A method for calculating the speed and flow rate matching of a ship's circulating water pump and conducting operating condition simulation tests.

Abstract

This invention relates to the field of marine power plant control technology, specifically to a method for calculating and simulating the operating conditions of a ship's circulating water pump speed-flow matching. The method includes: obtaining the gravity flow speed of the circulating water pump unit under forward navigation conditions; determining the current gravity flow rate by querying a pre-generated gravity flow rate and gravity flow speed characteristic curve based on the gravity flow speed; obtaining the seawater demand flow rate of the condenser under the current operating conditions; determining the flow rate difference based on the gravity flow rate and the seawater demand flow rate; querying a pre-generated flow rate difference and speed difference characteristic curve to determine the required speed increase; and determining the required speed of the turbine circulating water pump unit based on the gravity flow speed and the speed increase. This invention calculates the real-time seawater flow rate and the required speed of the circulating water pump under different forward navigation conditions solely based on the pump's gravity flow speed and the seawater flow rate required by the condenser.

Description

Technical Field

[0001] This invention relates to the field of marine power plant control technology, specifically to a method for calculating the matching speed and flow rate of a marine circulating water pump and conducting operational condition simulation tests. Background Technology

[0002] The turbine circulating water pump unit is an important component of marine propulsion systems, drawing seawater to provide a cold source for cooling the condensers in the propulsion system. By controlling the rotational speed of the turbine circulating water pump unit, different flow rates of cooling water are supplied to the condensers, ensuring the safe operation of the propulsion system. When the ship is sailing forward, due to the relative motion between the hull and the seawater, seawater enters the turbine circulating water pump unit through the bottom valve. The flow rate into the turbine circulating water pump unit at this time is called the gravity flow rate. Under the action of water gravity flow, the impeller will automatically rotate to generate a rotational speed, called the gravity speed. When the ship is sailing forward at different speeds, the required flow rate and gravity flow rate of the condenser will vary under each operating condition.

[0003] Due to the compact layout of the ship's propulsion system, environmental conditions are unsuitable for installing flow meters to measure seawater flow, making it impossible to determine the seawater flow rate that the turbine circulating water pump unit can provide at a certain speed. To ensure that the water supply from the turbine circulating water pump unit meets the condenser's water requirements, it has traditionally been necessary to spend considerable time determining the required speed of the turbine circulating water pump unit at different ship speeds using extensive navigation test data and engineering experience. This method is not only time-consuming and labor-intensive, but also yields inaccurate speed measurements, which is detrimental to the ship's economic efficiency. To ensure the condenser's water requirements and improve the ship's navigation economy, a method is needed to calculate the required speed of the circulating water pump under different navigation conditions based solely on the circulating water pump speed and the seawater flow rate required by the condenser, as well as a test method simulating the ship's forward navigation conditions. Summary of the Invention

[0004] This invention addresses the technical problems existing in the prior art by providing a method for calculating the matching speed and flow rate of a ship's circulating water pump and conducting operational condition simulation tests.

[0005] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A method for calculating the matching speed and flow rate of a ship's circulating water pump and conducting operating condition simulation tests, comprising the following steps:

[0006] S101. Obtain the gravity flow speed of the circulating water pump set when the ship is sailing forward;

[0007] S102. Based on the self-flow speed, query the pre-generated self-retained flow rate and self-flow speed characteristic curve to determine the current self-flow flow rate;

[0008] S103. Obtain the seawater demand flow rate of the condenser under the current operating conditions. Based on the gravity flow rate and the seawater demand flow rate, determine the flow rate difference. Query the pre-generated characteristic curve of flow rate difference and speed difference to determine the required speed increase value.

[0009] S104. Based on the gravity flow speed and the speed increase value, determine the required speed of the turbine circulating water pump set.

[0010] Furthermore, in step S101, seawater, under the influence of the ship's forward kinetic energy, flows into the turbine circulating water pump unit through seawater pipes and seabed valves at the bottom of the hull, driving its impeller to idle, thereby generating a gravity-driven rotational speed converted from the ship's kinetic energy. ;

[0011] Gravity rotation speed The mechanical speed is directly measured by a speed measuring device installed on the turbine circulating water pump unit. The measured mechanical signal is converted into an electrical signal, which is then received, converted, and processed by a data acquisition and processing system, and finally output. Numerical value.

