An experimental device and method for water erosion of low-pressure last two stages of blades of a thermal power steam turbine under deep peak regulation conditions

Abstract

The application discloses a kind of experimental device and method of low-pressure last two stages blade water erosion of thermal power steam turbine under deep peak regulation condition, the experimental device includes steam generator, ball valve a, pressure reducing valve, vortex flowmeter, nozzle, penultimate stage static blade, penultimate stage moving blade, last stage static blade, last stage moving blade, cylinder, rolling shaft, vacuum valve, air pump, high-speed camera, computer, air compressor, particle generator, ball valve b, high-speed motor.The method can explore the water erosion damage of thermal power steam turbine last two stages blade under deep peak regulation condition, by air pump and computer end control, different pressure in cylinder can be changed, to reach the pressure value in last two stages under different conditions in the process of deep peak regulation, nozzle is set along the height of blade, the flow state of steam in last two stages blade passage can be better simulated, last two stages blade staggered arrangement can truly reflect the single channel of low-pressure cylinder last two stages blade of steam turbine.

Description

Technical Field

[0001] This invention relates to an experimental apparatus and method for water erosion of turbine blades, specifically to an experimental apparatus and method for water erosion of the last two stages of low-pressure turbine blades under deep peak shaving conditions. Background Technology

[0002] Currently, deep peak shaving of steam turbines is quite common in order to absorb new energy sources. Under deep peak shaving conditions, the working environment of the last two stages of the low-pressure turbine blades is quite harsh. The steam humidity inside the last two stages of the blades is relatively high, making them prone to water erosion. Small pits and pits appear on the surface of the last two stages of the blades. Over time, this can even cause the blades to break, seriously threatening the safe and stable operation of the steam turbine.

[0003] CN100575917C discloses a turbine blade water erosion test device, which uses the collision between high-speed rotating blades and water droplets to simulate the water erosion caused by high-speed impact of water droplets on blades in the low-pressure cylinder of a turbine; CN201653838U discloses a water erosion test device, which simulates the water erosion suffered by the last stage blades of a turbine through the collision between a high-pressure pulsed water jet and the specimen; CN102252927B discloses a high-pressure water jet rotating impact water erosion test device, which simulates the erosion of turbine blades by water droplets through the collision between a high-speed jet and a rotating specimen; CN113267416B discloses a dynamic water erosion test device for nuclear power plant turbine blades, which can realize accelerated testing of the water erosion process of nuclear power turbine blades.

[0004] In summary, constructing a water erosion experimental platform using rotating, real moving blades presents certain challenges. Furthermore, current technologies only focus on water erosion in the final stage of steam turbines, and have not conducted experimental studies on water erosion in the last two stages of the low-pressure turbine blades under deep peak-shaving conditions in thermal power plants. Summary of the Invention

[0005] To study the water erosion mechanism of the last two stages of a thermal power turbine under deep peak shaving conditions, this invention provides an experimental apparatus and method for water erosion of the last two stages of a thermal power turbine under deep peak shaving conditions, providing a theoretical basis for the safe operation and protection of the last stage blades of the turbine.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] An experimental apparatus for water erosion of the last two stages of low-pressure turbine blades under deep peak-shaving conditions includes a steam generator, ball valve a, pressure reducing valve, vortex flow meter, nozzle, second-to-last stage stationary blade, second-to-last stage moving blade, last stage stationary blade, last stage moving blade, cylinder block, rolling shaft, vacuum valve, air pump, high-speed camera, computer, air compressor, particle generator, ball valve b, and high-speed motor, wherein:

[0008] The steam generator is connected to one end of ball valve a via the main steam pipeline, and the other end of ball valve a is connected to one end of pressure reducing valve via the main steam pipeline. The other end of pressure reducing valve is connected to vortex flow meter via the main steam pipeline.

[0009] The air compressor is connected to the particle reactor through a branch pipe. The particle reactor is connected to one end of the ball valve b through a branch pipe. The other end of the ball valve b is connected to the main steam pipe through a branch pipe. The air compressor carries water droplets of different diameters in the particle reactor into the main steam pipe through the branch pipe, where they move together with the superheated steam generated by the steam generator.

