Method and system for determining air volume of fan
By setting up a test board and heating element in the air duct, the fan airflow is determined using the temperature rise and thermal resistance values, which solves the problem of inaccurate wind speed measurement and achieves high accuracy and convenient detection of fan airflow.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHENZHEN POWEROAK NEWENER CO LTD
- Filing Date
- 2026-04-28
- Publication Date
- 2026-05-29
AI Technical Summary
The existing technology for determining fan airflow by measuring wind speed is inaccurate, leading to inaccurate airflow determination.
By setting up a test board and heating element in the air duct, the air volume of the fan is determined by the temperature rise value, the heating power value and thermal resistance value of the heating element, thus avoiding the dependence on high-precision wind tunnels and anemometers, and using the temperature rise value to determine the air volume of the fan.
It improves the accuracy of fan airflow determination, avoids inaccurate airflow caused by unreasonable wind tunnel settings and anemometer positions, and enhances the accuracy and convenience of airflow detection.
Smart Images
Figure CN122108288A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of airflow detection technology, and in particular to a method and system for determining the airflow of a fan. Background Technology
[0002] As the core component of a cooling system, the fan's airflow determines the cooling efficiency, making it a key indicator for evaluating fan cooling performance, optimizing cooling design, and verifying product cooling reliability.
[0003] When a fan is running, its rotation causes air to flow, thus generating wind. In related technologies, wind speed is often measured using an anemometer, and the fan's airflow is determined based on the measured wind speed.
[0004] However, the method of determining the air volume of a fan by measuring wind speed in related technologies has the problem of inaccurate determination of the air volume of the fan. Summary of the Invention
[0005] Based on this, this application provides a method and system for determining the air volume of a fan, which can improve the accuracy of the determined fan air volume.
[0006] In a first aspect, this application provides a method for determining the airflow of a fan, wherein the fan is disposed at one end of an air duct to drive airflow within the air duct, a test board is disposed in the air duct, and a heating element is disposed on the test board; the method includes:
[0007] Obtain the first temperature detection value of the test board when the heating element is not heating up, and obtain the second temperature detection value of the test board when the fan is running and the heating element is heating up;
[0008] Based on the first and second temperature detection values, determine the temperature rise of the test board caused by the fan running and the heating element heating up;
[0009] The airflow value of the fan is determined based on the temperature rise of the test board, the heating power of the heating element, the thermal resistance of the heating element, and the area ratio between the area of the test board and the air outlet area of the fan.
[0010] In some embodiments, the temperature rise value of the test board includes multiple target temperature rise values, and the heating power value of the heating element includes multiple target heating power values; the multiple target temperature rise values and the multiple target heating power values correspond one-to-one.
[0011] The fan airflow value is determined based on the temperature rise of the test board, the heating power of the heating element, the thermal resistance of the heating element, and the area ratio between the test board area and the fan outlet area. This includes:
[0012] Based on the target temperature rise value and the target heating power value, as well as the thermal resistance value and area ratio value of the heating element, the undetermined air volume value is determined respectively;
[0013] Based on the various undetermined airflow values, determine the fan's airflow value.
[0014] In some embodiments, the airflow value of the fan is determined based on the temperature rise of the test board, the heating power of the heating element, the thermal resistance of the heating element, and the area ratio between the area of the test board and the air outlet area of the fan, including:
[0015] Obtain the airflow expression among the area ratio, thermal resistance of the heating element, fan airflow variable, temperature rise of the test board caused by fan operation and heating of the heating element, and heating power variable of the heating element;
[0016] The fan's airflow value is determined based on the airflow expression, the temperature rise of the test board, and the heating power of the heating element.
[0017] In some embodiments, obtaining the airflow expression among the area ratio, the thermal resistance of the heating element, the airflow variable of the fan, the temperature rise of the test board caused by the fan running and the heating element generating heat, and the heating power variable of the heating element includes:
[0018] Based on the definition of specific heat capacity of air, a first expression is established between the variables of heat dissipation, area ratio, fan airflow, and temperature rise of the test board caused by fan operation.
[0019] Based on the heat balance law of the test board, a second expression is established between the temperature rise variable, the heating power variable of the heating element, the heat dissipation variable, and the thermal resistance value of the heating element;
[0020] Substituting the first expression into the second expression, we obtain the air volume expression.
[0021] In some embodiments, based on the definition of air specific heat capacity, a first expression is established relating the heat dissipation variable, area ratio, fan airflow variable, and temperature rise variable caused by fan operation on the test board, including:
[0022] Based on the definition of air specific heat capacity, a third expression is established between the heat dissipation variable, the fan airflow variable, and the temperature rise variable;
[0023] Based on the third expression and the area ratio, the first expression is determined.
[0024] In some embodiments, the first expression is: ;
[0025] in, This indicates the variable in heat dissipation from the test board caused by fan operation; Indicates the area of the test board; Indicates the air outlet area of the fan; Indicates air density; This indicates the specific heat capacity of air; This represents the airflow variable of the fan; This represents the temperature rise of the test board caused by the operation of the fan and heating elements.
