Fan anti-stall calculation method and system based on dial parameters

Abstract

The invention discloses a fan anti-stall calculation method and system based on dial plate parameters, and the method comprises the steps: obtaining the flow, total pressure, efficiency and blade angle of fan operation through measurement and calculation, and recording the dial plate opening degree and the dial plate pressure difference; the actually measured fan total pressure-dial pressure difference is obtained; a comparison result is obtained; obtaining a function relationship between the dial plate opening degree and the blade angle marked by the design performance curve when the fan leaves the factory; calculating to obtain safe total pressure under each opening degree; and when the measured safe pressure difference value of the dial plate is reached during operation, continuing to increase the load is stopped, or the pressure difference of the dial plate is reduced. The system comprises a measurement and calculation module, a calibration module, a comparison module, a fitting module, a calculation module and an execution module. According to the method, no measuring equipment is added, the safety pressure difference value of the dial plate under each opening degree on the dial plate is calculated only depending on the dial plate display value and serves as an operation reference, and the robustness is high.

Description

Technical Field

[0001] The invention belongs to the technical field of online monitoring of fan operating status, and specifically relates to a fan anti-stall calculation method and system based on dial parameters, which is suitable for axial flow fans in power stations. Background Art

[0002] At present, the operation monitoring system of power station fans is generally a common DCS system in power plants. Most fans above 300MW use axial flow fans. Compared with centrifugal fans, axial flow fans have a large stall zone. Improper selection or improper operation can easily cause stall, affecting the safe and stable operation of the unit.

[0003] Most fans do not have anti-stall switches, and the differential pressure stall switches used by some are not very accurate. Stall alarms often occur while the actual operation is normal, and stalls actually occur but no alarm is given. Summary of the invention

[0004] The purpose of the present invention is to provide a fan anti-stall calculation method and system based on dial parameters. By combining field testing and dial data display, the safe operating differential pressure at various openings of the fan is calculated, thereby improving the safety of fan operation and providing convenience for operation monitoring personnel. This method does not add any measuring equipment, but only relies on the dial display value to calculate the dial safety differential pressure value at various openings on the dial as an operation reference, and has strong robustness.

[0005] In order to achieve the above object, the present invention adopts the following technical solution: A fan anti-stall calculation method based on dial parameters, comprising: Calculate the flow rate, total pressure, efficiency and blade angle of the fan, and record the dial opening and dial pressure difference; According to the measurement results, the dial pressure difference is calibrated to obtain the measured fan total pressure - dial pressure difference; The actually measured flow rate and total pressure are marked on the design performance curve of the fan when it leaves the factory. The design performance curve of the fan when it leaves the factory is marked with the efficiency and blade angle. The actually measured efficiency and blade angle are compared with the efficiency and blade angle marked on the design performance curve of the fan when it leaves the factory to obtain the comparison result. According to the comparison results, determine whether the measured performance of the fan is consistent with the design performance curve of the fan when it leaves the factory. When the measured performance of the fan is consistent with the corrected design performance curve, obtain the functional relationship between the dial opening and the blade angle marked on the design performance curve of the fan when it leaves the factory; On the design performance curve of the fan when it leaves the factory, find the total pressure at the stall point corresponding to each angle, leave a set stall margin, and calculate the safe total pressure at each opening; Based on the functional relationship between the measured fan total pressure - dial pressure difference, dial opening - blade angle marked on the design performance curve of the fan when it leaves the factory, and the safe total pressure at each opening, the dial safety pressure difference value at each opening on the dial is deduced and used as an operating reference. When the measured dial safety pressure difference value is reached during operation, stop increasing the load or reduce the dial pressure difference.

[0006] A further improvement of the present invention is that, through field tests of the fan, the flow rate, total pressure, efficiency and blade angle of the fan operation are measured and obtained.

[0007] A further improvement of the present invention is that when judging whether the actual measured performance of the fan is consistent with the design performance curve of the fan when it leaves the factory, if not, the design performance curve of the fan when it leaves the factory is corrected until the actual measured performance of the fan is consistent with the corrected design performance curve.

