A method for dynamically compensating field application performance of a split type voluteless fan

Abstract

The present application relates to the technical field of split type voluteless fan, and discloses a split type voluteless fan field application performance dynamic compensation method; first, the fan factory calibration is completed under the laboratory standard speed, the corresponding relationship curve of the inlet cavity static pressure and the air inlet ring pressure tap static pressure is established, and the unique flow coefficient is calculated; the fan running speed and the two static pressure parameters are collected in real time, the parameter conversion is completed based on the ventilation fan similarity law, the matching state is determined by the deviation between the measured and theoretical static pressures, and the matching state is determined as the matching state when the deviation exceeds 3%. At this time, the micro displacement execution module step adjustment of the motor installation foot is controlled by the edge controller, and the static pressure deviation is restored to within 3% until the matching state is maintained. The method does not need to add a complex displacement sensor, realizes the edge amount dynamic compensation through the pneumatic parameter closed loop control, guarantees the efficient and stable operation of the fan, supports the single and multiple fan cluster control, and is suitable for various split type voluteless ventilation systems.

Description

Technical Field

[0001] This invention relates to the field of volute-less fan technology, specifically a method for dynamic performance compensation in field applications of split-type volute-less fans. Background Technology

[0002] The main shortcomings of existing technologies lie in the systematic mismatch in four dimensions: structural design, operating condition adaptability, condition monitoring and closed-loop control.

[0003] In terms of structural design, the volute-less fan adopts a split layout, that is, the inlet ring mounting plate and the motor base are independent of each other and lack rigid connection. Although a "fitting" can be achieved and a reasonable overlap can be maintained in the static state, in actual operation, sufficient negative pressure generated in the inlet cavity will cause the installed inlet ring mounting plate to deform uncontrollably (even if the mounting plate is reinforced, it will still deform under the action of high negative pressure). Meanwhile, the motor base that fixes the impeller does not deform, which leads to a continuous reduction in the overlap between the inlet ring and the impeller, eventually forming a "fitting" without overlap, which fundamentally destroys the internal leakage mode of the original design of the fan.

[0004] In terms of adaptability to operating conditions, the resistance of pipeline systems at engineering sites varies greatly. Even for the same model of product and the same installation structure, the degree of deterioration of the overlap varies in different projects due to changes in system pipeline conditions. In addition, the impeller and air inlet ring are deeply placed in a closed cavity, making it impossible to visually inspect or easily access displacement sensors. As a result, the actual overlap state during operation is in a "not visible and not measurable" state for a long time.

[0005] At the condition monitoring level, the industry commonly uses the static pressure difference (P1 - P0) measured by the pressure tap at the air inlet ring, combined with the flow coefficient K calibrated in the laboratory, to infer the flow rate. However, when the overlap is lost, the flow field undergoes severe separation, resulting in a lower static pressure difference at the pressure tapping point and distorted static pressure difference signal. In the field, variable frequency drives are often used to increase the speed of the running motor to meet the design static pressure difference, causing the final flow rate calculation result to deviate significantly from the measured value. The product operates in an inefficient range for a long time, resulting in energy waste. At the same time, the increased speed also brings greater centrifugal force and vibration risks, effectively rendering the actual static pressure difference monitoring function ineffective.

[0006] In terms of closed-loop control, current technology completely lacks the ability to perceive changes in edge overlap and has no dynamic compensation mechanism. There is neither an effective deformation feedback signal nor an actuator to adjust the axial / radial position of the air inlet ring. This causes the fan to be in a state of continuous disconnect between "design state" and "actual state" from factory calibration and on-site installation to long-term operation, and there is no technical foundation to ensure efficient and stable operation. Summary of the Invention

[0007] The purpose of this invention is to provide a dynamic performance compensation method for split-type volute-less fans in field applications, so as to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a method for dynamic performance compensation in field applications of a split-type volute-less fan, comprising the following steps: S1. The split-type volute-less fan is pre-calibrated in the laboratory at the standard speed. Static pressure of the inlet cavity under multiple working conditions was tested. 1. Inlet ring pressure tap static pressure and traffic The flow coefficient was calculated. and establish and The corresponding relationship curve; S2. Real-time on-site acquisition of the actual operating speed of the split-type volute-less fan. Measured static pressure of the oral cavity and the measured static pressure of the air inlet ring pressure tap ; S3. Based on the similarity law of ventilation fans, the static pressure of the inlet cavity measured on site... Converted to standard speed Equivalent static pressure under ; S4, Based on equivalent static pressure In the pre-established and The standard rotational speed is obtained from the corresponding curve by interpolation. The equivalent flow rate below Then, based on the similarity law of ventilation fans, the equivalent flow rate is... Converted to actual speed Theoretical flow rate ; S5. Utilizing the flow coefficient at different fan speeds for the same fan By maintaining constant characteristics, the actual rotational speed is calculated. Theoretical static pressure of the lower air inlet ring pressure tap ; S6. Compare the measured static pressure of the air inlet ring pressure tap. Compared with theoretical static pressure If the deviation, If so, it is determined that the air inlet ring and impeller have changed from a sleeve fit to a mating fit; S7. When a proper fit is determined, the edge controller controls the micro-displacement actuator installed on the motor mounting base to move the motor mounting base towards the air inlet ring until the static pressure measured at the air inlet ring pressure tap is reached. Maintain the proper fit between the air inlet ring and the impeller.