[0026] In some embodiments, the second expression is: ;
[0027] in, This represents the temperature rise of the test board caused by the operation of the fan and heating elements. This represents the variable of heating power of the heating element; This indicates the variable in heat dissipation from the test board caused by fan operation; This indicates the thermal resistance value of the heating element.
[0028] In some embodiments, the air volume expression is: ;
[0029] in, This represents the airflow variable of the fan; Indicates the air outlet area of the fan; Indicates the area of the test board; Indicates air density; This indicates the specific heat capacity of air; This represents the variable of heating power of the heating element. , This indicates the voltage supplied to the heating element. Indicates the resistance value of the heating element; This represents the temperature rise of the test board caused by the operation of the fan and heating elements. This indicates the thermal resistance value of the heating element.
[0030] In a second aspect, this application provides a fan airflow determination system, which includes a fan, an air duct, a test board, and a controller. The fan is disposed at one end of the air duct and is used to drive air to flow within the air duct. The cross-sectional area of the air duct is matched with the air outlet area of the fan. The test board is disposed in the air duct and has a heating element. The heating element is connected to the controller, which is used to execute the method of any one of the first aspects.
[0031] In some embodiments, the test board is further provided with a thermistor and a fixed resistor. The voltage at the first end of the thermistor is a preset operating voltage. The second end of the thermistor is connected to the first end of the fixed resistor. The second end of the thermistor is also connected to the controller. The second end of the fixed resistor is grounded.
[0032] In the technical solution provided in this application embodiment, since this application embodiment does not measure wind speed, which would require high airflow quality, the fan speed is determined by the cooling capacity of the fan reflected by the temperature rise value of the test board, the heating power value of the heating element, and the thermal resistance value of the heating element. Since the cooling capacity of the fan has low requirements for airflow quality, the fan can be placed in the air duct. The air duct's requirements for airflow quality are lower than those of a wind tunnel, thus eliminating the need for a high-precision wind tunnel to determine the fan's airflow. This avoids unreasonable wind tunnel setup and ensures accurate fan airflow measurement. The method of determining the fan airflow improves the accuracy of fan airflow determination. Furthermore, this embodiment determines the fan airflow based on the temperature rise of the test board, the heating power of the heating element, the thermal resistance of the heating element, and the area ratio between the test board area and the fan's outlet area. It does not determine the fan airflow based on the wind speed measured by an anemometer, but rather through the temperature rise of the test board. This avoids the problem of inaccurate wind speed measurements due to improper relative positions of the anemometer and the fan, thus further improving the accuracy of fan airflow determination. Attached Figure Description
[0033] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0034] Figure 1 A schematic diagram of the system structure for determining the fan's airflow;
[0035] Figure 2 A flowchart illustrating a method for determining the airflow of a fan as provided in some embodiments;
[0036] Figure 3 A schematic diagram showing the connection between the test board and the controller provided in the first embodiment;
[0037] Figure 4 A schematic diagram showing the connection between the test board and the controller provided in the second embodiment;
[0038] Figure 5 A schematic diagram of the airflow determination device for a fan provided in some embodiments;
[0039] Figure 6 A schematic diagram of the controller provided for some embodiments. Detailed Implementation
[0040] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.
[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.
[0042] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined. In the description of the embodiments of this application, "each" means each of the multiple options, unless otherwise explicitly defined.
[0043] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0044] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.
[0045] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0046] In some cases, determining a fan's wind speed requires placing the fan in a high-precision wind tunnel and installing an anemometer within it. The airflow is then determined by measuring the wind speed. However, the accuracy of the fan's airflow depends heavily on the accuracy of the wind tunnel, which has higher requirements for airflow quality than a typical duct. Therefore, an improperly configured wind tunnel can lead to inaccurate determinations of the fan's airflow. Furthermore, an improper relative position between the anemometer and the fan can cause deviations in the detected wind speed, further contributing to inaccurate determinations of the fan's airflow.
[0047] The quality of airflow is determined based on at least one of the following: the consistency of wind speed at each point on the cross section, the proportion of irregular pulsating components in the airflow, and the stability of wind speed, flow direction, and temperature over a long period of time.
[0048] Based on this, this application proposes a new method for determining the airflow of a fan. The fan is installed in an air duct, and the airflow quality requirements of the air duct are lower than those of a wind tunnel. Therefore, the airflow of the fan can be determined without relying on a high-precision wind tunnel, thus avoiding the impact of an unreasonable wind tunnel setting on the accuracy of the fan airflow determination and improving the accuracy of the fan airflow determination. Furthermore, this application does not determine the fan airflow by measuring the wind speed with an anemometer, but by determining the fan airflow by measuring the temperature rise value of the test board. This avoids the problem of the wind speed being deviated due to an unreasonable relative position between the anemometer and the fan, which would further lead to an inaccurate determination of the fan airflow, and further improves the accuracy of the fan airflow determination.
[0049] Figure 1 A schematic diagram of the system structure is used to determine the airflow of the fan, such as... Figure 1 As shown, the fan airflow determination system includes a fan, air duct, test board, and controller.
