IVR (Interactive Voice Response) self-adaptive control-based non-uniform incoming flow optimization method for water-jet propeller

Abstract

The invention discloses a water-jet propeller non-uniform incoming flow optimization method based on IVR self-adaptive regulation and control, and the method comprises the steps: vortex generators VG and jet type vortex generators VGJ which are used for regulation and control are vertically installed at the bottom of a high-speed water platform in pairs, and the vortex generators VG and the jet type vortex generators VGJ are vertically installed at the positions, away from an inlet of a water inlet runner of a water-jet propeller by one time of the diameter of an outflow surface, on incoming flow; a dual-threshold piecewise linear control model based on the IVR change direction is provided for controlling blade deflection of the VG; the VGJ is located on the upper wall face of the water inlet flow channel and the middle of the driving shaft and actively jets into the flow channel through two arc gaps formed in the wall face of the pipeline, and the jet flow ratio of the VGJ under the full IVR working condition is 1.3. By jointly using the jet flow type vortex generator and the vortex generator with the variable blade angle, the phenomenon of slope flow separation vortex and elbow secondary flow can be reduced, optimization of uneven fluid in a water inlet runner is achieved, the efficiency of the water inlet runner is improved, and finally the propulsive efficiency is effectively improved.

Description

Technical Field

[0001] This invention relates to a non-uniform inflow optimization method for waterjet propulsion based on IVR adaptive control, belonging to the field of ship propulsion technology. Background Technology

[0002] Waterjet propulsion boasts advantages such as high propulsion efficiency at high speeds, good operational performance, strong adaptability, stable operation, and low noise, making it widely used in high-speed ships, amphibious vehicles, and other high-speed water platforms. During actual operation, fluid enters the impeller through the inlet channel. However, the curved inlet channel of the waterjet propulsion system causes non-uniform flow, which adversely affects the hydraulic performance and blade load characteristics of the propulsion system, severely reducing its propulsion efficiency and operational stability. Currently, the control of non-uniform flow in waterjet propulsion mainly focuses on optimizing the configuration of the inlet channel itself. This method has weak adaptability to changes in operating conditions and is easily limited by installation space and design costs. Optimization methods for eddy current control mainly involve using eddy current generators and jet-type eddy current generators. The mechanism involves actively and passively inducing controllable vortex systems to promote momentum mixing between high- and low-speed fluids, thereby reducing flow non-uniformity. These methods are characterized by simple and reliable structures. However, eddy current generators and jet-type eddy current generators have the limitation of poor adaptability to operating conditions, and eddy current generators with fixed drive angles will lead to significant additional flow losses. Summary of the Invention

[0003] To address the issues of reduced efficiency and increased vibration caused by non-uniform flow in existing waterjet propulsion systems, this invention aims to provide an optimization method for non-uniform inflow in waterjet propulsion based on IVR adaptive control. This method controls the blade deflection angle of the vortex generator blades using a piecewise linear control model with dual thresholds based on the IVR change direction, achieving adaptive control to operating conditions and improving the energy utilization efficiency of the inlet channel and the overall propulsion performance of the waterjet propulsion system.

[0004] The objective of this invention is achieved through the following method.

[0005] This invention discloses a non-uniform inflow optimization method for waterjet propulsion based on IVR adaptive control. It controls the blade deflection angle of the vortex generator blades using a piecewise linear control model with dual thresholds based on the IVR change direction, achieving adaptive control to operating conditions. First, vortex generators and jet-type vortex generators are spatially coordinated to control the non-uniform inflow through the inlet channel. The key to the entire method lies in the definition of core parameters, including the inflow ratio (IVR), a condition parameter characterizing the waterjet propulsion's operating state, and the velocity non-uniformity parameter characterizing the flow field state through the inlet channel. Total pressure distortion index DC60, controlled variable eddy current generator blade deflection angle Subsequently, based on simulation or experiment, the characteristic parameters of the advance ratio for different typical inflow modes are calibrated, and the characteristic parameters of the blade deflection angle of the vortex generator are obtained under different advance ratio conditions to determine the key advance ratio and blade deflection angle threshold for control mode switching. Different control stages of blade deflection angle change are divided according to IVR, and the control path is determined by real-time determination of the direction of IVR change. Finally, the control model is used to make blade deflection angle decisions, and the target angle decision is executed by the blade actuator of the vortex generator, that is, to realize the non-uniform inflow optimization of the waterjet propulsion based on IVR adaptive control.

[0006] Furthermore, the joint control method is as follows: vortex generators and jet-type vortex generators are spatially arranged in a coordinated manner to control the non-uniform inflow of the inlet channel; since the vortex generator has the effect of optimizing the control of the non-uniform inflow under the IVR=0.7 condition and the negative optimization control effect under the IVR=1.3 condition, its optimal control condition is high speed and low IVR condition; while the jet-type vortex generator has the effect of optimizing the control of the non-uniform inflow under the IVR=1.3 condition, its optimal control condition is low speed and high IVR condition; therefore, in order to achieve the control of the non-uniform inflow of the inlet channel under all speed conditions, vortex generators and jet-type vortex generators are arranged in a coordinated manner.

