Performance evaluation method for supercritical carbon dioxide compressor

Abstract

The invention provides a supercritical carbon dioxide compressor performance evaluation method which can be applied to the technical field of compressors. The method comprises the following steps: acquiring total enthalpy and theoretical sound velocity from a physical property database according to total temperature and total pressure under the condition that the compressor operates in an inlet working condition; according to the total temperature, the total pressure, the total enthalpy, the theoretical sound velocity and a given axial Mach number, determining an iterative sound velocity from a physical property database; under the condition that a first error between the iteration sound velocity and the theoretical sound velocity is larger than a first preset threshold value, the theoretical sound velocity is updated to the iteration sound velocity, the steps are executed repeatedly till the first error is smaller than the first preset threshold value, and the target sound velocity is obtained; based on the target sound velocity, determining mass flow and rotating speed; fluid simulation is conducted on the compressor through the mass flow and the rotating speed, and performance parameters are obtained; and the performance of the compressor is evaluated through the incidence relations corresponding to the multiple sets of different inlet working condition parameters.

Description

Technical Field

[0001] This disclosure relates to the field of compressor technology, and more specifically to a performance evaluation method for a supercritical carbon dioxide compressor. Background Technology

[0002] Thermodynamic cycle systems using supercritical carbon dioxide (S-CO2) as the working fluid have attracted considerable attention in recent years due to their potential advantages such as high efficiency and compactness. In the supercritical state, carbon dioxide can reduce equipment size, decrease compression work requirements, and improve system efficiency, especially near the critical state, where its compression work requirements decrease significantly, further enhancing system performance. However, under this condition, the flow characteristics are complex, and the physical properties of supercritical carbon dioxide exhibit significant nonlinear changes, making it difficult to evaluate the performance of supercritical carbon dioxide compressors using the equivalent flow rate (or equivalent speed) of existing ideal gases. Summary of the Invention

[0003] In view of the above problems, this disclosure provides a method and apparatus for evaluating the performance of a supercritical carbon dioxide compressor.

[0004] According to a first aspect of this disclosure, a performance evaluation method for a supercritical carbon dioxide compressor is provided, comprising: with the compressor operating under inlet conditions, obtaining the total enthalpy and theoretical velocity of supercritical carbon dioxide from a property database based on the total temperature and total pressure of supercritical carbon dioxide, wherein the inlet conditions are total temperature and total pressure, and the theoretical velocity of sound is the propagation speed of sound waves in the non-flowing supercritical carbon dioxide inside the compressor under the inlet conditions; determining an iterative velocity of sound from the property database based on the total temperature and total pressure, total enthalpy, theoretical velocity of sound, and a given axial Mach number, wherein the iterative velocity of sound waves is the theoretical propagation speed of sound waves in the flowing supercritical carbon dioxide inside the compressor under the inlet conditions; and updating the theoretical velocity of sound to the iterative velocity of sound waves if a first error between the iterative velocity and the theoretical velocity of sound is greater than a first preset threshold. Repeat the above steps until the first error is less than the first preset threshold to obtain the target speed of sound; based on the target speed of sound, determine the mass flow rate corresponding to the axial Mach number and the rotational speed corresponding to the circumferential Mach number; use the mass flow rate and rotational speed to perform fluid simulation on the compressor to obtain the performance parameters corresponding to the Mach array, which includes the axial Mach number and the circumferential Mach number; with the inlet conditions unchanged, change the Mach array and repeat the above steps to obtain the performance parameters corresponding to multiple different Mach arrays, and based on the performance parameters corresponding to multiple different Mach arrays, determine the correlation between the performance parameters under the inlet conditions and the different Mach arrays; according to the compressor flow similarity theory, evaluate the compressor performance by using the correlation between the performance parameters under different inlet conditions and the different Mach arrays.

[0005] According to embodiments of this disclosure, determining the iterative speed of sound from a property database based on total temperature and pressure, total enthalpy, theoretical speed of sound, and a given axial Mach number includes: determining the actual static enthalpy of the compressor under inlet conditions based on total enthalpy, theoretical speed of sound, and axial Mach number; and obtaining the iterative speed of sound from the property database based on the actual static enthalpy and total temperature and pressure.

[0006] According to embodiments of this disclosure, the actual static enthalpy is determined based on the difference between the total enthalpy and the kinetic energy, which is determined based on the product of the target speed of sound and the axial Mach number.

[0007] According to embodiments of this disclosure, fluid simulation of the compressor is performed using mass flow rate and rotational speed to obtain performance parameters corresponding to the Mach array. This includes: based on the relationship between compression volume and pressure during the compression process of the compressor, fluid simulation of the compressor is performed according to the mass flow rate and the actual inlet pressure, temperature and rotational speed of the compressor to obtain performance parameters corresponding to the Mach array.

[0008] According to embodiments of this disclosure, the rotational speed is determined based on the compressor's circumferential Mach number and the target speed of sound.

[0009] According to embodiments of this disclosure, the performance of a compressor is evaluated using the correlation between performance parameters under different inlet conditions and different Mach arrays, including: when supercritical carbon dioxide is the total temperature and total pressure to be evaluated, determining the target correlation relationship corresponding to the total temperature and total pressure to be evaluated from multiple sets of correlation relationships corresponding to different inlet conditions; and evaluating the performance of the compressor using the target correlation relationship based on the Mach array corresponding to the total temperature and total pressure to be evaluated, thereby obtaining the performance evaluation parameters of the compressor.

[0010] According to embodiments of this disclosure, determining the mass flow rate corresponding to the axial Mach number based on a target sound speed includes: obtaining the density of supercritical carbon dioxide of the compressor from a property database based on the target sound speed; and determining the mass flow rate corresponding to the axial Mach number based on the density of supercritical carbon dioxide.

[0011] According to embodiments of this disclosure, the correlation between the performance parameters under the inlet operating condition and the different Mach arrays is determined based on the performance parameters corresponding to multiple different Mach arrays. This includes: using interpolation to interpolate the performance parameters corresponding to multiple different Mach arrays to obtain a dataset to be fitted; and fitting the data in the dataset to be fitted using a fitting algorithm to obtain an operating condition performance curve, wherein the operating condition performance curve represents the correlation.

[0012] According to embodiments of this disclosure, the horizontal axis of the operating condition performance curve represents the axial Mach number, and the vertical axis of the operating condition performance curve represents the performance parameters.

[0013] According to embodiments of this disclosure, the compressor type is a turbo compressor, which includes at least one of the following: centrifugal compressor and axial compressor; the performance parameters include at least one of the following: pressure ratio and isentropic efficiency, wherein the pressure ratio is the ratio of the compressor's outlet pressure to its inlet pressure.

