Pre-whirl synergistic centrifugal liquid film self-drainage anti-erosion system

Abstract

The utility model provides a pre-whirl synergetic centrifugal liquid film self-drainage anti-erosion system which comprises a compressor inlet section and a plurality of channels distributed along the inner side of the compressor inlet section in the circumferential direction, the channels are spirally distributed at intervals, and the discharge ends of the channels are communicated to a low-pressure area pipeline so that liquid drops can flow into the low-pressure area pipeline under the action of pre-whirl centrifugal force. The water enters a channel and is discharged into a low-pressure area pipeline; a steam-water separator does not need to be arranged, the equipment cost is reduced, the pressure loss of an inlet of the compressor can be effectively reduced, and meanwhile the situation that liquid drops enter the compressor to damage an impeller of the compressor is avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to centrifugal compressor field especially relates to pre-rotation cooperative centrifugal liquid film self-liquid-discharge anti-erosion system. BACKGROUND

[0002] In industrial production, centrifugal water vapor compressor can effectively improve steam quality, convert low-quality steam into high-quality steam and then put into industrial production, thereby improving steam utilization rate. However, in industrial production, low-pressure water vapor compressed by water vapor is often in a saturated state, and condensate droplets are accompanied before entering the water vapor compressor. When the condensate droplets enter the compressor, they have a great impact on the high-speed rotating centrifugal impeller, causing irreversible serious damage to the impeller in a long time of operation, greatly reducing the service life of the centrifugal water vapor compressor.

[0003] At present, when dealing with the liquid droplet problem, a gas-liquid separator is usually designed at the inlet of the compressor, the water content in the incoming steam is reduced to below 1% by using the gas-liquid separator, and then the high-temperature steam at the outlet of the compressor is mixed into the inlet steam through backflow, so that the temperature of the water vapor compressor inlet is overheated by more than 5℃. However, the existing treatment method has a great influence on the efficiency and service life of the water vapor compressor: 1. The increase of the inlet steam temperature can significantly reduce the compression efficiency of the compressor; 2. The backflow of the compressor outlet steam will lead a large part of the compressed high-pressure steam to the inlet for re-compression, resulting in serious electric energy loss; 3. The gas-liquid separator and backflow heating cannot guarantee the superheat degree of the inlet steam during the start and stop of the unit, and the liquid droplets will cause serious damage to the compressor during the start and stop of the unit; 4. When the working condition of the backflow heating inlet steam changes, over-regulation phenomenon occurs, and the liquid droplets in the inlet steam enter the compressor, causing damage to the centrifugal impeller.

[0004] In addition, before the steam enters the centrifugal compressor, the centrifugal effect caused by the pipeline bending and the pre-rotation effect of the impeller make the liquid droplets deviate from the shaft, making the leading edge of the inlet blade more susceptible to erosion by the liquid droplets carried in the steam. INVENTION CONTENTS

[0005] The utility model discloses a pre-rotation cooperative centrifugal liquid film self-liquid-discharge anti-erosion system which does not need to set a steam-water separator, reduces the equipment cost, effectively reduces the compression loss of the compressor inlet, and avoids the damage of the liquid droplets to the compressor impeller.

[0006] To solve the above technical problems, the utility model provides a pre-rotation cooperative centrifugal liquid film self-liquid-discharge anti-erosion system, which comprises a compressor inlet section and a plurality of grooves arranged along the inner side of the compressor inlet section in a circumferential direction. The grooves are distributed in a spiral shape at intervals, and the discharge end of the groove is connected to the low-pressure zone pipeline. Under the action of the pre-rotation centrifugal force, the liquid droplets enter the groove and are discharged into the low-pressure zone pipeline.

[0007] Further, the spiral angle of the channel is set as alpha = arctan (v θ / v z ) ± delta alpha, wherein v θ is the circumferential velocity, v z is the axial velocity, and the correction angle delta alpha = 0°-10°.

[0008] Further, the ratio of the channel width to the diameter of the compressor inlet pipe is in the range of 0.01-0.05.

[0009] Further, the minimum channel depth d of the channel is 0.05D, wherein D is the diameter of the compressor inlet. p , wherein d p is the droplet diameter, rho is the droplet density, v z is the circumferential velocity, L is the channel length, mu is the gas dynamic viscosity, R is the compressor inlet section radius, and v max is the axial velocity.

[0010] Further, the maximum channel depth h max of the channel is 0.08D, wherein D is the diameter of the compressor inlet.

[0011] Further, the number of the channels arranged circumferentially along the inner side of the compressor inlet section is 2-10.

[0012] Further, the discharge end of the channel is provided with a drainage hole in the radial direction of the compressor inlet section, and the drainage hole is communicated to the low pressure zone pipe through a drainage pipe.

[0013] Further, the inner diameter of the discharge end of the channel is larger than the inner diameter of the inlet end.

[0014] Further, a hydrophobic valve is arranged between the drainage pipe and the low pressure zone pipe.

