds and wind angles, with the unit being kN. The wind angle is a relative value, with the bow direction being 0°.

[0008] W K This is a global wind probability matrix, where each element represents the probability of wind speed and wind direction relative to the ship's heading. The sum of all elements is 1, and it is dimensionless.

[0009] P(V ref ) K The power consumption matrix represents the power required for the wind-powered booster to operate, and has a relationship with F(V). ref ) K and W K Same size, unit: kW.

[0010] Where F(V) ref) K With P(V) ref ) K It characterizes the performance characteristics of the wind-powered booster, which can be calculated from the aerodynamic characteristics of the device.

[0011] Current methods for testing the aerodynamic characteristics of wind-powered propulsion devices all use model-scale devices as the test objects and ignore the scale effect, directly applying model-scale measurement data to full-scale wind-powered propulsion devices. Since the scale effect of wind-powered propulsion devices is not yet fully understood, the reliability of this method is questionable.

[0012] Therefore, we propose a real-ship testing method for the aerodynamic characteristics of marine wind-powered propulsion devices.

[0013] Application content

[0014] To address the shortcomings of existing production technologies, this applicant provides a real-ship testing method for the aerodynamic characteristics of marine wind-powered propulsion devices. For wind-powered propulsion rotors, the method can obtain the lift coefficient, drag coefficient, and power coefficient of the rotor under different speed ratios; for airfoil sails, the method can obtain the lift coefficient and drag coefficient of the sail under different angles of attack. The measured aerodynamic characteristics can be used to calculate the thrust matrix and consumption matrix of the wind-powered propulsion device, which can be used to calculate the EEDI contribution of the wind-powered propulsion device.

[0015] The technical solution adopted in this application is as follows:

[0016] A method for conducting on-ship testing of the aerodynamic characteristics of a marine wind-powered propulsion device includes the following steps:

[0017] Step 1: Conduct a variable load self-propulsion test on the target ship using the forced self-propulsion method. Based on the model test results, predict the relationship between the actual ship load changes and the impact of surface speed on the propeller shaft speed. Obtain the variable load coefficient ξ under different surface speeds through linear fitting. R :

[0018]

[0019] Where dn is the propeller speed variation and dΔR is the load variation, the variable load coefficient ξ is obtained. R Relationship between speed and water speed;

[0020] Step 2: Conduct the first speed measurement during a full-scale sea trial of the target vessel. Start the wind-powered propulsion rotor, avoiding tailwind or headwind conditions. After the vessel speed has stabilized for 10 minutes, use differential GPS to measure the vessel's ground speed. The rotational speed of the wind-driven rotor is measured using a speed sensor. The power consumption P of the wind-powered booster rotor was measured using a shaft power meter. rotor The ship's speed relative to the water was calculated using the tidal correction method. The propeller speed n under ideal conditions of no wind and no waves was calculated using the direct power method.

[0021] Calculate the relative wind speed acting on the wind-powered booster rotor.

[0022]

[0023] in, This refers to the absolute wind speed within the test voyage area;

[0024] Calculate the wind-powered booster rotor speed ratio α rotor :

[0025]

[0026] Where φ is the diameter of the wind-powered rotor;

[0027] Calculate the load change ΔR under the current operating conditions of water speed and propeller speed:

[0028]

[0029] Where, n0 is the interpolation value based on the relationship between the actual ship load change and the influence of the water speed on the propeller shaft speed in the first step. Propeller speed when load change ΔR is 0; ξ R To interpolate the water speed based on the relationship between the variable load coefficient and the water speed in the first step, The variable load factor at that time;

[0030] Calculate the thrust T of the wind-powered booster rotor rotor :

[0031] T rotor =-ΔR(5);

[0032] The rotor thrust is dimensionlessly processed as follows to obtain the thrust coefficient C. T :

[0033]

[0034] Where H is the height of the wind-powered rotor; ρ is the air density calculated based on the air temperature measured in the test zone before the test.

[0035] Calculate the power coefficient C of the wind-powered booster rotor P :

[0036]

[0037] Step 3: The target ship conducts the second speed measurement during the actual sea trial. The wind-powered propulsion rotor is activated, and after the ship speed stabilizes for 10 minutes, the speed relative to the ground is measured. Wind-assisted rotor speed Power consumption P' of the wind-powered rotor rotor The ship's speed relative to the water was calculated using the tidal correction method. The propeller speed n' under ideal conditions of no wind and no waves was calculated using the direct power method.