[0007] Furthermore, the adaptive method of the joint control for the operating conditions is as follows: the control effect of the jet vortex generator is related to the jet ratio, that is, the ratio of the jet velocity to the mainstream velocity. When the jet ratio is less than 1, there is no obvious control effect, and when the jet ratio is greater than 1.5, the energy loss caused by the jet itself is too large. Therefore, in order to balance the control effect and the jet energy consumption, the jet vortex generator maintains a constant basic jet ratio of 1.3 under all operating conditions to provide continuous energy input to the inlet channel. At the same time, the blade deflection angle of the vortex generator is dynamically adjusted according to the actual inlet velocity ratio. Its angle change follows a piecewise linear control model based on the dual threshold of the IVR change direction. That is, according to the specific value of IVR and the change direction, the blade deflection angle changes between different velocities. The vortex generator undertakes the task of actively adjusting with the velocity change.

[0008] Furthermore, the method for spatially arranging the vortex generator is as follows: the vortex generator should be located at the bottom of the high-speed floating platform, upstream of the inlet of the water inlet, and at a distance of one minor axis D from the inlet of the water inlet. The vortex generator consists of two trapezoidal blades arranged symmetrically about the major axis of the water inlet, with a distance of 0.4D between the blades; the angle between the projection of the vortex generator onto the bottom of the ship and the inlet direction is the blade deflection angle. ,in At the blade deflection angle During the process of change, the blades of the eddy current generator maintain a mirror symmetry relationship.

[0009] Furthermore, the method for spatially arranging the jet vortex generator is as follows: the jet vortex generator should be located above the inlet channel and jets into the channel through two mutually symmetrical arc-shaped jet slits opened on the wall of the inlet channel, with the jet flow rate not exceeding 1% of the main flow; the side projections of the two jet slits lie on a circle with the side projection of the drive shaft center axis as the center and 0.3 times the minor axis D of the inlet channel as the radius, the included angle between the projections of the two jet slits is 40°, and the side projection area of ​​a single jet slit is 1 cm². 2 .

[0010] Furthermore, the method for characterizing the operating condition parameter of the waterjet propulsion system, namely the advance ratio IVR, is as follows: real-time monitoring of the sailing speed of the high-speed water platform and the average velocity of the outlet section of the inlet channel to obtain the trend of the advance ratio IVR over time at the sailing speed; the state parameter characterizing the flow field of the inlet channel is the velocity nonuniformity. The total pressure distortion index and the total pressure distortion index reflect the uniformity of the velocity distribution in the inlet channel and the degree to which the total fluid pressure is affected by non-uniform flow, respectively; the controlled variable is the blade deflection angle. .

[0011] Furthermore, the method for calibrating the characteristic operating parameters of different typical inflow modes is as follows: selecting a sailing speed that makes the inflow mode a ramp inflow. Under this operating condition, the average velocity at the outlet section is At this time, the advance ratio is The navigation speed required to balance the ramp inflow at the inlet section of the inlet channel with the lip inflow is: Under this operating condition, the average velocity at the outlet section of the inlet channel is At this time, the advance ratio is The speed at which the inflow method is lip inflow is Under this operating condition, the average velocity at the outlet section is At this time, the advance ratio is .

[0012] Furthermore, the control variable, blade deflection angle, is obtained under different characteristic operating conditions. The method for eigenvalues ​​is as follows: [The text abruptly ends here, likely due to an incomplete sentence or a formatting error.] , as well as Under operating conditions, dynamically adjust the blade deflection angle. Numerical values, monitoring multiple blade deflection angles The variations in the average values ​​of velocity nonuniformity and total pressure distortion index in the lower inlet channel were investigated. An evaluation system for inlet channel nonuniformity based on these two factors was established, and the blade deflection angle that minimizes the inlet channel nonuniformity was obtained. , as well as .

[0013] Furthermore, the blade deflection angle is determined as a control variable based on the advance ratio (IVR) value, which is a working condition parameter. The different control stages are as follows: Stage I is... With the flow primarily originating from a slope, the blade deflection angle changes as follows during this stage: Phase II is With the flow primarily originating from a slope, the blade deflection angle changes as follows during this stage: ;

[0014] Furthermore, the method for determining the direction of change of operating parameters in real time is as follows: determine the direction of change of IVR s based on the rate of change of IVR:

[0015]

[0016] when At this time, the IVR increases, and the high-speed water platform tends to cruise or decelerate; when At this time, the IVR decreases, and the high-speed water platform tends to accelerate.

[0017] Furthermore, the decision-making regarding the control variables involves determining whether the current IVR value falls within stage I or stage II of the blade deflection angle change based on the ratio of the current high-speed surface platform's travel speed to the average velocity at the inlet channel's outlet section. Then, based on the stage and the direction of change (s), the target blade angle is calculated using the following piecewise linear function. :

[0018]

[0019] .

[0020] Beneficial effects:

[0021] 1. The non-uniform inflow optimization method for waterjet propulsion based on IVR adaptive control disclosed in this invention optimizes the inflow by coupling a mirror-symmetrical vortex generator located at the bottom of a high-speed water platform upstream of the inflow and at a distance of one outlet diameter from the inlet of the inlet channel, and a jet-type vortex generator located at the middle of the upper wall of the inlet channel and the drive shaft, which injects water into the channel through an arc-shaped jet slit. This optimization method can reduce the non-uniformity of the inflow in the inlet channel, improve the efficiency of the inlet channel, thereby improving the efficiency of capturing and converting the energy of the inflow, and significantly improving the overall propulsion efficiency of the waterjet propulsion system.