[0050] The air duct can be funnel-shaped, with the funnel opening and throat opening at both ends. The fan is installed at the funnel opening end of the air duct, and when the fan is running, it can drive the air to flow in the air duct.
[0051] The test board is disposed in the air duct and at the target cross-section of the air duct, the area of which is the same as the air outlet area of the fan. Exemplarily, one side of the test board's mounting element can be perpendicular to the airflow direction, or parallel to the airflow direction, or at an acute angle to the airflow direction; this embodiment does not impose any limitations on these aspects.
[0052] The fan's exhaust area represents its effective sweeping area, which is the area swept by the fan blades when they rotate. The fan's exhaust area is a ring-shaped region, and it is the difference between the circular area enclosed by the outer edges of the blades and the circular area occupied by the central hub when the fan rotates.
[0053] The test board is equipped with a heating element and is connected to a controller, which can acquire the temperature of the test board. In some embodiments, the heating element can be a voltage-driven heating device, connected to the controller, which drives the heating element to generate heat. In other embodiments, the heating element can be a self-heating device (e.g., a heating pack or phase change heating material), which can generate heat independently without the controller's drive. The heating power value of the heating element is determined by the mapping relationship between its heating time data and heating power data, and by the heating duration. In some embodiments, the test board can be equipped with a temperature sensor connected to the controller, allowing the controller to acquire the temperature value of the test board. In other embodiments, the test board can be equipped with a thermistor (e.g., a thermistor or platinum resistance thermometer), connected to the controller. The controller determines the resistance of the thermistor by acquiring the voltage across the thermistor and the current through the thermistor, determines the temperature of the thermistor based on its resistance, and then determines the temperature value of the test board based on the temperature value of the thermistor.
[0054] In this embodiment of the application, the ratio between the area of the test plate and the area of the target cross-section of the air duct where the test plate is located is less than or equal to the target ratio, so that the obstruction effect (wind resistance) of the test plate on the airflow has a negligible impact on the airflow of the fan.
[0055] In this embodiment of the application, the method for determining the airflow of a fan is described using an example of a fan installed at one end of an air duct to drive airflow within the air duct, a test board installed in the air duct, a heating element installed on the test board, and the test board connected to a controller so that the controller can obtain the temperature value of the test board.
[0056] Figure 2 A flowchart illustrating a method for determining fan airflow in some embodiments, such as... Figure 2 As shown, this method is applied to a controller and includes the following steps:
[0057] S201. Obtain the first temperature detection value of the test board when the heating element is not heating up, and obtain the second temperature detection value of the test board when the fan is running and the heating element is heating up.
[0058] For example, a controller may include an integration of any one or more of the following: a general-purpose processor, an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field-programmable gate array (FPGA), a central processing unit (CPU), a graphics processing unit (GPU), an embedded neural network processing unit (NPU), a controller, a microcontroller, a microprocessor, a programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, a quantum computing-based data processing logic unit, an artificial intelligence (AI) processor, etc. For example, a general-purpose processor may be a microprocessor or any conventional processor, etc.
[0059] For example, the controller can be located in a computer device. The computer device may include an industrial control computer, a computer, a host computer, or a control device, etc., and the embodiments of this application do not limit this.
[0060] In this embodiment, the heating element may include a heating resistor or a heating wire, etc. In other embodiments of this application, the heating element may be other heating devices, such as a heating chip, etc., and this application does not limit this.
[0061] In some embodiments, the first temperature detection value of the test board when the heating element is not heating can be the temperature detection value of the test board when the fan is running and the heating element is not heating. For example, when the fan is running and the heating element is not heating, the temperature detection value of the test board is detected multiple times, and the average of these multiple temperature detection values is determined as the first temperature detection value.
[0062] In other embodiments, the first temperature detection value of the test board when the heating element is not heating can be the temperature detection value of the test board when the fan is stopped and the heating element is not heating. For example, when the fan is stopped and the heating element is not heating, the temperature detection value of the test board is measured multiple times, and the average of these multiple temperature detection values is determined as the first temperature detection value.
[0063] In some other embodiments, the first temperature detection value of the test board when the heating element is not heating can be obtained by acquiring at least one temperature detection value of the test board when the fan is running and the heating element is not heating, acquiring at least one temperature detection value of the test board when the fan is stopped and the heating element is not heating, and determining the average value of these temperature detection values as the first temperature detection value of the test board when the heating element is not heating.
[0064] In some embodiments, multiple temperature detection values of the test board can be obtained when the fan is running and the heating element is heating up, and the average value of the multiple temperature detection values is determined as a second temperature detection value.
[0065] Unless otherwise specified, the operation of the fan in this embodiment means that the fan is running at a preset power or a preset speed, and the determined air volume value of the fan is the air volume value when the fan is running at a preset power or a preset speed.
[0066] S202. Based on the first temperature detection value and the second temperature detection value, determine the temperature rise value of the test board caused by the fan running and the heating element heating.
