Valve seat with rectifying channel and steam turbine regulating valve

Abstract

The invention relates to the field of steam turbines, in particular to a valve seat steam turbine regulating valve with a rectifying channel. A circle of wall tooth-shaped structure is arranged on the valve seat, wall teeth are separated through grooves, and the wall teeth and the grooves are alternately arranged to form a whole circle of rectification channel structure. After the valve is opened, steam passes through the grooves between the city wall teeth, and the steam flow is divided into a plurality of small steam flows which enter the steam turbine to do work. The steam turbine regulating valve comprises the valve seat and the valve disc. According to the valve seat with the rectifying channel and the steam turbine regulating valve, the vibration level and the noise are low under the small opening degree.

Description

Technical Field

[0001] The present invention relates to the field of steam turbines, and particularly to a control valve of a valve seat steam turbine with a rectifying channel. Background Art

[0002] The control valve of a steam turbine is a core component for controlling the steam flow rate and ensuring the stable operation of the unit. The control valve of a steam turbine is used to adjust the steam inlet volume (unit output) of the steam turbine to meet the power demand of the power grid or maintain the frequency of the power grid. When the unit suddenly loses load, it should be able to quickly close slightly to prevent overspeed and maintain stable operation of the unit under no-load or low-load conditions. Generally, there can be four to eight control valves, which can be opened sequentially or simultaneously to achieve nozzle control or throttle control. Advanced electronic control systems also have a valve management function, that is, they operate in a throttling mode at low loads or during the initial operation period, and then can be switched to the nozzle control mode for operation.

[0003] During the design process of the control valve, the steam flow velocity at the valve throat is a relatively important parameter. The steam flow velocity determines the corresponding diameter of the valve, which is related to the economy of the unit, the valve pressure loss, the valve vibration and noise, etc. If the flow velocity is too low, it will lead to too large a valve diameter and an increase in the initial investment; if the flow velocity is too high, it will lead to an increase in the valve vibration level and noise, bringing potential safety risks to the operation of the unit. According to relevant design specifications, when the steam turbine operates under rated conditions, the flow velocity at the control valve throat can generally be controlled at about 100 m / s.

[0004] Figures 1 to 2 is the structure of a conventional valve seat and valve disc of a steam turbine control valve. When the valve is in the closed state, the valve seat 1 and the valve disc 2 are in close contact to block the steam from entering the steam turbine. After the valve is opened, the valve disc 2 moves away from the valve seat 1, and a channel 3 is formed between the two, and the steam enters the steam turbine interior through this channel 3 to do work.

[0005] During the actual operation process of the unit, the steam turbine often faces some working conditions where the valve cannot be fully opened, such as the unit startup stage, the low-power platform test working condition, the load reduction operation due to power grid regulation needs, etc. The control valve needs to maintain a small opening to reduce the steam entering the steam turbine. In this case, the steam flow velocity passing through the valve disc and valve seat of the control valve is often higher, resulting in an increase in the vibration level and noise of the valve disc and valve stem, and the unit is also prone to some operation safety problems due to excessive vibration. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a valve seat and a steam turbine control valve with a rectifying channel, which have low vibration level and low noise under a small opening.

[0007] The present invention provides a valve seat with a rectifying channel. A ring of castellated teeth structure is arranged on the valve seat. The castellated teeth are separated by grooves, and the castellated teeth and the grooves are arranged alternately to form a complete ring of rectifying channel structure.

[0008] After the valve is opened, steam passes through the grooves between the castellated teeth, and the steam flow is divided into several small jets of steam and enters the steam turbine to do work.

[0009] In a specific embodiment of the present invention, the end of the castellated tooth facing the inner circle is of the same width as the end facing the outer circle, and the groove gradually tapers along the air flow direction.

[0010] In a specific embodiment of the present invention, the top of the castellated tooth is arc-shaped.

[0011] In a specific embodiment of the present invention, a ring of castellated teeth is uniformly arranged on the valve seat.

[0012] In a specific embodiment of the present invention, 10 to 20 castellated teeth are arranged on the valve seat.

