CN212131708U - A Drainage Near T-tube of a Three-stage Heat Recovery System - Google Patents

Abstract

The utility model discloses a three-stage heat-regeneration system drainage near T-shaped pipe. The utility model adopts the first section of the inlet straight pipe section structure at the drainage elbow of the thermal system, and the second section of the inlet straight pipe section structure is connected to the second section of the micro-horn type. The gradually expanding pipe section structure, the inlet straight pipe section structure is provided with a third section of hyperbolic outlet pipe structure, and the end of the micro-flare gradually expanding pipe section structure is provided with a removable hemispherical bowl-shaped water storage head, which replaces the traditional carbon The steel elbow structure can effectively reduce the erosion momentum of discrete droplets in the vapor-liquid two-phase flow on the elbow, enhance the service life of the pipeline, and improve the safety and stability of the unit operation.

Description

A Drainage Near T-tube of a Three-stage Heat Recovery System

technical field

The utility model belongs to the field of flow transmission of a thermal power system of a large thermal power generating set, in particular to a three-stage heat-regeneration system drainage near T-shaped pipe.

Background technique

The regenerative cycle is widely used in the design of the current large thermal power plant system, and the regenerative cycle is realized by configuring the feed water heater. Feedwater heater is an important equipment to improve the economy of thermal power plant. The extraction steam of the steam turbine passes through the heater tube bundle to heat the feed water and condensate water, and then condenses to form a hydrophobicity. Due to the different working pressures, the drains of the heaters at all levels flow into the lower heating stage by gravity, and finally collect into the condenser. In the drain self-flow pipeline of the heater, there is usually a drain control valve to ensure the balanced relationship between the water levels of each heater.

In the current engineering design, subject to factors such as the selection, design, installation and manufacture of the drain control valve, during the process of increasing the flow to the lower level, the gasification will occur after the drain control valve due to a sharp drop in pressure, forming gas and liquid. The phenomenon of two phases flowing at the same time. In addition, under the influence of factors such as power peak regulation, when the generator set is running at low partial load, the pressure difference between the extraction steam at all levels is reduced, and the motive force of the heater in the drainage self-flow mode is weakened, and the flow characteristics of vapor-liquid two-phase flow are more likely to appear. .

When the drainage thermal system pipeline behind the drainage regulating valve is equipped with a curved pipe structure, the discrete high-speed phase in the two-phase flow cannot change the flow direction due to inertia, and will directly impact the inner wall of the curved pipe, which will cause damage to the bend of the downstream pipe. Significant erosion shock. Due to the low pressure resistance level of carbon steel structure with economical cost, the drainage pipe of the thermal system often wears or even cracks under the impact of discrete droplets of two-phase flow, which endangers the safety of the unit.

SUMMARY OF THE INVENTION

The purpose of this utility model is to overcome the above-mentioned deficiencies and provide a three-stage heat-regeneration system drainage near T-shaped pipe, which can significantly improve the stability of the thermal drainage system of the unit, ensure the steam-water circulation quality of the thermal system, and reduce the occurrence of working fluid in the pipeline. The phase transition shortens the life of the hydrophobic structure, thus endangering the operation safety of the unit, which is beneficial to improve the operation safety of the unit.

In order to achieve the above purpose, the utility model comprises an inlet straight pipe section structure, a micro-flare type gradually expanding pipe section structure is connected to the inlet straight pipe section structure, a hyperbolic type outlet pipe structure is arranged on the inlet straight pipe section structure, and the hyperbolic type outlet pipe structure is The inlet is facing the micro-flare type gradually expanding pipe section structure, the inner tube wall of the straight pipe section structure is provided with a triangular micro-vortex generator, and the end of the micro-flare type gradually expanding pipe section structure is provided with a removable hemispherical bowl-shaped water storage head.

The axial direction of the triangular microvortex generator is parallel to the flow direction of the pipeline.

The triangular micro-vortex generators are micro-vortex generators with several triangular structures, and all the micro-vortex generators are arranged on the inner pipe wall of the inlet of the straight pipe section structure at equal angles.

The hemispherical bowl type water storage head is installed at the end of the micro-flare type gradually expanding pipe section structure through the flange.

The structure of the micro-flare gradually expanding pipe section is a trumpet-shaped gradually expanding structure.

The lower part of the hyperbolic outlet pipe structure intersects with the inlet straight pipe section structure is hyperbolic, and the upper pipe section of the hyperbolic outlet pipe structure is formed by a hyperbolic tangent.

The diameter of the hemispherical bowl-shaped water storage head is larger than the diameter of the end of the micro-flare gradually expanding pipe section structure.

The transition section between the spherical bowl-shaped water storage head and the end of the micro-flare gradually expanding pipe section is in the form of a step.

