Reciprocating labyrinth compressor with double-sided labyrinth seal structure

Abstract

The present application belongs to the field of mechanical seal, and particularly relates to a double-side labyrinth seal structure of a reciprocating labyrinth compressor, wherein a cycloid type tooth is used for a piston side sealing tooth, and a triangle type tooth is used for a cylinder side sealing tooth; the cycloid tooth shape parameters are obtained through simulation calculation and optimization based on a finite volume method FLUENT application software, by embedding a drawing two-dimensional cycloid CAD curve software package module into a CAD application software; a dynamic circle radius A of the piston side sealing tooth is 0.4-0.6 mm; a ratio of a line depth to a straight line depth U is 4:1; a tooth root inclination angle is +30 DEG; the cylinder side tooth is an isosceles triangle; and a geometric ratio of the cylinder side sealing tooth to the piston side sealing tooth is 1:4. The present application has a good sealing effect and a strong ability of dissipating the sealed medium energy in a sealing area.

Description

Technical Field

[0001] This invention belongs to the field of mechanical seals, and particularly relates to a double-sided labyrinth seal structure for a reciprocating labyrinth compressor. Background Technology

[0002] Reciprocating labyrinth compressors operate at high exhaust temperatures and pressures, subjecting their cylinders and pistons to significant thermal and mechanical loads. Excessive thermal and mechanical loads can negatively impact the compressor's stability and lifespan. Labyrinth seals, due to their simple structure, ease of use, and reliable operation, are widely used in reciprocating compressors, blowers, and steam turbines. The emergence of labyrinth compressors has provided efficient and reliable solutions for many fields. As machinery evolves towards higher speeds, higher pressures, multi-stage operation, higher power, and higher reliability, the demands on labyrinth compressors are also increasing. Therefore, researching the factors affecting the sealing performance of labyrinth compressors and developing sealing structures with excellent sealing performance is of great significance to the development of labyrinth compressors in my country. Summary of the Invention

[0003] The present invention aims to overcome the shortcomings of the prior art and provide a double-sided labyrinth seal structure for a reciprocating labyrinth compressor with good sealing effect and strong ability to dissipate the energy of the sealed medium in the sealing area.

[0004] To solve the above-mentioned technical problems, the present invention is implemented as follows:

[0005] The reciprocating labyrinth compressor has a double-sided labyrinth seal structure for labyrinth sealing between the piston and cylinder or between the piston rod and cylinder body. The piston-side sealing teeth adopt cycloidal teeth, and the cylinder-side sealing teeth adopt triangular teeth. The cycloidal tooth profile parameters are obtained by simulation calculation and optimization based on the finite volume method FLUENT application software through a software package module for drawing two-dimensional cycloidal CAD curves embedded in the CAD application software.

[0006] Furthermore, by analyzing the analytical formula (1), the coordinate values ​​of the cycloidal tooth are input into Excel. After importing the coordinate values ​​from Excel into the CAD software application platform, the cycloidal part shape of the two-dimensional cycloidal tooth is drawn. The mathematical relationship formula (3) of the cycloidal tooth parameters is established to obtain the overall shape of the piston-side cycloidal tooth.

[0007]

[0008] In equation (1), the piston parameters are: X and Y, which are the two coordinate variables of the two-dimensional cycloidal equation of the piston tooth profile; A is the radius of the moving circle; θ is the rotation angle of the moving circle; in equation (2), the piston parameters are: K is the cycloidal depth (mm), L is the linear depth; h is the cavity depth; b is the cavity width; π is pi; and U is the ratio of the cycloidal depth to the linear depth.

[0009] Furthermore, the moving circle radius of the piston-side sealing tooth is A = 0.4–0.6 mm.

[0010] Furthermore, the ratio of cycloidal depth to linear depth, U, is 4:1.

[0011] Furthermore, the root inclination angle is +30°.

[0012] Furthermore, the cylinder side sealing teeth have an isosceles triangular structure.

[0013] Furthermore, the geometric ratio of the cylinder-side sealing teeth to the piston-side sealing teeth is 1:4.