[0014] The second aspect of this disclosure provides a performance evaluation device for a supercritical carbon dioxide compressor, comprising: a first determining module, configured to, when the compressor is operating under inlet conditions, obtain the total enthalpy and theoretical velocity of supercritical carbon dioxide from a property database based on the total temperature and total pressure of supercritical carbon dioxide, wherein the inlet conditions are total temperature and total pressure, and the theoretical velocity of sound is the propagation speed of sound waves in the non-flowing supercritical carbon dioxide inside the compressor under the inlet conditions; a second determining module, configured to, based on the total temperature and total pressure, total enthalpy, theoretical velocity of sound, and a given axial Mach number, determine an iterative velocity of sound from the property database, wherein the iterative velocity of sound waves is the theoretical propagation speed of sound waves in the flowing supercritical carbon dioxide inside the compressor under the inlet conditions; and an updating module, configured to, if a first error between the iterative velocity and the theoretical velocity of sound is greater than a first preset threshold, update the theoretical velocity of sound to the iterative velocity of sound, and repeat the above steps. The process continues until the first error is less than a first preset threshold, at which point the target speed of sound is obtained. A third determining module is used to determine the mass flow rate corresponding to the axial Mach number and the rotational speed corresponding to the circumferential Mach number based on the target speed of sound. A fluid simulation module is used to perform fluid simulation on the compressor using the mass flow rate and rotational speed to obtain performance parameters corresponding to the Mach array, which includes the axial Mach number and the circumferential Mach number. A fourth determining module is used to change the Mach array and repeat the above steps while keeping the inlet conditions unchanged, obtaining performance parameters corresponding to multiple different Mach arrays, and determining the correlation between the performance parameters under the inlet conditions and the different Mach arrays based on these performance parameters. Finally, an evaluation module is used to evaluate the compressor's performance based on the compressor flow similarity theory and the correlation between the performance parameters under different inlet conditions and the different Mach arrays.

[0015] A third aspect of this disclosure provides an electronic device comprising: one or more processors; and a memory for storing one or more computer programs, wherein the one or more processors execute the one or more computer programs to implement the steps of the method described above.

[0016] A fourth aspect of this disclosure also provides a computer-readable storage medium having a computer program or instructions stored thereon, which, when executed by a processor, implement the steps of the above-described method.

[0017] The fifth aspect of this disclosure also provides a computer program product, including a computer program or instructions that, when executed by a processor, implement the steps of the above-described method.

[0018] According to embodiments of this disclosure, since the Mach number array is difficult to measure directly, this scheme directly provides the Mach number array and iteratively converges to the theoretical speed of sound to obtain the target speed of sound. Based on the target speed of sound, the mass flow rate corresponding to the axial Mach number and the rotational speed corresponding to the circumferential Mach number are determined. Fluid simulation of the compressor is performed using the mass flow rate and rotational speed to obtain performance parameters corresponding to the Mach number array. Then, with the total temperature and pressure (inlet conditions) remaining constant, the set circumferential Mach number and its corresponding multiple axial Mach numbers are changed, and the above operation is repeated to obtain performance parameters corresponding to multiple different Mach number combinations. Based on these performance parameters, the correlation between the Mach number and performance parameters under the given total temperature and pressure (inlet conditions) is determined. Since the axial Mach number and the circumferential Mach number are consistent, the flow field of supercritical carbon dioxide remains similar, and the performance of the compressor can be determined. Therefore, the performance evaluation of supercritical carbon dioxide compression can be carried out using multiple sets of correlations under different total temperature and pressure (inlet conditions). Attached Figure Description

[0019] The foregoing contents, as well as other objects, features, and advantages of this disclosure, will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0020] Figure 1 The performance curves of a conventional media compressor according to an embodiment of the present disclosure are illustrated schematically.

[0021] Figure 2A The schematic diagram illustrates a multi-condition general performance curve for the stagnation point pressure ratio according to an embodiment of the present disclosure;

[0022] Figure 2B The diagram illustrates the multi-condition general performance curves of isentropic efficiency according to embodiments of the present disclosure;

[0023] Figure 3 A flowchart illustrating a performance evaluation method for a supercritical carbon dioxide compressor according to an embodiment of the present disclosure is shown schematically.

[0024] Figure 4 A simulation model of a two-stage compressor according to an embodiment of the present disclosure is illustrated schematically;

[0025] Figure 5 A schematic diagram illustrating a performance evaluation method for a supercritical carbon dioxide compressor according to an embodiment of the present disclosure is shown.

[0026] Figure 6The schematic diagram illustrates the performance curves of various total temperature and total pressure (inlet conditions) at axial Mach numbers according to embodiments of the present disclosure;

[0027] Figure 7 The schematic diagram illustrates the performance curves of various total temperature and total pressure (inlet conditions) at reduced flow rates according to embodiments of the present disclosure;

[0028] Figure 8 The supercritical carbon dioxide characteristic curves according to embodiments of the present disclosure are illustrated schematically.

[0029] Figure 9 A schematic diagram illustrating a performance evaluation method for a supercritical carbon dioxide compressor according to another embodiment of the present disclosure is shown.

[0030] Figure 10 A schematic block diagram of a performance evaluation apparatus for a supercritical carbon dioxide compressor according to an embodiment of the present disclosure is shown.

[0031] Figure 11 A block diagram schematically illustrates an electronic device suitable for implementing a performance evaluation method for a supercritical carbon dioxide compressor according to an embodiment of the present disclosure. Detailed Implementation

[0032] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0033] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0034] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0035] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0036] The performance of compressors is evaluated using performance curves of common media compressors (air compressors, gas turbine compressors, aero-engine compressors, etc.). The performance curves of common media compressors are shown below. Figure 1 As shown, the flow-pressure ratio curve and the flow-efficiency curve are displayed. The horizontal axis represents the flow rate. (Also known as mass flow rate), the vertical axis represents performance (efficiency η or pressure ratio), and the rotational speed. As a second variable, each speed corresponds to a performance curve, such as speeds of 63krpm (63,000 revolutions per minute), 72krpm, 81krpm, 90krpm, and 99krpm.

[0037] However, the conventional performance curve (e.g.) Figure 1 The performance curve set in the middle) is under a specific operating condition (mainly referring to the total temperature at the compressor inlet). and total pressure The performance curves are drawn based on the aerodynamic characteristics of (centrifugal or axial) compressors. Because of these characteristics, if the compressor's inlet temperature and pressure change, the corresponding performance curve set will be completely different, requiring re-plotting. Using this method of expressing performance curves, compressor manufacturers will have to plot countless performance curves under various operating conditions when delivering compressor products to customers, resulting in a performance chart that could be hundreds or even thousands of pages long. This not only significantly increases factory testing costs but also causes considerable inconvenience for customers.