[0067] In some embodiments, the difference between the second temperature detection value and the first temperature detection value is determined as the temperature rise value of the test board. In other embodiments, to avoid the influence of temperature detection errors on the temperature detection value, or considering that the fan airflow value determined in the embodiments of this application is the fan's calibrated airflow value, and the calibrated airflow value is generally smaller than the actual airflow value, so as to ensure that the minimum heat dissipation requirements can still be met under conditions such as batch differences, aging, and temperature changes, the difference between the second temperature detection value and the first temperature detection value can be determined first, and then the sum of the difference and a preset temperature value greater than 0 can be determined as the temperature rise value of the test board.
[0068] S203. Determine the fan's airflow value based on the temperature rise of the test board, the heating power of the heating element, the thermal resistance of the heating element, and the area ratio between the area of the test board and the air outlet area of the fan.
[0069] In some embodiments, the heating element may include a heating resistor, and the heating power value of the heating resistor is determined based on a preset current or a preset voltage applied to the heating resistor. For example, a preset current is applied to the heating resistor. The resistance of the heating resistor is The heating power value of the heating resistor = For example, applying a preset voltage to the heating resistor. The resistance of the heating resistor is The heating power value of the heating resistor .
[0070] In this embodiment of the application, the thermal resistance value of the heating element represents the thermal resistance from the highest temperature point inside the heating element to the environment. In other embodiments of this application, the thermal resistance value of the heating element represents the thermal resistance from the highest temperature point inside the heating element to the outer casing of the heating element, expressed as... In other embodiments of this application, the thermal resistance value of the heating element represents the thermal resistance from the highest temperature point inside the heating element to the circuit board, expressed as... This indicates that the thermal resistance value of the heating element can be obtained from the attribute parameters of the heating element.
[0071] In this embodiment of the application, the area of the test board is a fixed value, the air outlet area of the fan is a fixed value, and thus the area ratio between the area of the test board and the air outlet area of the fan is also a fixed value.
[0072] In the technical solution provided in this application embodiment, since this application embodiment does not measure wind speed, which would require high airflow quality, the fan speed is determined by the cooling capacity of the fan reflected by the temperature rise value of the test board, the heating power value of the heating element, and the thermal resistance value of the heating element. Since the cooling capacity of the fan has low requirements for airflow quality, the fan can be placed in the air duct. The air duct's requirements for airflow quality are lower than those of a wind tunnel, thus eliminating the need for a high-precision wind tunnel to determine the fan's airflow. This avoids the impact of an improperly designed wind tunnel on the accuracy of the fan's airflow. This improves the accuracy of determining the fan's airflow. Furthermore, in this embodiment, the fan's airflow is determined based on the temperature rise of the test board, the heating power of the heating element, the thermal resistance of the heating element, and the area ratio between the test board's area and the fan's outlet area. Instead of determining the fan's airflow through an anemometer, the temperature rise of the test board determines the airflow. This avoids deviations in the detected airflow caused by improper relative positions of the anemometer and the fan, which could lead to inaccurate airflow determination and further improves the accuracy of fan airflow determination.
[0073] Figure 3 This is a schematic diagram of the connection between the test board and the controller provided in the first embodiment, as shown below. Figure 3 As shown, the test board is equipped with a heating resistor, and the resistance of the heating resistor is [value missing]. The first terminal of the heating resistor is connected to the controller, and the second terminal of the heating resistor is grounded. The controller can apply a preset voltage to the heating resistor. .
[0074] The test board is also equipped with a thermistor (shown as NTC) and a fixed resistor (shown as R0). The first end of the thermistor is connected to the controller, which applies a preset operating voltage to the thermistor. The second end of the thermistor is connected to the controller as a voltage detection terminal, so that the controller can determine the temperature value of the thermistor based on the voltage at the voltage detection terminal. The second end of the thermistor is also connected to the first end of the fixed resistor, and the second end of the fixed resistor is grounded.
[0075] In this embodiment, the temperature detection value of the test board can be determined in the following ways: the current value of the thermistor is determined based on the detection voltage value at the second end of the thermistor and the resistance value of the fixed resistor; the resistance value of the thermistor is determined based on the current value of the thermistor, the preset operating voltage, and the detection voltage value at the second end of the thermistor; and the temperature detection value of the test board is determined based on the resistance value of the thermistor.
[0076] For example, the temperature value of the thermistor can be determined based on its resistance value; the temperature value of the test board can then be determined based on the thermistor's temperature value. In some embodiments, the temperature value of the thermistor can be used as the temperature value of the test board. In other embodiments, a correction factor between the temperature value of the test board and the temperature value of the thermistor can be obtained, and the temperature value of the thermistor can be corrected based on this correction factor to obtain the temperature value of the test board.
[0077] For example, obtaining the first temperature detection value of the test board when the heating element is not heating includes: determining the first current value of the thermistor based on the first detection voltage value of the second terminal of the thermistor and the resistance value of the fixed resistor when the heating element is not heating; determining the first resistance value of the thermistor based on the first current value of the thermistor, the preset operating voltage and the first detection voltage value of the second terminal of the thermistor; and determining the first temperature detection value based on the first resistance value of the thermistor.