[0009] Furthermore, in step S1, the flow coefficient By standard speed The rated operating point parameters are calculated using the following formula: ,in The rated operating point flow rate, The static pressure at the inlet pressure tap of the air inlet ring is the rated operating point. The static pressure of the inlet cavity at the rated operating point.

[0010] Furthermore, in step S3, the equivalent static pressure The calculation formula is: .

[0011] Furthermore, in step S4, the interpolation method uses linear interpolation, when the equivalent static pressure Static pressure of the inlet cavity at two adjacent calibration points and Between, equivalent flow The calculation formula is: ,in and These are the flow rates at standard speed N1 for two adjacent calibration operating points P0.i and P0.(i+1), respectively.

[0012] Furthermore, in step S4, the theoretical flow rate The calculation formula is: .

[0013] Furthermore, in step S7, the micro-displacement execution module adopts a step-by-step adjustment method, and after moving a preset distance towards the air inlet ring side each time, it re-collects data. and And perform deviation judgment until... .

[0014] Furthermore, when At that time, using the flow coefficient Calculate the actual operating flow rate of the fan The calculation formula is: .

[0015] Furthermore, the edge controller communicates with the field PLC or DCS system via the ModbusTCP protocol to upload wind turbine operating parameters and issue compensation control commands.

[0016] Furthermore, in step S2, the operating speed of the fan is... , oral cavity static pressure and the static pressure of the air inlet ring pressure tap The sampling frequency is no less than 1Hz.

[0017] Furthermore, the method can be applied simultaneously to the cluster control of multiple split-type volute-less fans, with each fan configured with an independent micro displacement execution module, and dynamic compensation control performed by the same edge controller or multiple edge controllers in collaboration.

[0018] Compared with the prior art, the beneficial effects of the present invention are: This invention addresses the problem in engineering projects where excessive negative pressure on the inlet side causes deformation of the inlet ring mounting plate, leading to a change in the aerodynamic performance of the inlet ring and impeller from a "sleeve fit" to a "butt fit." This problem is caused by deviations from the design values. The method involves real-time monitoring of the fan speed. 1. Inlet ring pressure tap static pressure and oral cavity static pressure Combined with the factory-calibrated flow coefficient And based on the similarity theory of ventilation fans, construct A relational model is used; and based on this model, the displacement of the motor mounting bracket is controlled in a closed loop to dynamically compensate for the deformation of the mounting plate and maintain [the desired stability]. and The invention ensures that the actual operating conditions of the fan on site are consistent with its factory condition, effectively maintaining its efficient and stable operation, and is suitable for various types of split-type volute-less ventilation systems.

[0019] This application uses the method of quickly locating the operating speed of the ventilation fan on site. 1. Inlet ring pressure tap static pressure , oral cavity static pressure Combined with the operating speed inside the laboratory At that time, the static pressure of the corresponding air inlet ring pressure tap is... , oral cavity static pressure Based on the similarity law of ventilators, and the characteristic that the flow coefficient K of the inlet ring remains constant during the speed change process of a volute-less fan, the pressure tapping nozzle test of the inlet ring at constant speed is determined. Compared with theoretical static pressure Is the size deviation less than 3%? If it is greater than 3%, the fitting form between the impeller and the inlet ring becomes a misaligned form, and the displacement actuator on the motor mounting bracket needs to be adjusted to ensure that the impeller and the inlet ring re-form a fitting form. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the factory test and corresponding parameters of the present invention; Figure 2 This is a schematic diagram of the field operation and corresponding parameters of the present invention; Figure 3 This is a schematic diagram showing that when N2 is converted to N1 in the field test of the present invention, it falls within the 3% deviation from the factory specifications. Figure 4 When converting N2 to N1 in the field test of this invention, it is not within the 3% deviation of the factory standard.