[0022] 2. The non-uniform inflow optimization method for waterjet propulsion based on IVR adaptive control disclosed in this invention addresses the non-uniform inflow problem of waterjet propulsion by performing coupled numerical calculations on multiple moving components, including the inlet channel, impeller, and vortex generator. In the calculation, an overlapping mesh method is used to achieve high-precision numerical simulation of the aforementioned dynamic moving components. By increasing the energy utilization efficiency of the inlet channel for the incoming flow, the non-uniform flow phenomenon within the channel is improved, further increasing the propulsion efficiency of the waterjet propulsion system.

[0023] 3. The non-uniform inflow optimization method for water jet propulsion based on IVR adaptive control disclosed in this invention allows the optimized vortex generator blades to adapt to changes in operating conditions, thereby reducing the working resistance of the vortex generator while ensuring the inflow control effect.

[0024] 4. The non-uniform incoming flow optimization method for water jet propulsion based on IVR adaptive control disclosed in this invention optimizes the incoming flow by arranging a vortex generator in front of the water inlet channel and combining it with the top double-slit jet method. This reduces the non-uniformity of the incoming flow in the water inlet channel, improves the efficiency of the channel itself, and thus improves the efficiency of capturing and converting the energy of the incoming flow, significantly improving the overall propulsion efficiency of the water jet propulsion system. Attached Figure Description

[0025] Figure 1 This is a three-dimensional model diagram of the coupled eddy current control and water jet propulsion in an example of the present invention;

[0026] Figure 2 This is a flowchart of the adaptive waterjet propulsion non-uniform inflow optimization method based on eddy current joint control of the present invention;

[0027] Figure 3 This is a numerical simulation flowchart of the adaptive waterjet propulsion non-uniform inflow optimization method based on eddy current joint control disclosed in this invention.

[0028] Figure 4 This is a comparison diagram of the flow resistance experienced by the fixed-angle blades and variable-angle blades of the vortex generator under different advance ratios in an example of the present invention.

[0029] Figure 5 This is a comparison diagram of the axial velocity of the outlet section of the inlet channel before and after the optimization of the eddy current control method in this invention example;

[0030] Figure 6 This is a comparison chart of the vortex control method's effect on the efficiency optimization of the inlet channel under different inlet velocity ratios in an example of the present invention;

[0031] Figure 7 This is a comparison chart showing the effect of vortex control method on propulsion efficiency optimization under different advance ratios in an example of the present invention. Detailed Implementation

[0032] To better illustrate the purpose and advantages of the present invention, the invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0033] Example 1:

[0034] like Figure 2 As shown in this embodiment, the non-uniform inflow optimization method for waterjet propulsion based on IVR adaptive control includes the following steps:

[0035] Step 1: Determine the scheme for combined vortex control. This involves spatially coordinating vortex generators and jet-type vortex generators to control the non-uniform inflow through the inlet channel, such as... Figure 1 As shown; since the vortex generator has the effect of optimizing the non-uniform inflow control under IVR=0.7 condition and the negative optimization control effect under IVR=1.3 condition, its optimal control condition is high speed and low IVR condition; while the jet vortex generator has the effect of optimizing the non-uniform inflow control under IVR=1.3 condition, its optimal control condition is low speed and high IVR condition; therefore, in order to achieve the control of the non-uniform inflow of the inlet channel under all speed conditions, the vortex generator and the jet vortex generator are arranged in a coordinated manner.

[0036] Step 2: Determine the adaptive velocity control scheme for combined vortex control. The control effect of the jet vortex generator is related to the jet ratio, i.e., the ratio of the jet velocity to the mainstream velocity. When the jet ratio is less than 1, there is no obvious control effect; when the jet ratio is higher than 1.5, the energy loss caused by the jet itself is too large. Therefore, in order to balance the control effect and the jet energy consumption, the jet vortex generator maintains a constant basic jet ratio of 1.3 under all operating conditions to provide continuous energy input to the inlet channel. At the same time, the blade deflection angle of the vortex generator is dynamically adjusted according to the actual inlet velocity ratio. Its angle change follows a piecewise linear control model based on the dual threshold of the IVR change direction. That is, according to the specific value and change direction of IVR, the blade deflection angle changes between different velocities, and the vortex generator undertakes the task of actively adjusting with the velocity change.

[0037] Step 3: Determine the spatial arrangement of the vortex generator in the combined vortex control. To ensure the vortex generator has an optimized effect on non-uniform incoming flow, it should be located at the bottom of the high-speed floating platform, upstream of the incoming flow, and at a distance of one outlet diameter D from the inlet of the inlet channel. The vortex generator consists of two trapezoidal blades that are mirror-symmetrical about the centerline, with a distance of 0.4D between them. The angle between the projection of the vortex generator onto the bottom of the ship and the inlet direction is the blade deflection angle. ,in At the blade deflection angle During the process of change, the blades of the eddy current generator maintain a mirror symmetry relationship.

[0038] Step 4: Determine the spatial arrangement of the jet vortex generator in the combined vortex control. The jet vortex generator should be located in the middle of the upper wall of the inlet channel and the drive shaft. It actively jets water into the channel through two arc-shaped gaps opened on the pipe wall, and the jet flow rate does not exceed 1% of the mainstream flow rate.

[0039] Step 5: Define core parameters. The operating parameter characterizing the waterjet propulsion system is the advance ratio (IVR). Real-time monitoring of the high-speed water platform's speed and the average velocity at the inlet channel's outlet section yields the trend of IVR over time at different speeds. The state parameter characterizing the inlet channel flow field is the velocity nonuniformity. The total pressure distortion index and the total pressure distortion index reflect the uniformity of the velocity distribution in the inlet channel and the degree to which the total fluid pressure is affected by non-uniform flow, respectively; the controlled variable is the blade deflection angle. .