[0078] For example, obtaining the second temperature detection value of the test board when the fan is running and the heating element is heating includes: determining the second current value of the thermistor based on the second detection voltage value of the second terminal of the thermistor and the resistance value of the fixed resistor when the fan is running and the heating element is heating; determining the second resistance value of the thermistor based on the second current value of the thermistor, the preset operating voltage and the second detection voltage value of the second terminal of the thermistor; and determining the second temperature detection value based on the second resistance value of the thermistor.
[0079] It should be noted that, Figure 3 The embodiment shown depicts a test board with one set of thermistors and fixed resistors. In other embodiments, the test board may also have multiple sets of resistors, each set including a thermistor and a fixed resistor, with the connection relationship between the thermistor and fixed resistor in each set being as follows: Figure 3Similar to the embodiment, the average value of the temperature values of the multiple thermistors, which can be obtained one-to-one with the multiple sets of resistors, is determined as the temperature value of the test board.
[0080] It should be noted that the fan airflow determination system provided in the foregoing embodiments includes a single test board. In other embodiments, multiple test boards can be set in the air duct, and an initial airflow value for a fan can be determined using each test board. Then, the fan's actual airflow value can be determined based on the multiple initial airflow values. For example, the average or minimum value of the multiple initial airflow values can be determined as the fan's actual airflow value.
[0081] For example, in the fan airflow determination system, a test board can be set up. The first temperature value of the test board when the heating element is not heating is acquired once every preset time interval, resulting in multiple first temperature values. The second temperature value of the test board when the fan is running and the heating element is heating is acquired once every preset time interval, resulting in multiple second temperature values. The multiple second temperature values correspond one-to-one with the multiple first temperature values. The difference between each second temperature value and each first temperature value is obtained, and the average value of these differences is determined as the temperature rise value of the test board.
[0082] For example, in the fan airflow determination system, multiple test boards can be set up. For each test board, a temperature rise value can be obtained, thereby obtaining multiple temperature rise values corresponding to the multiple test boards one by one. The average value of the multiple temperature rise values is determined as the temperature rise value of the test board.
[0083] In some embodiments, the temperature rise value of the test board includes multiple target temperature rise values, and the heating power value of the heating element includes multiple target heating power values; the multiple target temperature rise values and the multiple target heating power values correspond one-to-one; the airflow value of the fan is determined based on the temperature rise value of the test board, the heating power value of the heating element, the thermal resistance value of the heating element, and the area ratio between the area of the test board and the air outlet area of the fan, including: determining each undetermined airflow value based on each target temperature rise value and each target heating power value, and based on the thermal resistance value and the area ratio of the heating element; and determining the airflow value of the fan based on each undetermined airflow value.
[0084] In the technical solution provided by this application embodiment, considering that if only a single target heating power value and its corresponding single target temperature rise value are used for calculation, the determined air volume value is prone to deviate from the true value due to the random fluctuations in a single measurement, this application embodiment obtains multiple different target heating power values and their corresponding target temperature rise values, calculates multiple independent undetermined air volume values, and then uses multiple undetermined air volume values to comprehensively determine the final fan air volume value. This can effectively offset the random errors introduced by instantaneous power fluctuations, slight changes in test contact state, or environmental airflow disturbances in a single measurement. In addition, this application embodiment does not require repeated acquisition of thermal resistance value and area ratio value, and only needs one calibration to be used for independent calculation of multiple sets of data. Therefore, the final determined fan air volume value reflects the overall air delivery capacity of the fan under various heating conditions, improves the accuracy and repeatability of air volume detection, and avoids the increase in system complexity and test cost caused by adding additional flow test equipment.
[0085] In some embodiments, determining the fan airflow value based on the temperature rise of the test board, the heating power of the heating element, the thermal resistance of the heating element, and the area ratio between the area of the test board and the air outlet area of the fan includes: determining a first product by multiplying the area ratio between the area of the test board and the air outlet area of the fan, the air density, and the specific heat capacity of air; determining a first ratio by dividing 1 by the first product; determining a second ratio by dividing the heating power of the heating element by the temperature rise of the test board; determining a third ratio by dividing 1 by the thermal resistance of the heating element; determining a target difference between the second ratio and the third ratio; and determining the fan airflow value by multiplying the first ratio and the target difference.
[0086] In some embodiments, the airflow value of the fan is determined based on the temperature rise of the test board, the heating power value of the heating element, the thermal resistance value of the heating element, and the area ratio between the area of the test board and the air outlet area of the fan. This includes: obtaining an airflow expression relating the area ratio, the thermal resistance value of the heating element, the airflow variable of the fan, the temperature rise variable of the test board caused by the fan running and the heating element heating, and the heating power variable of the heating element; and determining the airflow value of the fan based on the airflow expression, the temperature rise of the test board, and the heating power value of the heating element.
[0087] In some embodiments, the airflow expression may be pre-stored in the controller. In some embodiments, the airflow expression may be obtained from the cloud.