[0014] This invention allows for dynamic observation of the internal flow field of a double-sided labyrinth seal tooth structure. Compared to traditional labyrinth seal structures with triangular or rectangular teeth of the same size and parameters, this structure offers a more ideal sealing effect and significantly improves the ability to dissipate the energy of the sealed medium in the sealing region. The FLUENT simulation employs dynamic mesh technology, which, unlike other steady-state simulations, demonstrates the transient flow state of the double-sided labyrinth seal teeth of this invention. This allows for detailed observation of the internal flow field at every moment of piston movement and a more accurate analysis of the advantages and characteristics of this invention. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. The scope of protection of the present invention is not limited to the descriptions below.

[0016] Figure 1 This is a schematic diagram of the novel cycloidal parameters of the present invention;

[0017] Figure 2 This invention provides five novel cycloidal teeth with different U values.

[0018] Figure 3 This is a schematic diagram of the novel cycloidal tooth sealing structure of the present invention;

[0019] Figure 4 Gas turbulent kinetic energy cloud diagrams for different novel cycloidal teeth;

[0020] Figure 5 This is a vector diagram showing the gas velocity of different novel cycloidal teeth of the present invention;

[0021] Figure 6 Five different types of labyrinth sealing teeth;

[0022] Figure 7 This represents the average leakage rate for different tooth profiles in this invention.

[0023] Figure 8 This is a model of the toothed sealing structure with an inclination angle of +30° according to the present invention;

[0024] Figure 9 Gas turbulent kinetic energy cloud diagrams of cycloidal tooth sealing structures at different tilt angles according to the present invention;

[0025] Figure 10 This is a vector diagram showing the gas velocity of the cycloidal tooth sealing structure at different tilt angles according to the present invention.

[0026] Figure 11 The average leakage of the cycloidal tooth seal structure with different tilt angles of the present invention;

[0027] Figure 12 The diagram shows a sealing structure model of the present invention with different bilateral proportions.

[0028] Figure 13 This is a model diagram of the sealing structure for different cylinder side tooth profiles of the present invention;

[0029] Figure 14 This is a gas turbulent kinetic energy cloud diagram of the sealed labyrinth structure with different cylinder side tooth profiles according to the present invention;

[0030] Figure 15 The gas turbulent kinetic energy cloud diagrams of the double-sided labyrinth sealing structure with different geometric proportions of the present invention;

[0031] Figure 16 This is a velocity vector diagram of the sealing labyrinth structure with different cylinder side tooth profiles according to the present invention;

[0032] Figure 17 The average leakage rate was simulated for different labyrinth sealing structures of this invention.

[0033] Figure 18 This is a schematic diagram of the final optimized structure of the present invention;

[0034] Figure 19 This is the gas turbulent kinetic energy cloud diagram of the final optimized model of this invention;

[0035] Figure 20 This is a vector diagram of the gas velocity in the final optimized model of this invention;

[0036] Figure 21 This represents the gas leakage rate of the final model under different pressure ratios in this invention.

[0037] Figure 22 This represents the average leakage rate of the final optimized model under different piston speeds in this invention.

[0038] Figure 23 This represents the total leakage of the final optimized model under five different piston speeds in this invention.

[0039] Figure 24 The diagram shows the leakage rate of the novel cycloidal teeth with different moving circle radii according to the present invention.

[0040] Figure 25 This is a comparison chart of leakage rates of cylinder side sealing teeth with different tooth profiles according to the present invention. Detailed Implementation

[0041] As shown in the figure, the reciprocating labyrinth compressor has a double-sided labyrinth seal structure for labyrinth sealing between the piston and the cylinder or between the piston rod and the cylinder body. The piston-side sealing teeth adopt cycloidal teeth, and the cylinder-side sealing teeth adopt triangular teeth. The cycloidal tooth profile parameters are obtained by simulation calculation and optimization based on the finite volume method FLUENT application software through a software package module for drawing two-dimensional cycloidal CAD curves embedded in the CAD application software.

[0042] By analyzing the analytical formula (1), the coordinate values ​​of the cycloidal tooth are input into Excel. After importing the coordinate values ​​from Excel into the CAD software application platform, the cycloidal part shape of the two-dimensional cycloidal tooth is drawn. The mathematical relationship formula (3) of the cycloidal tooth parameter is established to obtain the overall shape of the piston-side cycloidal tooth.

[0043]

[0044] In equation (1), the piston parameters are: X and Y, which are the two coordinate variables of the two-dimensional cycloidal equation of the piston tooth profile; A is the radius of the moving circle; θ is the rotation angle of the moving circle; in equation (2), the piston parameters are: K is the cycloidal depth (mm), L is the linear depth; h is the cavity depth; b is the cavity width; π is pi; and U is the ratio of the cycloidal depth to the linear depth.

