A model stage amplification modeling design method for centrifugal compressor

Abstract

The present application relates to centrifugal compressor technical field, specifically disclose a kind of centrifugal compressor model stage amplification modeling design method, the amplification modeling design method includes following process: according to amplification factor, the geometric dimension of centrifugal compressor original model is enlarged;On the basis of amplification model, with the correction criterion of diffuser factor, corresponding design is carried out to each stage impeller and diffuser, to ensure the overall performance similarity and flow field similarity between amplification model and original model.The present application takes diffuser factor as correction criterion, and the overall performance similarity and flow field similarity between amplification model and original model are ensured by optimizing design to each stage impeller and diffuser of amplification model, so as to ensure that the efficiency, pressure ratio of amplification model is substantially equal to original model, and the obtained flow field change trend can as far as possible comprehensively, accurately reflect the flow field change trend of centrifugal compressor original model.

Description

Technical Field

[0001] This invention relates to the field of centrifugal compressor technology, specifically a model-level scale-up and modular design method for centrifugal compressors. Background Technology

[0002] Centrifugal compressors, as pressure-generating machines, are a type of turbine compressor and play a crucial role in industrial applications. The work done by a centrifugal compressor on a gas is achieved by the gas moving radially perpendicular to the compressor shaft, which increases the gas's pressure and kinetic energy under centrifugal force.

[0003] To improve the performance of centrifugal compressors, their optimized design is necessary. This optimization requires a thorough understanding of the detailed flow field within the compressor. A deep and meticulous analysis of the internal flow field structure is crucial to understanding the mechanisms of various losses, enabling the development of targeted improvement technologies. Therefore, a reliable grasp of the detailed flow field within a centrifugal compressor is a key technical requirement for its optimized design.

[0004] However, to date, it is difficult to obtain detailed flow fields inside centrifugal compressors directly; they are obtained indirectly through experiments and simulations.

[0005] Currently, among these indirect methods of obtaining data through experiments and simulations, the most economical and practical approach is the scale-up modeling method. This involves designing a scaled-up model of the centrifugal compressor based on its technical characteristics, making the performance of the centrifugal compressor similar to that of the corresponding scaled-up model. The experimental results of the scaled-up centrifugal compressor at low speed are then used to reflect the changing trends of the flow field structure and flow parameters of the original model.

[0006] However, current scaled-up modeling designs for centrifugal compressors focus on the overall performance similarity between the scaled-up model and the original model, neglecting the similarity of the flow field. They rely on this overall performance similarity to infer and analyze flow field trends. Repeated experiments have revealed that under off-design conditions, especially unsteady conditions, the overall performance of centrifugal compressors, excluding the flow field, deviates significantly. This makes inferring flow field trends based on overall performance similarity incomplete and incorrect. Therefore, current scaled-up modeling design methods for centrifugal compressors struggle to comprehensively and accurately reflect the flow field trends of the original model, thus making it difficult to provide comprehensive and sufficient evidence to support the optimized design of centrifugal compressors. Summary of the Invention

[0007] The technical objective of this invention is to address the specific characteristics of the above-mentioned centrifugal compressor optimization design and the shortcomings of existing technologies for scaled-up modeling design of centrifugal compressors. This invention provides a centrifugal compressor model-level scaled-up modeling design method that ensures the similarity of the flow field between the scaled-up model and the original model during scaled-up modeling design, thereby comprehensively and accurately reflecting the flow field variation trend of the original centrifugal compressor model.

[0008] The technical objective of this invention is achieved through the following technical solution: a model-level scaled-up modular design method for centrifugal compressors, comprising the following process steps: S1. According to the magnification factor, the geometric dimensions of the original centrifugal compressor model are enlarged to obtain the magnified model; S2. Using the diffuser factor as the correction criterion, the impellers of each stage are designed accordingly; S3. Design the diffuser accordingly to ensure that the diffusion factor of each stage of the impeller and diffuser is consistent; S4. Ultimately, the scaled-up model maintains overall performance and flow field similarity with the original model; The design of the impeller and diffuser, using the diffuser factor as a correction criterion, satisfies the following relationship: ; In the formula, D The diffuser factor of the impeller; w 1 represents the relative velocity at the impeller inlet; w 2 represents the relative velocity at the impeller outlet; This refers to the difference in circumferential velocity between the inlet and outlet of the impeller. This is the relative gate pitch.