[0012] Furthermore, in S102, the gravity flow rate and gravity speed characteristic curves are obtained by simulating different gravity flow conditions encountered during ship navigation in a laboratory environment by closing the air inlet valve of the circulating water pump and adjusting the speed of the booster pump. For each set stable self-flow rate A two-dimensional coordinate point is constructed, and after repeated experiments on all gravity flow target values, a discrete data point set covering the expected flow range is obtained.

[0013] Furthermore, based on the acquired discrete data point set, a continuous curve is generated by fitting using the least squares method for a set of experimental data points. ， Assume that the fitted polynomial curve is:

[0014]

[0015] Where n represents the predicted rotational speed of the gravity flow output by the fitted polynomial, and Q represents the gravity flow rate. , , , The coefficient vector represents the polynomial coefficients, k represents the polynomial order, and the coefficient vector is determined. To minimize the objective function S, the following system of equations is solved:

[0016]

[0017] Specifically, S can be represented as:

[0018]

[0019] Where m represents the total number of test points, that is, the number of test data pairs participating in the fitting. This represents the measured value of the gravity flow speed at the i-th test point. Let X represent the measured gravity flow rate at the i-th test point, X represent the design matrix, a represent the coefficient vector, and n represent the number of observations. This represents the product of the transpose of the design matrix and itself. Let X represent the product of the transpose of the design matrix and the observation vector. For the design matrix X, its elements are defined as:

[0020]

[0021] n is the observation vector, which can be represented as:

[0022]

[0023] Where j represents the column index of the design matrix, and T is the matrix transpose symbol;

[0024] For any self-flowing speed falling within the test range Find the corresponding gravity flow rate value through the continuous curve. This includes: the real-time measured rotational speed of the free-flowing engine. As input conditions, through preset... Perform query and matching operations on the characteristic curve, map and output the gravity flow value corresponding to the current navigation condition. .

[0025] Furthermore, in step S103, the current operating condition is identified, and the corresponding function is directly invoked. The value is used to calculate the difference in traffic flow, which can be specifically represented as:

[0026]

[0027] like This indicates insufficient gravity supply, requiring the calculation process to increase rotational speed. If the flow rate is within the required range, it indicates that the gravity flow rate has met the demand, and the process can proceed directly to the gravity flow condition determination stage.

[0028] Furthermore,

[0029] Furthermore, when When querying Characteristic curves determine the speed increase value During the query, first determine if there is a match for the current self-flowing flow. Completely Corresponding If the curve exists, then directly based on... The value is uniquely determined on the curve. If it does not exist, the interpolation calculation process needs to be started.

[0030] Furthermore, interpolation calculations require obtaining data related to the current... Two adjacent test gravity flow values and and its corresponding Characteristic curves, based on the same flow rate difference The first speed increase value was found on both curves. 1 and the second speed increase value Subsequently, with For input variables, in 1 and Linear interpolation is performed between them, and the specific calculation formula is as follows:

[0031]

[0032] Based on linear interpolation, the applicable value is calculated. Speed ​​increase value .

[0033] Furthermore, after completing the gravity flow... Once determined, execute the condition determination branch. If so, it is directly determined that the current condition is gravity flow and the required speed is determined. Equal to the rotational speed of gravity At this time, the turbine circulating water pump set does not require steam drive. When the ship switches from operating condition a to operating condition b, if the relationship between the gravity flow rate and the demand flow rate changes from... Transform into b≤ If b, then condition b is determined to be the switching point between gravity flow and gravity flow conditions.

[0034] Furthermore, in S104, based on the self-flowing speed... With query Speed ​​increase value determined by characteristic curve n, perform arithmetic composition calculations to determine the required speed of the turbine circulating water pump set. The specific calculation formula is as follows: .