[0038] For the performance curves of compressors using ideal gases as the working fluid, the reduced flow rate and reduced speed are normalized. To address this issue, the compressor engineering field typically uses a multi-condition universal performance curve, where the horizontal axis (the first variable) is represented by the reduced flow rate. The second variable is the reduced rotational speed. By incorporating the compressor inlet operating parameters (total temperature and total pressure) into these two variables, the system effectively addresses varying operating conditions. For example... Figure 2A As shown, the horizontal axis represents the equivalent flow rate, the vertical axis represents the stagnation point pressure ratio, and the second variable is the equivalent rotational speed. Figure 2BAs shown, the horizontal axis represents the reduced flow rate, the vertical axis represents the stagnation pressure ratio, and the second variable is the reduced speed. During compressor testing, only one set of characteristic curves needs to be plotted for a specific inlet condition. For other inlet conditions, only the reduced flow rate and reduced speed values ​​need to be calculated. The corresponding performance values ​​(vertical axis) can generally be found on this multi-condition universal characteristic curve. This allows a single characteristic curve diagram to fully represent the complete performance spectrum of the compressor under different operating conditions, greatly facilitating the delivery and use of compressor products.

[0039] However, under this operating condition, the flow characteristics of supercritical carbon dioxide are complex, and its physical properties exhibit significant nonlinear changes, making it difficult to evaluate the performance of supercritical carbon dioxide compressors using the equivalent flow rate (or equivalent speed) of existing ideal gases.

[0040] In view of this, embodiments of the present disclosure provide a performance evaluation method for a supercritical carbon dioxide compressor, comprising: under target operating conditions, determining an iterative sound velocity based on the total temperature and pressure (inlet conditions), total enthalpy, theoretical sound velocity, and axial Mach number of the supercritical carbon dioxide in the compressor, wherein the theoretical sound velocity is the theoretical propagation speed of sound waves in the supercritical carbon dioxide flowing inside the compressor under the target operating conditions; if a first error between the theoretical sound velocity and the iterative sound velocity is greater than a first preset threshold, updating the theoretical sound velocity to the iterative sound velocity, and repeating the above steps until the first error is less than the first preset threshold. A threshold is used to obtain the target speed of sound. Based on the target speed of sound, the mass flow rate corresponding to the axial Mach number is determined. Fluid simulation of the compressor is performed using the mass flow rate to obtain the performance parameters corresponding to the axial Mach number. With the total temperature and pressure (inlet conditions) unchanged, the above steps are repeated after changing the axial Mach number to obtain the performance parameters corresponding to multiple different axial Mach numbers. Based on the performance parameters corresponding to multiple different axial Mach numbers, the correlation between the axial Mach number and the performance parameters under the total temperature and pressure (inlet conditions) is determined. The performance of the compressor is evaluated using the correlations corresponding to multiple sets of different total temperature and pressure (inlet conditions).

[0041] Figure 3 A flowchart illustrating a performance evaluation method for a supercritical carbon dioxide compressor according to an embodiment of the present disclosure is shown schematically.

[0042] like Figure 3 As shown, the performance evaluation method for the supercritical carbon dioxide compressor in this embodiment includes operations S310 to S370.

[0043] When operating S310, with the compressor running at the inlet condition, the total enthalpy and theoretical velocity of supercritical carbon dioxide are obtained from the physical property database based on the total temperature and total pressure of supercritical carbon dioxide. The inlet condition is the total temperature and total pressure.

[0044] When operating S320, the iterative sound velocity is determined from the physical property database based on total temperature and pressure, total enthalpy, theoretical sound velocity, and given axial Mach number. The iterative sound velocity is the theoretical propagation speed of sound waves in supercritical carbon dioxide flowing inside the compressor under inlet operating conditions.

[0045] In operation S330, if the first error between the iterative speed and the theoretical speed is greater than the first preset threshold, the theoretical speed is updated to the iterative speed, and the above steps are repeated until the first error is less than the first preset threshold, and the target speed is obtained.

[0046] In operation S340, based on the target speed of sound, the mass flow rate corresponding to the axial Mach number and the rotational speed corresponding to the circumferential Mach number are determined.

[0047] When operating the S350, fluid simulation of the compressor is performed using mass flow rate and rotational speed to obtain performance parameters corresponding to the Mach array, which includes axial Mach number and circumferential Mach number.

[0048] When operating S360, with the input conditions unchanged, the Mach array is changed and the above steps are executed again to obtain the performance parameters corresponding to multiple different Mach arrays. Based on the performance parameters corresponding to multiple different Mach arrays, the correlation between the performance parameters under the input conditions and the different Mach arrays is determined.

[0049] When operating the S370, the compressor performance is evaluated based on the flow similarity theory of the compressor and the correlation between the performance parameters under different inlet conditions and different Mach numbers.

[0050] Many physical properties influence the characteristics of fluid machinery. Dimensional analysis can typically transform these numerous variables representing physical phenomena into a smaller number of dimensionless parameters. For the same turbo compressor, the similarity criterion is that once the Mach number and Reynolds number are determined, the flow field is similar, and the compressor's performance is fixed. Furthermore, when the Reynolds number exceeds a certain critical value, the flow enters a fully developed turbulent state, where the influence of viscous forces is negligible compared to inertial forces, and performance parameters no longer change with the Reynolds number. At this point, the flow parameters exhibit self-similarity; this state is defined as the self-similarity region. High-speed machinery such as compressors typically operate in the self-similarity region, where only the dimensionless parameter Mach number is needed to achieve flow field similarity.

[0051] The mass flow rate of the compressor can be derived based on the ideal gas one-dimensional pipe flow theory. It can be expressed as follows:

[0052] (1);

[0053] make K is the Kappa coefficient. isentropic exponent, It is the gas constant; P is the axial Mach number. 01 T is the total pressure at the compressor inlet. 01 The total temperature at the compressor inlet is A, and the flow area is A.

[0054] make , This is called the flow function.

[0055] Therefore, mass flow rate can be simplified to:

[0056] (2);

[0057] This translates to flow rate. This can be expressed as:

[0058] (3);

[0059] For the same compressor, the flow area A is a constant; for the same working fluid, due to the gas constant... It is a constant, an isentropic exponent. The variation is generally small, so the equivalent flow rate is the axial Mach number at the compressor inlet. The only function, given a fixed reduced flow rate, is the axial Mach number. It is certain.

[0060] Circumferential Mach number at compressor inlet This can be expressed as:

[0061] (4);

[0062] 'a' represents the speed of sound, 'N' represents the rotational speed (rad / s), and 'D' represents the diameter of rotation. Therefore, the converted rotational speed... This can be expressed as:

[0063] (5);

[0064] For the same compressor, the rotational diameter D is a constant; for the same working fluid, due to the gas constant... It is a constant, an isentropic exponent. The changes are generally not significant, so the equivalent rotational speed is the circumferential Mach number. The only function of the circumferential Mach number when the reduced rotational speed is determined. It is certain.

[0065] In summary, when the equivalent flow rate and equivalent speed are both determined, the inlet Mach number... Two components and Everything is confirmed, the Mach number. Therefore, based on the similarity criterion mentioned earlier, once the Mach number is determined, the flow fields are similar, and the compressor performance is determined.