[0009] Furthermore, the amplified model is obtained by keeping the mass flow coefficient and machine Mach number constant.

[0010] Furthermore, in the process of obtaining the scaled-up model, the mass flow rate coefficient satisfies the following relationship: ; In the formula, Mass flow rate coefficient; Q This refers to the inlet volumetric flow rate of the centrifugal compressor. The circumferential speed of the impeller; The diameter is the impeller diameter.

[0011] Furthermore, during the process of obtaining the magnified model, the machine Mach number satisfies the following relationship: ; In the formula, The machine's Mach number; The circumferential speed of the impeller; The adiabatic index; It is the gas constant; The total temperature of the imported goods.

[0012] The beneficial technical effects of this invention are as follows: The above-mentioned technical measures, tailored to the specific characteristics of the centrifugal compressor optimization design, use the diffusion factor as a correction criterion to optimize the design of each stage of the centrifugal compressor scaled-up model's impellers and diffusers, ensuring overall performance similarity and flow field similarity, especially flow field similarity, between the scaled-up model and the original model. Because the scaled-up model design of the centrifugal compressor emphasizes the flow field similarity between the scaled-up model and the original model, the flow fields of the scaled-up model and the original model have a high degree of similarity. This ensures that the efficiency and pressure ratio of the scaled-up model are essentially equal to those of the original model, eliminating the influence of deviations under non-design conditions. The obtained flow field change trend can reflect the flow field change trend of the original centrifugal compressor model as comprehensively and accurately as possible, thus providing comprehensive and sufficient evidence support for the optimization design of the centrifugal compressor. Attached Figure Description

[0013] Figure 1 This is a process flow diagram of the present invention.

[0014] Figure 2 This is a performance comparison diagram between the geometrically enlarged model and the original model in the experimental examples of this invention.

[0015] Figure 3 This is a comparison diagram of the diffusion factor between the geometrically enlarged model and the original model in the experimental examples of this invention.

[0016] Figure 4 This is a performance comparison chart of the amplified model corrected by the diffusion factor criterion and the original model in the experimental examples of this invention.

[0017] Figure 5 This is a comparative diagram of the flow field analysis of the impeller in the experimental example of this invention. Detailed Implementation

[0018] This invention relates to the field of centrifugal compressor technology, specifically a model-level scaled-up modular design method for centrifugal compressors. The following description, in conjunction with the accompanying drawings, illustrates this method. Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 The technical solution of this invention will be clearly and thoroughly explained.

[0019] It should be noted that the accompanying drawings of this invention are schematic, and unnecessary details have been simplified to clarify the technical objectives of this invention, so as to avoid obscuring the technical solutions contributed by this invention to the prior art. Furthermore, the terms "approximately" or "basically" used below to refer to quantities or fit relationships mean that reasonable assembly and processing errors are allowed in the industry, and do not literally describe absolute quantities or fit relationships.

[0020] See Figure 1 As shown, this invention, as a model-level scaled-up design method for centrifugal compressors, involves enlarging the geometric dimensions of the original centrifugal compressor model based on a scaling factor, while maintaining the mass flow coefficient and machine Mach number unchanged. Then, based on the scaled-up model, using the diffusion factor as a criterion, the geometry of each impeller and diffuser is designed accordingly to correct the diffusion factor of the impeller and diffuser, thereby improving the overall performance similarity and flow field similarity between the scaled-up model and the original model. This ensures that the designed scaled-up centrifugal compressor model has a high degree of flow field similarity to the original model, thus guaranteeing that the efficiency and pressure ratio of the scaled-up model are essentially equal to those of the original model.