[0035] Furthermore, the required rotational speed As the ultimate speed control target for the turbine circulating water pump unit, the steam flow rate entering the driving turbine is adjusted by controlling the opening of the intake valve, thereby adjusting the actual speed of the turbine circulating water pump unit to... To determine the circulating water flow rate and the seawater demand flow rate of the condenser. Matching.

[0036] The beneficial effects of this invention are:

[0037] 1. This invention effectively utilizes the test data from the land-based test bench of the turbine circulating water pump set, establishing a relationship between the gravity flow speed and gravity flow rate obtained in the laboratory test and the speed increment and seawater flow increment during forward navigation of the ship. During actual ship navigation, the real-time seawater flow rate and the required speed of the circulating water pump under different forward navigation conditions can be calculated solely based on the water pump gravity flow speed and the seawater flow rate required by the condenser. This solves the problem that there is no flow meter on the actual ship, making it impossible to obtain the circulating water flow rate and quickly determine the circulating water pump speed.

[0038] 2. Based on this calculation method, by consulting the ΔQ-Δn characteristic curve and comparing the required flow rate of the condenser with the actual seawater flow rate, the switching point of gravity flow can be quickly determined, thereby improving the economy of the ship during navigation. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the test system of the present invention;

[0040] Figure 2 A schematic diagram of the actual ship installation of the circulating water pump;

[0041] Figure 3 To determine the gravity flow rate Q 自 ;

[0042] Figure 4 The interpolation calculation yields Δn;

[0043] Figure 5 Self-flowing flow Q 自1 The ΔQ-Δn curve under the given conditions;

[0044] Figure 6 A set of ΔQ-Δn curves under different gravity flow rates;

[0045] Figure 7 Gravity flow rate and gravity flow speed Q 自 -n 自 curve;

[0046] Figure 8 Flowchart of ship navigation condition simulation test;

[0047] Figure 9 Flowchart of the method for calculating the required rotational speed of a real ship;

[0048] Figure 10 This is a flowchart of the method of the present invention. Detailed Implementation

[0049] The present invention will now be further described with reference to the accompanying drawings.

[0050] like Figure 1 The laboratory's testing system mainly consists of a turbine circulating water pump unit 1, a booster pump 2, a data acquisition and processing system 3, a steam inlet valve 4, a speed measuring device 5, and a flow meter 6. The booster pump 2 provides the required gravity flow to the turbine circulating water pump unit 1; the data acquisition and processing system 3 records and processes the data; the steam inlet valve 4 adjusts the steam flow entering the turbine circulating water pump unit 1 to control its speed; the speed measuring device 5 measures the speed of the turbine circulating water pump unit 1; and the flow meter 6 measures the flow rate of the circulating water.

[0051] like Figure 2 When the circulating water pump is installed on the actual ship, it is directly connected to the seawater pipe 7 at the bottom of the hull 8. Under the relative movement between the hull and the seawater, the seawater flows through the seawater pipe 7 and the turbine circulating water pump set 1 in sequence before entering the condenser 9.

[0052] like Figure 1-10 This embodiment provides a method for calculating the matching speed and flow rate of a ship's circulating water pump and conducting operational condition simulation tests, including the following steps:

[0053] S101. Obtain the gravity flow speed of the circulating water pump set when the ship is sailing forward. ;

[0054] Furthermore, under the influence of the ship's forward kinetic energy, seawater flows into the turbine circulating water pump unit through seawater pipes and sea valves at the bottom of the hull, driving its impeller to rotate freely, thereby generating a rotational speed converted from the ship's kinetic energy. This rotational speed is defined as the gravity flow speed. ;

[0055] Gravity rotation speed The mechanical speed is directly measured by a speed measuring device installed on the turbine circulating water pump unit. The measured mechanical signal is converted into an electrical signal, which is then received, converted, and processed by a data acquisition and processing system, and finally output. Numerical value.