[0010] The nozzle is placed at the end of the main steam pipe and at the front end of the secondary final stage stationary blade, spraying steam with water droplets into the blade channel through the outlet.

[0011] The secondary and final stage stationary vanes and the final stage stationary vane are fixed on the cylinder body, and the secondary and final stage moving vanes and the final stage moving vane are fixed on the rolling shaft. The secondary and final stage stationary vanes, the secondary and final stage moving vanes, the final stage stationary vanes, and the final stage moving vane are installed alternately. The rolling shaft drives the secondary and final stage moving vanes and the final stage moving vane to rotate under the action of the high-speed motor.

[0012] The cylinder is provided with an exhaust port, which collects the water that condenses inside the cylinder.

[0013] One end of the vacuum valve is connected to the cylinder body through a pipe, and the other end of the vacuum valve is connected to the air pump through a pipe. The air pump performs air extraction on the cylinder body under the control of the vacuum valve.

[0014] The high-speed camera is connected to a computer to record the water erosion rate and changes on the blade surface;

[0015] The ball valve a and the pressure reducing valve are connected to a computer and used to control the steam flow and steam pressure in the main steam pipeline;

[0016] The vortex flow meter is connected to a computer for the control, monitoring, and acquisition of flow data.

[0017] An experimental method for water erosion of the last two stages of low-pressure turbine blades under deep peak-shaving conditions includes the following steps:

[0018] Step 1: Connect the experimental apparatus in sequence. The second and last stage stationary blades and the last stage stationary blade are fixed on the cylinder body, and the second and last stage moving blades and the last stage moving blade are fixed on the rolling shaft.

[0019] Step 2: Open the vacuum valve, turn on the air pump, and set the pressure inside the cylinder to the pressure of the last two stages of the turbine under deep peak shaving conditions. The pressure value is displayed and controlled by the computer.

[0020] Step 3: Mix the steam generated by the steam generator with the water droplets generated by the particle generator, and spray them out through the nozzles into the single flow channel of the last two stages of the steam turbine blades;

[0021] Step 4: Turn on the high-speed motor to drive the rolling shaft to rotate;

[0022] Step 5: The experiment is over. Remove the last two stages of turbine blades.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. By utilizing the impact effect of water droplets on two small-sized real blades, the water erosion damage mechanism of the last two stages of the low-pressure turbine blades under deep peak shaving conditions was studied.

[0025] 2. By utilizing the interaction between water vapor and water droplets on the rotating two-stage small-sized real blades, the water erosion process of the last two stages of low-pressure blades during the deep peak shaving process of the steam turbine is realistically reflected.

[0026] 3. By setting up a high-speed camera, the water erosion process can be recorded in real time from multiple angles, which is beneficial for carrying out research on the water erosion evolution process of small-sized real blades. Attached Figure Description

[0027] Figure 1 This is an experimental block diagram of water erosion of the last two stages of low-pressure turbine blades in a thermal power plant under deep peak shaving conditions; in the diagram: 1 Steam generator, 2 Ball valve a, 3 Pressure reducing valve, 4 Vortex flow meter, 5 Nozzle, 6 Secondary last stage stationary blade, 7 Secondary last stage moving blade, 8 Last stage stationary blade, 9 Last stage moving blade, 10 Cylinder block, 11 Rolling shaft, 12 Exhaust port, 13 Vacuum valve, 14 Air pump, 15 High-speed camera, 16 Computer, 17 Air compressor, 18 Particle generator, 19 Ball valve b, 20 High-speed motor;

[0028] Figure 2 This is a flowchart of the experimental method. Detailed Implementation

[0029] The technical solution of the present invention will be further described below with reference to the accompanying drawings, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0030] This invention provides an experimental apparatus for water erosion of the last two stages of low-pressure turbine blades under deep peak-shaving conditions, such as... Figure 1As shown, the device includes a steam generator 1, ball valve a2, pressure reducing valve 3, vortex flow meter 4, nozzle 5, secondary and final stage stationary vane 6, secondary and final stage moving vane 7, final stage stationary vane 8, final stage moving vane 9, cylinder 10, rolling shaft 11, exhaust port 12, vacuum valve 13, air pump 14, high-speed camera 15, computer 16, air compressor 17, pellet generator 18, ball valve b19, and high-speed motor 20, wherein:

[0031] The steam generator 1 is connected to one end of the ball valve a2 via the main steam pipeline. The temperature and pressure of the steam at the outlet of the steam generator 1 can be set by itself.

