Multi-pump multi-nozzle independent control experimental device and method suitable for turbine blade erosion

Abstract

The invention discloses a multi-pump multi-nozzle independent control experimental device and method suitable for turbine blade erosion, and relates to the technical field of turbine blade erosion research. The water supply tank is connected with the experiment cavity through a plurality of branches which are connected in parallel, each branch comprises a self-priming pump, a high-pressure plunger pump, a bypass valve, a pressure transmitter, an ultrasonic flowmeter, a pneumatic needle valve and a nozzle which are communicated in sequence, a test blade is fixed at the rear part in the experiment cavity, and a baffle is inserted in the middle of the experiment cavity; the buffer water tank is communicated with the bottom of the experiment cavity and bypass ports of the bypass valves in the branches, the buffer water tank is communicated with the water supply tank through the centrifugal pump, and a filter is arranged between the centrifugal pump and the water supply tank. Through the design of multiple parallel branches and the adoption of independent adjustment of multiple pumps and multiple nozzles, the erosion mechanism and performance of the low-pressure complete blade of the steam turbine under different working conditions can be tested and analyzed, a blade water erosion area can be obtained more accurately, blade design optimization and protection measures are guided, the safety in the operation process of the blade is improved, and the service life of the blade in the operation process of the blade is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steam turbine blade erosion research, and particularly relates to a multi-pump and multi-nozzle independent control experimental device and method suitable for steam turbine blade erosion. BACKGROUND

[0002] Due to the frequent participation of steam turbine units in deep peak regulation, the last few stages of the low-pressure cylinder are operated for a long time under small volume flow conditions, which causes the steam turbine low-pressure last-stage blades to be frequently eroded by water droplets and the steam turbine blade water erosion phenomenon to occur. Through power plant maintenance and numerical simulation, it is found that the steam turbine low-pressure last-stage blade tip and root water erosion phenomenon is particularly serious, which will threaten the safety of the steam turbine unit and even the entire power plant over a long period of time. Therefore, carrying out relevant experimental research on steam turbine blades can help to provide certain reference value for the design and operation of steam turbine blades.

[0003] At present, some relevant experimental research has been carried out by industry insiders. For example, the Chinese invention patent with the announcement number CN100575917C discloses a steam turbine blade water erosion test device, which uses the collision between a high-speed rotating blade and water droplets to simulate the blade water erosion caused by the high-speed impact of water droplets on the blade in the low-pressure cylinder of the steam turbine. The Chinese utility model patent with the announcement number CN201653838U discloses a water erosion test device, which simulates the water erosion suffered by the last-stage blade of the steam turbine through the collision between high-pressure pulse water jet and the test piece. The Chinese invention patent with the announcement number CN102252927B discloses a high-pressure water jet rotary impact water erosion experimental device, which simulates the erosion of water droplets on the blade in the steam turbine through the collision between high-speed jet and rotating test piece. The Chinese invention patent with the announcement number CN113267416B discloses a nuclear power plant steam turbine blade dynamic water erosion experimental platform and use method, which can realize the accelerated experiment of the water erosion process of the nuclear power steam turbine blade. The Chinese invention patent with the announcement number CN119437968B discloses an experimental device and method for steam turbine low-pressure last two-stage multi-channel blade water erosion under different loads, which can explore the water erosion damage of the last two-stage blade of the thermal power steam turbine under different working conditions.

[0004] However, the above erosion experimental devices for steam turbine blades generally use a single nozzle, which is difficult to perform overall and perfect experimental research on the erosion morphology of all blades, or even if multiple nozzles are used, due to the single water pump, the outlet velocities of the nozzles are difficult to keep consistent, resulting in large experimental fluctuations and errors. Therefore, the existing experimental devices for steam turbine blade erosion have problems such as single experimental working condition and low test precision, and an experimental device and method capable of independently controlling the outlet velocity and time parameters of multiple nozzles are urgently needed to realize real and complete erosion research on steam turbine blades. SUMMARY

[0005] To solve the problems in the background art, the application provides a multi-pump multi-nozzle independent control experimental device and method suitable for turbine blade erosion, which is designed with multiple parallel branches and uses independent adjustment of multiple pumps and multiple nozzles, so as to help test and analyze the erosion mechanism and performance of turbine low-pressure complete blades under different working conditions, more accurately obtain the blade water erosion area, and further guide the blade design optimization and protection measures, and improve the safety and service life during operation.