[0088] In the technical solution provided in this application embodiment, an airflow expression is obtained among the area ratio, thermal resistance value, fan airflow variable, test board temperature rise variable, and heating element heating power variable. Then, based on this airflow expression, the test board temperature rise value, and the heating element heating power value, the fan airflow value is determined. This allows the airflow distribution difference caused by the mismatch between the test board and fan air outlet area, as well as the influence of the heating element thermal resistance value on temperature rise transfer, to be included in the same expression for unified analysis. This avoids the cumulative error introduced when separately correcting for area mismatch and thermal resistance effect. Furthermore, once the airflow expression is established, the airflow value can be directly calculated by simply substituting the test board temperature rise value and the heating element heating power value, without repeated iterations or reliance on additional flow calibration equipment, thereby improving the convenience of determining the fan airflow value.
[0089] In some embodiments, obtaining the airflow expression among the area ratio, the thermal resistance of the heating element, the fan airflow variable, the temperature rise of the test board caused by the fan running and the heating element, and the heating power variable of the heating element includes: establishing a first expression among the heat dissipation variable of the test board caused by the fan running, the area ratio, the fan airflow variable, and the temperature rise variable based on the definition of air specific heat capacity; establishing a second expression among the temperature rise variable, the heating power variable of the heating element, the heat dissipation variable, and the thermal resistance of the heating element based on the heat balance law of the test board; and substituting the first expression into the second expression to obtain the airflow expression.
[0090] The specific heat capacity of air is defined as the amount of heat absorbed or released by a unit mass of air when its temperature rises or falls by 1 Kelvin (or 1 degree Celsius).
[0091] The heat balance law of the test board means that the heat generation power of the heating element is equal to the sum of the heat dissipation of the test board caused by the fan operation and the net heat generation power of the test board through the thermal resistance path.
[0092] In the technical solution provided in this application embodiment, a first expression is established based on the definition of air specific heat capacity, and a second expression is established based on the heat balance law of the test board. Then, the second expression is substituted into the first expression to obtain the air volume expression. This eliminates the heat dissipation variable that cannot be directly measured from the expression, so that the final air volume expression only includes the area ratio, the thermal resistance value of the heating element, the air volume variable of the fan, the temperature rise variable, and the heating power variable of the heating element. The temperature rise variable and the heating power variable can be obtained through actual measurement, and the area ratio and thermal resistance value can be obtained through pre-calibration. This realizes a direct functional mapping between the air volume variable and the measurable physical quantity, avoiding the additional sensors and testing procedures required to measure the heat dissipation variable separately, and improving the convenience of determining the fan air volume value.
[0093] In some embodiments, based on the definition of air specific heat capacity, a first expression is established between the heat dissipation variable, area ratio, fan airflow variable, and temperature rise variable caused by fan operation of the test board, including: establishing a third expression between the heat dissipation variable, fan airflow variable, and temperature rise variable based on the definition of air specific heat capacity; and determining the first expression based on the third expression and the area ratio.
[0094] The third expression can be ;in, The heat carried away by the airflow driven by the fan; Indicates air density; This indicates the specific heat capacity of air; This represents the airflow variable of the fan; This represents the temperature rise of the test board caused by the operation of the fan and heating elements.
[0095] The area ratio can be ;in, Indicates the area of the test board; This indicates the air outlet area of the fan.
[0096] For example, the third expression and the area ratio can be combined to obtain the first expression. ;in, This indicates the variable in heat dissipation from the test board caused by fan operation.
[0097] In the technical solution provided in this application embodiment, considering that the fan airflow does not completely cover the surface of the test board, if a third expression is directly established based on the definition of air specific heat capacity to establish the relationship between the heat dissipation variable, the fan airflow variable, and the temperature rise variable, this third expression implicitly assumes the ideal of full airflow coverage. However, in reality, the area of the test board and the air outlet area of the fan are often not equal, which leads to an overestimation of the actual heat dissipation when the third expression is directly used. This application embodiment, by establishing the third expression and then further determining the first expression based on the ratio of the third expression and the area, can accurately determine the ratio between the effective heat exchange area and the airflow coverage area. The area ratio is introduced into the expression, making the heat dissipation variable in the first expression equal to the area ratio multiplied by the fan airflow variable, air density, air specific heat capacity, and temperature rise variable. This corrects the calculation deviation caused by the airflow not completely covering the test board, avoiding hardware modifications required to redesign the test board size or change the fan outlet shape due to area mismatch. The physical relationship between heat dissipation, airflow, and temperature rise can be accurately expressed within the original thermal balance framework using only the area ratio correction parameter, improving the flexibility of the solution to adapt to test boards of different sizes and fans of different specifications.
[0098] In some embodiments, the first expression is: ;
[0099] in, This indicates the variable in heat dissipation from the test board caused by fan operation; Indicates the area of the test board; Indicates the air outlet area of the fan; Indicates air density; This indicates the specific heat capacity of air; This represents the airflow variable of the fan; This represents the temperature rise of the test board caused by the operation of the fan and heating elements.