[0040] Step Six: Calibrate the characteristic operating parameters for different typical inlet flow patterns. The inlet flow pattern of the waterjet propulsion system is related to the sailing speed of the high-speed water platform. Under high sailing speed and low IVR conditions, the fluid enters the flow channel from the ramp; under low sailing speed and high IVR conditions, the fluid enters the flow channel from the lip. During the transition from ramp inlet to lip inlet, there exists an intermediate value between the sailing speed and IVR that balances the two inlet flow patterns. Therefore, the sailing speed at which the inlet flow pattern is determined to be ramp inlet is... Under this operating condition, the average velocity at the outlet section is At this time, the advance ratio is The navigation speed required to balance the ramp inflow at the inlet section of the inlet channel with the lip inflow is: Under this operating condition, the average velocity at the outlet section is At this time, the advance ratio is The speed at which the inflow method is lip inflow is Under this operating condition, the average velocity at the outlet section is At this time, the advance ratio is .

[0041] Step 7: Obtain the control variable, blade deflection angle, under different characteristic operating conditions. Eigenvalues. (The remaining text appears to be incomplete and possibly contains errors.) , as well as Under operating conditions, the blade deflection angle is dynamically adjusted, and the changes in the average values ​​of velocity nonuniformity and total pressure distortion index in the inlet flow channel are monitored at multiple blade deflection angles. An evaluation system for inlet flow channel nonuniformity based on velocity nonuniformity and total pressure distortion index is established, and the blade deflection angle that minimizes inlet flow channel nonuniformity is obtained. , as well as .

[0042] Step 8: Determine the control variable, blade deflection angle, based on the feed ratio (IVR) value according to the operating conditions. Different control stages. Stage I is... With the flow primarily originating from a slope, the blade deflection angle changes as follows during this stage: Phase I is With the flow primarily originating from a slope, the blade deflection angle changes as follows during this stage: .

[0043] Step 9: Determine the direction of change of operating parameters. Determine the direction of change of IVR (s) based on the rate of change of IVR:

[0044]

[0045] Specifically, when At this time, the IVR increases, and the high-speed water platform tends to cruise or decelerate; when At this time, the IVR decreases, and the high-speed water platform tends to accelerate.

[0046] Step 10: Decision-making regarding control variables. Based on the ratio of the current speed of the high-speed floating platform to the average velocity at the outlet section of the inlet channel, determine whether the current IVR value falls within stage I or stage II of the blade deflection angle change. Based on the stage and s from Step 6, calculate the target blade angle using the following piecewise linear function. :

[0047]

[0048]

[0049] Step 11: Execute the decision. Calculate the target angle... The blade driver, sent to the eddy current generator, drives the blade to rotate to the specified blade deflection angle.

[0050] In step three, the vortex generator is trapezoidal in shape, with a height of 0.4 times the diameter D of the propeller pump impeller, a base of 0.2 times the diameter D of the propeller pump impeller, and an angle of 70° between the hypotenuse and the base. The two vortex generator blades are 0.4 times the diameter D of the propeller pump impeller and are one time the diameter D of the propeller pump impeller from the inlet of the water inlet channel.

[0051] In step four, the jet vortex generator injects jet into the flow channel through double jet slots. The side projection of these jet slots lies on a circle with a radius of 0.3D centered on the side projection of the drive shaft's central axis. The angle between the projections of the two jet slots is 40°, and the side projection area of ​​a single jet slot is 1 cm². 2 .

[0052] In step five, the advance ratio IVR (the ratio of the average velocity at the outlet surface of the inlet channel to the speed of the high-speed floating platform) is an important parameter characterizing the operating state of the waterjet propulsion system and the flow acquisition state of the inlet channel. IVR is defined as follows:

[0053]

[0054] in, The sailing speed of a high-speed water platform, The average velocity at the outlet surface of the inlet channel is generally the higher the sailing speed, the smaller the velocity ratio.

[0055] In step five, velocity non-uniformity The most important indicator characterizing the uniformity of velocity distribution in the inlet channel is expressed as follows:

[0056]

[0057] in: The volumetric flow rate of the inlet channel cross-section. For cross-sectional area, The axial velocity on the cross section, denoted as the average axial velocity of the cross section. The larger the value, the more uneven the flow velocity at the outlet surface of the inlet channel, which is more likely to aggravate the periodic pulsation in the propulsion pump, and also means that the outflow quality of the water jet propulsion unit is low.

[0058] In step five, the total pressure distortion index is quantified using the 60° sector distortion index DC60, commonly used in turbomachinery flow stability assessment. This index is a standard for evaluating the inlet airflow field of aero-engines and is widely referenced for assessing the flow uniformity of the waterjet propulsion inlet channel. It is defined as the relative difference between the average total pressure of the lowest pressure region at a cross-section 60° away from the outlet section of the inlet channel and the overall average total pressure of the entire cross-section. DC60 describes the degree to which the total pressure of the fluid in the inlet channel is affected by non-uniform flow, reflecting the compatibility between the inlet channel and the waterjet propulsion pump. Increasing DC60 will lead to a deterioration in the performance of the waterjet propulsion pump. Its expression is:

[0059]

[0060] in, This represents the average total pressure across the cross-section; here, the average total pressure at the outlet cross-section of the inlet channel is used. It is the minimum average total pressure of the cross-sections adjacent to each other at 60° at the outlet.