[0006] To achieve the above-mentioned purpose, the application adopts the following technical solutions: A multi-pump multi-nozzle independent control experimental device suitable for turbine blade erosion, comprising a water supply tank, an experimental chamber, a buffer water tank, a centrifugal pump and multiple branches. The multiple branches are connected between the water supply tank and the experimental chamber in parallel, each branch comprises a self-priming pump, a high-pressure plunger pump, a bypass valve, a pressure transmitter, an ultrasonic flowmeter, a pneumatic needle valve and a nozzle connected in sequence through pipelines, the inlet end of the self-priming pump is connected with the water supply tank through a pipeline, and the nozzles are positioned and fixed on the front sidewall of the experimental chamber. A test blade is fixed at the rear of the experimental chamber, and the test blade is pre-adjusted according to the required erosion angle, and a baffle is inserted in the middle position of the experimental chamber to shield the nozzles of each branch from the test blade. The buffer water tank is connected with the bottom of the experimental chamber and the bypass port of the bypass valve in each branch through pipelines, and the centrifugal pump is connected with the water supply tank through a pipeline, and a filter is arranged in the pipeline between the centrifugal pump and the water supply tank.

[0007] Further, the high-pressure plunger pump of each branch is connected with a variable frequency motor for variable frequency operation.

[0008] Further, the variable frequency motor, the pressure transmitter and the ultrasonic flowmeter of each branch are connected with a computer respectively, the ultrasonic flowmeter feeds back the flow rate of each branch to the computer, and the computer can control the variable frequency motor and the pressure transmitter to adjust the flow rate and pressure of each branch.

[0009] Further, a plurality of positioning holes are arranged on the front sidewall of the experimental chamber, and the nozzles of each branch are fixed in the positioning holes at the corresponding positions according to the jet position requirement of the test blade.

[0010] Further, the test blade is selected as a turbine low-pressure stage blade.

[0011] A multi-pump multi-nozzle independent control experimental method suitable for turbine blade erosion, comprising the following steps: S1: Assemble the experimental device, select the test blade and fix it in the rear of the experimental chamber according to the erosion angle requirements in advance; S2: Start the computer, centrifugal pump, self-priming pump and high-pressure plunger pump of each branch, and determine that the water flow of each branch is unobstructed by combining the feedback of the ultrasonic flow meter in each branch; S3: The jet velocity set value of each branch nozzle is determined in advance, and then the jet velocity actual value of the nozzle is adjusted by the computer control variable frequency motor and pressure transmitter of each branch; S4: When the jet velocity actual value of each branch nozzle reaches the jet velocity set value, remove the baffle in the middle of the experimental chamber to start the erosion experiment formally; S5: After reaching the required erosion time of the experiment, turn off the experimental device, remove the test blade and perform subsequent performance test and analysis.

[0012] Further, in step S3, the jet velocity set value of each branch nozzle is calculated and obtained according to the speed triangle of the test blade in the actual operation process of the steam turbine.

[0013] Compared with the prior art, the beneficial effects of the present application are: 1. The present application adopts multiple parallel branches, each branch is independent and controlled, and the start and stop of each branch can be controlled on the computer, thereby improving the safety and stability of the experimental device; 2. The present application can independently adjust the working state of multiple pumps and multiple nozzles, the angle of the blade can be set in advance, the outlet speed of each nozzle and the erosion experiment time can be freely controlled, and the setting is integrated on the computer, so that complex multi-condition blade erosion experiments can be realized, and the comprehensiveness of the experimental device is improved; 3. The present application not only can perform erosion experiment on the steam turbine blade, but also can be extended to erosion experiment on the fan blade, water turbine blade and some equipment pipelines and cutters in different fields according to a certain scale reduction, and has certain flexibility and multifunctionality. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a structural schematic diagram of the experimental device of the present application; Figure 2 is a flow chart of the experimental method of the present application.

[0015] In the figure: 1, water supply tank; 2, self-priming pump; 3, high-pressure plunger pump; 4, variable frequency motor; 5, bypass valve; 6, computer; 7, pressure transmitter; 8, ultrasonic flow meter; 9, pneumatic needle valve; 10, nozzle; 11, baffle; 12, test blade; 13, experimental chamber; 14, buffer tank; 15, centrifugal pump; 16, filter. DETAILED DESCRIPTION

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0017] like Figure 1 As shown, a multi-pump, multi-nozzle independent control experimental device suitable for turbine blade erosion includes a water supply tank 1, a self-priming pump 2, a high-pressure plunger pump 3, a variable frequency motor 4, a bypass valve 5, a computer 6, a pressure transmitter 7, an ultrasonic flow meter 8, a pneumatic needle valve 9, a nozzle 10, a baffle 11, a test blade 12, an experimental chamber 13, a buffer water tank 14, a centrifugal pump 15, and a filter 16.