[0100] In some embodiments, the second expression is: ;
[0101] in, This represents the temperature rise of the test board caused by the operation of the fan and heating elements. This represents the variable of heating power of the heating element; This indicates the variable in heat dissipation from the test board caused by fan operation; This indicates the thermal resistance value of the heating element.
[0102] In some embodiments, the air volume expression includes variable terms and constant terms; the variable terms are determined by the area ratio, temperature rise variable, and heating power variable of the heating element; the constant terms are determined by the area ratio and thermal resistance value.
[0103] In some embodiments, the air volume expression is: ;
[0104] in, This represents the airflow variable of the fan; Indicates the air outlet area of the fan; Indicates the area of the test board; Indicates air density; This indicates the specific heat capacity of air; This represents the variable of heating power of the heating element. , This indicates the voltage supplied to the heating element. Indicates the resistance value of the heating element; This represents the temperature rise of the test board caused by the operation of the fan and heating elements. This indicates the thermal resistance value of the heating element.
[0105] The following derivation follows the process of deriving the air volume expression based on the first and second expressions:
[0106] Substituting the first expression into the second expression, we get Expanding the formula on the right side of the equals sign, we get... Rearranging terms yields Then divide both sides of the equation by... ,get Divide both sides of the equation by The air volume expression is obtained. .
[0107] This application also provides a fan airflow determination system, which includes a fan, an air duct, a test board, and a controller. The fan is disposed at one end of the air duct and is used to drive airflow within the air duct. The cross-sectional area of the air duct matches the air outlet area of the fan. The test board is disposed in the air duct and has a heating element. The heating element is connected to the controller, which is used to execute the method in any embodiment of this application. Exemplarily, the structure of the fan airflow determination system can be... Figure 1 The structure shown.
[0108] In some embodiments, the test board is further provided with a thermistor and a fixed resistor. The voltage at the first end of the thermistor is a preset operating voltage. The second end of the thermistor is connected to the first end of the fixed resistor. The second end of the thermistor is also connected to the controller. The second end of the fixed resistor is grounded.
[0109] Figure 4 A schematic diagram of the connection between the test board and the controller provided in the second embodiment is shown below. Figure 4 As shown, the test board is equipped with a thermistor (shown as NTC) and a fixed resistor (shown as R0). The voltage at the first end of the thermistor is the preset operating voltage. The second end of the thermistor is connected to the first end of the fixed resistor. The second end of the thermistor is also connected to the controller. The second end of the fixed resistor is grounded.
[0110] The first end of the thermistor is connected to the controller, which applies a preset operating voltage to the thermistor. The second end of the thermistor is connected to the controller as a voltage detection terminal, so that the controller can determine the temperature value of the thermistor based on the voltage at the voltage detection terminal.
[0111] In some embodiments, the test board is further provided with a heating resistor, the resistance of which is [value missing]. The first terminal of the heating resistor is connected to the controller, and the second terminal of the heating resistor is grounded. The controller can apply a preset voltage to the heating resistor. The test board also includes a heating resistor structure, which can be referenced. Figure 3 The description of the embodiments will not be repeated here.
[0112] Figure 5 A schematic diagram of a fan airflow determination device provided in some embodiments, the fan airflow determination device including:
[0113] The acquisition module is used to acquire the first temperature detection value of the test board when the heating element is not heating, and to acquire the second temperature detection value of the test board when the fan is running and the heating element is heating.
[0114] The temperature rise determination module is used to determine the temperature rise of the test board caused by the operation of the fan and the heating element based on the first temperature detection value and the second temperature detection value.
[0115] The airflow determination module is used to determine the airflow value of the fan based on the temperature rise value of the test board, the heating power value of the heating element, the thermal resistance value of the heating element, and the area ratio between the area of the test board and the air outlet area of the fan.
[0116] Figure 6 A schematic diagram of the controller provided for some embodiments, such as Figure 6 As shown, the controller includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of the method of any embodiment of this application.
[0117] This application also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the method of any embodiment of this application.
[0118] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the method of any embodiment of this application.
[0119] The memory or computer-readable storage medium in any embodiment of this application may include at least one of non-volatile memory and volatile memory. Non-volatile memory includes integration of one or more of the following: Read Only Memory (ROM), Programmable Read-Only Memory (PROM), Erasable Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Ferromagnetic Random Access Memory (FRAM), Flash Memory, Magnetic Surface Memory, Optical Disc, Compact Disc Read-Only Memory (CD-ROM), Magnetic Tape, Floppy Disk, Flash Memory, Optical Memory, High-Density Embedded Non-Volatile Memory, Resistive Random Access Memory (ReRAM), Magnetoresistive Random Access Memory (MRAM), Ferroelectric Random Access Memory (FRAM), Phase Change Memory (PCM), Graphene Memory, Volatile Memory, etc. Volatile memory includes one or more of the following: Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).
[0120] The acquisition, transmission, storage, use, and processing of data in this application comply with relevant national laws and regulations. It should be noted that certain software, components, models, and other existing industry solutions may be mentioned in the embodiments of this application. These should be considered exemplary, intended only to illustrate the feasibility of implementing the technical solution of this application, and do not imply that the applicant has already used or necessarily used such solutions.