[0061] Example 2:

[0062] like Figure 1As shown in the figure, the specific implementation steps of the non-uniform inflow optimization method for waterjet propulsion based on eddy current control disclosed in this embodiment are as follows:

[0063] Step 1: Determine the scheme for combined vortex control. Vortex generators and jet-type vortex generators are spatially arranged in a coordinated manner to control the non-uniform inflow into the inlet channel. Since the vortex generator has an optimizing effect on the non-uniform inflow at IVR=0.7, but a negative optimizing effect at IVR=1.3, its optimal control condition is high speed and low IVR. The jet-type vortex generator, on the other hand, has an optimizing effect on the non-uniform inflow at IVR=1.3, and its optimal control condition is low speed and high IVR. Therefore, to achieve control of the non-uniform inflow into the inlet channel across all speed conditions, vortex generators and jet-type vortex generators are arranged in a coordinated manner.

[0064] Step 2: Determine the adaptive velocity control scheme for combined vortex control. The control effect of the jet vortex generator is related to the jet ratio, i.e., the ratio of the jet velocity to the mainstream velocity. When the jet ratio is less than 1, there is no obvious control effect; when the jet ratio is higher than 1.5, the energy loss caused by the jet itself is too large. Therefore, in order to balance the control effect and the jet energy consumption, the jet vortex generator maintains a constant basic jet ratio of 1.3 under all operating conditions to provide continuous energy input to the inlet channel. At the same time, the blade deflection angle of the vortex generator is dynamically adjusted according to the actual inlet velocity ratio. Its angle change follows a piecewise linear control model based on the dual threshold of the IVR change direction. That is, according to the specific value and change direction of IVR, the blade deflection angle changes between different velocities, and the vortex generator undertakes the task of actively adjusting with the velocity change.

[0065] Step 3: Determine the spatial arrangement of the vortex generator in the combined vortex control. To ensure the vortex generator has an optimized effect on non-uniform incoming flow, it should be located at the bottom of the high-speed floating platform, upstream of the incoming flow, and at a distance of one outlet diameter D from the inlet of the inlet channel. The vortex generator consists of two trapezoidal blades that are mirror-symmetrical about the centerline, with a distance of 0.4D between them. The angle between the projection of the vortex generator onto the bottom of the ship and the inlet direction is the blade deflection angle. ,in At the blade deflection angle During the process of change, the blades of the eddy current generator maintain a mirror symmetry relationship.

[0066] In this invention, the vortex generator is trapezoidal in shape, with a height of 0.4 times the diameter D of the propulsion pump impeller, a base of 0.2 times the diameter D of the propulsion pump impeller, and an angle of 70° between the hypotenuse and the base. The two vortex generator blades are 0.4 times the diameter D of the propulsion pump impeller and are one time the diameter D of the propulsion pump impeller from the inlet of the water inlet channel.

[0067] Step 4: Determine the spatial arrangement of the vortex generator in the combined vortex control. To ensure that the vortex generator has an optimized effect on non-uniform incoming flow, the jet-type vortex generator should be located in the middle of the upper wall of the inlet channel and the drive shaft. It actively jets flow into the channel through two arc-shaped gaps opened on the pipe wall, and the jet flow rate does not exceed 1% of the mainstream flow.

[0068] In this invention embodiment, the jet vortex generator injects jets into the flow channel through double jet slots. The side projection of each jet slot lies on a circle with a radius of 0.3D centered on the side projection of the drive shaft's central axis. The angle between the projections of the two jet slots is 40°, and the side projection area of ​​a single jet slot is 1 cm². 2 .

[0069] Step 5: Define core parameters. The operating parameter characterizing the waterjet propulsion system is the advance ratio (IVR). Real-time monitoring of the high-speed water platform's speed and the average velocity at the inlet channel's outlet section yields the trend of IVR over time at different speeds. The state parameter characterizing the inlet channel flow field is the velocity nonuniformity. The total pressure distortion index and the total pressure distortion index reflect the uniformity of the velocity distribution in the inlet channel and the degree to which the total fluid pressure is affected by non-uniform flow, respectively; the controlled variable is the blade deflection angle. .

[0070] In this invention, the advance ratio IVR (the ratio of the average velocity of the outflow surface of the inlet channel to the speed of the high-speed floating platform) is an important parameter characterizing the operating state of the waterjet propulsion system and the flow acquisition state of the inlet channel. IVR is defined as follows:

[0071]

[0072] in, For the high-speed sailing speed of the water platform, The average velocity at the outlet surface of the inlet channel is generally the higher the speed of a high-speed water platform, the smaller the velocity ratio.

[0073] In the examples of this invention, velocity non-uniformity The most important indicator characterizing the uniformity of velocity distribution in the inlet channel is expressed as follows:

[0074]

[0075] in: The volumetric flow rate of the inlet channel cross-section. For cross-sectional area, The axial velocity on the cross section, denoted as the average axial velocity of the cross section. The larger the value, the more uneven the flow velocity at the outlet surface of the inlet channel, which is more likely to aggravate the periodic pulsation in the propulsion pump, and also means that the outflow quality of the water jet propulsion unit is low.