[0045] The piston-side sealing tooth of this invention has a moving circle radius A of 0.4–0.6 mm. The cycloidal depth to linear depth ratio U is 4:1. The tooth root inclination angle is +30°. The cylinder-side sealing tooth has an isosceles triangular structure. The geometric ratio of the cylinder-side sealing tooth to the piston-side sealing tooth is 1:4.

[0046] This invention allows for the creation of cycloidal tooth models with different geometric parameters and novel cycloidal tooth sealing structure models with different tilt angles, while keeping other parameters constant. Furthermore, the optimized novel cycloidal axial labyrinth sealing tooth structure on the piston side is analyzed and verified using the dynamic mesh technology of the FLUENT finite volume method application software.

[0047] A cycloidal sealing tooth with an optimized dynamic circle radius of 0.5 mm and strong sealing performance was established as the piston-side sealing tooth. While maintaining the same piston-side sealing tooth shape, three different cylinder-side sealing tooth shapes—triangular, rectangular, and cycloidal—were established. Using the finite volume method and FLUENT software's dynamic mesh technology, an optimized piston-side double-sided sealing tooth structure with a novel cycloidal shape was obtained.

[0048] Simulations were conducted on the final optimized results under different working conditions to obtain the sealing performance of the final optimized results under different working conditions: In terms of piston speed, the final optimized sealing model can exhibit better sealing performance when the piston speed is greater than 3m / s; in terms of pressure ratio, the final optimized model can achieve the best sealing performance when the pressure ratio is less than 4.

[0049] In its specific implementation, this invention utilizes the EXCAL spreadsheet software for the parametric design and development of a novel cycloidal labyrinth sealing tooth. A schematic diagram defining the novel cycloidal parameters is shown below. Figure 1 Three cycloidal tooth tips with moving circle radii of 0.4 mm, 0.5 mm and 0.6 mm were constructed.

[0050] Furthermore, for each type of cycloidal tooth with a different moving circle radius, five different ratios of straight depth to cycloidal depth (U values ​​of 4:0, 4:1, 4:2, 4:3, and 4:4) were designed for cycloidal tooth structures (see...). Figure 2 ), and designed a schematic diagram of the cycloidal tooth seal structure (see Figure 3 Through dynamic mesh simulation, turbulent kinetic energy cloud diagram analysis, velocity vector diagram analysis, and leakage analysis were performed on the established model. The turbulent kinetic energy analysis diagram is shown in [link to diagram]. Figure 4 As can be seen, the new cycloidal teeth optimized with linear height enhancement generally have higher turbulent kinetic energy compared to traditional cycloidal teeth. This phenomenon is most pronounced in the model with a U value of 4:1, which also exhibits the lowest leakage among the four sets of cycloidal teeth, demonstrating the best sealing performance. (See velocity vector analysis diagram). Figure 5 It can be observed that with cycloidal teeth, the airflow organization is relatively orderly and can form obvious vortices. This leads to a dramatic conversion between gas kinetic energy and internal energy, as well as significant energy dissipation, achieving an ideal sealing effect. Leakage analysis (see...) Figure 24 It can be observed that the leakage rate exhibits a certain similarity with the change of U value, and the magnitude of the leakage rate directly reflects the level of sealing performance. Therefore, we can conclude that among the new cycloidal teeth with the same moving circle radius, the order of sealing performance from strong to weak is: U=4:1, U=4:4, U=4:2, U=4:3, U=4:0.

[0051] Furthermore, in the leakage of the novel cycloidal teeth with three different moving circle radii, the leakage of the traditional cycloidal teeth (U=4:0) without height optimization was 16.6%-20.8% higher than that of cycloidal teeth with the same moving circle radius. This indicates that the sealing performance of the cycloidal teeth of the present invention is significantly better than that of traditional cycloidal teeth. In the simulation results of the three groups of cycloidal teeth, the leakage of the cycloidal teeth with U=4:1 was significantly less than that of the other novel cycloidal teeth. Taking all factors into consideration, the optimal novel cycloidal model was determined to have a tooth tip to tooth root ratio of U=4:1.