[0066] The working fluid in a supercritical carbon dioxide compressor is supercritical carbon dioxide. Supercritical carbon dioxide is a phase between liquid and gas, and its properties deviate significantly from those of an ideal gas. Therefore, the previous formulas (1) to (5) do not hold true. Even with approximation, K in formula (3) is no longer a constant. No longer The reduced flow rate is no longer a unique function of the axial Mach number; that is, the reduced flow rate and the axial Mach number are no longer in a one-to-one correspondence. Therefore, the reduced flow rate can no longer normalize the compressor performance under different inlet conditions. Similarly, the reduced speed no longer corresponds to a unique circumferential relative Mach number under different operating conditions, and therefore no longer has a normalizing function.

[0067] However, conversely, since the similarity criterion itself is universally applicable to both air and supercritical carbon dioxide, as long as the axial Mach number and circumferential Mach number are consistent, the flow field remains similar, and the compressor performance remains deterministic. Therefore, instead of using the reduced flow rate and reduced speed calibration method, the axial Mach number (horizontal axis) and circumferential Mach number (second variable) are directly used to calibrate the multi-condition performance curves of the supercritical carbon dioxide compressor. The resulting family of curves theoretically remains normalized for different inlet conditions. This is the fundamental solution to the problem of drawing universal characteristic curves for multi-condition supercritical carbon dioxide compressors.

[0068] Although the axial Mach number (and circumferential Mach number) has the ability to normalize the characteristic curve, people in related fields may rule out this method at first glance, because neither the axial Mach number nor the circumferential Mach number can be directly measured. The equivalent flow rate and equivalent rotational speed in related methods can be obtained directly and explicitly by measuring the flow rate, inlet temperature and pressure.

[0069] Therefore, the total temperature and pressure (inlet conditions), total enthalpy, and theoretical speed of sound of supercritical carbon dioxide in the compressor are obtained from the database based on the inlet operating conditions, without the need for direct measurement of the axial Mach number.

[0070] According to embodiments of this disclosure, the inlet operating conditions may include total temperature and total pressure. For example, the inlet operating conditions may be a total temperature of 36 degrees Celsius and a total pressure of 8 MPa.

[0071] According to embodiments of this disclosure, total temperature and total pressure (inlet operating condition) and axial Mach number can be parameters of the compressor inlet.

[0072] According to embodiments of this disclosure, the theoretical speed of sound is the propagation speed of sound waves in supercritical carbon dioxide in a non-flowing state inside the compressor under inlet operating conditions.

[0073] According to embodiments of this disclosure, the first preset threshold can be set according to actual needs. For example, the first preset threshold can be 0, that is, the target speed of sound is obtained when the theoretical speed of sound and the target speed of sound are equal.

[0074] According to embodiments of this disclosure, the static temperature, static pressure, and density of supercritical carbon dioxide can also be obtained from a physical property database (such as the NIST database) based on the target speed of sound. The mass flow rate can be determined based on at least one of the static temperature, static pressure, and density of supercritical carbon dioxide.

[0075] According to embodiments of this disclosure, a three-dimensional model of a supercritical carbon dioxide compressor can be performed to obtain a compressor model.

[0076] like Figure 4 As shown, a three-dimensional model of a two-stage compressor for supercritical carbon dioxide is performed to obtain a simulation model of the two-stage compressor.

[0077] The simulation employs a turbulence model, switching between a cavitation model and an evaporation-condensation model as needed. Using the simulation model of the two-stage compressor, performance parameters corresponding to the axial Mach number can be obtained by modifying the pressure outlet boundary conditions and adjusting the outlet pressure value based on the mass flow rate.

[0078] According to embodiments of this disclosure, during operations S310-S350, performance parameters corresponding to an axial Mach number under a total temperature and pressure (inlet operating condition) are obtained. To obtain a performance curve for the axial Mach number under a total temperature and pressure (inlet operating condition), while keeping the total temperature and pressure (inlet operating condition) constant, operations S310-S350 are performed again after changing the axial Mach number, resulting in multiple performance parameters corresponding to different axial Mach numbers. This determines the correlation between the axial Mach number and the performance parameters under the total temperature and pressure (inlet operating condition).

[0079] By changing the total temperature and pressure (inlet operating condition) and then repeating operations S310~S360, the correlation between the axial Mach number and performance parameters corresponding to different total temperature and pressure (inlet operating conditions) can be obtained.

[0080] According to embodiments of this disclosure, since the Mach number array is difficult to measure directly, this scheme directly provides the Mach number array and iteratively converges to the theoretical speed of sound to obtain the target speed of sound. Based on the target speed of sound, the mass flow rate corresponding to the axial Mach number and the rotational speed corresponding to the circumferential Mach number are determined. Fluid simulation of the compressor is performed using the mass flow rate and rotational speed to obtain performance parameters corresponding to the Mach number array. Then, with the total temperature and pressure (inlet conditions) remaining constant, the set circumferential Mach number and its corresponding multiple axial Mach numbers are changed, and the above operation is repeated to obtain performance parameters corresponding to multiple different Mach number combinations. Based on these performance parameters, the correlation between the Mach number and performance parameters under the given total temperature and pressure (inlet conditions) is determined. Since the axial Mach number and the circumferential Mach number are consistent, the flow field of supercritical carbon dioxide remains similar, and the performance of the compressor can be determined. Therefore, the performance evaluation of supercritical carbon dioxide compression can be carried out using multiple sets of correlations under different total temperature and pressure (inlet conditions).

[0081] According to embodiments of this disclosure, the compressor type is a turbo compressor, which includes at least one of the following: centrifugal compressor and axial compressor; the performance parameters include at least one of the following: pressure ratio and isentropic efficiency, wherein the pressure ratio is the ratio of the compressor's outlet pressure to its inlet pressure.

[0082] According to embodiments of this disclosure, determining the iterative speed of sound from a property database based on total temperature and pressure, total enthalpy, theoretical speed of sound, and a given axial Mach number includes: determining the actual static enthalpy of the compressor under inlet conditions based on total enthalpy, theoretical speed of sound, and axial Mach number; and obtaining the iterative speed of sound from the property database based on the actual static enthalpy and total temperature and pressure.

[0083] According to embodiments of this disclosure, the actual static enthalpy is determined based on the difference between the total enthalpy and the kinetic energy, which is determined based on the product of the target speed of sound and the axial Mach number.

[0084] h total =h+(M la *u) 2 / 2 (6);

[0085] h is the static enthalpy, u is the target speed of sound, and M is the target speed of sound. la It is the axial Mach number.

[0086] According to embodiments of this disclosure, fluid simulation of the compressor is performed using mass flow rate and rotational speed to obtain performance parameters corresponding to the Mach array. This includes: based on the relationship between compression volume and pressure during the compression process of the compressor, fluid simulation of the compressor is performed according to the mass flow rate and the actual inlet pressure, temperature and rotational speed of the compressor to obtain performance parameters corresponding to the Mach array.