[0021] In the diagram: 1. Inlet ring mounting plate; 2. Inlet ring; 3. Inlet ring pressure tap. Detailed Implementation

[0022] Please see Figure 1 —4. A method for dynamic performance compensation in field applications of a split-type volute-less fan, comprising the following steps: Step S1: Perform factory performance calibration of the split-type volute-less fan in a standard laboratory testing environment. Install the fan on a standard test bench, ensuring that the inlet ring 2 and the impeller are in the designed fit, and ensuring that the overlap meets the factory technical specifications.

[0023] At standard speed Under these conditions, by adjusting the throttling device on the test bench, the fan was operated at at least 7 different operating points. The static pressure P0 of the inlet chamber and the static pressure of the inlet ring pressure tap 3 were tested and recorded for each operating point. and traffic Among them, the static pressure of the oral cavity The static pressure of the air inlet ring pressure tap 3 is measured by a static pressure sensor installed on the wall of the inlet cavity. The flow rate is measured by connecting a pressure sensor to the pressure tap 3 on the fan's built-in air inlet ring. Measured using a standard ventilation chamber or Pitot tube method.

[0024] Based on the multiple sets of operating condition data obtained from the test, establish and The corresponding relationship curve was obtained, and the unique flow coefficient of the fan was calculated. Flow coefficient By standard speed The calculation formula is as follows: ,in The rated operating point flow rate, The static pressure at the inlet pressure tap 3 is the pressure at the rated operating point. The static pressure of the inlet cavity at the rated operating point.

[0025] Simultaneously, calculate the static pressure difference at each set of operating points. Verify the flow coefficient under the sleeve fit condition. The calibration data should remain essentially constant across different operating points, with deviations controlled within ±1%. The corresponding curves are stored in the edge controller's memory and serve as a benchmark for determining field performance.

[0026] Step S2: After the wind turbine is installed and put into operation at the site, the operating parameters of the wind turbine are collected in real time through the edge controller. The collected parameters include: the actual operating speed of the wind turbine. The static pressure of the inlet cavity is obtained by means of a speed sensor or frequency converter output signal mounted on the motor shaft; The static pressure is obtained through a static pressure sensor installed on the inlet cavity body; the static pressure of the inlet ring pressure tap 3 is measured. The pressure is obtained by connecting the pressure sensor of the air inlet ring 3 of the fan.

[0027] To ensure the real-time performance and accuracy of the data, the acquisition frequency of the above parameters is no less than 1Hz. The edge controller filters the acquired raw data to remove noise interference and obtain stable and reliable operating parameter values.

[0028] Step S3: According to the similarity law of ventilation fans, the static pressure of the inlet cavity at the actual measured rotational speed N2 is calculated. Converted to standard speed Equivalent static pressure under This is to allow for comparison with the factory calibration data. Equivalent static pressure The calculation formula is:

[0029] This conversion is based on the similarity theory of fans, which states that pressure is proportional to the square of the rotational speed, and is applicable to parameter conversion of fans under similar operating conditions.

[0030] Step S4: Based on the equivalent static pressure obtained from the conversion In the pre-established and Find its corresponding interval in the curve. When the equivalent static pressure Static pressure of the inlet cavity at two adjacent calibration points and When the time interval is reached, the standard rotational speed is calculated using linear interpolation. The equivalent flow rate below .

[0031] Equivalent flow The calculation formula is:

[0032] in, and These represent the two adjacent calibration operating points P0.i and P0.(i+1) at the standard speed. Traffic volume.

[0033] Then, according to the similarity law of fans, the standard speed is... The equivalent flow rate below Converted to actual speed Theoretical flow rate Theoretical flow The calculation formula is:

[0034] This conversion is based on the similarity theory of ventilation fans, which states that flow rate is directly proportional to rotational speed.

[0035] Step S5: Utilize the flow coefficient at different fan speeds for the same fan The unchanging characteristics, and the flow coefficient under the sleeve fit condition. The definition formula is used to calculate the actual rotational speed. Below, when the oral cavity static pressure is At that time, the theoretical static pressure of the air inlet ring pressure tap 3 .

[0036] Theoretical static pressure The calculation formula is:

[0037] This formula is derived from the definition of the flow coefficient. This is derived from the shape and reflects the inherent relationship between the static pressure of the air inlet ring pressure tap 3 and the flow rate, as well as the static pressure of the inlet cavity body, under the condition of sleeve fit.

[0038] Step S6: Compare the measured static pressure of the inlet ring pressure tap 3 Compared with theoretical static pressure The size of the air inlet ring 2 is used to determine the fit between the air inlet ring 2 and the impeller.