[0052] Furthermore, novel cycloidal linear tooth, triangular, and rectangular labyrinth tooth structures with A=0.5 and U=4:1 were established (see...). Figure 6 )Analyze the average leakage of different tooth profiles (see Figure 7 The results showed that the sealing performance of the new cycloidal tooth was 5% and 17% better than that of the rectangular tooth and the triangular tooth, respectively.

[0053] Furthermore, the tilt angle of the cycloidal tooth profile of the present invention was optimized to establish cycloidal tooth sealing structure models with tilt angles of +15°, +30°, +45°, and +60° respectively. Figure 8 A +30° cycloidal toothed seal structure model was created and analyzed. The turbulent kinetic energy cloud diagram analysis results are shown in [see...]. Figure 9 As can be observed from the figure, the region with high gas turbulent kinetic energy is larger in the maze structure model with an inclination angle of +30°, which can form a high-mass turbulent kinetic energy cloud. However, the turbulent kinetic energy clouds in both models are generally located near the lower right corner of the maze cavity. (See the velocity vector diagram analysis results.) Figure 10 The gas organization within the cavity reveals that in the cycloidal toothed seal structure with an inclination angle of +30°, the gas organization is relatively regular, forming elliptical-shaped vortices, which achieves relatively high gas energy dissipation. (See the leakage analysis results diagram.) Figure 11 The leakage trend shows that when the tilt angle is +30°, the leakage decreases significantly, by about 6% compared to the 0° model. This indicates that the cycloidal tooth labyrinth seal structure achieves the best sealing effect at a tilt angle of +30°. The final piston-side sealing tooth structure was determined to be the cycloidal sealing tooth with a moving circle radius of 0.5mm and a tilt angle of +30°.

[0054] Furthermore, three different cylinder-side sealing tooth shapes—triangular, rectangular, and cycloidal—common in engineering, were established. Three sealing structure models with different double-sided ratios were also created in conjunction with the piston-side sealing teeth (see...). Figure 12 Seal structure model diagrams for different cylinder side tooth types (see) Figure 13 ).

[0055] Furthermore, a comparison chart of leakage rates for cylinder side seal teeth with different tooth profiles was analyzed (see...). Figure 25 It can be observed that the sealing performance of the single-sided cycloidal seal structure is far inferior to that of the double-sided one, with a leakage rate 25.8% to 56.0% higher than that of the 15 double-sided tooth model. This indicates that the sealing effect of the double-sided tooth seal structure is far superior to that of the single-sided tooth seal structure.

[0056] Furthermore, the gas turbulent kinetic energy cloud diagram of the sealed labyrinth structure of the cylinder side tooth profile was analyzed (see...). Figure 14As can be clearly seen from the figure, the turbulent kinetic energy of the triangular cylinder side sealing tooth model is concentrated in the middle region of the cavity, forming a vortex that is more conducive to kinetic energy dissipation, thus exhibiting good sealing performance. Gas turbulent kinetic energy cloud diagrams of double-sided labyrinth seal structures with different geometric proportions (see...) Figure 15 When the geometric ratio is 1:4, the turbulent kinetic energy of the gas within the cavity model is highest in the central region of the cavity, and the kinetic energy loss in each cavity is relatively even, which is beneficial for kinetic energy dissipation. Furthermore, the main turbulent kinetic energy is concentrated in the piston-side cavity, where the gas energy dissipates rapidly, resulting in a high utilization rate of the sealed cavity and a relatively ideal sealing effect. In summary, based on the analysis of the turbulent kinetic energy cloud diagram, the double-sided sealing structure with triangular cylinder-side sealing teeth in a 1:4 geometric ratio (cylinder-side sealing teeth to piston-side sealing teeth) is the optimal structure.

[0057] Furthermore, the velocity vector diagrams of the sealed labyrinth structures with different cylinder side tooth profiles (see...) Figure 16 The airflow organization of the triangular cylinder side sealing tooth model is relatively regular, and it can form more obvious airflow vortices. Average leakage analysis of the double-sided tooth model (see...) Figure 17 It can be seen that the triangular cylinder-side sealing tooth model has the lowest leakage and the best sealing performance. Considering different geometric ratios of the piston-side and cylinder-side sealing teeth, the leakage is lowest for all three tooth shapes when the ratio is 1:4. Flow field analysis and comparison of labyrinth seal leakage for 15 different models show that the triangular cylinder-side sealing tooth has the best sealing performance among the three tooth shapes. Among different geometric ratios, 1:4 is most beneficial for labyrinth seal performance.