[0018] The water supply tank 1 serves as the water source supply device at the front end of the apparatus, and the experimental chamber 13 serves as the erosion test chamber at the rear end of the apparatus. The water supply tank 1 provides jets to the required locations in the experimental chamber 13 through multiple parallel branches. The number of branches and the jet locations are determined according to the experimental requirements of the test blades 12. Each branch includes a self-priming pump 2, a high-pressure plunger pump 3, a bypass valve 5, a pressure transmitter 7, an ultrasonic flow meter 8, a pneumatic needle valve 9, and a nozzle 10 arranged in a front-to-back sequence. The inlet end of the self-priming pump 2 is connected to the water supply tank 1 through a pipeline to draw out the water stored in the water supply tank 1. The outlet end of the self-priming pump 2 is connected to the inlet end of the high-pressure plunger pump 3 through a pipeline to transport the drawn water to the high-pressure plunger pump 3. The high-pressure plunger pump 3 is matched and connected to the variable frequency motor 4. The variable frequency motor 4 is mainly used to drive the high-pressure plunger pump 3 to work in a variable frequency manner. The outlet end of the high-pressure plunger pump 3 is connected to the inlet end of the bypass valve 5 through a pipeline. The outlet end of the bypass valve 5 is connected in sequence to a pressure transmitter 7, an ultrasonic flow meter 8, a pneumatic needle valve 9 and a nozzle 10 via pipelines. The bypass port of the bypass valve 5 is used to divert a portion of the water. The nozzle 10 is positioned and embedded on the front side wall of the experimental chamber 13. Several positioning holes can be arrayed on the front side wall of the experimental chamber 13. According to the jet position requirements of the test blade 12, the nozzle 10 of each branch is fixed in the positioning hole at the corresponding position.

[0019] The test blade 12 is a complete low-pressure stage blade of a steam turbine. Before each experiment, the erosion angle is adjusted according to the requirements and fixed in the rear of the test chamber 13.

[0020] The baffle 11 is inserted in the middle of the experimental cavity 13 to shield the nozzles 10 of each branch from the test blade 12, so as to avoid the influence of the early jet velocity of each branch on the experimental accuracy, and to remove the water flow through the nozzles 10 to erode the test blade 12 after the jet of each branch is stabilized.

[0021] The computer 6 is connected with the variable frequency motor 4, the pressure transmitter 7 and the ultrasonic flowmeter 8 of each branch, the ultrasonic flowmeter 8 feeds back the flow rate of each branch to the computer 6, and the computer 6 can control the variable frequency motor 4 and the pressure transmitter 7 to adjust the flow rate and pressure of each branch.

[0022] The buffer tank 14 is connected with the bottom of the experimental cavity 13 and the bypass port of the bypass valve 5 of each branch through pipelines, so as to collect and store the water in the experimental cavity 13 after erosion and the water shunted by the bypass valve 5.

[0023] The inlet end of the centrifugal pump 15 is connected with the buffer tank 14 through a pipeline, so as to suck out the water stored in the buffer tank 14, and the outlet end of the centrifugal pump 15 is connected with the water supply tank 1 through a pipeline, so as to recycle the experimental water, wherein a filter 16 is arranged in the pipeline between the centrifugal pump 15 and the water supply tank 1, and the filter 16 is used for filtering and purifying the experimental water.

[0024] As shown in Figures 1-2 A kind of multiple-pump multiple-nozzle independent control experimental method suitable for steam turbine blade erosion, comprising the following steps: S1: after the experimental device is assembled, select the test blade 12 and fix it in the rear of the experimental cavity 13 according to the erosion angle requirement in advance (in an embodiment, the test blade 12 is selected as the low-pressure last-stage blade of steam turbine, and the length is 1049mm); S2: start the computer 6, the centrifugal pump 15 and the self-priming pump 2 and the high-pressure plunger pump 3 of each branch, determine that the water flow of each branch is unobstructed in combination with the feedback of the ultrasonic flowmeter 8 in each branch; S3: determine the jet velocity set value of the nozzle 10 of each branch in advance (in an embodiment, 5 branches are adopted, and the jet velocities of the nozzles 10 of each branch from top to bottom are set as 500m / s, 400m / s, 300m / s, 200m / s and 100m / s respectively), which is calculated according to the speed triangle of the test blade 12 in the actual operation process of the steam turbine, and then the jet velocity actual value of the nozzle 10 is adjusted by the computer 6 controlling the variable frequency motor 4 and the pressure transmitter 7 of each branch, and the jet velocity curve of each branch nozzle 10 can be observed in real time on the computer 6 interface in combination with the monitoring system; S4: when the jet velocity actual value of the nozzle 10 of each branch reaches the jet velocity set value, remove the baffle 11 in the middle of the experimental cavity 13 to start the erosion experiment formally; S5: After reaching the required erosion time of the experiment (in an embodiment, the erosion time is set to 30 min), the experimental device is closed, and the test blade 12 is removed for subsequent performance testing and analysis.