[0038] Calculate the relative wind speed according to formula (2). The wind-assisted rotor speed ratio α' is calculated according to formula (3). rotor If α' rotor ≠α rotor The measurement result is invalid; adjust the wind-driven rotor speed according to the direction of deviation, and after the ship speed stabilizes, measure again and recalculate the wind-driven rotor speed ratio α'. rotor , until α' rotor =α rotor ;

[0039] Based on the relationship between the actual ship load changes and the influence of the water speed on the propeller shaft speed in the first step, interpolation is performed for the water speed. When the load change ΔR is 0, the propeller speed n'0; based on the relationship between the variable load coefficient and the water speed in the first step, the water speed is interpolated as follows: Load variation coefficient ξ' R ;

[0040] Calculate the drag change ΔR' according to formula (4); calculate the wind-assisted rotor thrust T' according to formula (5). rotor ; Calculate the thrust coefficient C' according to formula (6) T ;

[0041] Step 4: Based on the results of the two sea trials and speed measurements, the following system of equations is established:

[0042]

[0043] Solving this equation yields the calculated speed ratio α. rotor Under operating conditions, the lift coefficient C of the wind-powered booster rotor L With drag coefficient C D ;

[0044] Step 5: Repeat steps 2, 3, and 4 to obtain the lift coefficient C of the wind-driven rotor under other speed ratio conditions. L With drag coefficient C D Establish an aerodynamic characteristic model:

[0045]

[0046] Its further features are:

[0047] In the first step, during the variable load test, the load change ΔR m The range of variation is:

[0048]

[0049] Among them, R m For the resistance of the ship model.

[0050] In the first step, the water speed during the variable load test is at least V. ref Five speed points were selected within a range of ±2 (kn);

[0051] Among them, V ref Given a reference speed.

[0052] In the second step, the absolute wind speed in the test zone... Measurements were taken before the actual ship underwent sea trials.

[0053] If the target ship uses an airfoil sail, the rotational speed ratio α will be... rotor The angle of attack α was changed to an airfoil sail. wing Angle of attack α wing For the chord of the airfoil and The angle between the two speed tests is ensured; to ensure the angle of attack is the same during both speed tests, and that the airfoil sail consumes no power during operation, the aerodynamic characteristic model is established as follows:

[0054]

[0055] The beneficial effects of this application are as follows:

[0056] This application features a compact and reasonable structure, and is easy to operate. Rapid model tests were conducted on the target vessel during its design process using a forced self-propulsion method. The test data required to establish this relationship can be directly obtained from the model test report, eliminating the need for additional model tests. The ship speed, wind speed, and propeller speed measured during the actual sea trials are all physical quantities required by existing sea trial procedures. Only the wind-powered propulsion rotor speed and power consumption, and the angle of attack of the airfoil sail, require additional measurement. Compared to existing actual sea trial procedures, this requires fewer additional procedures and equipment. Compared to methods for measuring aerodynamic characteristics of wind-powered propulsion devices based on model-scale measurements, the measurement environment of this application more closely resembles the real-world environment of marine wind-powered propulsion devices, resulting in more reasonable test results.

[0057] In addition, this application also has the following advantages:

[0058] (1) The thrust generated by the wind-powered propulsion device is regarded as a negative increase in the actual ship resistance. The thrust generated by the wind-powered propulsion device is calculated based on the relationship between load changes and the influence of the water speed on the propeller speed. Furthermore, the thrust coefficient is decomposed into the lift coefficient and drag coefficient of the wind-powered propulsion device. The method of obtaining the thrust matrix is ​​simplified from measuring the thrust under different wind speeds and wind direction angles to measuring the lift coefficient and drag coefficient of the wind-powered propulsion device under different operating conditions.

[0059] (2) For wind-powered rotors, by controlling the rotor speed ratio to be the same during two speed measurements, a dimensionless mathematical relationship between the thrust coefficient, drag coefficient and lift coefficient is established to obtain the drag coefficient and lift coefficient.

[0060] (3) For airfoil sails, by controlling the angle of attack of the airfoil sail to be the same during the two speed measurements, a mathematical relationship between the dimensionless thrust coefficient, drag coefficient and lift coefficient is established to obtain the drag coefficient and lift coefficient. Attached Figure Description

[0061] Figure 1 This is a diagram showing the relationship between load variation and the influence of water speed on propeller shaft speed in this application.