[0087] According to embodiments of this disclosure, based on a set rotational speed, total temperature and total pressure of the inlet boundary conditions, and mass flow rate of the outlet boundary conditions, approximate results of the outlet parameters are obtained using fluid simulation; the range of the outlet pressure is estimated based on the approximate results, and a reference outlet pressure is determined therefrom.

[0088] Fluid simulation of the compressor was performed under the boundary condition of reference outlet pressure to obtain the performance parameters corresponding to the Mach array.

[0089] According to embodiments of this disclosure, fluid simulation of the compressor is performed based on the compressor speed and reference outlet pressure to obtain performance parameters corresponding to the Mach array, including: determining a target outlet pressure that meets an error condition based on the reference outlet pressure, wherein the error condition is that a second error between the target outlet pressure and the reference outlet pressure is less than a second preset threshold; and performing fluid simulation of the compressor based on the compressor speed and target outlet pressure to obtain performance parameters corresponding to the Mach array, wherein the speed is determined based on the compressor's circumferential Mach number and the target speed of sound.

[0090] According to embodiments of this disclosure, the second error can be that the difference between the target outlet pressure and the reference outlet pressure is less than 5 orders of magnitude, that is, the second preset threshold can be 0.00001.

[0091] The formula for rotational speed is as follows:

[0092] Rotational speed = circumferential Mach number × target speed of sound × 60 / (2 × 3.14 × entrance radius) (7);

[0093] According to embodiments of this disclosure, the circumferential Mach number and the axial Mach number are both pre-designed and set.

[0094] According to embodiments of this disclosure, in a fluid dynamics simulation, the rotational speed and target outlet pressure are input, and pressure outlet boundary conditions are used to perform fluid simulation on the compressor simulation model to obtain performance parameters corresponding to the axial Mach number.

[0095] According to embodiments of this disclosure, determining the mass flow rate corresponding to the axial Mach number based on a target sound speed includes: obtaining the density of supercritical carbon dioxide of the compressor from a property database based on the target sound speed; and determining the mass flow rate corresponding to the axial Mach number based on the density of supercritical carbon dioxide.

[0096] According to embodiments of this disclosure, static temperature, static pressure, etc., can also be obtained from the NIST database based on the target speed of sound.

[0097] According to embodiments of this disclosure, the density of supercritical carbon dioxide is obtained from the NIST database based on the target speed of sound.

[0098] According to embodiments of this disclosure, the formula for mass flow rate is as follows:

[0099] Mass flow rate = density × cross-sectional area × target speed of sound (8);

[0100] The density is the density of supercritical carbon dioxide, and the cross-sectional area is the flow area at the compressor inlet.

[0101] Figure 5 A schematic diagram illustrating a performance evaluation method for a supercritical carbon dioxide compressor according to an embodiment of the present disclosure is shown.

[0102] like Figure 5 As shown, the total enthalpy and theoretical speed of sound are obtained from the property database based on the inlet conditions (total temperature, total pressure). The static enthalpy is calculated based on the total enthalpy, theoretical speed of sound, and axial Mach number. The iterative speed of sound is obtained from the property database based on the total temperature, total pressure (inlet conditions), and static enthalpy. It is determined whether the first error between the iterative speed of sound and the theoretical speed of sound is greater than a first preset value. If so, the theoretical speed of sound is updated to the iterative speed of sound. The above steps are repeated until the first error is less than a first preset threshold, thus obtaining the target speed of sound. The static temperature, static pressure, and density are obtained from the property database based on the target speed of sound. The mass flow rate is determined based on the density and the target speed of sound. The rotational speed is determined based on the circumferential Mach number and the target speed of sound.

[0103] According to embodiments of this disclosure, the correlation between the Mach array and the performance parameters under total temperature and total pressure (inlet operating condition) is determined based on the performance parameters corresponding to multiple different Mach arrays. This includes: using interpolation to interpolate the performance parameters corresponding to multiple different Mach arrays to obtain a dataset to be fitted; and fitting the data in the dataset to be fitted using a fitting algorithm to obtain an operating condition performance curve, wherein the operating condition performance curve represents the correlation.

[0104] According to embodiments of this disclosure, the interpolation method may be Lagrange interpolation, cubic spline interpolation, polynomial interpolation, etc.

[0105] According to embodiments of this disclosure, the fitting algorithm can be the least squares method, polynomial fitting algorithm, linear fitting algorithm, etc., and the fitting algorithm is not limited.

[0106] According to embodiments of this disclosure, the horizontal axis of the operating condition performance curve represents the axial Mach number, and the vertical axis of the operating condition performance curve represents the performance parameters.

[0107] According to embodiments of this disclosure, the horizontal axis (first variable) of the operating performance curve is the axial Mach number, and the second variable of the operating performance curve is the circumferential Mach number at a set total temperature and total pressure (inlet operating condition) at the compressor inlet.

[0108] The operating condition performance curves of supercritical carbon dioxide compressors are used to describe their performance variations under different operating conditions and are widely used in advanced energy systems such as Brayton cycles, nuclear energy, and solar thermal power generation. These curves allow for the evaluation of the relationship between pressure ratio, flow rate, and efficiency, guiding the optimization of compressor control strategies under varying loads, start-up, shutdown, and stable operating conditions. This ensures the safe and efficient operation of the system under high-density, highly nonlinear flow near the critical point. The operating condition performance curves also assist in the design and matching of downstream heat exchangers and turbines, improving overall thermal cycle performance.

[0109] According to embodiments of this disclosure, the performance of a compressor is evaluated using multiple sets of correlation relationships corresponding to different total temperature and total pressure (inlet operating conditions). This includes: when the compressor is operating under inlet operating conditions and supercritical carbon dioxide is the total temperature and total pressure (inlet operating condition) to be evaluated, determining a target correlation relationship corresponding to the total temperature and total pressure (inlet operating condition) to be evaluated from multiple sets of correlation relationships corresponding to different total temperature and total pressure (inlet operating conditions); and evaluating the performance of the compressor using the target correlation relationship based on the axial Mach number to be evaluated corresponding to the total temperature and total pressure (inlet operating condition) to be evaluated, thereby obtaining performance evaluation parameters for the compressor.

[0110] Figure 6 The schematic diagram illustrates the performance curves of various total temperature and total pressure (inlet conditions) at axial Mach numbers according to embodiments of the present disclosure.

[0111] like Figure 6 As shown, the horizontal axis (first variable) of the operating performance curve can be the axial Mach number (inlet axial Mach number), and the second variable can be the total temperature and total pressure at the compressor inlet (inlet operating condition), such as 307.15K / 8.5MPa, 305.15K / 7.55MPa, 306.15K / 7.5MPa, 307.15K / 8MPa, etc. The vertical axis of the operating performance curve can be isentropic efficiency (or simply efficiency).