[0056] S102, Based on the aforementioned self-flowing speed Query the pre-generated retention flow rate and gravity flow rate characteristic curves to determine the current gravity flow rate. ;

[0057] Furthermore, the gravity flow rate and gravity speed characteristic curves were obtained by simulating different gravity flow conditions encountered during ship navigation in a laboratory environment by closing the air inlet valve of the circulating water pump and adjusting the speed of the booster pump. For each set stable self-flow rate A two-dimensional coordinate point is constructed, and after repeated experiments on all gravity flow target values, a set of discrete data points covering the expected flow range is obtained;

[0058] Based on this discrete data point set, a continuous curve is generated by fitting using the least squares method for a set of experimental data points. ， Assume that the fitted polynomial curve is:

[0059]

[0060] Where n represents the predicted rotational speed of the gravity flow output by the fitted polynomial, and Q represents the gravity flow rate. , , , The coefficient vector represents the polynomial coefficients, k represents the polynomial order, and the coefficient vector is determined. To minimize the objective function S, the following system of equations is solved:

[0061]

[0062] Specifically, S can be represented as:

[0063]

[0064] Where m represents the total number of test points, that is, the number of test data pairs participating in the fitting. This represents the measured value of the gravity flow speed at the i-th test point. Let X represent the measured gravity flow rate at the i-th test point, X represent the design matrix, a represent the coefficient vector, and n represent the number of observations. This represents the product of the transpose of the design matrix and itself. Let X represent the product of the transpose of the design matrix and the observation vector. For the design matrix X, its elements are defined as:

[0065]

[0066] n is the observation vector, which can be represented as:

[0067]

[0068] Where j represents the column index of the design matrix, and T is the matrix transpose symbol;

[0069] For any self-flowing speed falling within the test range The corresponding gravity flow rate can be found through this continuous curve. ， In practical applications, the self-flowing speed measured in real time will be used... As input conditions, through this preset By performing query and matching operations on the characteristic curve, the gravity flow value corresponding to the current navigation condition can be mapped and output. .

[0070] S103. Obtain the seawater demand flow rate of the condenser under the current operating conditions. Based on the self-flowing flow rate With seawater demand flow ， Determine the flow rate difference, query the pre-generated characteristic curve of flow rate difference versus speed difference, and determine the required speed increase value. n;

[0071] Furthermore, it identifies the current operating condition and directly calls the corresponding... The value is used to calculate the difference in traffic flow, which can be specifically represented as:

[0072]

[0073] like This indicates insufficient gravity supply, requiring the calculation process to increase rotational speed. If the flow rate is within the required range, it indicates that the gravity flow rate has met the demand and the process can proceed directly to the gravity flow condition determination stage.

[0074] when When querying Characteristic curves determine the speed increase value During the query, first determine if there is a match for the current self-flowing flow. Completely Corresponding If the curve exists, then directly based on... The value is uniquely determined on the curve. If it does not exist, the interpolation calculation process needs to be started;

[0075] Interpolation calculations require obtaining the current... Two adjacent test gravity flow values and and its corresponding Characteristic curves, based on the same flow rate difference The first speed increase value was found on both curves. 1 and the second speed increase value Subsequently, with For input variables, in 1 and Linear interpolation is performed between them, and the specific calculation formula is as follows:

[0076]

[0077] Based on linear interpolation, the applicable value is calculated. Speed ​​increase value ;

[0078] After completing the self-flowing flow Once determined, execute the condition determination branch. If so, it is directly determined that the current condition is gravity flow and the required speed is determined. Equal to the rotational speed of gravity At this time, the turbine circulating water pump set does not require steam drive. When the ship switches from operating condition a to operating condition b, if the relationship between the gravity flow rate and the demand flow rate changes from... Transform into b≤ If condition b is selected, then condition b is determined to be the switching point of gravity flow. The identification of this switching point realizes the automatic optimization of power supply. Under the premise of ensuring the water demand of the condenser, the gravity flow effect of navigation is utilized to the maximum extent to improve the economy of the ship.

[0079] S104, Based on gravity flow speed With speed increase value n, determine the required speed of the turbine circulating water pump set. .