[0039] when This indicates that the deviation between the measured static pressure and the theoretical static pressure is within 3%, the inlet ring 2 and the impeller are still in a fitted state, and the aerodynamic performance of the fan has not deviated significantly. At this time, the flow coefficient is... It can be used directly for calculating on-site flow rates.

[0040] when If the measured static pressure deviates from the theoretical static pressure by more than 3%, the inlet ring mounting plate 1 has been significantly deformed, causing the inlet ring 2 and the impeller to change from a sleeve fit to a butt fit. The aerodynamic performance of the fan has deviated from the design value, and dynamic compensation adjustment is required.

[0041] Step S7: When it is determined that the air inlet ring 2 and the impeller are properly matched, the edge controller sends a control command to the micro displacement execution module installed on the motor mounting base, and controls the micro displacement execution module to move the motor mounting base towards the air inlet ring 2.

[0042] The micro-displacement actuator uses a step-by-step adjustment method. After moving a preset distance to both sides of the air inlet ring each time, the adjustment is paused, and the measured static pressure of the inlet cavity is collected again. Measured static pressure of air inlet ring and pressure tap 3 Then, the deviation determination is performed again according to the methods in steps S3 to S6.

[0043] Repeat the above step adjustment and deviation judgment process until the measured static pressure at the air inlet ring pressure tap 3 is reached. At this point, the air inlet ring 2 and the impeller have returned to the original fitting state, and adjustment is stopped.

[0044] During the subsequent operation of the wind turbine, the edge controller continuously monitors the turbine's operating parameters, and when it detects again... The above dynamic compensation process is repeated to achieve real-time dynamic compensation of the wind turbine performance.

[0045] When the inlet ring 2 and the impeller are in a fitted state, the flow coefficient is used. The actual operating flow rate Q of the fan is calculated using the following formula:

[0046] The edge controller communicates with the PLC or DCS system on site via the Modbus TCP protocol, uploads the wind turbine's operating parameters to the host computer system, and receives control commands from the host computer system to achieve remote monitoring and management.

[0047] When the fan is powered off, the edge controller sends a control command to the miniature displacement actuator mounted on the motor mounting base, causing the miniature displacement actuator to move and restore the motor mounting base to its initial state. This prevents the inlet ring from rubbing against the impeller due to excessive depth of the sleeve caused by reduced pressure.

[0048] This method can be applied to the cluster control of multiple split-type volute-less fans. In scenarios where multiple fans operate in a cluster, each fan is equipped with an independent micro-displacement actuator module, which is dynamically compensated and controlled by the same edge controller or multiple edge controllers in collaboration, thereby optimizing the performance of the entire ventilation system. Example 1

[0049] For a specific design operating point, test data under standard variable overlap conditions in the laboratory were used, including laboratory data at rotational speeds. Test static pressure With air inlet ring pressure tap Relationship curves, and factory standard flow coefficients According to the on-site test speed The measured inlet static pressure is at At that time, the corresponding Whether it falls into If the curve deviation is within 3%, and exceeds the tolerance, the edge controller will control the micro-displacement actuator to move the motor mounting feet towards both sides of the air inlet ring until it is in place on site. Under these circumstances, the tested Falling out of the factory Curve deviation within 3%.

[0050] volute-less fan according to Figure 1 The installation and measurement methods were used to obtain the factory test performance, as shown in Table 1:

[0051] Table 1. Normal overlap (sleeve type) of the volute-less fan at N1 speed (factory data); in: Calculated using formula (1): (1) The K1 coefficient can be calculated using formula (2): (2) K1 remains constant at different fan speeds; K1 remains constant under effective sleeve configurations.

[0052] according to Figure 2 The parameters of the volute-less fan were tested on-site during actual operation. , , ), See Table 2.

[0053] Table 2. Data and judgment of overlap amount under actual operating conditions of the volute-less fan.

[0054] Based on the on-site test data, determine whether it falls within the factory specifications. Within the curve with a deviation of 3%.

[0055] According to the similarity law of ventilation fans: the test will be conducted. Below Parameter conversion hour See the formula; (3) determination If it falls within the area of ​​Table 1, assume Operating conditions falling under Table 1 and Between them, by interpolation, we obtain Value. See formula (4).

[0056] (4) According to the similarity law of ventilation fans, At speed Convert to Flow rate at rotational speed ,based on Invariant property, when in At the specified rotational speed, the static pressure in the static pressure chamber is: At that time, the theoretical static pressure of the air inlet ring pressure tap 3 of the ventilation fan is as follows: See formula (5) for details. (5) determination and size: when , fall Within a 3% deviation of the curve, see Figure 3 If the impeller and the air inlet ring 2 are still in a socket configuration, the K1 value can be directly used for on-site flow rate Q calculation.