[0062] Figure 2 This is a graph showing the relationship between the ship's speed over water and the propeller speed when the ship is unloaded, as per this application.

[0063] Figure 3 This is a diagram showing the relationship between the actual ship's speed and the load coefficient in this application.

[0064] Figure 4 This is a schematic diagram of the aerodynamic characteristics model of the wind-powered booster rotor in this application.

[0065] Figure 5 This is a schematic diagram of the aerodynamic model of the airfoil sail in this application.

[0066] Figure 6 This is a schematic diagram showing the wind speed, ship speed, and forces acting on the wind-powered propulsion rotor of this application.

[0067] Figure 7 This is a schematic diagram of the wind speed, ship speed, and forces of the airfoil sail in this application.

[0068] Figure 8 This is a schematic diagram of the actual ship trial process for this application.

[0069] Figure 9 This is a flowchart of the testing method for this application. Detailed Implementation

[0070] The specific embodiments of this application are described below with reference to the accompanying drawings.

[0071] like Figures 1-8As shown, a method for conducting on-ship testing of the aerodynamic characteristics of a marine wind-powered propulsion device includes the following steps:

[0072] Step 1: Conduct a variable load self-propulsion test on the target ship using the forced self-propulsion method. Based on the model test results, predict the relationship between the actual ship load changes and the impact of surface speed on the propeller shaft speed. Obtain the variable load coefficient ξ under different surface speeds through linear fitting. R :

[0073]

[0074] Where dn is the propeller speed variation and d(ΔR) is the load variation, the variable load coefficient ξ is obtained. R Relationship between speed and water speed;

[0075] Step 2: Conduct the first speed measurement during a full-scale sea trial of the target vessel. Start the wind-powered propulsion rotor, avoiding tailwind or headwind conditions. After the vessel speed has stabilized for 10 minutes, use differential GPS to measure the vessel's ground speed. The rotational speed of the wind-driven rotor is measured using a speed sensor. The power consumption P of the wind-powered booster rotor was measured using a shaft power meter. rotor The ship's speed relative to the water was calculated using the tidal correction method. The propeller speed n under ideal conditions of no wind and no waves was calculated using the direct power method.

[0076] Calculate the relative wind speed acting on the wind-powered booster rotor.

[0077]

[0078] in, The absolute wind speed in the sea trial area is measured before the actual ship's sea trial.

[0079] Calculate the wind-powered booster rotor speed ratio α rotor :

[0080]

[0081] Where φ is the diameter of the wind-powered rotor;

[0082] Calculate the load change ΔR under the current operating conditions of water speed and propeller speed:

[0083]

[0084] Where, n0 is the interpolation value based on the relationship between the actual ship load change and the influence of the water speed on the propeller shaft speed in the first step. Propeller speed when load change ΔR is 0; ξ RTo interpolate the water speed based on the relationship between the variable load coefficient and the water speed in the first step, The variable load factor at that time;

[0085] Calculate the thrust T of the wind-powered booster rotor r0tor :

[0086] T rotor =-ΔR(5)

[0087] The rotor thrust is dimensionlessly processed as follows to obtain the thrust coefficient C. T :

[0088]

[0089] Where H is the height of the wind-powered rotor; ρ is the air density calculated based on the air temperature measured in the test zone before the test.

[0090] Calculate the power coefficient C of the wind-powered booster rotor P :

[0091]

[0092] Step 3: The target ship conducts the second speed measurement during the actual sea trial. The wind-powered propulsion rotor is activated, and after the ship speed stabilizes for 10 minutes, the speed relative to the ground is measured. Wind-assisted rotor speed Power consumption P' of the wind-powered rotor rotor The ship's speed relative to the water was calculated using the tidal correction method. The propeller speed n' under ideal conditions of no wind and no waves was calculated using the direct power method.