[0080] Furthermore, based on the aforementioned self-flowing speed... With query Speed ​​increase value determined by characteristic curve n, perform arithmetic composition calculations to determine the required speed of the turbine circulating water pump set. The specific calculation formula is as follows:

[0081]

[0082] The required rotation speed As the ultimate speed control target for the turbine circulating water pump unit, the steam flow rate entering the driving turbine is adjusted by controlling the opening of the intake valve, thereby adjusting the actual speed of the turbine circulating water pump unit to... Ultimately, the circulating water flow rate is matched with the seawater demand flow rate of the condenser under this operating condition. Matching.

[0083] Example 2

[0084] This embodiment provides a test method for simulating the forward navigation of a ship to obtain... - and Methods for obtaining characteristic curves include:

[0085] For different gravity flow conditions (Include , ...... ), The characteristic curves are different, so different gravity flow rates are required. Experiments under the conditions of gravity flow rate Taking conditional experiments as an example:

[0086] Step 1: Given the maximum circulating water flow rate for the experiment This value represents the maximum flow rate that needs to be achieved during the test, and... ~ Set k flow recording points between them , ...... , .

[0087] Step 2: Close the steam inlet valve 4 of the circulating water pump, and adjust the speed of the booster pump 2 to change the gravity flow rate until the gravity flow rate reaches the target value. Maintain the speed of the pre-pump 2 until then, and record the gravity flow speed at this point. and ;

[0088] Step 3: Increase the opening of the steam inlet valve 4, gradually increase the speed of the turbine circulating water pump unit 1, thereby increasing the circulating water flow rate. Each time the circulating water flow rate reaches the flow recording point... (Include , ...... , When the turbine circulating water pump unit 1 rotates at that time, record the corresponding rotational speed. (Include , ...... , );

[0089] Step 4: Calculation = - (Include = - ...... = - )and = - (Include = - ...... = - After the calculation is completed, the resulting plot is obtained based on the multiple data points. Figure 5 The gravity flow rate shown Under the conditions - curve;

[0090] Step 5: Using gravity flow rate replace Using these as initial conditions, repeat steps 2-4 until all gravity flow is completed. (Include , ...... The experiment, based on calculations and , generate as Figure 6 The curve group shown; based on the data recorded in step 2. (Include ...... ), (Include , ...... ), can yield results such as Figure 7 gravity flow rate and gravity rotation speed - Characteristic curves curve group and - The curve is used to guide the calculation of the required rotational speed of the circulating water pump during actual navigation.

Claims

1. A method for calculating the matching speed and flow rate of a ship's circulating water pump and conducting operational condition simulation tests, characterized in that, Includes the following steps: S101. Obtain the gravity flow speed of the circulating water pump set when the ship is sailing forward; S102. Based on the self-flow speed, query the pre-generated self-retained flow rate and self-flow speed characteristic curve to determine the current self-flow flow rate; S103. Obtain the seawater demand flow rate of the condenser under the current operating conditions. Based on the gravity flow rate and the seawater demand flow rate, determine the flow rate difference. Query the pre-generated characteristic curve of flow rate difference and speed difference to determine the required speed increase value. Identify the current operating condition and directly call the corresponding function. The value is used to calculate the difference in traffic flow, which can be specifically represented as: like This indicates insufficient gravity supply, requiring the calculation process to increase rotational speed. If the flow rate is within the required range, it indicates that the gravity flow rate has met the demand and the process can proceed directly to the gravity flow condition determination stage. when When querying Characteristic curves determine the speed increase value During the query, first determine if there is a match for the current self-flowing flow. Completely Corresponding If the curve exists, then directly based on... The value is uniquely determined on the curve. If it does not exist, the interpolation calculation process needs to be started; Interpolation calculations require obtaining the current... Two adjacent test gravity flow values and and its corresponding Characteristic curves, based on the same flow rate difference The first speed increase value was found on both curves. 1 and the second speed increase value Subsequently, with For input variables, in 1 and Linear interpolation is performed between them, and the specific calculation formula is as follows: Based on linear interpolation, the applicable value is calculated. Speed ​​increase value ; S104. Based on the gravity flow speed and the speed increase value, determine the required speed of the turbine circulating water pump set.