[0076] In this invention, the total pressure distortion index is quantified using the 60° sector distortion index (DC60), commonly used in turbomachinery flow stability assessment. This index is a standard for evaluating the inlet airflow field of aero-engines and is widely referenced for assessing the flow uniformity of the waterjet propulsion inlet channel. It is defined as the relative difference between the average total pressure of the lowest pressure region at a cross-section 60° away from the outlet cross-section of the inlet channel and the overall average total pressure of the entire cross-section. DC60 describes the degree to which the total pressure of the fluid in the inlet channel is affected by non-uniform flow, reflecting the compatibility between the inlet channel and the waterjet propulsion pump. Increasing DC60 leads to a deterioration in the performance of the waterjet propulsion pump, and its expression is:

[0077]

[0078] in, This represents the average total pressure across the cross-section; here, the average total pressure at the outlet cross-section of the inlet channel is used. It is the minimum average total pressure of the cross-sections adjacent to each other at 60° at the outlet.

[0079] Step Six: Determine the spatial arrangement of the jet vortex generator in the vortex combined control. To ensure the jet vortex generator has an optimizing effect on non-uniform incoming flow, it should be located above the inlet channel and inject water into the channel through two symmetrical arc-shaped jet slits on the inlet channel wall. The jet flow rate should not exceed 1% of the mainstream flow rate. Considering jet energy loss, the jet velocity should be selected as 1.3 times the mainstream velocity (i.e., jet ratio). ).

[0080] In this invention, the numerical calculation method for the integrated coupling of a waterjet propulsion device and an eddy current control device includes: establishing a geometric model and importing it into fluid dynamics software; selecting a suitable physical model and establishing a computational fluid dynamics model; creating a computational domain and setting boundary and initial conditions; dividing the computational domain into a mesh and setting a refinement region; defining field functions and physical quantities, and creating a monitor and report; setting solver parameters and convergence conditions; initializing the computational domain and starting the calculation; and visualizing the calculation results to obtain the flow field information of the waterjet propulsion device based on eddy current joint control, as shown in the appendix. Figure 2 As shown.

[0081] Step 7: Calibrate the characteristic operating parameters for different typical inlet flow patterns. The inlet flow pattern of the waterjet propulsion system is related to the speed of the high-speed water platform. Under high speed and low IVR conditions, the fluid enters the flow channel from the ramp; under low speed and high IVR conditions, the fluid enters the flow channel from the lip. During the transition from ramp inlet to lip inlet, there exists an intermediate value between the speed and IVR that balances the two flow patterns. Therefore, the speed at which the ramp inlet flow pattern is determined is... Under this operating condition, the average velocity at the outlet section is At this time, the advance ratio is The navigation speed required to balance the ramp inflow at the inlet section of the inlet channel with the lip inflow is: Under this operating condition, the average velocity at the outlet section is At this time, the advance ratio is The speed at which the inflow method is lip inflow is Under this operating condition, the average velocity at the outlet section is At this time, the advance ratio is .

[0082] Step 8: Obtain the control variable, blade deflection angle, under different characteristic operating conditions. Eigenvalues. (The remaining text appears to be incomplete and possibly contains errors.) , as well as Under operating conditions, the blade deflection angle is dynamically adjusted, and the changes in the average values ​​of velocity nonuniformity and total pressure distortion index in the inlet flow channel are monitored at multiple blade deflection angles. An evaluation system for inlet flow channel nonuniformity based on velocity nonuniformity and total pressure distortion index is established, and the blade deflection angle that minimizes inlet flow channel nonuniformity is obtained. , as well as .

[0083] Step 9: Determine the control variable, blade deflection angle, based on the feed ratio (IVR) value according to the operating conditions. Different control stages. Stage I is... With the flow primarily originating from a slope, the blade deflection angle changes as follows during this stage: Phase I is With the flow primarily originating from a slope, the blade deflection angle changes as follows during this stage: .

[0084] Step 10: Determine the direction of change of operating parameters. Determine the direction of change of IVR (s) based on the rate of change of IVR:

[0085]

[0086] Specifically, when At this time, the IVR increases, and the high-speed water platform tends to cruise or decelerate; when At this time, the IVR decreases, and the high-speed water platform tends to accelerate.

[0087] Step 11: Decision-making on control variables. Based on the ratio of the current sailing speed to the average velocity at the inlet channel outlet section, determine whether the current IVR value is in stage I or stage II of the blade deflection angle change; based on the stage and s from step seven, use the following piecewise linear function to calculate the target blade angle. :

[0088]

[0089]

[0090] Step 12: Execute the decision. Calculate the target angle... The blade driver, sent to the eddy current generator, drives the blade to rotate to the specified blade deflection angle.

[0091] Step 13: Optimization Effect Evaluation. The inlet channel efficiency is used as a key parameter to evaluate the inlet channel's utilization of incoming flow energy, and the water jet propulsion efficiency is used to comprehensively evaluate the optimization effect of the combined control at different inlet velocity ratios.

[0092] In this invention, the inlet flow channel efficiency is a key parameter used to evaluate the degree to which the inlet flow channel utilizes the energy of the incoming flow, and its expression is as follows:

[0093]

[0094] in: The total energy at the outlet (outflow surface) of the inlet channel. To obtain the total energy of the flow surface, according to the recommendations of the 24th ITTC Jet Propulsion Expert Committee meeting, the flow surface is a semi-elliptical cross section located 1D (i.e., one impeller diameter) outside the inlet of the inlet channel, and the flow rate of the flow surface is equal to that of the outlet surface, satisfying the mass conservation.

[0095] In this invention, propulsion efficiency is a key indicator for measuring how well a waterjet propulsion system converts input power into effective thrust. Its definition is as follows:

[0096]

[0097] in, To improve efficiency, For thrust power, Shaft power; The fluid density is taken as 998 kg / m³. For traffic, The velocity of the nozzle jet is... For speed; For the driving shaft torque, This refers to the drive shaft speed.