[0057] when , fall on In addition to the 3% deviation of the curve, see Figure 4 This indicates that the impeller and the inlet ring 2 are now aligned. The value cannot be used for on-site flow calculation. Instead, the micro displacement actuator should be controlled by the edge controller to move the motor mounting feet toward the two sides of the air inlet ring until the final pressure deviation is within 3%.

Claims

1. A method for dynamic performance compensation in field applications of a split-type volute-less fan, characterized in that, Includes the following steps: S1. The split-type volute-less fan is pre-calibrated in the laboratory at the standard speed. Static pressure of the inlet cavity under multiple working conditions was tested.

1. Inlet ring pressure tap static pressure and traffic The flow coefficient was calculated. and establish and The corresponding relationship curve; S2. Real-time on-site acquisition of the actual operating speed of the split-type volute-less fan. Measured static pressure of the oral cavity and the measured static pressure of the air inlet ring pressure tap ; S3. Based on the similarity law of ventilation fans, the static pressure of the inlet cavity measured on site... Converted to standard speed Equivalent static pressure under ; S4, Based on equivalent static pressure In the pre-established and The standard rotational speed is obtained from the corresponding curve by interpolation. The equivalent flow rate below Then, based on the similarity law of ventilation fans, the equivalent flow rate is... Converted to actual speed Theoretical flow rate ; S5. Utilizing the flow coefficient at different fan speeds for the same fan By maintaining constant characteristics, the actual rotational speed is calculated. Theoretical static pressure of the lower air inlet ring pressure tap ; S6. Compare the measured static pressure of the air inlet ring pressure tap. Compared with theoretical static pressure If the deviation, If so, it is determined that the air inlet ring and impeller have changed from a sleeve fit to a mating fit; S7. When a proper fit is determined, the edge controller controls the micro-displacement actuator installed on the motor mounting base to move the motor mounting base towards the air inlet ring until the static pressure measured at the air inlet ring pressure tap is reached. Maintain the proper fit between the air inlet ring and the impeller.

2. The method for dynamic performance compensation of split-type volute-less fans in field applications according to claim 1, characterized in that, In step S1, the flow coefficient By standard speed The rated operating point parameters are calculated using the following formula: ,in The rated operating point flow rate, The static pressure at the inlet pressure tap of the air inlet ring is the rated operating point. The static pressure of the inlet cavity at the rated operating point.

3. The method for dynamic performance compensation of a split-type volute-less fan in field application according to claim 1, characterized in that, In step S3, the equivalent static pressure The calculation formula is: .

4. The method for dynamic performance compensation of split-type volute-less fans in field applications according to claim 1, characterized in that, In step S4, the interpolation method uses linear interpolation. When the equivalent static pressure P0' falls within the inlet cavity static pressure of two adjacent calibration points... and Between, equivalent flow The calculation formula is: in and These represent the flow rates at standard speed N1 for two adjacent calibration operating points.

5. The method for dynamic performance compensation of a split-type volute-less fan in field application according to claim 1, characterized in that, In step S4, the theoretical flow rate The calculation formula is: .

6. The method for dynamic performance compensation of a split-type volute-less fan in field application according to claim 1, characterized in that, In step S7, the micro-displacement execution module adopts a step-by-step adjustment method, and after moving a preset distance towards the air inlet ring side each time, it re-collects data. and And perform deviation judgment until... .

7. The method for dynamic performance compensation of a split-type volute-less fan in field application according to claim 1, characterized in that, when At that time, using the flow coefficient Calculate the actual operating flow rate of the fan The calculation formula is: .

8. The method for dynamic performance compensation of a split-type volute-less fan in field application according to claim 1, characterized in that, The edge controller communicates with the PLC or DCS system on site via the ModbusTCP protocol to upload wind turbine operating parameters and issue compensation control commands.

9. The method for dynamic performance compensation of a split-type volute-less fan in field application according to claim 1, characterized in that, In step S2, the actual operating speed of the fan is... Measured static pressure of the oral cavity Measured static pressure of air inlet ring and pressure tap The sampling frequency is no less than 1Hz.

10. The method for dynamic performance compensation in field applications of a split-type volute-less fan according to claim 1, characterized in that, The method can be applied to the cluster control of multiple split-type volute-less fans. Each fan is equipped with an independent micro displacement actuator module, and dynamic compensation control is performed by the same edge controller or multiple edge controllers in collaboration.

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