[0015] The beneficial effects of the utility model lie in that: the compressor inlet section is arranged at the inlet of the centrifugal compressor, and a plurality of channels are arranged in the compressor inlet section, the high-speed rotating impeller in the centrifugal compressor applies a certain pre-rotation action to the gas at the inlet of the centrifugal compressor, thereby causing the low pressure water vapor at the compressor inlet section to produce a certain rotational motion, the liquid droplets are thrown into the channel under the pre-rotation action, and the liquid droplets move to the outer wall of the compressor inlet section under the pre-rotation centrifugal force because the density of the liquid droplets is greater than the density of the steam, the liquid droplets finally impact the inner wall of the channel and are captured, the steam has low density and weak centrifugal force, and follows the main stream to flow axially, a small part of the steam entering the channel will follow the main stream to flow continuously because the steam cannot pass through the liquid film due to the existence of the liquid film, thereby achieving the effect of discharging only the liquid droplets but not the steam.

[0016] Wherein, the liquid drop is gradually dissipated by the constraint of the wall surface when impacting the inner wall of the channel by the centrifugal force, the liquid drop surface is significantly deformed due to the inertial force, a dynamic expanding liquid sheet is formed, the liquid sheet converges into a continuous liquid film, the surface tension maintains its stability, and a small part of the steam entering the channel is blocked. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is the structural schematic diagram of the utility model.

[0018] The figure sign: 1, compressor inlet section;2, channel. DETAILED DESCRIPTION

[0019] The technical scheme in the embodiments of the utility model will be clearly and completely described below in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art belong to the scope of protection of the utility model.

[0020] Those skilled in the art should understand that in the disclosure of the utility model, the orientation or position relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore the above terms cannot be understood as a limitation on the utility model.

[0021] It can be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of one element can be one, and in another embodiment, the number of the element can be multiple, and the term "one" cannot be understood as a limitation on the number.

[0022] As Figure 1 The utility model provides a kind of pre-rotation cooperative centrifugal liquid film self-liquid drainage erosion resistance system, including compressor inlet section 1, several channels 2 are arranged along the circumferential direction of the inner side of compressor inlet section 1, the several channels 2 are spaced distribution in spiral shape, the discharge end of the channel 2 is connected to low pressure zone pipeline, to make liquid drop under the action of pre-rotation centrifugal force, into channel 2 and discharge to low pressure zone pipeline.

[0023] By setting a compressor inlet section at the inlet of the centrifugal compressor, and spirally arranging a plurality of channels in the compressor inlet section, a certain pre-rotation is applied to the gas at the inlet of the centrifugal compressor by the high-speed rotating impeller in the centrifugal compressor, so as to cause the low-pressure water vapor at the compressor inlet section to produce a certain rotational motion, so that the liquid droplets are thrown into the channels under the pre-rotation, and due to the fact that the density of the liquid droplets is greater than the density of the steam, the liquid droplets move to the outer wall of the compressor inlet section under the pre-rotation centrifugal force, and finally the liquid droplets impact the inner wall of the channel and are captured, while the steam has low density and weak centrifugal force, and follows the main stream axial flow, and a small part of the steam entering the channel will continue to flow with the main stream due to the existence of the liquid film, so as to achieve the effect of discharging only the liquid droplets but not the steam.

[0024] Wherein, when the liquid droplets impact the inner wall of the channel by the centrifugal force, the momentum of the liquid droplets is gradually dissipated by the constraint of the wall surface, the surface of the liquid droplets is significantly deformed due to the inertial force, a dynamic expanding liquid sheet is formed, the liquid sheet converges into a continuous liquid film, the surface tension maintains its stability, and then the small part of the steam entering the channel is blocked.

[0025] In an embodiment of the present scheme, the channel 2 is arranged at a position of 0-1500 mm from the inlet of the centrifugal compressor.

[0026] Preferably, the spiral angle of the channel 2 is set as α = arctan (ν θ / ν z ) ± Δα, where ν θ is the circumferential velocity, ν z is the axial velocity, and the correction angle Δα = 0°-10°.

[0027] Specifically, by matching the spiral angle of the channel with the pre-rotation angle of the fluid at the inlet of the compressor, the driving efficiency of the centrifugal force on the liquid droplets is maximized.

[0028] Preferably, the ratio of the channel width of the channel 2 to the diameter of the compressor inlet pipe is in the range of 0.01-0.05.

[0029] Specifically, since the channel width needs to be sufficient to accommodate the thickness of the liquid film to avoid secondary entrainment caused by overflow of the liquid film, and too large channel width will cause gas leakage through the channel and reduce the efficiency of the compressor, therefore, by limiting the ratio of the channel width to the diameter of the compressor inlet pipe, the appropriate size of the channel width can be effectively ensured.

[0030] Preferably, the minimum channel depth d of the channel 2 is greater than 2.5 times the liquid droplet diameter d p . p d p is the liquid droplet diameter, ρ p is the liquid droplet density, νθ is the circumferential velocity, L is the channel length, μ is the dynamic viscosity of the gas, R is the radius of the compressor inlet section, and ν z is the axial velocity.