[0098] First, a 3D model of the fluid computational domain was created using 3D software. This model included the fluid region, inlet channel, drive shaft, impeller, guide vanes, and vortex generator. The impeller diameter D was 149.5 mm, the nozzle diameter was 105 mm, and the vortex generator was trapezoidal in shape with a length 0.4 times the impeller diameter D. The distance between two blades was 0.4 times the impeller diameter D, and the distance from the inlet channel inlet was one times the impeller diameter D. The 3D model was then imported into a newly created example in Starccm+.

[0099] Select a physics model in Starccm+, including Reynolds-averaged Navier-Stokes equations and SST. Turbulence model, implicit unsteady-state model, three-dimensional model, full y+wall treatment model, constant density model, fluid medium is room temperature water at 25℃.

[0100] In Starccm+, create a computational domain including a background domain, inlet channel, impeller, guide vanes, and vortex generator, and set boundary and initial conditions. The background domain is approximately 16D×7D×6D in size. The area in front of the waterjet propeller is designated as the pressure outlet, and the area behind it is designated as the velocity inlet, with the velocity magnitude set to the ship's speed. The top surface of the background domain is designated as a wall, and the bottom surface as the velocity inlet with a velocity magnitude of 0.01 m / s. The two sides of the background domain are designated as symmetrical planes. The guide vane outlet is designated as a pressure outlet. The jet slit in the inlet channel is designated as a velocity inlet with a jet velocity of 10 m / s and a jet flow rate not exceeding 1% of the total flow rate, parallel to the drive axis and inside the inlet channel. The remaining computational domain planes are designated as walls.

[0101] A cut-body mesh generator was used to generate the background domain and the mesh cells of the water jet propulsion unit and the vortex generator. Six layers of prism mesh were generated on the top wall (bottom of the ship), the surface of the vortex generator and near the wall of the water jet propulsion unit to capture the accurate flow characteristics in the vicinity. In addition, two layers of transition mesh were set to gradually refine the flow field around the vortex generator and to densify all wall areas.

[0102] Create solution parameters including inlet flow channel efficiency, propulsion efficiency, and vortex generator blade drag. Create a monitor and report, set the time step to 0.000625s and convergence conditions, and begin the solution operation after initializing the computational domain. After the calculation is complete, the computational structure can be visualized.

[0103] As attached Figure 4The figure shows a comparison of the flow resistance experienced by the blades of the vortex generator. As can be seen from the figure, the angle between the vortex generator and the incoming flow direction changes with different advance ratios, which is beneficial to reducing flow resistance.

[0104] As attached Figure 5 As shown in the figure, the axial velocity of the inlet channel outlet section is compared after using the eddy current control method. As can be seen from the figure, the eddy current control method reduces the low-velocity zone of the inlet channel, thereby enabling the control of the uneven inflow of the inlet channel.

[0105] As attached Figure 6 and attached Figure 7 As shown in the figure, the vortex control method has a comparative effect on the efficiency of the inlet channel and the propulsion efficiency under different inlet speed ratios. The figure shows that the vortex control method can increase the energy utilization efficiency of the inlet channel for the incoming flow, improve the uneven flow phenomenon in the channel, and further increase the propulsion efficiency of the water jet propulsion.

[0106] This invention utilizes a vortex generator arranged before the inlet of the water inlet channel and combined with a top double-slit jet method to coordinately regulate the incoming flow. This optimization method effectively reduces the non-uniformity of the incoming flow within the water inlet channel, improves the efficiency of the channel itself, thereby enhancing the efficiency of capturing and converting the energy of the incoming flow and significantly improving the overall propulsion efficiency of the water jet propulsion system.

[0107] Based on the eddy current-controlled internal flow field information of the waterjet propeller predicted by the above steps, the influence of the inlet flow on the internal flow state and external characteristics of the waterjet propeller impeller can be further observed. This can provide key basis for the flow analysis and structural optimization design of the waterjet propeller impeller, and help to solve the problem of non-uniform inlet flow in the entire flow channel of the waterjet propeller.

[0108] In summary, the above-described specific details further illustrate the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above description is merely a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A non-uniform inflow optimization method for waterjet propulsion based on IVR adaptive control, characterized in that: The blade deflection angle of the vortex generator blades is controlled by a piecewise linear control model based on a dual threshold value according to the direction of IVR variation, achieving adaptive joint control to the operating conditions. Firstly, vortex generators and jet-type vortex generators are spatially coordinated to control the non-uniform inflow in the inlet channel. The defined core parameters include the inflow ratio IVR, a condition parameter characterizing the waterjet propulsion system, and velocity non-uniformity, a parameter characterizing the flow field state in the inlet channel. Total pressure distortion index DC60, controlled variable eddy current generator blade deflection angle Based on simulation or experiment, the characteristic parameters of the advance ratio for different typical inflow modes are calibrated, and the characteristic parameters of the blade deflection angle of the vortex generator are obtained under different advance ratio conditions to determine the key advance ratio and blade deflection angle threshold for control mode switching. Different control stages of blade deflection angle change are divided according to IVR, and the control path is determined by real-time determination of the direction of IVR change. Finally, the control model is used to make blade deflection angle decisions, and the target angle decision is executed by the blade actuator of the vortex generator, that is, to realize the non-uniform inflow optimization of the waterjet propulsion based on IVR adaptive control.