[0013] In a specific embodiment of the present invention, 12 to 15 castellated teeth are arranged on the valve seat.

[0014] In a specific embodiment of the present invention, the radius of curvature R of the arc at the top of the castellated tooth satisfies: 0.1W ≤ R ≤ 0.3W, where W is the width of the castellated tooth; the inclination angle θ of the castellated tooth satisfies: 10° ≤ θ ≤ 30°.

[0015] In a specific embodiment of the present invention, the ratio of the inlet width W1 to the outlet width W2 of the groove satisfies: 1.5 ≤ W1 / W2 ≤ 3.0.

[0016] In a specific embodiment of the present invention, the ratio of the height H of the castellated tooth to the diameter D of the valve seat satisfies: 0.05D ≤ H ≤ 0.1D, and the ratio of the width W of the castellated tooth to the diameter D of the valve seat should satisfy: 0.02D ≤ W ≤ 0.05D.

[0017] The present invention provides a steam turbine control valve, including the valve seat and the valve disc described in the above technical solution.

[0018] Compared with the prior art, the valve seat with a rectifying channel and the steam turbine regulating valve of the present invention effectively change the steam flow path through the valve seat by designing a crenel structure with a certain angle on the valve seat, dividing the overall diffraction flow into several small channel jets. The Reynolds number of the flow around the valve seat profile is reduced by dozens of times, reducing the fluid inertial force. At the same time, the flow-through damping force is increased, and the two-way action makes the noise frequency shift to the high frequency and the amplitude attenuate significantly, effectively solving the vibration and noise problems that are prone to occur at small valve openings. This structure can also effectively disperse the steam pressure, reduce local wear, and improve the service life of the valve.

[0019] The existence of the channel effectively reduces the noise in the 3000Hz frequency band of the supersonic impact jet and suppresses the audible popping sound caused by the pressure jump triggered by the shock wave train to a certain extent. When the valve opening is small, the channel formed between the groove and the arc surface of the valve disc eliminates the valve disc vibration caused by the pressure fluctuation generated by the steam flow-through, and at the same time reduces the pressure fluctuation of the steam behind the valve, avoiding damage to the downstream pipeline behind the valve.

[0020] The valve seat structure of the present invention also considers the safety of the unit operation, effectively preventing the operation safety problems caused by excessive vibration, and improving the reliability and stability of the system. Further, the top of the crenel is arc-shaped, reducing the erosion of the steam on the crenel and improving the service life. Description of the Drawings

[0021] Figure 1 It shows the connection state diagram of the valve seat and valve disc of the steam turbine regulating valve in the valve closed state in the prior art;

[0022] Figure 2 It shows the connection state diagram of the valve seat and valve disc of the steam turbine regulating valve in the valve open state in the prior art;

[0023] Figure 3 It shows the schematic diagram of the valve seat structure of the steam turbine regulating valve;

[0024] Figure 4 It shows the connection state diagram of the valve seat and valve disc of the steam turbine regulating valve in the valve open state of the present invention;

[0025] Figure 5 It shows the connection state diagram of the valve seat and valve disc of the steam turbine regulating valve in the valve closed state of the present invention;

[0026] Figure 6 It shows the schematic diagram of the steam flow field through the rectifying channel;

[0027] In the figure, 1-valve seat, 2-valve disc, 3-channel, 4-crenel, 5-groove. Detailed Embodiments

[0028] To further understand the present invention, the embodiments of the present invention will be described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the present invention.

[0029] An embodiment of the present invention discloses a valve seat with a rectifying channel. As Figure 3 shown, a circle of castellated teeth structure is provided on the valve seat 1. The castellated teeth 4 are separated by grooves 5, and the castellated teeth 4 and the grooves 5 are arranged alternately to form a complete circle of rectifying channel structure;

[0030] After the valve is opened, steam passes through the grooves 5 between the castellated teeth 4, and the steam flow is divided into several small bundles of steam flows, which enter the steam turbine to do work.

[0031] One end of the castellated teeth 4 facing the inner circle is of the same width as the end facing the outer circle, and the groove 5 tapers along the air flow direction.