[0031] Preferably, the maximum groove depth h of the groove 2 is 0.08D, D being the diameter of the compressor inlet. max =0.08D,D is the diameter of the compressor inlet.

[0032] Specifically, since the groove depth needs to be greater than the centrifugal migration distance of the liquid droplets and ensure that the liquid droplets enter the groove instead of being re-entrained by the gas flow, while if the groove is too deep, it will increase the risk of flow separation, resulting in local vortex and pressure loss, therefore, the groove depth size needs to be controlled within a suitable range to ensure the stable entry and subsequent discharge of the liquid droplets.

[0033] Preferably, the number of the groove 2 arranged along the inner side of the compressor inlet section 1 is 2-10.

[0034] Specifically, by limiting the number of circumferential arrangement of the groove, the groove spacing is less than the circumferential displacement of the liquid droplets during centrifugal rotation, so as to avoid the liquid droplets flowing out from between two grooves.

[0035] Preferably, the discharge end of the groove 2 is provided with a drainage hole in the radial direction of the compressor inlet section 1, and the drainage hole is communicated to the low-pressure zone pipeline through a drainage pipe, so that the liquid film formed by the liquid droplets flows to the drainage hole at the end of the guide groove under the blowing of the steam, and then is sucked out through the pressure difference at the low-pressure zone pipeline.

[0036] In an embodiment of the present scheme, the inner wall of the groove is coated with a hydrophobic material, so that the liquid film formed can flow along the groove to the drainage hole at the end of the guide groove under the blowing of the steam.

[0037] Preferably, the inner diameter of the discharge end of the groove 2 is greater than the inner diameter of the inlet end.

[0038] Specifically, the liquid forms a continuous liquid film in the groove, and due to the surface tension of the liquid film, the steam cannot pass through the liquid film and can only flow along the main flow channel. At the same time, the steam has low density and small inertia, and it is difficult to change the flow direction along with the fluid at the spiral bend in the groove, thereby realizing separation.

[0039] In an embodiment of the present scheme, the groove outlet is designed as a narrow hole structure or a fine slit form, and the surface tension of the liquid droplets forms a "liquid seal" to prevent the steam from passing through.

[0040] Preferably, a hydrophobic valve is arranged between the drainage pipe and the low-pressure zone pipeline, so as to discharge the liquid droplets collected in the groove, while preventing the leakage of steam.

[0041] The utility model is not limited to the above-mentioned best implementation, anyone can draw other various forms of products under the enlightenment of the utility model, but no matter in its shape or structure makes any change, if it has the same or similar technical scheme with the present application, falls in the protection scope of the utility model.

Claims

1. A pre-swirl co- centrifugal liquid film self-draining erosion resistant system characterized by: The compressor inlet section (1) comprises a plurality of channels (2) arranged along the inner side of the compressor inlet section (1) in a helical manner, the channels (2) being spaced apart, and the discharge ends of the channels (2) being connected to a low-pressure area pipeline, so that liquid droplets enter the channels (2) and are discharged into the low-pressure area pipeline under the action of a pre-whirl centrifugal force.

2. The pre-swirl co- centrifugal liquid film self-draining erosion mitigation system of claim 1, wherein: The spiral angle of the channel (2) is set as α = arctan (v θ / ν z ) ± Δα, wherein v θ is the circumferential velocity, v z is the axial velocity, and the correction angle Δα = 0° ~ 10°.

3. The pre-swirl co- centrifugal liquid film self-draining erosion mitigation system of claim 1, wherein: The ratio of the channel width of the channels (2) to the diameter of the compressor inlet pipeline is in the range of 0.01-0.

05.

4. The pre-swirl co- centrifugal liquid film self-draining erosion mitigation system of claim 1, wherein: Minimum slot depth of the channel (2) d p Droplet diameter, p p Droplet density, v θ Circumferential velocity, L is the channel length, μ is the gas dynamic viscosity, R is the compressor inlet section radius, v z Axial velocity.

5. The pre-swirl co- centrifugal liquid film self-draining erosion mitigation system of claim 1, wherein: The maximum groove depth h of the groove (2) max = 0.08D, D is the compressor inlet diameter.

6. The pre-swirl co- centrifugal liquid film self-draining erosion mitigation system of claim 1, wherein: The number of said channels (2) arranged circumferentially along the inner side of the compressor inlet section (1) 7. The pre-swirl co- centrifugal liquid film self-draining erosion mitigation system of claim 1, wherein: The discharge ends of the channels (2) are provided with flow guide holes along the radial direction of the compressor inlet section (1), and the flow guide holes are connected to the low-pressure area pipeline through flow guide pipes.

8. The pre-swirl co- centrifugal liquid film self-draining erosion mitigation system of claim 1, wherein: The inner diameter of the discharge end of the channels (2) is greater than the inner diameter of the inlet end.

9. The pre-swirl co- centrifugal liquid film self-draining erosion mitigation system of claim 7, wherein: A hydrophobic valve is arranged between the flow guide pipe and the low-pressure area pipeline.

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