[0008] A further improvement of the present invention is that, on the design performance curve of the fan when it leaves the factory, the total pressure P0 of the stall point corresponding to each angle is found, a set stall margin k is left, and the safe total pressure P1 at each opening is calculated, and the calculation formula is: P1=(1-k)×P0.

[0009] A further improvement of the present invention is that the industry standard requirement for the stall margin k is at least 1.35.

[0010] A fan anti-stall calculation system based on dial parameters, comprising: The measurement module is used to measure the flow rate, total pressure, efficiency and blade angle of the fan, and record the dial opening and dial pressure difference; The calibration module is used to calibrate the dial pressure difference according to the measurement results to obtain the measured fan total pressure - dial pressure difference; A comparison module is used to mark the actually measured flow rate and total pressure on the design performance curve of the fan when it leaves the factory. The design performance curve of the fan when it leaves the factory has the efficiency and blade angle marked on it, and compare the actually measured efficiency and blade angle with the efficiency and blade angle marked on the design performance curve of the fan when it leaves the factory to obtain a comparison result; The fitting module is used to determine whether the actual measured performance of the fan is consistent with the design performance curve of the fan when it leaves the factory based on the comparison results. When the actual measured performance of the fan is consistent with the corrected design performance curve, the functional relationship between the dial opening and the blade angle marked on the design performance curve of the fan when it leaves the factory is obtained; The calculation module is used to find the total pressure at the stall point corresponding to each angle on the design performance curve of the fan when it leaves the factory, leaving a set stall margin, and calculate the safe total pressure at each opening; The execution module is used to reversely deduce the dial safety pressure difference value at each opening on the dial based on the obtained functional relationship between the measured fan total pressure-disc pressure difference, the dial opening-the blade angle marked on the design performance curve of the fan when it leaves the factory, and the safe total pressure at each opening, as an operation reference. When the measured dial safety pressure difference value is reached during operation, stop increasing the load or reduce the dial pressure difference.

[0011] A further improvement of the present invention is that, in the calculation module, the flow rate, total pressure, efficiency and blade angle of the fan operation are calculated through field tests of the fan.

[0012] A further improvement of the present invention is that, in the fitting module, when judging whether the actual measured performance of the fan is consistent with the design performance curve of the fan when it leaves the factory, if not, the design performance curve of the fan when it leaves the factory is corrected until the actual measured performance of the fan is consistent with the corrected design performance curve.

[0013] A further improvement of the present invention is that, in the calculation module, on the design performance curve of the fan when it leaves the factory, the total pressure P0 of the stall point corresponding to each angle is found, leaving a set stall margin k, and the safe total pressure P1 at each opening is calculated, and the calculation formula is: P1=(1-k)×P0.

[0014] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the computer program implements the steps of a fan anti-stall calculation method based on dial parameters.

[0015] Compared with the prior art, the present invention has at least the following beneficial technical effects: The present invention provides a fan anti-stall calculation method and system based on dial parameters, which does not add any measuring equipment and only relies on the dial display value to calculate the dial safety pressure difference value at each opening on the dial as an operation reference. It can save costs to the maximum extent, and can also eliminate the error in the installation position of the DCS measuring point and the error between the dial opening and the actual blade angle, providing convenience for the operation and adjustment of the operation monitoring personnel. By combining the method of on-site testing with dial display, it not only reduces the on-site workload, but also eliminates the limitations of measurement errors to the maximum extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is a flow chart of a fan anti-stall calculation method based on dial parameters.

[0017] Figure 2 This is a schematic diagram of the performance curve of the induced draft fan of an existing power plant.

[0018] Figure 3 The present invention is a structural block diagram of a fan anti-stall calculation system based on dial parameters. DETAILED DESCRIPTION