[0032] The pressure reducing valve 3 is connected to the other end of the ball valve a through the main steam pipeline, and the pressure reducing valve 3 can regulate the steam pressure in the main steam pipeline.

[0033] The vortex flow meter 4 is connected to the pressure reducing valve 3 through the main steam pipeline, and the vortex flow meter 4 can measure the steam flow rate in the main steam pipeline.

[0034] The air compressor 17 is connected to the particle reactor 18 through a branch pipe. The particle reactor 18 is connected to one end of the ball valve b19 through a branch pipe. The other end of the ball valve b19 is connected to the main steam pipe through a branch pipe. The air compressor 17 carries water droplets of different diameters in the particle reactor 18 into the main steam pipe through the branch pipe, where they move together with the superheated steam generated by the steam generator 1.

[0035] The nozzle 5 is placed at the end of the main steam pipe and at the front end of the secondary final stage stationary blade 6, so that steam with water droplets is sprayed from the outlet to the blade channel.

[0036] The secondary stage stationary blade 6 is provided with a row of nozzles along the blade height to realistically simulate the flow of steam along the blade height.

[0037] The secondary and final stage stationary blades 6 and 8 are fixed on the cylinder body 10, and the secondary and final stage moving blades 7 and 9 are fixed on the rolling shaft 11. The secondary and final stage stationary blades 6, 7, 8, and 9 are installed alternately. The rolling shaft 11 drives the secondary and final stage moving blades 7 and 9 to rotate under the action of the high-speed motor 20.

[0038] The secondary and final stage moving blades are arranged in a cycle of 2n+2, where n≧1. The blades are scaled down to 1:5 of their actual size, and the rotation speed is set to 1000r / min.

[0039] Under the control of the vacuum valve 13, the vacuum pump 14 can perform vacuuming on the cylinder 10, so that the pressure value inside the cylinder 10 is almost close to the pressure value in the last two stages of the low-pressure cylinder of the steam turbine under the actual deep peak shaving condition. By changing different pressure values ​​inside the cylinder 10, the actual pressure in the last two stages of the low-pressure cylinder under the deep peak shaving condition of the steam turbine can be achieved. The magnitude of the pressure value can be displayed by the computer 16.

[0040] The exhaust port 12 can collect the condensed water inside the cylinder 10;

[0041] The high-speed camera 15 can record the water erosion rate and changes on the blade surface;

[0042] The ball valve a and the pressure reducing valve 3 are connected to the computer 16 to control the steam flow and steam pressure in the main steam pipeline;

[0043] The vortex flow meter 4 and the high-speed camera 15 are connected to the computer 16, enabling flow monitoring and data acquisition.

[0044] This invention also provides an experimental method for water erosion of the last two stages of low-pressure turbine blades under deep peak-shaving conditions. This method can investigate the water erosion damage of the last two stages of turbine blades under deep peak-shaving conditions. By controlling the air pump and computer, different pressures within the turbine cylinder can be changed to achieve the pressure values ​​within the last two stages under different operating conditions during deep peak-shaving. Nozzles are placed along the blade height to better simulate the flow state of steam in the last two stages of the blades. The staggered arrangement of the last two stages of blades can realistically represent the single-channel design of the last two stages of the turbine's low-pressure cylinder. Figure 2 As shown, the specific steps include the following:

[0045] Step 1: Prepare the blade patterns for the last two stages of the low-pressure turbine, including 1 second-to-last stage stationary blade, 2n+2 second-to-last stage moving blades, 1 last-stage stationary blade, and 2n+2 last-stage moving blades.