[0058] Furthermore, the optimal cylinder-side sealing tooth structure was determined to be a triangular cylinder-side sealing tooth with a geometric ratio of 1:4 to the piston-side labyrinth teeth. Simulation results show that compared to a single-sided sealing structure, the optimized model exhibits a significant reduction in leakage, decreasing from 0.039 kg / s to 0.025 kg / s, indicating a substantial improvement in sealing performance.

[0059] Furthermore, determine the final optimized structure (see...) Figure 18 The final optimized model gas turbulent kinetic energy cloud diagram was obtained through analysis (see...). Figure 19 As shown in the figure, the gas can form a very large turbulent kinetic energy cloud, which is relatively round and mostly close to the center of the labyrinth cavity. Its turbulent kinetic energy is high, reaching a maximum of 7300 m² / s². Therefore, it can be inferred that this optimized model can achieve a very good sealing effect. The final optimized model gas velocity vector diagram (see...) Figure 20 As can be seen, the gas in the labyrinth cavity of the optimized model can form orderly vortices, and the flow velocity is significantly reduced relative to the gas in the labyrinth cavity, achieving a very ideal sealing effect. This indicates that the final optimized model has the best sealing effect and has achieved the purpose of optimizing the sealing structure design.

[0060] Furthermore, the final model was subjected to a final optimized structural sealing performance analysis under varying operating conditions. The gas leakage rate of the final model under different pressure ratios was plotted in line graphs (see...). Figure 21 The final model exhibits a small rate of change in leakage with varying pressure ratios, indicating that it maintains a stable sealing effect and demonstrates excellent sealing performance under different pressure ratios. Furthermore, when the pressure ratio is less than 4, the leakage of the final model remains within a small range, with leakage fluctuations not exceeding 6% at different pressure ratios. This demonstrates that the optimized final model achieves the best sealing performance when the pressure ratio is less than 4.

[0061] Furthermore, the average leakage of the final optimized model at different piston speeds (see...) Figure 22 As can be seen, the leakage increases positively with increasing piston speed; that is, the higher the piston speed, the greater the average leakage. The total leakage of the final optimized model under five different piston speeds (see...) Figure 23 As shown in the figure, the gas leakage of the labyrinth seal decreases with increasing piston speed. When the piston speed is less than 3 m / s, the rate of decrease in leakage is relatively large; when the piston speed is greater than 3 m / s, the rate of decrease in total leakage decreases, and the leakage value is smaller. This indicates that the final optimized sealing model exhibits superior sealing performance when the piston speed is greater than 3 m / s.

[0062] In the description of this invention, it should be understood that the orientation or positional relationship indicated by the terms is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0063] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. Double-sided labyrinth seal structure for reciprocating labyrinth compressor, for the labyrinth seal of a piston and a cylinder or a piston rod and a cylinder, characterized in that: The piston side sealing tooth adopts a cycloid type tooth, and the cylinder side sealing tooth adopts a triangular tooth; the cycloid type tooth parameters are obtained through simulation calculation and optimization based on a finite volume method FLUENT application software, and are drawn by embedding a two-dimensional cycloid CAD curve software package module into a CAD application software; the coordinate values of the cycloid type tooth are input into an excel according to an analytical expression (1), and the two-dimensional cycloid type tooth is drawn after the coordinate values of the excel are imported into a CAD software application platform; a mathematical relationship of the cycloid type tooth parameters is established to obtain the overall shape of the piston side cycloid type tooth: In the expression (1), X and Y are two coordinate variables of a two-dimensional cycloid equation of the piston tooth shape; A is a moving circle radius; and θ is a moving circle rotation angle; in the expression (2), K is a cycloid depth, L is a straight line depth, h is a cavity depth, b is a cavity width, π is a circular constant, and U is a ratio of the cycloid depth to the straight line depth; the moving circle radius A of the piston side sealing tooth is 0.4-0.6 mm; the ratio U of the cycloid depth to the straight line depth is 4:1; the tooth root inclination angle is +30°; the cylinder side sealing tooth is an isosceles triangle structure; and the geometric ratio of the cylinder side sealing tooth to the piston side sealing tooth is 1:4.

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