[0019] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0020] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0021] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0022] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0023] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0024] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0025] Example 1 like Figure 1 As shown, this embodiment provides a fan anti-stall calculation method based on dial parameters, including: Calculate the flow rate, total pressure, efficiency and blade angle of the fan, and record the dial opening and dial pressure difference; According to the measurement results, the dial pressure difference is calibrated to obtain the measured fan total pressure - dial pressure difference; The actually measured flow rate and total pressure are marked on the design performance curve of the fan when it leaves the factory. The design performance curve of the fan when it leaves the factory is marked with the efficiency and blade angle. The actually measured efficiency and blade angle are compared with the efficiency and blade angle marked on the design performance curve of the fan when it leaves the factory to obtain the comparison result. According to the comparison results, determine whether the measured performance of the fan is consistent with the design performance curve of the fan when it leaves the factory. When the measured performance of the fan is consistent with the corrected design performance curve, obtain the functional relationship between the dial opening and the blade angle marked on the design performance curve of the fan when it leaves the factory; On the design performance curve of the fan when it leaves the factory, find the total pressure at the stall point corresponding to each angle, leave a set stall margin, and calculate the safe total pressure at each opening; Based on the functional relationship between the measured fan total pressure - dial pressure difference, dial opening - blade angle marked on the design performance curve of the fan when it leaves the factory, and the safe total pressure at each opening, the dial safety pressure difference value at each opening on the dial is deduced and used as an operating reference. When the measured dial safety pressure difference value is reached during operation, stop increasing the load or reduce the dial pressure difference.

[0026] In this embodiment, the stall point total pressure P0 corresponding to each angle is found on the design performance curve of the fan when it leaves the factory, and a set stall margin k is left to calculate the safe total pressure P1 at each opening, and the calculation formula is: P1=(1-k)×P0. Among them, the industry standard requirement for the stall margin k is at least 1.35.

[0027] Example 2 like Figure 1 As shown, the present embodiment provides a fan anti-stall calculation method based on dial parameters, comprising the following steps: 1) Through the on-site test of the fan, the flow rate, total pressure, efficiency and blade angle of the fan are calculated, and the dial opening and dial pressure difference are recorded; 2) According to the measurement results, the dial pressure difference is calibrated to obtain the measured fan total pressure - dial pressure difference; 3) The actually measured flow rate and total pressure are marked on the design performance curve of the fan when it leaves the factory. The efficiency and blade angle are marked on the design performance curve of the fan when it leaves the factory. The actually measured efficiency and blade angle are compared with the efficiency and blade angle marked on the design performance curve of the fan when it leaves the factory to obtain the comparison result; 4) According to the comparison results, determine whether the measured performance of the fan is consistent with the design performance curve of the fan when it leaves the factory. If not, correct the design performance curve of the fan when it leaves the factory until the measured performance of the fan is consistent with the corrected design performance curve, and obtain the functional relationship between the dial opening and the blade angle marked on the design performance curve of the fan when it leaves the factory; 5) On the design performance curve of the fan when it leaves the factory, find the stall point total pressure P0 corresponding to each angle, leaving the set stall margin k, and calculate the safe total pressure P1=(1-k)×P0 at each opening; 6) Based on the functional relationship between the measured fan total pressure and dial pressure difference, the dial opening and the blade angle marked on the design performance curve of the fan when it leaves the factory, and the safe total pressure at each opening, the dial safety pressure difference value at each opening on the dial is reversed and used as an operating reference. When the measured dial safety pressure difference value is reached during operation, stop increasing the load or take other measures to reduce the dial pressure difference to achieve the purpose of preventing the fan from stalling.

[0028] In this embodiment, the industry standard requirement for the stall margin is at least 1.35, and an appropriate stall margin can be selected according to actual operating conditions.

[0029] Example 3 The induced draft fan of a domestic thermal power plant unit boiler often has wind grabbing and stalling. Such failures occur suddenly, without warning, and are not easy to detect. It is also inconvenient to issue early warnings, causing economic losses to the power plant. After testing by technical personnel, it was found that the operator only monitored the current of the induced draft fan and ignored the inlet and outlet pressures of the induced draft fan. Only monitoring the current cannot accurately determine the actual operating position of the fan on the performance curve. As a result, when the actual operating point is in the stall zone of low flow and high pressure, the operator did not receive the alarm signal and could not make adjustments in time, which caused the fan to stall.