[0112] The total temperature and pressure (inlet condition) to be evaluated can be 307.15 K / 8.5 MPa, and the axial Mach number to be evaluated can be 0.15. Determine the performance curve for the condition with a total temperature and pressure (inlet condition) of 307.15 K / 8.5 MPa from multiple total temperature and pressure (inlet condition) options (as shown by the curve with the green inverted triangle in the figure). Based on the axial Mach number of 0.15 to be evaluated, determine the value of the isentropic efficiency on the ordinate from the performance curve for the condition with a total temperature and pressure (inlet condition) of 307.15 K / 8.5 MPa.

[0113] When the inlet conditions are 307.15K / 8.5MPa (total temperature and pressure to be evaluated, inlet operating condition) and 0.15 axial Mach number to be evaluated, the expected efficiency of the two compressors is approximately 91%; it can be used as input for system simulation models, equipment selection decisions, or real-time operation control and adjustment targets.

[0114] At the same axial Mach number, the trend of isentropic efficiency with relative entropy can also be inferred from adjacent curves.

[0115] Figure 7 The schematic diagram illustrates the operating performance curves of various total temperature and total pressure (inlet conditions) at reduced flow rates according to embodiments of the present disclosure.

[0116] like Figure 7 As shown, the horizontal axis of the performance curve (the first variable) is the reduced flow rate. The second variable can be the total temperature and total pressure at the inlet of the supercritical carbon dioxide compressor (inlet condition), such as 305.15K / 7.55MPa, 306.15K / 7.5MPa, 307.15K / 8MPa, 307.15K / 8.5MPa, etc. The vertical axis of the performance curve can be isentropic efficiency (or simply efficiency). However, from... Figure 7 In this study, the equivalent flux of supercritical carbon dioxide does not exhibit normalization.

[0117] Figure 8 The schematic diagram illustrates the characteristic curves of supercritical carbon dioxide according to an embodiment of the present disclosure.

[0118] like Figure 8 As shown, the supercritical carbon dioxide characteristic curves are obtained from the performance curves under multiple total temperature and total pressure (inlet conditions) at axial Mach numbers. The black lines represent the saturation lines. In the coordinate graph where the horizontal axis represents total temperature and total pressure (inlet conditions) and the vertical axis represents temperature, a total temperature and total pressure (inlet conditions) of 1.0 indicates the supercritical state. The cavitation inlet condition is represented by the green data points in the graph, and the condensation inlet condition by the red data points in the graph; both are near the two-phase region. The cavitation inlet condition and the condensation inlet condition are clearly shown in the coordinate graph where the horizontal axis represents temperature and the vertical axis represents pressure.

[0119] According to the embodiments of this disclosure, the essence of iteration is that, whether in the derivation formulas above or in the actual measured variables, the main application is the total temperature and pressure at the compressor inlet (also known as stagnation temperature and stagnation pressure), rather than the static temperature and static pressure. However, the static temperature and static pressure are actually what determine the physical properties of the working fluid (such as density, isentropic index, etc.), and the parameters are connected by velocity and total temperature and pressure (inlet conditions).

[0120] Figure 9 A schematic diagram illustrating a performance evaluation method for a supercritical carbon dioxide compressor according to another embodiment of the present disclosure is shown.

[0121] like Figure 9 As shown, using density as the iterative parameter, the mass flow rate is first established (i.e., a series of known mass flow rate points are manually provided), and then the axial Mach number corresponding to each mass flow rate point is iteratively calculated. Specifically, the total temperature, total pressure (inlet condition), total enthalpy, and density are obtained from the NIST database based on the operating parameters (total temperature, total pressure). The static enthalpy is determined based on the mass flow rate, axial velocity, actual density, and total enthalpy. The theoretical density is determined based on the total temperature, total pressure (inlet condition), and static enthalpy. It is then determined whether the actual density and theoretical density converge (e.g., whether the error is less than a preset value). If they converge, the speed of sound corresponding to the actual density is determined; otherwise, the theoretical density is replaced with the actual density, and the above steps are repeated until the actual density and theoretical density converge. The axial Mach number is determined based on the speed of sound, static temperature, and static pressure.

[0122] Using the speed of sound as the iteration parameter, the axial Mach number must first be set up (that is, a series of known axial Mach number points are given manually), and then the mass flow rate corresponding to each axial Mach number is calculated iteratively.

[0123] Using the axial Mach number as the abscissa, it is often necessary to first arrange and traverse the Mach numbers (that is, using the Mach number as a known quantity, which can maximize the control over the distribution spacing and range of the abscissa and the second variable, resulting in a more aesthetically pleasing and widely applicable curve), and then iteratively calculate the mass flow rate and rotational speed corresponding to each Mach number. Finally, the mass flow rate and rotational speed are used to control the boundary conditions of numerical simulation or experimental testing to calculate the performance (pressure ratio or efficiency), thereby completing the plotting of the entire family of performance curves. Therefore, by using sonic iterative control to solve for the mass flow rate and rotational speed, uniform and controllable abscissa points of the general characteristic curve under operating conditions based on Mach number are achieved.

[0124] Based on conventional compressor similarity theory, this paper proposes using axial and circumferential Mach numbers as plotting standards. By iteratively calculating the thermodynamic parameters at operating points using the NIST database, and employing fluid dynamics simulation to verify and adjust the outlet pressure, the consistency between simulation results and design conditions is ensured. Through simulation analysis of the performance of a supercritical carbon dioxide compressor, the plotted general characteristic curves exhibit higher fitting accuracy and consistency, significantly improving their practicality and readability. This method fills the gap in the field of general characteristic curve plotting for supercritical carbon dioxide compressors, providing an effective tool for compressor performance evaluation and design optimization, and has broad engineering application prospects.

[0125] Figure 10 A schematic block diagram of a performance evaluation apparatus for a supercritical carbon dioxide compressor according to an embodiment of the present disclosure is shown.

[0126] like Figure 10As shown, the performance evaluation device 1000 for a supercritical carbon dioxide compressor in this embodiment includes a first determination module 1010, a second determination module 1020, an update module 1030, a third determination module 1040, a fluid simulation module 1050, a fourth determination module 1060, and an evaluation module 1070.

[0127] The first determining module 1010 is used to obtain the total enthalpy and theoretical speed of sound of supercritical carbon dioxide from a property database based on the total temperature and total pressure of supercritical carbon dioxide when the compressor is operating under inlet conditions. The inlet conditions are the total temperature and total pressure, and the theoretical speed of sound is the propagation speed of sound waves in the non-flowing state of supercritical carbon dioxide inside the compressor under inlet conditions. In one embodiment, the first determining module 1010 can be used to perform the operation S310 described above, which will not be repeated here.

[0128] The second determining module 1020 is used to determine the iterative speed of sound from a property database based on total temperature and pressure, total enthalpy, theoretical speed of sound, and a given axial Mach number. The iterative speed of sound is the theoretical propagation speed of sound waves flowing through supercritical carbon dioxide inside the compressor under inlet operating conditions. In one embodiment, the second determining module 1020 can be used to perform the operation S320 described above, which will not be repeated here.

