A flow velocity monitoring and compensation device for a water jet propulsion pump

Abstract

The technical solution of the present invention provides a flow velocity monitoring and compensation device for a water jet propulsion pump, which is characterized by including an inlet flow velocity sensor; a nozzle flow velocity sensor; and a controller. The present invention designs a flow velocity monitoring and compensation device for a water jet propulsion pump to monitor the flow velocities at the water inlet and the water jet nozzle. The controller calculates and processes the monitored data and sends an analog signal to the main shaft to compensate for the impeller rotation speed, effectively solving the problem of the impeller rotation speed not reaching the required value caused by mechanical wear, device aging, and the non-linearity of the rotation speed curve, and improving the accuracy of thrust control. At the same time, flow velocity sensors at the inlet and nozzle positions are redundantly designed, and the data is weighted processed, increasing the reliability of the device.

Description

Technical Field

[0001] The present invention relates to the field of automatic control of water jet propulsion devices, and particularly to a fault detection device for water jet propulsion devices. Background Art

[0002] The water jet propulsion pump sucks water into the pump through the inlet flow passage, and after being rectified and accelerated by the impeller, it is ejected from the nozzle. In actual engineering applications, due to the influence of mechanical wear, device aging, etc., and the fact that the speed-thrust curve is a non-linear relationship, the rotational speed of the impeller often cannot reach the expected value of the curve obtained through calculation. Therefore, the overall propulsion efficiency of the pump will also decrease accordingly.

[0003] Bi Zhiyue studied the structure, parameters, uncertainties and non-linearity of the dredger mud pipeline system in "Control Theory and Applications" (No. 03, 2009), combined with the non-identification adaptive control algorithm proposed by Marsik and Streic to correct the control parameters online, and added a Smith predictor to the control scheme to improve the robustness and adaptability of the prediction algorithm.

[0004] Xu Xinjian designed an infusion flow rate monitoring device in "China Medical Equipment" (No. 10, 2019) to monitor the infusion flow rate of drugs. The AT89C52 chip was used as the main control chip, and an optoelectronic sensor was used to monitor the flow rate of drug infusion.

[0005] However, the existing technical solutions cannot solve the problem that the overall propulsion efficiency of the pump decreases due to the fact that the rotational speed of the impeller cannot reach the expected value of the curve obtained through calculation. Summary of the Invention

[0006] The object of the present invention is: Since there is a certain error between the thrust magnitude at different ship speeds and the given curve graph, it is necessary to correct and compensate the actual thrust of the water jet thruster.

[0007] In order to achieve the above object, the technical solution of the present invention is to provide a flow rate monitoring and compensation device for a water jet pump, which is characterized by comprising:

[0008] An inlet flow rate sensor for monitoring the flow rate of the water inlet;

[0009] A nozzle flow rate sensor for monitoring the flow rate of the water jet;

[0010] A controller for calculating and processing the monitoring data obtained by the inlet flow rate sensor and the nozzle flow rate sensor, and then sending an analog signal to the main shaft to compensate for the rotational speed of the impeller.

[0011] Preferably, redundant said inlet flow rate sensors are designed to realize weighted processing of the monitoring data obtained by said inlet flow rate sensors.

[0012] Preferably, redundant nozzle flow rate sensors are designed to perform weighted processing on the monitoring data obtained by the nozzle flow rate sensors.

[0013] Preferably, the water flow velocity at the nozzle is measured by the nozzle flow rate sensor as v 喷 , and the water flow velocity at the inlet is measured by the inlet flow rate sensor as v 进 , v 喷 and v 进 are in a non-linear mapping relationship.

[0014] Preferably, the controller takes the weighted average of the water flow velocity v 喷 at the nozzle measured by the nozzle flow rate sensor and the water flow velocity v 进 at the inlet measured by the inlet flow rate sensor to obtain a negative feedback signal v i .

[0015] Preferably, the negative feedback signal v i is calculated by the following formula:

[0016] where F(·) is a mapping function used to represent the non-linear mapping relationship between v 喷 and v 进 .

[0017] Preferably, the controller compares and calculates the negative feedback signal v i with the expected nozzle water flow velocity v d given manually to obtain a deviation value e, e = v d - v i .

[0018] Preferably, the controller realizes closed-loop control of the impeller speed based on the deviation value e and the measurement accuracy σ.

[0019] Preferably, during the operation of the main shaft, the controller works in the following two situations:

[0020] Situation 1: When , the actual flow velocity and the expected flow velocity are within the error tolerance range, and the controller does not compensate the impeller speed;

[0021] Situation 2: When , the controller sends an instruction to compensate the speed, and when Situation 1 is satisfied, the controller stops working.

[0022] Preferably, the rated thrust is corrected by adjusting the impeller speed, and the thrust adaptive adjustment from the main shaft to the pump and then to the ship is completed, improving the working efficiency.