[0046] Step 2: Connect the experimental apparatus in sequence. Fix the second and last stage stationary blades and the last stage stationary blades on the cylinder body, and fix the second and last stage moving blades and the last stage moving blades on the rolling shaft.

[0047] Step 3: Open the vacuum valve and turn on the vacuum pump. Set the pressure inside the cylinder to the pressure of the last two stages of the turbine under deep peak shaving conditions; the pressure value is displayed and controlled by the computer.

[0048] Step 4: Mix the high-temperature, high-pressure, high-speed steam generated by the steam generator with the water droplets generated by the particle generator, and spray them out through the nozzles into the single flow channel of the last two stages of the turbine blades.

[0049] Step 5: Turn on the high-speed motor to drive the rolling shaft to rotate.

[0050] Step 6: Set the experiment time to 1 hour. After the time is up, remove the last two stages of turbine blades.

[0051] Example:

[0052] Taking the water erosion test of the last two stages of the low-pressure turbine blades as an example, this paper provides a detailed description of the experimental setup for water erosion of the last two stages of a thermal power turbine under deep peak shaving conditions.

[0053] An air compressor is connected to the pellet reactor, which carries water droplets of different diameters from the pellet reactor into the main steam pipe through a branch pipe, where they move together with the superheated steam generated by the steam generator.

[0054] The nozzles are placed at the front end of the secondary stationary blade at the end of the main steam pipe. There are 20 nozzles along the height of the secondary stationary blade, which spray steam with water droplets into the blade channel through the outlet.

[0055] The main water erosion process takes place within the cylinder. There are a total of 10 blade specimens: one secondary-to-final stage stationary blade and one final-stage stationary blade, four secondary-to-final stage moving blades, and four final-stage moving blades, namely, secondary-to-final stage stationary blade, secondary-to-final stage moving blade, final-stage stationary blade, and final-stage moving blade. The secondary-to-final stage stationary blade and the final-stage stationary blade are fixed to the cylinder, while the secondary-to-final stage moving blade and the final-stage moving blade are fixed to a rolling shaft. The rolling shaft drives the two moving blades to rotate under the action of a motor.

[0056] Four secondary and final stage blades were set up per revolution. The blades were scaled down to 1:5 of their actual size. That is, the actual length of the secondary and final stage blades was 100 cm, while the length of the secondary and final stage blades used in the experiment was 20 cm. The actual length of the final stage blades was 150 cm, while the length of the blades used in the experiment was 30 cm. The rotation speed was set to 1000 r / min.

[0057] Under the control of the vacuum valve, the pump can pump air from the cylinder, making the pressure inside the cylinder almost close to the pressure in the last two stages of the low-pressure cylinder of the turbine under actual deep peak shaving conditions.

[0058] The exhaust port can collect the water that condenses inside the cylinder, and the high-speed camera can record the water erosion rate and changes on the blade surface.

[0059] Ball valve A and pressure reducing valve are connected to the computer to control the flow and pressure of steam in the main pipeline; vortex flow meter and high-speed camera are connected to the computer to monitor and collect flow data.

[0060] Its experimental methods mainly include:

[0061] Step 1: Prepare samples of the last two stages of the low-pressure turbine blades, including 1 second-to-last stage stationary blade, 4 second-to-last stage moving blades, 1 last-stage stationary blade, and 4 last-stage moving blades, for a total of 10 blade samples.

[0062] Step 2: Connect the experimental apparatus in sequence. Fix the second and last stage stationary blades and the last stage stationary blades on the cylinder body, and fix the second and last stage moving blades and the last stage moving blades on the rolling shaft.

[0063] Step 3: Open the vacuum valve and turn on the vacuum pump. Set the pressure inside the cylinder to the pressure of the last two stages of the turbine under deep peak shaving conditions. The pressure value is displayed and controlled by the computer.

[0064] Step 4: The high-temperature, high-pressure, and high-speed steam generated by the steam generator is mixed with the water droplets generated by the particle generator and sprayed out through 20 nozzles into the single flow channel of the last two stages of the steam turbine blades.

[0065] Step 5: Turn on the high-speed motor to drive the rolling shaft to rotate.