[0021] Specifically, the scaled-up modular design method of the present invention includes the following processes: S1. According to the magnification factor ( SF The geometric dimensions of the original centrifugal compressor model are enlarged, while the influence of the Reynolds number is ignored based on the principle of partial similarity, so as to keep the mass flow coefficient and machine Mach number unchanged and obtain the enlarged model. In the process of obtaining the scaled-up model, the mass flow coefficient satisfies the following relationship: ; In the formula, Mass flow rate coefficient; Q This refers to the inlet volumetric flow rate of the centrifugal compressor. The circumferential speed of the impeller; The diameter of the impeller; During the process of obtaining the scaled-up model, the machine Mach number satisfies the following relationship: ; In the formula, The machine's Mach number; The circumferential speed of the impeller; The adiabatic index; It is the gas constant; Total import temperature; S2. Based on the flow characteristics of centrifugal compressors, when the flow fields are similar, the impeller's diffusion factor ( The diffuser factor should remain unchanged. Therefore, based on the scaled-up model, the diffuser factor is used as the correction criterion to design the impellers for each stage accordingly. The impeller modification design based on the diffuser factor satisfies the following relationship: ; In the formula, D The diffuser factor of the impeller; w 1 represents the relative velocity at the impeller inlet; w 2 represents the relative velocity at the impeller outlet; This refers to the difference in circumferential velocity between the inlet and outlet of the impeller. Relative gate pitch; S3. Based on the scaled-up model, the diffuser is designed accordingly, taking the diffuser factor as the correction criterion and in conjunction with the design of each stage of the impeller, to ensure that the diffuser factor of each stage of the impeller and the diffuser is consistent. S4. Finally, ensure the overall performance similarity and flow field similarity between the scaled-up model and the original model; Improve overall performance similarity based on flow field similarity.

[0022] The present invention will be described in detail below using a scaled-up modular design of a centrifugal compressor as an example.

[0023] See Figure 2 As shown, the performance of the original model after its geometric dimensions are enlarged by a ratio of 4:1 is compared with that of the original model. It can be seen from the figure that at the design point, the level isentropic efficiency error is 2.73% and the pressure ratio error is 1.99%.

[0024] See Figure 3 As shown, after correction using the diffusion factor as the criterion, it can be ensured that the diffusion factors between the original model and the amplified model are basically consistent.

[0025] See Figure 4 As shown, after correction using the diffusion factor as the criterion, the efficiency error at the design point is reduced to 0.32% and the pressure ratio error is reduced to 0.33%. In other non-design conditions, the performance of the corrected amplified model is also very similar to that of the original model.

[0026] See Figure 5As shown, after correction using the diffusion factor as the criterion, the flow field of the scaled-up model is extremely similar to that of the original model at the design point.

[0027] Therefore, based on the above experimental examples, it can be concluded that the flow field of the scaled-up model of the centrifugal compressor model-level scaled-up model design is highly similar to that of the original model.

[0028] The above specific technical solutions are only used to illustrate the present invention, and are not intended to limit it.

[0029] Although the present invention has been described in detail with reference to the specific technical solutions described above, those skilled in the art should understand that modifications can still be made to the specific technical solutions described above, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the present invention.

Claims

1. A model-level scaled-up modular design method for centrifugal compressors, characterized in that, The scaled-up modular design method includes the following process steps: S1. According to the magnification factor, the geometric dimensions of the original centrifugal compressor model are enlarged to obtain the magnified model; S2. Using the diffuser factor as the correction criterion, the impellers of each stage are designed accordingly; S3. Design the diffuser accordingly to ensure that the diffusion factor of each stage of the impeller and diffuser is consistent; S4. Ultimately, the scaled-up model maintains overall performance and flow field similarity with the original model; The design of the impeller and diffuser, using the diffuser factor as a correction criterion, satisfies the following relationship: ； In the formula, D The diffuser factor of the impeller; w 1 represents the relative velocity at the impeller inlet; w 2 represents the relative velocity at the impeller outlet; This refers to the difference in circumferential velocity between the inlet and outlet of the impeller. This is the relative gate pitch.

2. The centrifugal compressor model-level scaled-up modular design method according to claim 1, characterized in that, The amplified model is obtained by keeping the mass flow coefficient and machine Mach number constant.

3. The centrifugal compressor model-level scaled-up modular design method according to claim 2, characterized in that, During the process of obtaining the scaled-up model, the mass flow rate coefficient satisfies the following relationship: ； In the formula, Mass flow rate coefficient; Q This refers to the inlet volumetric flow rate of the centrifugal compressor. The circumferential speed of the impeller; The diameter is the impeller diameter.

4. The centrifugal compressor model-level scaled-up modular design method according to claim 2, characterized in that, During the process of obtaining the magnified model, the machine Mach number satisfies the following relationship: ； In the formula, The machine's Mach number; The circumferential speed of the impeller; The adiabatic index; It is the gas constant; The total temperature of the imported goods.

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