[0025] In summary, the experimental device and experimental method of the present application can study the erosion damage of the low-pressure blade of the steam turbine under different working conditions. Through centralized control on the computer side, independent control and work between each branch are realized without interference, the nozzle outlet speed and erosion time are changed, the complex and multi-condition erosion experiment of the low-pressure blade of the steam turbine is met, and the blades in related fields can also be subjected to erosion experiment, and the use is flexible.

[0026] It will be obvious to a person skilled in the art that, without departing from the spirit or essential characteristics of the application, the present application can be implemented in other specific forms than those described and illustrated herein. Thus, the embodiments described and illustrated are to be considered only as illustrative and not restrictive, the scope of the application being defined by the appended claims rather than by the specification, which is intended to embrace all changes and modifications that fall within the meaning and range of equivalents of the claims. Any reference signs in the claims should not be construed as limiting the claims concerned.

[0027] In addition, it should be understood that, although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be properly combined to form other embodiments that those skilled in the art can understand.

Claims

1. A multi-pump, multi-nozzle independent control experimental device for turbine blade erosion, characterized in that: It includes a water supply tank (1), an experimental chamber (13), a buffer water tank (14), a centrifugal pump (15), and multiple branch lines; The water supply tank (1) and the experimental chamber (13) are connected by multiple branches arranged in parallel. Each branch includes a self-priming pump (2), a high-pressure plunger pump (3), a bypass valve (5), a pressure transmitter (7), an ultrasonic flow meter (8), a pneumatic needle valve (9), and a nozzle (10) that are connected in sequence through pipelines. The inlet end of the self-priming pump (2) is connected to the water supply tank (1) through pipelines. The nozzle (10) is fixedly embedded in the front side wall of the experimental chamber (13). The test blade (12) is fixed at the rear of the experimental chamber (13). The test blade (12) is pre-adjusted to the erosion angle according to the requirements. A baffle (11) is inserted in the middle of the experimental chamber (13) to block the nozzles (10) of each branch and the test blade (12). The buffer water tank (14) is connected to the bottom of the experimental chamber (13) and the bypass port of the bypass valve (5) in each branch through pipelines. The centrifugal pump (15) is connected to the buffer water tank (14) and the water supply tank (1) through pipelines, and a filter (16) is installed on the pipeline between the centrifugal pump (15) and the water supply tank (1).

2. The multi-pump, multi-nozzle independent control experimental device for turbine blade erosion according to claim 1, characterized in that: The high-pressure plunger pump (3) of each branch is connected to the variable frequency motor (4) for variable frequency operation.

3. The multi-pump, multi-nozzle independent control experimental device for turbine blade erosion as described in claim 2, characterized in that: The variable frequency motor (4), pressure transmitter (7) and ultrasonic flow meter (8) of each branch are respectively connected to the computer (6). The ultrasonic flow meter (8) feeds back the flow rate of each branch to the computer (6). The computer (6) can control the variable frequency motor (4) and pressure transmitter (7) to adjust the flow rate and pressure of each branch.

4. The multi-pump, multi-nozzle independent control experimental device for turbine blade erosion as described in claim 1, characterized in that: The experimental chamber (13) has several positioning holes arrayed on the front side wall. According to the jet position requirements of the test blade (12), the nozzles (10) of each branch are fixed in the corresponding positioning holes.

5. The multi-pump, multi-nozzle independent control experimental device for turbine blade erosion according to claim 1, characterized in that: The test blade (12) is selected from the low-pressure stage blade of the steam turbine.

6. A multi-pump, multi-nozzle independent control experimental method for turbine blade erosion, characterized in that: The experimental apparatus according to claim 3, wherein the experimental method comprises the following steps: S1: After assembling the experimental device, select the test blade (12) and fix it in the back of the experimental cavity (13) according to the erosion angle requirements; S2: Start the computer (6), centrifugal pump (15), and the self-priming pump (2) and high-pressure plunger pump (3) of each branch. Combine the feedback from the ultrasonic flow meter (8) in each branch to determine that the water flow in each branch is smooth and unobstructed. S3: Predetermine the jet velocity setting value of each branch nozzle (10), and then use the computer (6) to control the variable frequency motor (4) and pressure transmitter (7) of each branch to adjust the actual jet velocity value of the nozzle (10). S4: When the actual jet velocity of each branch nozzle (10) reaches the set jet velocity value, remove the baffle (11) in the middle of the experimental chamber (13) and officially start the erosion experiment. S5: After the required erosion time for the experiment is reached, the experimental device is shut down and the test blade (12) is removed for subsequent performance testing and analysis.

7. The multi-pump, multi-nozzle independent control experimental method for turbine blade erosion according to claim 6, characterized in that: In step S3, the jet velocity setting value of each branch nozzle (10) is obtained by rounding the calculation based on the velocity triangle of the test blade (12) during the actual operation of the steam turbine.

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