[0023] The present invention designs a flow velocity monitoring and compensation device for a water jet propulsion pump, which monitors the flow velocities at the water inlet and the water jet outlet, calculates and processes the monitored data through a controller, and sends an analog signal to the main shaft to compensate for the impeller rotation speed, effectively solving the problem of insufficient impeller rotation speed caused by mechanical wear, device aging, and the non-linearity of the rotation speed curve, and improving the accuracy of thrust control. At the same time, the flow velocity sensors at the inlet and the nozzle positions are redundantly designed, and the data is weighted processed, increasing the reliability of the device. Brief Description of the Drawings

[0024] Figure 1 It is a schematic diagram of the installation position of the flow velocity sensor. In the figure, 1 - nozzle flow velocity sensor; 2 - nozzle; 3 - inlet flow channel; 4 - inlet flow velocity sensor;

[0025] Figure 2 It is a block diagram of the control system of the flow velocity monitoring device;

[0026] Figure 3 It is a schematic connection diagram of the flow velocity monitoring device. Detailed Embodiments

[0027] The following further elaborates the present invention in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0028] The present invention installs flow velocity sensors at the rear of the inlet and the end of the nozzle respectively, and connects the fed-back analog signals into the control system for calculation, compensating the impeller rotation speed to reach the rated rotation speed and improving the propulsion efficiency.

[0029] As Figure 1 shown, the technical solution disclosed by the present invention installs an inlet flow velocity sensor and a nozzle flow velocity sensor at the inlet and the nozzle respectively to measure the water flow velocities at the inlet and the nozzle. Connect the inlet flow velocity sensor and the nozzle flow velocity sensor to the controller, and convert the analog quantities measured by the inlet flow velocity sensor and the nozzle flow velocity sensor into digital quantities and send them to the controller for calculation and processing.

[0030] The control system flow chart of the entire device is as Figure 2 shown, where v d is the expected nozzle water flow velocity given artificially. The controller sends a command signal to control the main shaft to act on the impeller to obtain the actual nozzle water flow velocity v i .

[0031] The water flow velocity at the nozzle is measured by a nozzle flow velocity sensor installed at the nozzle and is v 喷 .

[0032] To increase the reliability of the detection device and prevent measurement errors caused by the degradation of the performance of a single sensor, an inlet flow velocity sensor is additionally installed at the inlet. The water flow velocity measured by the inlet flow velocity sensor installed at the inlet flow channel is v 进 . Among them, v 喷 and v 进 are in a non-linear mapping relationship. Different models of spray pumps have different mapping functions. The device of the present invention is applicable to various models of spray pumps. Therefore, the mapping function F(·) is used to generalize the relationship between the two.

[0033] The measured and calculated nozzle flow velocities are weighted and averaged to obtain Among them, v i is the negative feedback signal in the control block diagram as shown in Figure 2 .

[0034] The above negative feedback signal is compared with the expected value to calculate the deviation value e, e = v d - v i .

[0035] Thus, the closed-loop control of the entire flow velocity monitoring device control system is obtained.

[0036] During the operation of the main shaft, the impeller speed controller of the present device works in the following two situations, where σ is the measurement accuracy:

[0037] (1) When , the actual flow velocity and the expected flow velocity are within the error tolerance range, and the impeller speed controller does not need to compensate the impeller speed.

[0038] (2) When , the controller needs to send an instruction to compensate the speed. When condition (1) is satisfied, the impeller speed controller stops working.

[0039] The connection relationship of the device is as shown in the appendix Figure 3 .

[0040] The rated thrust is corrected by adjusting the impeller speed, and the thrust adaptive adjustment from the main shaft → pump → ship is completed, improving the working efficiency.

Claims

1. A flow velocity monitoring and compensation device for a water jet propulsion pump, characterized in that, Including: An inlet flow rate sensor for monitoring the flow rate of the water inlet; A nozzle flow rate sensor for monitoring the flow rate of the water spray nozzle; A controller for calculating and processing the monitoring data obtained by the inlet flow rate sensor and the nozzle flow rate sensor, and then sending an analog signal to the main shaft to compensate for the impeller speed; The water flow velocity at the nozzle is measured as v by the nozzle flow velocity sensor 喷 , and the water flow velocity at the inlet is measured as v by the inlet flow velocity sensor 进 , v 喷 and v 进 are in a non - linear mapping relationship; The controller will measure the water flow velocity v at the nozzle through the nozzle flow velocity sensor 喷 and the water flow velocity v at the inlet through the inlet flow velocity sensor 进 to perform weighted averaging to obtain a negative feedback signal v i : where F(·) is a mapping function used to represent the non-linear mapping relationship between v 喷 and v 进 ; The controller compares the negative feedback signal v i with the expected nozzle water flow velocity v d manually given, and calculates the deviation value e through comparison, where e = v d - v i ; The controller realizes closed-loop control of the impeller speed based on the deviation value e and the measurement accuracy σ.

2. The flow velocity monitoring and compensation device of a water jet propulsion pump according to claim 1, characterized in that Redundant inlet flow rate sensors are designed to achieve weighted processing of the monitoring data obtained by the inlet flow rate sensors.

3. The flow velocity monitoring and compensation device for a water jet propulsion pump according to claim 1, characterized in that Redundant nozzle flow rate sensors are designed to achieve weighted processing of the monitoring data obtained by the nozzle flow rate sensors.

4. The flow velocity monitoring and compensation device of a water jet pump as claimed in claim 1, wherein, During the operation of the main shaft, the controller works in the following two situations: Case 1: When the actual flow velocity is within the allowable error range of the expected flow velocity, the controller does not compensate the impeller rotation speed; Case 2: When e ≥ σ%, the controller sends an instruction to compensate the rotational speed. When Case 1 is satisfied, v d The controller stops working.

5. The flow velocity monitoring and compensation device for a water jet propulsion pump according to claim 4, characterized in that, The rated thrust is corrected by adjusting the impeller speed, and the thrust adaptive adjustment from the main shaft to the pump and then to the ship is completed, improving the working efficiency.

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