[0129] The update module 1030 is used to update the theoretical speed of sound to the iterative speed of sound when the first error between the iterative speed of sound and the theoretical speed of sound is greater than a first preset threshold. This process is repeated until the first error is less than the first preset threshold, thus obtaining the target speed of sound. In one embodiment, the update module 1030 can be used to perform the operation S330 described above, which will not be repeated here.

[0130] The third determining module 1040 is used to determine the mass flow rate corresponding to the axial Mach number and the rotational speed corresponding to the circumferential Mach number based on the target speed of sound. In one embodiment, the third determining module 1040 can be used to perform the operation S340 described above, which will not be repeated here.

[0131] The fluid simulation module 1050 is used to perform fluid simulation of the compressor using mass flow rate to obtain performance parameters corresponding to the Mach array. In one embodiment, the fluid simulation module 1050 can be used to perform the operation S350 described above, which will not be repeated here.

[0132] The fourth determining module 1060 is used to change the Mach array and repeat the above steps under the same inlet operating conditions to obtain performance parameters corresponding to multiple different Mach arrays. Based on the performance parameters corresponding to the multiple different Mach arrays, the module determines the correlation between the performance parameters under the inlet operating conditions and the different Mach arrays. In one embodiment, the fourth determining module 1060 can be used to perform the operation S360 described above, which will not be repeated here.

[0133] The evaluation module 1070 is used to evaluate the performance of the compressor based on the compressor flow similarity theory, utilizing the correlation between performance parameters under different inlet operating conditions and different Mach arrays. In one embodiment, the evaluation module 1070 can be used to perform the operation S370 described above, which will not be repeated here.

[0134] According to embodiments of this disclosure, the first determining module 1010 includes a first determining submodule and a second determining submodule. The first determining submodule is used to determine the actual static enthalpy of the compressor under inlet operating conditions based on the total enthalpy, theoretical speed of sound, and axial Mach number; the second determining submodule is used to query the iterative speed of sound from a physical property database based on the actual static enthalpy and total temperature and total pressure.

[0135] According to embodiments of this disclosure, the fluid simulation module 1050 includes a fluid simulation submodule. The fluid simulation submodule is used to perform fluid simulation on the compressor based on the relationship between compression volume and pressure during the compressor's compression process, and according to the mass flow rate and the compressor's actual inlet pressure, temperature, and rotational speed, to obtain performance parameters corresponding to the Mach array.

[0136] According to embodiments of this disclosure, the evaluation module 1070 includes a third determination submodule and an evaluation submodule. The third determination submodule is used to determine the target correlation relationship corresponding to the total temperature and total pressure to be evaluated from multiple sets of correlation relationships corresponding to different inlet operating conditions when supercritical carbon dioxide is the total temperature and total pressure to be evaluated; the evaluation submodule is used to evaluate the performance of the compressor based on the Mach array to be evaluated corresponding to the total temperature and total pressure to be evaluated, using the target correlation relationship, to obtain the performance evaluation parameters of the compressor.

[0137] According to embodiments of this disclosure, the third determining module 1040 includes a fourth determining submodule and a fifth determining submodule. The fourth determining submodule is used to obtain the density of supercritical carbon dioxide in the compressor based on the target speed of sound; the fifth determining submodule is used to determine the mass flow rate corresponding to the axial Mach number based on the density of supercritical carbon dioxide.

[0138] According to embodiments of this disclosure, the fourth determining module 1060 includes an interpolation submodule and a fitting submodule. The interpolation submodule is used to interpolate the performance parameters corresponding to multiple different Mach arrays using an interpolation method to obtain a dataset to be fitted; the fitting submodule is used to fit the data in the dataset to be fitted based on a fitting algorithm to obtain a working condition performance curve, wherein the working condition performance curve represents the correlation relationship.

[0139] According to embodiments of this disclosure, any multiple modules among the first determining module 1010, the second determining module 1020, the updating module 1030, the third determining module 1040, the fluid simulation module 1050, the fourth determining module 1060, and the evaluation module 1070 can be combined into one module, or any one of these modules can be split into multiple modules. Alternatively, at least some of the functionality of one or more of these modules can be combined with at least some of the functionality of other modules and implemented in one module. According to embodiments of this disclosure, at least one of the first determining module 1010, the second determining module 1020, the updating module 1030, the third determining module 1040, the fluid simulation module 1050, the fourth determining module 1060, and the evaluation module 1070 can be at least partially implemented as hardware circuits, such as field-programmable gate arrays (FPGAs), programmable logic arrays (PLAs), systems-on-a-chip, systems-on-a-substrate, systems-on-package, application-specific integrated circuits (ASICs), or any other reasonable means of integrating or packaging circuits, or implemented in software, hardware, or firmware, or in any suitable combination of any of these three implementation methods. Alternatively, at least one of the first determining module 1010, the second determining module 1020, the updating module 1030, the third determining module 1040, the fluid simulation module 1050, the fourth determining module 1060, and the evaluation module 1070 can be at least partially implemented as computer program modules, which can perform corresponding functions when the computer program module is run.

[0140] Figure 11 A block diagram schematically illustrates an electronic device suitable for implementing a performance evaluation method for a supercritical carbon dioxide compressor according to an embodiment of the present disclosure.

[0141] like Figure 11As shown, an electronic device 1100 according to an embodiment of the present disclosure includes a processor 1101, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1102 or a program loaded from a storage portion 1108 into a random access memory (RAM) 1103. The processor 1101 may include, for example, a general-purpose microprocessor (e.g., a CPU), an instruction set processor and / or an associated chipset and / or a special-purpose microprocessor (e.g., an application-specific integrated circuit (ASIC)), etc. The processor 1101 may also include onboard memory for caching purposes. The processor 1101 may include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present disclosure.

[0142] RAM 1103 stores various programs and data required for the operation of electronic device 1100. Processor 1101, ROM 1102, and RAM 1103 are interconnected via bus 1104. Processor 1101 performs various operations of the method flow according to embodiments of the present disclosure by executing programs in ROM 1102 and / or RAM 1103. It should be noted that the programs may also be stored in one or more memories other than ROM 1102 and RAM 1103. Processor 1101 may also perform various operations of the method flow according to embodiments of the present disclosure by executing programs stored in said one or more memories.

[0143] According to embodiments of this disclosure, the electronic device 1100 may further include an input / output (I / O) interface 1105, which is also connected to a bus 1104. The electronic device 1100 may also include one or more of the following components connected to the input / output (I / O) interface 1105: an input section 1106 including a keyboard, mouse, etc.; an output section 1107 including a cathode ray tube (CRT), liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 1108 including a hard disk, etc.; and a communication section 1109 including a network interface card such as a LAN card, modem, etc. The communication section 1109 performs communication processing via a network such as the Internet. A drive 1110 is also connected to the input / output (I / O) interface 1105 as needed. A removable medium 1111, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on the drive 1110 as needed so that computer programs read from it can be installed into the storage section 1108 as needed.