[0121] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this application. The above embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this application. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.
Claims
1. A method for determining the airflow of a fan, characterized in that, The fan is located at one end of the air duct and is used to drive air to flow within the air duct. A test board is provided in the air duct, and a heating element is provided on the test board. The method includes: Obtain a first temperature detection value of the test board when the heating element is not heating, and obtain a second temperature detection value of the test board when the fan is running and the heating element is heating; Based on the first temperature detection value and the second temperature detection value, determine the temperature rise of the test board caused by the operation of the fan and the heating element. The airflow value of the fan is determined based on the temperature rise value of the test board, the heating power value of the heating element, the thermal resistance value of the heating element, and the area ratio between the area of the test board and the air outlet area of the fan.
2. The method according to claim 1, characterized in that, The temperature rise value of the test board includes multiple target temperature rise values, and the heating power value of the heating element includes multiple target heating power values; the multiple target temperature rise values and the multiple target heating power values correspond one-to-one. The step of determining the airflow value of the fan based on the temperature rise value of the test board, the heating power value of the heating element, the thermal resistance value of the heating element, and the area ratio between the area of the test board and the air outlet area of the fan includes: Each undetermined airflow value is determined based on the target temperature rise value, the target heating power value, the thermal resistance value of the heating element, and the area ratio value. Based on the aforementioned undetermined airflow values, the airflow value of the fan is determined.
3. The method according to claim 1 or 2, characterized in that, The step of determining the airflow value of the fan based on the temperature rise value of the test board, the heating power value of the heating element, the thermal resistance value of the heating element, and the area ratio between the area of the test board and the air outlet area of the fan includes: Obtain an expression for the airflow among the area ratio, the thermal resistance of the heating element, the airflow variable of the fan, the temperature rise of the test board caused by the fan running and the heating element heating, and the heating power variable of the heating element; The airflow value of the fan is determined based on the airflow expression, the temperature rise value of the test board, and the heating power value of the heating element.
4. The method according to claim 3, characterized in that, The method of obtaining the airflow expression between the area ratio, the thermal resistance of the heating element, the airflow variable of the fan, the temperature rise of the test board caused by the fan running and the heating element generating heat, and the heating power variable of the heating element includes: Based on the definition of air specific heat capacity, a first expression is established between the heat dissipation variable of the test board caused by the operation of the fan, the area ratio, the air volume variable of the fan, and the temperature rise variable; Based on the heat balance law of the test board, a second expression is established between the temperature rise variable, the heating power variable of the heating element, the heat dissipation variable, and the thermal resistance value of the heating element; Substituting the first expression into the second expression yields the air volume expression.
5. The method according to claim 4, characterized in that, The first expression, based on the definition of air specific heat capacity, establishes a relationship between the heat dissipation variable of the test board caused by the fan operation, the area ratio, the fan airflow variable, and the temperature rise variable, including: Based on the definition of air specific heat capacity, a third expression is established between the heat dissipation variable, the fan airflow variable, and the temperature rise variable; The first expression is determined based on the third expression and the area ratio.
6. The method according to claim 4, characterized in that, The first expression is ; in, This indicates the change in heat dissipation from the test board caused by the operation of the fan; This indicates the area of the test board; This indicates the air outlet area of the fan; Indicates air density; This indicates the specific heat capacity of air; This represents the airflow variable of the fan; This represents the temperature rise of the test board caused by the operation of the fan and the heating element.
7. The method according to claim 4, characterized in that, The second expression is ; in, This represents the temperature rise of the test board caused by the operation of the fan and the heating element. This represents the variable in heating power of the heating element; This indicates the change in heat dissipation from the test board caused by the operation of the fan; This indicates the thermal resistance value of the heating element.
8. The method according to claim 3, characterized in that, The air volume expression is: ; in, This represents the airflow variable of the fan; This indicates the air outlet area of the fan; This indicates the area of the test board; Indicates air density; This indicates the specific heat capacity of air; This represents the variable in heating power of the heating element. , This indicates the voltage supplied to the heating element. This indicates the resistance value of the heating element; This represents the temperature rise of the test board caused by the operation of the fan and the heating element. This indicates the thermal resistance value of the heating element.
9. A fan airflow determination system, characterized in that, The fan airflow determination system includes a fan, an air duct, a test board, and a controller; the fan is disposed at one end of the air duct and is used to drive air to flow within the air duct; the cross-sectional area of the air duct is matched with the air outlet area of the fan; the test board is disposed in the air duct; a heating element is disposed on the test board; the heating element is connected to the controller; and the controller is used to execute the method described in any one of claims 1-8.
10. The system according to claim 9, characterized in that, The test board is also equipped with a thermistor and a fixed resistor. The voltage at the first end of the thermistor is a preset operating voltage. The second end of the thermistor is connected to the first end of the fixed resistor. The second end of the thermistor is also connected to the controller. The second end of the fixed resistor is grounded.