[0032] The top of the castellated teeth 4 is arc-shaped.

[0033] A circle of castellated teeth 4 is uniformly arranged on the valve seat 1, preferably 10 - 20 castellated teeth 4, and more preferably 12 - 15 castellated teeth 4.

[0034] The radius of curvature R of the arc at the top of the castellated teeth 4 satisfies: 0.1W ≤ R ≤ 0.3W, where W is the width of the castellated teeth. This design can reduce the erosion of steam on the castellated teeth and extend the service life. The inclination angle (θ) of the castellated teeth should satisfy: 10° ≤ θ ≤ 30°. This angle can ensure that the steam flow can be effectively divided when passing through the castellated teeth, while not increasing too much flow resistance.

[0035] The ratio of the inlet width (W1) to the outlet width (W2) of the groove 5 should satisfy: 1.5 ≤ W1 / W2 ≤ 3.0. This tapered design can ensure that the steam flow gradually accelerates when passing through the groove, reducing turbulence and noise.

[0036] For the valve seat with a rectifying channel, the ratio of the height (H) of the castellated teeth 4 to the valve seat diameter (D) should satisfy: 0.05D ≤ H ≤ 0.1D, and the ratio of the width (W) of the castellated teeth 4 to the valve seat diameter (D) should satisfy: 0.02D ≤ W ≤ 0.05D.

[0037] The design parameters of the castellated teeth 4 structure, such as the height, width, inclination angle, etc. of the teeth, all need to be accurately calculated and experimentally verified to ensure that while increasing the steam flow rate, it will not have a negative impact on the overall performance of the steam turbine control valve, such as increasing the flow resistance and reducing the closing performance of the valve. These parameters need to be determined according to specific working conditions, valve parameters, and design requirements.

[0038] An embodiment of the present invention also discloses a steam turbine control valve, which includes the valve seat 1 and the valve disc 2 described in the above technical solution.

[0039] To further understand the present invention, the valve seat with a rectifying channel and the steam turbine control valve provided by the present invention will be described in detail below in conjunction with embodiments. The protection scope of the present invention is not limited by the following embodiments.

[0040] Embodiment 1

[0041] The valve seat with a rectifying channel is as Figure 3 shown. A circle of castellated tooth structures is evenly arranged on the valve seat 1. The number of the castellated teeth 4 is 10, and the top of the castellated teeth 4 is arc-shaped.

[0042] The castellated teeth 4 are separated by grooves 5, and the castellated teeth 4 and the grooves 5 are arranged alternately to form a complete circle of rectifying channel structure;

[0043] The end of the castellated tooth 4 facing the inner circle is of the same width as the end facing the outer circle, and the groove 5 tapers along the air flow direction.

[0044] The radius of curvature R of the arc at the top of the castellated tooth 4 is 0.2W, where W is the width of the castellated tooth; this design can reduce the erosion of the castellated tooth by steam and extend the service life. The inclination angle (θ) of the castellated tooth 4 is 20°. This angle can ensure that the steam flow can be effectively divided when passing through the castellated tooth without increasing too much flow resistance.

[0045] The ratio of the inlet width (W1) to the outlet width (W2) of the groove 5 satisfies: W1 / W2 is 2. This tapered design can ensure that the steam flow gradually accelerates when passing through the groove, reducing turbulence and noise.

[0046] For the valve seat with a rectifying channel described above, the ratio of the height (H) of the castellated tooth 4 to the diameter (D) of the valve seat should satisfy: H = 0.1D, and the ratio of the width (W) of the castellated tooth 4 to the diameter (D) of the valve seat satisfies: W = 0.04D.

[0047] The design parameters of the castellated tooth 4 structure, such as the height, width, inclination angle, etc. of the tooth, all need to be accurately calculated and experimentally verified to ensure that while increasing the steam flow rate, it will not have a negative impact on the overall performance of the steam turbine control valve, such as increasing the flow resistance and reducing the closing performance of the valve. These parameters need to be determined according to specific working conditions, valve parameters and design requirements.