[0093] Calculate the relative wind speed according to formula (2). The wind-assisted rotor speed ratio α' is calculated according to formula (3). rotor If α' rotor ≠α rotor The measurement result is invalid; adjust the wind-driven rotor speed according to the direction of deviation, and after the ship speed stabilizes, measure again and recalculate the wind-driven rotor speed ratio α'. rotor , until α' rotor =α rotor ;

[0094] Based on the relationship between the actual ship load changes and the influence of the water speed on the propeller shaft speed in the first step, interpolation is performed for the water speed. When the load change ΔR is 0, the propeller speed n'0; based on the relationship between the variable load coefficient and the water speed in the first step, the water speed is interpolated as follows: Load variation coefficient ξ' R ;

[0095] Calculate the load change ΔR' according to formula (4); calculate the wind-assisted rotor thrust T' according to formula (5). rotor ; Calculate the thrust coefficient C' according to formula (6) T ;

[0096] Step 4: Based on the results of the two sea trials and speed measurements, the following system of equations is established:

[0097]

[0098] Solving this equation yields the calculated speed ratio α. rotor Under operating conditions, the lift coefficient C of the wind-powered booster rotor L With drag coefficient C D ;

[0099] Step 5: Repeat steps 2, 3, and 4 to obtain the lift coefficient C of the wind-driven rotor under other speed ratio conditions. L With drag coefficient C D Establish an aerodynamic characteristic model:

[0100]

[0101] In the first step, during the variable load test, the increase in resistance ΔR m The range of variation is:

[0102]

[0103] Among them, R m For the resistance of the ship model.

[0104] In the first step, the water speed during the variable load test is at least V. ref Five speed points were selected within a range of ±2 (kn);

[0105] Among them, V ref Given a reference speed.

[0106] The target ship uses an airfoil sail, with a rotational speed ratio of α. rotor The angle of attack α was changed to an airfoil sail. wing The angle of attack of an airfoil sail is as follows: Figure 7 As shown; α wing For the chord of the airfoil and The angle between the two speed tests is ensured; to ensure the angle of attack is the same during both speed tests, and that the airfoil sail consumes no power during operation, the aerodynamic characteristic model is established as follows:

[0107]

[0108] The target ship underwent rapid model tests using the forced self-propulsion method during its design process. The test data required to establish this relationship diagram can be directly obtained from the model test report, without the need for additional model tests.

[0109] The ship speed, wind speed, and propeller speed measured during the target ship's sea trials are all physical quantities required by existing sea trial procedures. Only the wind-powered propeller rotor speed and power consumption, and the angle of attack of the airfoil sail, require additional measurement. Compared to existing sea trial procedures, this method requires fewer additional procedures and equipment. Compared to methods that measure aerodynamic characteristics based on model-scale wind-powered propulsion devices, this method's measurement environment is closer to the real environment of marine wind-powered propulsion devices, resulting in more reasonable test results.

[0110] This method treats the thrust generated by the wind-powered propulsion system as a negative increase in the ship's resistance, calculating the thrust based on the relationship between load changes and the influence of onboard speed on propeller speed. Furthermore, the thrust coefficient is decomposed into the lift and drag coefficients of the wind-powered propulsion system, simplifying the method of obtaining the thrust matrix from measuring thrust at different wind speeds and angles to measuring the lift and drag coefficients of the wind-powered propulsion system under different operating conditions.

[0111] For wind-powered booster rotors, a method is used to obtain the drag coefficient and lift coefficient by establishing a dimensionless mathematical relationship between the rotor speed ratio during two speed measurements.

[0112] For airfoil sails, by controlling the angle of attack of the airfoil sail to be the same in two speed measurements, a mathematical relationship between the dimensionless thrust coefficient, drag coefficient, and lift coefficient is established to obtain the drag coefficient and lift coefficient.

[0113] The above description is an explanation of this application and not a limitation thereof. The scope of this application is defined by the claims. Within the scope of protection of this application, any form of modification may be made.