2. The method as described in claim 1, characterized in that: The joint control method is as follows: vortex generators and jet vortex generators are spatially arranged in a coordinated manner to control the non-uniform inflow of water into the inlet channel. Since the vortex generator has an optimization effect on the non-uniform inflow under IVR=0.7 and a negative optimization effect under IVR=1.3, its optimal control condition is high speed and low IVR. Meanwhile, the jet vortex generator has an optimization effect on the non-uniform inflow under IVR=1.3, and its optimal control condition is low speed and high IVR. Therefore, to achieve control of the non-uniform inflow of water into the inlet channel under all speed conditions, vortex generators and jet vortex generators are arranged in a coordinated manner.

3. The method as described in claim 1, characterized in that: The adaptive method of the joint control for the operating conditions is as follows: the control effect of the jet vortex generator is related to the jet ratio, that is, the ratio of the jet velocity to the mainstream velocity. When the jet ratio is less than 1, there is no obvious control effect. When the jet ratio is greater than 1.5, the energy loss caused by the jet itself is too large. Therefore, in order to balance the control effect and the jet energy consumption, the jet vortex generator maintains a basic jet with a constant jet ratio of 1.3 under all operating conditions to provide continuous energy input to the inlet channel. At the same time, the blade deflection angle of the vortex generator is dynamically adjusted according to the actual inlet velocity ratio. Its angle change follows a piecewise linear control model based on the dual threshold of the IVR change direction. That is, according to the specific value of IVR and the change direction, the blade deflection angle changes between different velocities. The vortex generator undertakes the task of actively adjusting with the velocity change.

4. The method as described in claim 1, characterized in that: The method for spatially arranging the vortex generator is as follows: the vortex generator should be located at the bottom of the high-speed floating platform, upstream of the incoming flow, and at a distance of one outlet diameter D from the inlet of the inlet channel. The vortex generator consists of two trapezoidal blades that are mirror-symmetrical about the centerline, with a distance of 0.4D between the blades. The angle between the projection of the vortex generator onto the bottom of the ship and the inlet direction is the blade deflection angle. ,in At the blade deflection angle During the process of change, the blades of the eddy current generator maintain a mirror symmetry relationship; The method for spatially arranging the jet vortex generator is as follows: the jet vortex generator should be located at the midpoint between the upper wall of the inlet channel and the drive shaft. It actively jets water into the channel through two arc-shaped slits opened on the pipe wall, with the jet flow rate not exceeding 1% of the main flow. The side projections of the two jet slits lie on a circle with a radius of 0.3D centered on the side projection of the drive shaft's central axis. The included angle between the projections of the two jet slits is 40°, and the side projection area of ​​a single jet slit is 1 cm². 2 .

5. The method as described in claim 2, characterized in that: The method for characterizing the advance ratio IVR, a condition parameter representing the operating state of the waterjet propulsion system, is as follows: Real-time monitoring of the high-speed water platform's travel speed and the average velocity at the outlet section of the inlet channel is used to obtain the trend of IVR variation over time at different travel speeds; the state parameter characterizing the flow field of the inlet channel is velocity nonuniformity. The total pressure distortion index and the total pressure distortion index respectively reflect the uniformity of the velocity distribution in the inlet channel and the degree to which the total pressure of the fluid is affected by non-uniform flow. The controlled variable is the blade deflection angle. .

6. The method as described in claim 3, characterized in that: The method for calibrating the characteristic operating parameters of different typical inflow modes is as follows: Select a sailing speed that makes the inflow mode a ramp inflow. Under this operating condition, the average velocity at the outlet section is At this time, the advance ratio is The navigation speed required to balance the ramp inflow at the inlet section of the inlet channel with the lip inflow is: Under this operating condition, the average velocity at the outlet section is At this time, the feed ratio is The speed at which the inflow method is lip inflow is Under this operating condition, the average velocity at the outlet section is At this time, the advance ratio is .

7. The method as described in claim 4, characterized in that: The control variable, blade deflection angle, is obtained under different characteristic operating conditions. The method for eigenvalues ​​is as follows: [The text abruptly ends here, likely due to an incomplete sentence or , as well as Under operating conditions, dynamically adjust the blade deflection angle. Numerical values, monitoring multiple blade deflection angles The variations in the average values ​​of velocity nonuniformity and total pressure distortion index in the lower inlet channel were investigated. An evaluation system for inlet channel nonuniformity based on these two factors was established, and the blade deflection angle that minimizes the inlet channel nonuniformity was obtained. , as well as .

8. The method as described in claim 5, characterized in that: Based on the advance ratio (IVR) value, the control variable is determined by the blade deflection angle. The different control stages are as follows: Stage I is... With the flow primarily originating from a slope, the blade deflection angle changes as follows during this stage: Phase II is With the flow primarily originating from a slope, the blade deflection angle changes as follows during this stage: .

9. The method as described in claim 6, characterized in that: The method for determining the direction of change of operating parameters in real time is as follows: determine the direction of change of IVR (s) based on the rate of change of IVR. ,when When this occurs, the IVR increases, and the platform tends to cruise or decelerate; when At this time, the IVR decreases, and the platform tends to accelerate.

10. The method as described in claim 7, characterized in that: Decision-making regarding control variables: Based on the ratio of the current speed of the high-speed floating platform to the average velocity at the outlet section of the inlet channel, determine whether the current IVR value falls within stage I or stage II of the blade deflection angle change; based on the stage and the direction of change s, calculate the target blade angle using the following piecewise linear function. : ， 。

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