[0048] After the steam turbine control valve is opened, as Figure 4 shown, the steam passes through the groove 5 between the castellated teeth 4, and the steam flow is divided into several small bundles of steam flows and enters the steam turbine to do work.

[0049] After the turbine regulating valve is closed, Figure 5 As shown in the figure, the valve seat 1 and the valve disc 2 form a close contact, blocking the steam from entering the steam turbine; at this time, the top arc-shaped design of the wall tooth 4 fits tightly with the contact surface of the valve disc 2, ensuring that steam cannot enter the steam turbine through the gap between the valve seat 1 and the valve disc 2. The groove 5 between the wall teeth 4 is completely closed by the valve disc 2 in the closed state, further enhancing the sealing effect. The structural design of the wall teeth 4 (such as height, width, tilt angle, etc.) has been precisely calculated to ensure that it will not be deformed or damaged when subjected to pressure from the valve disc 2, thereby ensuring the reliable closure of the valve in a high-pressure steam environment.

[0050] like Figure 6 As shown, by setting a rectifying groove structure on the valve seat of the regulating valve, the overall diffraction jet is divided into a dozen small groove jets, and the flow Reynolds number bypassing the valve seat profile is reduced by dozens of times, reducing the fluid inertia force and increasing the flow damping force. The two-way action shifts the noise frequency to high frequency and greatly attenuates the amplitude.

[0051] The existence of the grooves effectively reduces the 3000Hz frequency band noise of the supersonic impact jet and to a certain extent suppresses the pressure jump caused by the shock wave train to produce audible explosion sound, the so-called sonic boom.

[0052] When the valve opening is small, the channel formed between the groove 5 and the arc surface of the valve disc 2 eliminates the vibration of the valve disc caused by the pressure fluctuation caused by the steam flow, and also reduces the pressure fluctuation of the steam after the valve, avoiding damage to the downstream pipeline after the valve.

[0053] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0054] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A valve seat with a rectifying channel, characterized in that, A circle of castellated teeth structures is arranged on the valve seat. The castellated teeth are separated by grooves, and the castellated teeth and the grooves are arranged alternately to form a complete rectifying channel structure; After the valve is opened, steam passes through the grooves between the castellated teeth, and the steam flow is divided into several small steam flows, which enter the steam turbine to do work.

2. The valve seat with a rectifying channel according to claim 1, characterized in that, The end of the castellated tooth facing the inner circle is of the same width as the end facing the outer circle, and the groove gradually tapers along the air flow direction.

3. The valve seat with a rectifying channel according to claim 1, characterized in that, The top of the castellated tooth is arc-shaped.

4. The valve seat with a rectifying channel according to claim 1, characterized in that, A circle of castellated teeth is evenly arranged on the valve seat.

5. The valve seat with a rectifying channel according to claim 4, characterized in that, There are 10 to 20 castellated teeth arranged on the valve seat.

6. The valve seat with a rectifying channel according to claim 5, characterized in that, There are 12 to 15 castellated teeth arranged on the valve seat.

7. The valve seat with a rectifying channel according to claim 2, characterized in that, The radius of curvature R of the arc at the top of the castellated tooth satisfies: 0.1W ≤ R ≤ 0.3W, where W is the width of the castellated tooth; the inclination angle θ of the castellated tooth satisfies: 10° ≤ θ ≤ 30°.

8. The valve seat with a rectifying channel according to claim 1, characterized in that, The ratio of the inlet width W1 to the outlet width W2 of the groove satisfies: 1.5 ≤ W1 / W2 ≤ 3.

0.

9. The valve seat with a rectifying channel according to claim 1, characterized in that, The ratio of the height H of the castellated tooth to the diameter D of the valve seat satisfies: 0.05D ≤ H ≤ 0.1D, and the ratio of the width W of the castellated tooth to the diameter D of the valve seat should satisfy: 0.02D ≤ W ≤ 0.05D.

10. A steam turbine control valve, characterized in that, It includes the valve seat and the valve disc described in any one of claims 1 to 9.

Images