Compared with the prior art, the utility model adopts the first section of the inlet straight pipe section structure at the drainage elbow of the thermal system. The third section of the hyperbolic outlet pipe structure has a detachable hemispherical bowl-shaped water storage head at the end of the micro-flare gradually expanding pipe section structure, which replaces the traditional carbon steel elbow structure and effectively reduces the gas-liquid two-phase flow. The erosion momentum of the discrete drop on the elbow enhances the service life of the pipeline and improves the safety and stability of the unit operation.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Fig. 2 is the front view of the utility model;

Fig. 3 is the top view of the utility model;

Fig. 4 is the left side view of the utility model;

Fig. 5 is the sectional view of the utility model;

Fig. 6 is the schematic diagram of the spherical bowl type water storage head in the utility model;

7 is a schematic diagram of a triangular micro-vortex generator in the utility model;

Among them, 1. Inlet straight pipe section structure; 2. Micro-flare type gradually expanding pipe section structure; 3. Hyperbolic outlet pipe structure; 4. Triangular micro-vortex generator; 5. Hemispherical bowl type water storage head.

Detailed ways

The present utility model will be further described below in conjunction with the accompanying drawings.

Referring to FIGS. 1 to 5 , the present utility model includes an inlet straight pipe section structure 1, and the inlet straight pipe section structure 1 is connected with a micro-flare type gradually expanding pipe section structure 2, and the micro-flare type gradually expanding pipe section structure 2 is a flared gradually expanding type structure, The inlet straight pipe section structure 1 is provided with a hyperbolic outlet pipe structure 3, the inlet of the hyperbolic outlet pipe structure 3 faces the micro-flare gradually expanding pipe section structure 2, and the inner pipe wall of the mouth straight pipe section structure 1 is provided with a triangular microvortex The generator 4 is provided with a removable hemispherical bowl-shaped water storage head 5 at the end of the micro-flare type gradually expanding pipe section structure 2 . The lower part of the hyperbolic outlet pipe structure 3 intersects with the inlet straight pipe section structure 1 in a hyperbolic shape, and the upper pipe section of the hyperbolic outlet pipe structure 3 is formed by a hyperbolic tangent.

Referring to FIG. 6 , the hemispherical bowl-shaped water storage head 5 is installed at the end of the micro-flare-shaped gradually expanding pipe section structure 2 through a flange. The diameter of the hemispherical bowl-shaped water storage head 5 is larger than the diameter of the end of the micro-flare-shaped gradually expanding pipe section structure 2 . The transition section between the spherical bowl type water storage head 5 and the end of the micro-flare type gradually expanding pipe section structure 2 is in the form of a step.

Referring to FIG. 7 , the axial direction of the triangular micro-vortex generator 4 is parallel to the flow direction of the pipeline. The triangular micro-vortex generator 4 is a plurality of micro-vortex generators with triangular structure, and all the micro-vortex generators are arranged on the inner pipe wall of the inlet of the straight pipe section structure 1 at equal angles.

In the present invention, a triangular micro-vortex generator 4 is arranged on the inner wall surface of the traditional inlet straight pipe section structure 1, and the larger discrete droplet structure is stretched, broken and separated to form small secondary droplets after hitting the micro-vortex generator. and slug-wave flow, annular-wave flow, annular-diffuse flow and other return vortices, which directly weaken the initial impact momentum of the discrete phase. The inlet straight pipe section structure 1 is connected with a micro-flare gradually expanding pipe section structure 2. After the two phases of steam and water flow through the gradually expanding pipe section, the continuous phase expands and the discrete phase decelerates, which further weakens the kinetic energy of the incident droplets at the elbow. At the same time, a detachable stainless steel hemispherical bowl-shaped water storage head 5 is added at the end of the pipeline. On the one hand, by only improving the performance of the partial hemispherical bowl-shaped sealing plug material to match the impact force of the incident droplets, it avoids the overall replacement of the lifting bend. The cost of pipe material increases; on the other hand, the hemispherical bowl-shaped water storage head 5 is set as a flange-mounted detachable structure, which ensures that even if the plug is eroded and fails under extremely severe working conditions, the whole pipeline can still be installed. Meet the flexibility of installation and maintenance. In addition, the diameter of the hemispherical bowl-shaped water storage head 5 is larger than the terminal end of the micro-bell-shaped gradually expanding pipe section, which is also a capacity expansion structure, which can continue to reduce the impact energy of the two-phase fluid. Finally, through the analysis and calculation of the flow field, the outlet pipe is optimized, and a hyperbolic type is used to form an inclined and countercurrent tee structure, which not only ensures that the discrete droplets in the inlet flow will not directly hit the outlet pipe to form an erosion zone, but also makes the After impacting and sealing the plug, the discrete droplets in the vortex recirculation zone enter the downstream pipeline in the form of downstream flow, further reducing the impact momentum of the discrete droplets, and finally reducing the erosion of the pipeline by the two-phase flow discrete droplets, ensuring the thermal system. for operational security purposes.