2. The method for calculating the matching speed and flow rate of a ship's circulating water pump and simulating operating conditions according to claim 1, characterized in that, In step S101, seawater, driven by the ship's forward kinetic energy, flows into the turbine circulating water pump unit through seawater pipes and seabed valves at the bottom of the hull, driving its impeller to idle and thus generating a gravity-driven rotational speed converted from the ship's kinetic energy. ; Gravity rotation speed The mechanical speed is directly measured by a speed measuring device installed on the turbine circulating water pump unit. The measured mechanical signal is converted into an electrical signal, which is then received, converted, and processed by a data acquisition and processing system, and finally output. Numerical value.

3. The method for calculating the matching speed and flow rate of a ship's circulating water pump and conducting operational condition simulation tests according to claim 1, characterized in that, In step S102, the gravity flow rate and gravity speed characteristic curves are obtained by simulating different gravity flow conditions encountered during ship navigation in a laboratory environment by closing the air inlet valve of the circulating water pump and adjusting the speed of the booster pump. For each set stable self-flow rate A two-dimensional coordinate point is constructed, and after repeated experiments on all gravity flow target values, a discrete data point set covering the expected flow range is obtained.

4. The method for calculating the matching speed and flow rate of a ship's circulating water pump and simulating operating conditions according to claim 3, characterized in that, Based on the acquired discrete data point set, a continuous curve is generated by fitting using the least squares method for a set of experimental data points. ， Assume that the fitted polynomial curve is: Where n represents the predicted rotational speed of the gravity flow output by the fitted polynomial, and Q represents the gravity flow rate. , , , The coefficient vector represents the polynomial coefficients, k represents the polynomial order, and the coefficient vector is determined. To minimize the objective function S, the following system of equations is solved: Specifically, S can be represented as: Where m represents the total number of test points, that is, the number of test data pairs participating in the fitting. Indicates the i-th Measured values ​​of the gravity flow speed at the test point. Let X represent the measured gravity flow rate at the i-th test point, X represent the design matrix, a represent the coefficient vector, and n represent the number of observations. This represents the product of the transpose of the design matrix and itself. Let X represent the product of the transpose of the design matrix and the observation vector. For the design matrix X, its elements are defined as: n is the observation vector, which can be represented as: Where j represents the column index of the design matrix, and T is the matrix transpose symbol; For any self-flowing speed falling within the test range Find the corresponding gravity flow rate value through the continuous curve. This includes: the real-time measured rotational speed of the free-flowing engine. As input conditions, through preset... Perform query and matching operations on the characteristic curve, map and output the gravity flow value corresponding to the current navigation condition. .

5. The method for calculating the matching speed and flow rate of a ship's circulating water pump and conducting operational condition simulation tests according to claim 1, characterized in that, After completing the self-flowing flow Once determined, execute the condition determination branch. If so, it is directly determined that the current condition is gravity flow and the required speed is determined. Equal to the rotational speed of gravity At this time, the turbine circulating water pump set does not require steam drive. When the ship switches from operating condition a to operating condition b, if the relationship between the gravity flow rate and the demand flow rate changes from... Transform into b≤ If b, then condition b is determined to be the switching point between gravity flow and gravity flow conditions.

6. The method for calculating the matching speed and flow rate of a ship's circulating water pump and simulating operating conditions according to claim 1, characterized in that, In S104, based on the self-flowing speed... With query Speed ​​increase value determined by characteristic curve n, perform arithmetic composition calculations to determine the required speed of the turbine circulating water pump set. The specific calculation formula is as follows: .

7. The method for calculating the matching speed and flow rate of a ship's circulating water pump and conducting operational condition simulation tests according to claim 6, characterized in that, The required rotation speed As the ultimate speed control target for the turbine circulating water pump set, the steam flow rate entering the driving turbine is adjusted by controlling the opening of the intake valve, thereby controlling the turbine circulating water... The actual speed of the pump set is adjusted to To determine the circulating water flow rate and the seawater demand flow rate of the condenser. Matching.

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