[0030] Subsequently, the optimization design method of the fan flow meter measurement installation position was applied to optimize the anti-stall calculation method. When the fan differential pressure reaches the alarm value of the current opening, the operator makes timely adjustments, which enhances the safety and stability of the fan operation. The steps are as follows: 1) Through on-site fan tests, the flow rate, total pressure, efficiency, blade angle, and medium temperature of the fan are calculated; 2) According to the measurement results, the pressure and temperature of the dial are calibrated. Since the test measurement point and the dial measurement point are only different in position, after excluding the influence of pressure loss and temperature drop, the functional relationship of the measured fan total pressure-disk pressure difference and the measured fan inlet temperature-disk fan inlet temperature is obtained; 3) Mark the actual measured flow rate and total pressure on the fan performance curve, see Figure 2 and compare the actually calculated efficiency and blade angle with the values ​​marked on the performance curve; 4. According to the comparison results, it is found that the fan is consistent with the performance curve and no correction is required. The subsequent steps can be calculated according to the design point performance curve; 5) The functional relationship between the dial opening and the performance curve angle is obtained, which is a first-order relationship; 6. Find the stall point corresponding to each angle on the performance curve, leave a certain stall margin (a 12% pressure margin is selected in this embodiment), and calculate the safe pressure difference of the dial at each opening; 7) Based on the functional relationship between the measured fan total pressure-disc pressure difference, and the dial opening-performance curve angle obtained in steps 2) and 5), the dial safety pressure difference value at each dial opening is inferred as a reference for operation, see Table 1.

[0031] Table 1

[0032] Example 4 like Figure 3 As shown, this embodiment provides a fan anti-stall calculation system based on dial parameters, including: The measurement module is used to measure the flow rate, total pressure, efficiency and blade angle of the fan, and record the dial opening and dial pressure difference; The calibration module is used to calibrate the dial pressure difference according to the measurement results to obtain the measured fan total pressure - dial pressure difference; A comparison module is used to mark the actually measured flow rate and total pressure on the design performance curve of the fan when it leaves the factory. The design performance curve of the fan when it leaves the factory has the efficiency and blade angle marked on it, and compare the actually measured efficiency and blade angle with the efficiency and blade angle marked on the design performance curve of the fan when it leaves the factory to obtain a comparison result; The fitting module is used to determine whether the actual measured performance of the fan is consistent with the design performance curve of the fan when it leaves the factory based on the comparison results. When the actual measured performance of the fan is consistent with the corrected design performance curve, the functional relationship between the dial opening and the blade angle marked on the design performance curve of the fan when it leaves the factory is obtained; The calculation module is used to find the total pressure at the stall point corresponding to each angle on the design performance curve of the fan when it leaves the factory, leaving a set stall margin, and calculate the safe total pressure at each opening; The execution module is used to reversely deduce the dial safety pressure difference value at each opening on the dial based on the obtained functional relationship between the measured fan total pressure-disc pressure difference, the dial opening-the blade angle marked on the design performance curve of the fan when it leaves the factory, and the safe total pressure at each opening, as an operation reference. When the measured dial safety pressure difference value is reached during operation, stop increasing the load or reduce the dial pressure difference.

[0033] Example 5 This embodiment provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the steps of the fan anti-stall calculation method based on dial parameters.

[0034] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0035] The present application is described with reference to the flowcharts and / or block diagrams of the methods, systems and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A system that specifies the functions of a box or multiple boxes.

[0036] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0037] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0038] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0039] In addition, it should be understood that although this specification is described in accordance with the implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A fan anti-stall calculation method based on dial parameters, characterized in that: include: Calculate the flow rate, total pressure, efficiency and blade angle of the fan, and record the dial opening and dial pressure difference; According to the measurement results, the dial pressure difference is calibrated to obtain the measured fan total pressure - dial pressure difference; The actually measured flow rate and total pressure are marked on the design performance curve of the fan when it leaves the factory. The design performance curve of the fan when it leaves the factory is marked with the efficiency and blade angle. The actually measured efficiency and blade angle are compared with the efficiency and blade angle marked on the design performance curve of the fan when it leaves the factory to obtain the comparison result. According to the comparison results, determine whether the measured performance of the fan is consistent with the design performance curve of the fan when it leaves the factory. When the measured performance of the fan is consistent with the corrected design performance curve, obtain the functional relationship between the dial opening and the blade angle marked on the design performance curve of the fan when it leaves the factory; On the design performance curve of the fan when it leaves the factory, find the total pressure at the stall point corresponding to each angle, leave a set stall margin, and calculate the safe total pressure at each opening; Based on the functional relationship between the measured fan total pressure - dial pressure difference, dial opening - blade angle marked on the design performance curve of the fan when it leaves the factory, and the safe total pressure at each opening, the dial safety pressure difference value at each opening on the dial is deduced and used as an operating reference. When the measured dial safety pressure difference value is reached during operation, stop increasing the load or reduce the dial pressure difference.