[0066] Step 6: Set the experiment time to 1 hour. After the time is up, remove the last two stages of turbine blades.

Claims

1. An experimental apparatus for water erosion of the last two stages of low-pressure turbine blades under deep peak-shaving conditions, characterized in that... The experimental setup includes a steam generator, ball valve a, a pressure reducing valve, a vortex flow meter, a nozzle, a secondary and final stage stationary vane, a secondary and final stage moving vane, a final stage stationary vane, a final stage moving vane, a cylinder, a rolling shaft, a vacuum valve, a vacuum pump, a high-speed camera, a computer, an air compressor, a particle generator, ball valve b, and a high-speed motor, wherein: The steam generator is connected to one end of ball valve a via the main steam pipeline, and the other end of ball valve a is connected to one end of pressure reducing valve via the main steam pipeline. The other end of pressure reducing valve is connected to vortex flow meter via the main steam pipeline. The air compressor is connected to the particle reactor through a branch pipe. The particle reactor is connected to one end of the ball valve b through a branch pipe. The other end of the ball valve b is connected to the main steam pipe through a branch pipe. The air compressor carries water droplets of different diameters in the particle reactor into the main steam pipe through the branch pipe, where they move together with the superheated steam generated by the steam generator. The nozzle is placed at the end of the main steam pipe and at the front end of the secondary final stage stationary blade, spraying steam with water droplets into the blade channel through the outlet. The secondary and final stage stationary vanes and the final stage stationary vane are fixed on the cylinder block, and the secondary and final stage moving vanes and the final stage moving vane are fixed on the rolling shaft. The rolling shaft drives the secondary and final stage moving vanes and the final stage moving vane to rotate under the action of the high-speed motor. The cylinder is provided with an exhaust port, which collects the water that condenses inside the cylinder. One end of the vacuum valve is connected to the cylinder body through a pipe, and the other end of the vacuum valve is connected to the air pump through a pipe. The air pump performs air extraction on the cylinder body under the control of the vacuum valve. The high-speed camera is connected to a computer to record the water erosion rate and changes on the blade surface; The ball valve a and the pressure reducing valve are connected to a computer and used to control the steam flow and steam pressure in the main steam pipeline; The vortex flow meter is connected to a computer for the control, monitoring, and acquisition of flow data.

2. The experimental apparatus for water erosion of the last two stages of low-pressure turbine blades under deep peak-shaving conditions as described in claim 1, characterized in that... The secondary stage stationary blade has a row of nozzles along its blade height to realistically simulate the flow of steam along the blade height.

3. The experimental apparatus for water erosion of the last two stages of low-pressure turbine blades under deep peak-shaving conditions as described in claim 1, characterized in that... The secondary and final stage stationary blades, secondary and final stage moving blades, final stage stationary blades, and final stage moving blades are installed alternately.

4. The experimental apparatus for water erosion of the last two stages of low-pressure turbine blades under deep peak-shaving conditions as described in claim 1, characterized in that... The secondary and final stage moving blades are arranged in groups of 2n+2, where n≧1. The blades are scaled down to 1:5 of their actual size, and the rotation speed is set to 1000r / min.

5. An experimental method for water erosion of the last two stages of low-pressure turbine blades under deep peak-shaving conditions, characterized in that... The method includes the following steps: Step 1: Connect the experimental apparatus according to any one of claims 1-4 in sequence, with the second-stage stationary blade and the final-stage stationary blade fixed on the cylinder body, and the second-stage moving blade and the final-stage moving blade fixed on the rolling shaft. Step 2: Open the vacuum valve, turn on the air pump, and set the pressure inside the cylinder to the pressure of the last two stages of the turbine under deep peak shaving conditions. The pressure value is displayed and controlled by the computer. Step 3: Mix the steam generated by the steam generator with the water droplets generated by the particle generator, and spray them out through the nozzles into the single flow channel of the last two stages of the steam turbine blades; Step 4: Turn on the high-speed motor to drive the rolling shaft to rotate; Step 5: The experiment is over. Remove the last two stages of turbine blades.

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