Claims

1. A method for conducting on-ship testing of the aerodynamic characteristics of a marine wind-powered propulsion device, characterized in that, Includes the following steps: Step 1: Conduct a variable load self-propulsion test on the target ship using the forced self-propulsion method. Based on the model test results, predict the relationship between the actual ship load changes and the impact of surface speed on the propeller shaft speed. Obtain the variable load coefficient ξ under different surface speeds through linear fitting. R : Where dn is the propeller speed variation and dΔR is the load variation, the variable load coefficient ξ is obtained. R Relationship between speed and surface speed; Step 2: Conduct the first speed measurement during a full-scale sea trial of the target vessel. Start the wind-powered propulsion rotor, avoiding tailwind or headwind conditions. After the vessel speed has stabilized for 10 minutes, use differential GPS to measure the vessel's ground speed. The rotational speed of the wind-driven rotor is measured using a speed sensor. The power consumption p of the wind-powered booster rotor was measured using a shaft power meter. rotor The ship's speed relative to the water was calculated using the tidal correction method. The propeller speed n under ideal conditions of no wind and no waves was calculated using the direct power method. Calculate the relative wind speed acting on the wind-powered booster rotor. in, This refers to the absolute wind speed within the test voyage area; Calculate the wind-powered booster rotor speed ratio α rotor : Where φ is the diameter of the wind-powered rotor; Calculate the load change ΔR under the current operating conditions of water speed and propeller speed: Where, n0 is the interpolation value based on the relationship between the actual ship load change and the influence of the water speed on the propeller shaft speed in the first step. Propeller speed when load change ΔR is 0; ξ R To interpolate the water speed based on the relationship between the variable load coefficient and the water speed in the first step, The variable load factor at that time; Calculate the thrust T of the wind-powered booster rotor rotor : T rotor =-ΔR(5); The rotor thrust is dimensionlessly processed as follows to obtain the thrust coefficient C. T : Where H is the height of the wind-powered rotor; ρ is the air density calculated based on the air temperature measured in the test zone before the test. Calculate the power coefficient C of the wind-powered booster rotor P : Step 3: The target ship conducts the second speed measurement during the actual sea trial. The wind-powered propulsion rotor is activated, and after the ship speed stabilizes for 10 minutes, the speed relative to the ground is measured. Wind-assisted rotor speed Power consumption P' of the wind-powered rotor rotor The ship's speed relative to the water was calculated using the tidal correction method. The propeller speed n' under ideal conditions of no wind and no waves was calculated using the direct power method. Calculate the relative wind speed according to formula (2). The wind-assisted rotor speed ratio α' is calculated according to formula (3). rotor If α' rotor ≠α rotor The measurement result is invalid; adjust the wind-driven rotor speed according to the direction of deviation, and after the ship speed stabilizes, measure again and recalculate the wind-driven rotor speed ratio α'. rotor , until α' rotor =α rotor ; Based on the relationship between the actual ship load changes and the influence of the water speed on the propeller shaft speed in the first step, interpolation is performed for the water speed. When the load change ΔR is 0, the propeller speed n'0; based on the relationship between the variable load coefficient and the water speed in the first step, the water speed is interpolated as follows: Load variation coefficient ξ' R ; Calculate the drag change ΔR' according to formula (4); calculate the wind-assisted rotor thrust T' according to formula (5). rotor ; Calculate the thrust coefficient C' according to formula (6) T ; Step 4: Based on the results of the two sea trials and speed measurements, the following system of equations is established: Solving this equation yields the calculated speed ratio α. rotor Under operating conditions, the lift coefficient C of the wind-powered booster rotor L With drag coefficient C D ; Step 5: Repeat steps 2, 3, and 4 to obtain the lift coefficient C of the wind-driven rotor under other speed ratio conditions. L With drag coefficient C D Establish an aerodynamic characteristic model:

2. The method for conducting on-ship testing of the aerodynamic characteristics of a marine wind-powered propulsion device as described in claim 1, characterized in that: In the first step, during the variable load test, the load change ΔR m The range of variation is: Among them, R m For the resistance of the ship model.

3. The method for conducting on-ship testing of the aerodynamic characteristics of a marine wind-powered propulsion device as described in claim 1, characterized in that: In the first step, the water speed during the variable load test is at least V. ref Five speed points were selected within a range of ±2 (kn); Among them, V ref Given a reference speed.

4. The method for conducting on-ship testing of the aerodynamic characteristics of a marine wind-powered propulsion device as described in claim 1, characterized in that: In the second step, the absolute wind speed in the test zone... Measurements were taken before the actual ship underwent sea trials.

5. The method for conducting on-ship testing of the aerodynamic characteristics of a marine wind-powered propulsion device as described in claim 1, characterized in that: If the target ship uses an airfoil sail, the rotational speed ratio α will be... rotor The angle of attack α was changed to an airfoil sail. wing Angle of attack α wing For the chord of the airfoil and The angle between the two speed tests is ensured; to ensure the angle of attack is the same during both speed tests, and that the airfoil sail consumes no power during operation, the aerodynamic characteristic model is established as follows:

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