A triangular micro-vortex generator is arranged at the straight pipe section of the inlet, the axial direction of the vortex generator is parallel to the flow direction of the pipeline, and the inlet is periodically arranged along the circumferential surface of the pipeline. The number of cycles of the triangular microvortex generator ranges from 4 to 8, and the triangular windward angle ranges from 30° to 60°, which are selected after optimization based on numerical simulation.

The extension section behind the inlet pipe, that is, the second section of the pipe, is processed into a micro-flare type gradually expanding pipe section structure 2 . The scaling ratio of the inlet and outlet area of the involute channel, the scaling angle of the involute line, and the starting expansion position of the involute line are determined by numerical simulation optimization according to the minimum flow loss.

B(t)=P ₀ (1-t) ³ +3P ₁ t(1-t) ² +3P ₂ t ² (1-t)+P ₃ t ³ ,t∈[0,1] (1)

The hemispherical bowl-shaped sealing plug 5 is arranged at the end of the micro-flare type gradually expanding pipe section structure 2, and is connected with the micro-flare type gradually expanding pipe section structure 2 through a flange, and the diameter of the hemispherical bowl-shaped water storage head 5 is larger than that of the micro-flare type. The diameter of the end of the expanding pipe segment structure 2.

R _head = R _{gradually expanded terminal} + ΔR (2)

Among them: the range of ΔR is 5-25mm;

The outlet pipe section and the inlet pipe section form an inclined counter-current tee structure. The lower part of the hyperbolic outlet pipe structure 3 and the inlet straight pipe section structure 1 intersect with a hyperbolic type. The upper pipe section of the hyperbolic outlet pipe structure 3 is composed of a hyperbolic tangent. , where the hyperbola is generated by equation (3), and the axial starting position of the hyperboloid is determined after numerical simulation optimization.

x ² /a ² -y ² /b ² =1 (3)

The three-stage regenerative system can effectively improve the erosion and wear of the two-phase flow droplets in the drainage pipeline to the pipeline, improve the stability of the thermal drainage system of the unit, and ensure the steam-water circulation quality of the thermal system. security is improved.

Claims (8)

1. a three-section type heat-regeneration system drainage near T-shaped pipe, is characterized in that, comprises the inlet straight pipe section structure (1), is connected with the micro-flare type gradually expanding pipe section structure (2) after the inlet straight pipe section structure (1), The inlet straight pipe section structure (1) is provided with a hyperbolic outlet pipe structure (3), the inlet of the hyperbolic outlet pipe structure (3) faces the micro-flare type gradually expanding pipe section structure (2), and the mouth straight pipe section structure (1) A triangular micro-vortex generator (4) is arranged on the inner pipe wall of the pipe; 2 . The hydrophobic near-T-shaped tube of a three-stage heat recovery system according to claim 1 , wherein the triangular micro-vortex generator ( 4 ) is axially parallel to the flow direction of the pipeline. 3 . 3. a kind of three-stage heat-regeneration system hydrophobic near T-tube according to claim 1, is characterized in that, triangular micro-vortex generator (4) is the micro-vortex generator of some triangular structures, all micro-vortex generators Isometrically arranged on the inner pipe wall of the inlet of the straight pipe section structure (1). 4. A kind of three-stage heat recovery system drainage near T-shaped pipe according to claim 1, it is characterized in that, the hemispherical bowl type water storage head (5) is installed on the micro-flare type gradually expanding pipe section structure (5) through the flange. 2) at the end. 5 . The hydrophobic near-T-shaped tube of a three-section heat recovery system according to claim 1 , wherein the micro-flare type gradually expanding pipe section structure ( 2 ) is a trumpet-shaped gradually expanding type structure. 6 . 6. A three-section heat-regeneration system draining near-T-shaped pipe according to claim 1, wherein the lower part of the hyperbolic outlet pipe structure (3) and the inlet straight pipe section structure (1) intersect with the interval of Hyperbolic, the upper pipe section of the hyperbolic outlet pipe structure (3) is composed of hyperbolic tangents. 7. A kind of three-stage heat recovery system drainage near T-shaped pipe according to claim 1, characterized in that, the diameter of the hemispherical bowl type water storage head (5) is larger than the micro-flare type gradually expanding pipe section structure (2) diameter of the end. 8. A three-section type heat-regeneration system hydrophobic near-T-shaped pipe according to claim 1, characterized in that, the spherical bowl type water storage head (5) and the end of the micro-flare type gradually expanding pipe section structure (2) are connected. The transition is in the form of a step.

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