2. A fan anti-stall calculation method based on dial parameters according to claim 1, characterized in that: Through on-site tests of the fan, the flow rate, total pressure, efficiency and blade angle of the fan operation are calculated.

3. A fan anti-stall calculation method based on dial parameters according to claim 1, characterized in that: When judging whether the actual measured performance of the fan is consistent with the design performance curve of the fan when it leaves the factory, if not, the design performance curve of the fan when it leaves the factory is corrected until the actual measured performance of the fan is consistent with the corrected design performance curve.

4. A fan anti-stall calculation method based on dial parameters according to claim 1, characterized in that: On the design performance curve of the fan when it leaves the factory, find the total pressure P0 of the stall point corresponding to each angle, leave a set stall margin k, and calculate the safe total pressure P1 at each opening. The calculation formula is: P1=(1-k)×P0.

5. A fan anti-stall calculation method based on dial parameters according to claim 4, characterized in that: The industry standard for stall margin k is a minimum of 1.

35.

6. A fan anti-stall calculation system based on dial parameters, characterized in that: include: The measurement module is used to measure the flow rate, total pressure, efficiency and blade angle of the fan, and record the dial opening and dial pressure difference; The calibration module is used to calibrate the dial pressure difference according to the measurement results to obtain the measured fan total pressure - dial pressure difference; A comparison module is used to mark the actually measured flow rate and total pressure on the design performance curve of the fan when it leaves the factory. The design performance curve of the fan when it leaves the factory has the efficiency and blade angle marked on it, and compare the actually measured efficiency and blade angle with the efficiency and blade angle marked on the design performance curve of the fan when it leaves the factory to obtain a comparison result; The fitting module is used to determine whether the actual measured performance of the fan is consistent with the design performance curve of the fan when it leaves the factory based on the comparison results. When the actual measured performance of the fan is consistent with the corrected design performance curve, the functional relationship between the dial opening and the blade angle marked on the design performance curve of the fan when it leaves the factory is obtained; The calculation module is used to find the total pressure at the stall point corresponding to each angle on the design performance curve of the fan when it leaves the factory, leaving a set stall margin, and calculate the safe total pressure at each opening; The execution module is used to reversely deduce the dial safety pressure difference value at each opening on the dial based on the obtained functional relationship between the measured fan total pressure-disc pressure difference, the dial opening-the blade angle marked on the design performance curve of the fan when it leaves the factory, and the safe total pressure at each opening, as an operation reference. When the measured dial safety pressure difference value is reached during operation, stop increasing the load or reduce the dial pressure difference.

7. A fan anti-stall calculation system based on dial parameters according to claim 6, characterized in that: In the measurement module, the flow rate, total pressure, efficiency and blade angle of the fan are calculated through on-site tests of the fan.

8. A fan anti-stall calculation system based on dial parameters according to claim 6, characterized in that: In the fitting module, it is determined whether the actual measured performance of the fan is consistent with the design performance curve of the fan when it leaves the factory. If not, the design performance curve of the fan when it leaves the factory is corrected until the actual measured performance of the fan is consistent with the corrected design performance curve.

9. A fan anti-stall calculation system based on dial parameters according to claim 6, characterized in that: In the calculation module, the total pressure P0 of the stall point corresponding to each angle is found on the design performance curve of the fan when it leaves the factory, and the set stall margin k is left to calculate the safe total pressure P1 at each opening. The calculation formula is: P1=(1-k)×P0.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of a fan anti-stall calculation method based on dial parameters described in any one of claims 1 to 5 are implemented.

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