[0144] This disclosure also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiments; or it may exist independently and not assembled into the device / apparatus / system. The computer-readable storage medium carries one or more programs that, when executed, implement the method according to the embodiments of this disclosure.

[0145] According to embodiments of this disclosure, the computer-readable storage medium may be a non-volatile computer-readable storage medium, such as including, but not limited to: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this disclosure, the computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. For example, according to embodiments of this disclosure, the computer-readable storage medium may include ROM 1102 and / or RAM 1103 and / or one or more memories other than ROM 1102 and RAM 1103 described above.

[0146] Embodiments of this disclosure also include a computer program product comprising a computer program containing program code for performing the methods shown in the flowchart. When the computer program product is run on a computer system, the program code is used to enable the computer system to implement the performance evaluation method for supercritical carbon dioxide compressors provided in embodiments of this disclosure.

[0147] When the computer program is executed by the processor 1101, it performs the functions defined in the system / apparatus of this disclosure embodiments. According to embodiments of this disclosure, the systems, apparatuses, modules, units, etc., described above can be implemented by computer program modules.

[0148] In one embodiment, the computer program may rely on a tangible storage medium such as an optical storage device or a magnetic storage device. In another embodiment, the computer program may also be transmitted and distributed in the form of signals over a network medium, and may be downloaded and installed via the communication section 1109, and / or installed from the removable medium 1111. The program code contained in the computer program can be transmitted using any suitable network medium, including but not limited to: wireless, wired, etc., or any suitable combination thereof.

[0149] In such an embodiment, the computer program can be downloaded and installed from a network via communication section 1109, and / or installed from removable medium 1111. When the computer program is executed by processor 1101, it performs the functions defined in the system of this disclosure embodiment. According to embodiments of this disclosure, the systems, devices, apparatuses, modules, units, etc., described above can be implemented by computer program modules.

[0150] According to embodiments of this disclosure, program code for executing the computer programs provided in embodiments of this disclosure can be written in any combination of one or more programming languages. Specifically, these computational programs can be implemented using high-level procedural and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages ​​include, but are not limited to, languages ​​such as Java, C++, Python, "C", or similar programming languages. The program code can execute entirely on a user's computing device, partially on a user's device, partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0151] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0152] Those skilled in the art will understand that the features described in the various embodiments of this disclosure can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. In particular, the features described in the various embodiments of this disclosure can be combined and / or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0153] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A method of performance evaluation of a supercritical carbon dioxide compressor, characterized by, The method comprises: In the case where the compressor operates at an inlet operating condition, obtaining total enthalpy and theoretical sound speed of supercritical carbon dioxide from a property database according to total temperature and total pressure of the supercritical carbon dioxide, the inlet operating condition being the total temperature and total pressure, and the theoretical sound speed being a propagation speed of sound waves in the supercritical carbon dioxide in a non-flow state inside the compressor under the inlet operating condition; Determining an iterative sound speed from the property database according to the total temperature and total pressure, the total enthalpy, the theoretical sound speed, and a given axial Mach number, the iterative sound speed being a theoretical propagation speed of sound waves propagating in the supercritical carbon dioxide in a flow state inside the compressor under the inlet operating condition; In the case where a first error between the iterative sound speed and the theoretical sound speed is greater than a first preset threshold, updating the theoretical sound speed to the iterative sound speed, and repeatedly performing the above steps until the first error is less than the first preset threshold, to obtain a target sound speed; Based on the target sound speed, determining a mass flow corresponding to the axial Mach number and a rotating speed corresponding to the circumferential Mach number; Performing fluid simulation on the compressor by using the mass flow and the rotating speed, to obtain performance parameters corresponding to a Mach number array, the Mach number array comprising the axial Mach number and the circumferential Mach number; In the case where the inlet operating condition is unchanged, changing the Mach number array and performing the above steps again, to obtain the performance parameters corresponding to a plurality of different Mach number arrays respectively, and determining a correlation between the performance parameters and the different Mach number arrays under the inlet operating condition based on the performance parameters corresponding to the plurality of different Mach number arrays respectively; According to a compressor flow similarity theory, evaluating the performance of the compressor by using the correlation between the performance parameters and the different Mach number arrays under the different inlet operating conditions.

2. The method of claim 1, wherein, The method comprises: Determining actual static enthalpy of the compressor under the inlet operating condition according to the total enthalpy, the theoretical sound speed, and the axial Mach number; Obtaining the iterative sound speed from the property database according to the actual static enthalpy and the total temperature and total pressure.

3. The method of claim 2, wherein, The actual static enthalpy is determined according to a difference between the total enthalpy and kinetic energy, the kinetic energy being determined according to a product of the theoretical sound speed and the axial Mach number.

4. The method of claim 1, wherein, The method comprises: Performing fluid simulation on the compressor by using the mass flow and the rotating speed, to obtain performance parameters corresponding to a Mach number array, the Mach number array comprising the axial Mach number and the circumferential Mach number; 5. The method of claim 3, wherein, The rotating speed is determined according to the circumferential Mach number and the target sound speed of the compressor.

6. The method of claim 1, wherein, The method comprises: In the case that the supercritical carbon dioxide is total temperature and total pressure to be evaluated, the target correlation corresponding to the total temperature and total pressure to be evaluated is determined from the correlations corresponding to the plurality of different inlet working conditions respectively; Based on the Mach number to be evaluated corresponding to the total temperature and total pressure to be evaluated, the performance of the compressor is evaluated by using the target correlation, and a performance evaluation parameter of the compressor is obtained.

7. The method of claim 1, wherein, The target sound speed is used to determine the mass flow corresponding to the axial Mach number, including: Based on the target sound speed, the density of the supercritical carbon dioxide of the compressor is obtained from the property database; According to the density of the supercritical carbon dioxide, the mass flow corresponding to the axial Mach number is determined.

8. The method of claim 1, wherein, The performance parameters corresponding to a plurality of different Mach numbers are used to determine the correlation between the performance parameters and different Mach numbers under the inlet working condition, including: The performance parameters corresponding to a plurality of different Mach numbers are interpolated by using an interpolation method to obtain a fitting data set; Based on a fitting algorithm, the data in the fitting data set is fitted to obtain a working condition performance curve, and the working condition performance curve represents the correlation.

9. The method of claim 8, wherein, The abscissa of the working condition performance curve is the axial Mach number, and the ordinate of the working condition performance curve is the performance parameter.

10. The method of any one of claims 1-9, wherein, The type of the compressor is a turbine compressor, and the turbine compressor includes at least one of a centrifugal compressor and an axial flow compressor; the performance parameter includes at least one of a pressure ratio and an isentropic efficiency, and the pressure ratio is the ratio of the outlet pressure to the inlet pressure of the compressor.

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