A precision temperature-controlled fluid heating system based on vortex tube cooling

Abstract

This invention relates to the field of fluid heating and temperature control technology, and discloses a precision temperature-controlled fluid heating system based on vortex tube cooling. The system includes a reference temperature sensor and a disturbance temperature sensor connected in series along the flow channel, a miniature vortex tube located downstream, and an acoustic sensor located at its exhaust port. The control unit controls the miniature vortex tube in a feedforward manner based on the temperature difference signal from the temperature sensor, and uses the signal from the acoustic sensor to correct the control timing online. This invention uses the upstream temperature difference change as a feedforward signal for thermal disturbance to predict and instantly cancel the thermal disturbance, thereby changing the control method that relies on hysteresis feedback. This avoids control oscillations caused by thermal inertia, and by utilizing the accompanying information of the actuator, it achieves online adaptive adjustment to changes in the fluid state.

Description

Technical Field

[0001] This invention relates to a precision temperature-controlled fluid heating system based on vortex tube cooling, belonging to the field of fluid heating and temperature control technology. Background Technology

[0002] When current application scenarios place higher demands on the dynamic response and accuracy of temperature control, such as in precision injection molding processes, rapid changes in external loads can frequently cause instantaneous fluctuations in fluid temperature. At this point, the inherent limitations of the aforementioned technical methods begin to emerge. This is because the thermal inertia of the fluid itself causes a time delay in the execution of any control command. The heating effect of the heating unit and the cooling effect of the cooling unit often conflict with each other. The compensation command issued by the control system based on the delayed temperature information itself becomes a new source of disturbance, causing the system temperature to oscillate continuously around the target value.

[0003] One direct approach to improvement is to further enhance the response speed of the control system and the power of the actuators. However, this would exacerbate the energy conflict between heating and cooling actions, amplify the control overshoot, and also increase equipment costs and operating energy consumption.

[0004] Analysis reveals several shortcomings of existing technologies: the execution of control actions lags behind the actual occurrence of thermal disturbances; the system can only compensate for existing temperature deviations, but cannot suppress disturbances at their source; and the control system lacks online sensing of changes in the fluid's physical properties, rendering the original control model inaccurate when the fluid's viscosity or flow rate changes. Therefore, the technical problem this invention aims to solve is how to construct a fluid heating system capable of predicting and instantly canceling thermal disturbances, while also sensing fluid state changes online to adaptively adjust the control logic. Summary of the Invention

[0005] This invention provides a precision temperature-controlled fluid heating system based on vortex tube cooling. Its main purpose is to solve the problems in the prior art that it is impossible to predict and cancel thermal disturbances due to thermal inertia lag, and that it is impossible to sense changes in fluid state online to adaptively adjust the control logic.

[0006] To achieve the above objectives, the present invention provides a precision temperature-controlled fluid heating system based on vortex tube cooling, the system comprising:

[0007] A flow channel is set along the fluid flow direction, a reference temperature sensor is set in the upstream section of the flow channel and a disturbance temperature sensor is set downstream of the reference temperature sensor; a quenching zone is set downstream of the disturbance temperature sensor, and a micro vortex tube is set in the quenching zone; an acoustic sensor is set at the exhaust port of the micro vortex tube.

[0008] The control unit is connected to a reference temperature sensor, a disturbance temperature sensor, a micro vortex tube, and an acoustic sensor. The system stores a gradient threshold and an initial transit time characterizing the thermal disturbance from the location of the disturbance temperature sensor to the location of the quenching zone. The control unit is configured to: calculate the temperature difference between the temperature readings of the reference temperature sensor and the disturbance temperature sensor; determine a transit time correction parameter based on the acoustic characteristics of the exhaust noise collected by the acoustic sensor; and when the absolute value of the temperature difference exceeds the gradient threshold, the control unit determines a quenching control command based on the temperature difference, the initial transit time, and the transit time correction parameter, and outputs the quenching control command to the micro vortex tube.

[0009] Preferably, the system stores a mapping relationship between acoustic features and transit time correction parameters; the control unit is configured to determine the transit time correction parameters based on the acoustic features of exhaust noise collected by the acoustic sensor, including: the control unit collects the sound pressure signal of exhaust noise in a predetermined frequency band and calculates the spectral entropy value of the sound pressure signal as an acoustic feature; and the control unit determines the transit time correction parameter corresponding to the spectral entropy value based on the mapping relationship.

[0010] Preferably, a passive phase change energy storage section is provided downstream of the quenching zone; the system also stores a rate threshold; the control unit is further configured to: periodically control the micro-vortex tube to inject cold gas pulses of fixed duration into the phase change energy storage section; and calculate the temperature recovery rate of the temperature response curve based on the temperature response curve collected by the disturbance temperature sensor after the cold gas pulse injection; and when the absolute value of the temperature recovery rate is less than the rate threshold, i.e. The control unit increases the gain coefficient it uses to determine the quenching control command; among which, This represents the absolute value of the temperature recovery rate. This is the rate threshold.

[0011] Preferably, the quenching control command includes an activation command for the micro vortex tube and duration information characterizing the duration of its jet of cold air.

[0012] Preferably, when the control unit determines the duration information, the duration information is directly proportional to the absolute value of the temperature difference.

[0013] Preferably, the miniature vortex tube is connected to a compressed air pipeline, which is connected to an existing compressed air source at the location of the industrial equipment carrying the system.

[0014] Preferably, both the reference temperature sensor and the disturbance temperature sensor are infrared temperature sensors.

[0015] Preferably, the system also includes an air guide pipe, one end of which is connected to the cold air outlet of the micro vortex tube, and the other end is opened in front of the lens of the infrared temperature sensor to form an air curtain that isolates water vapor from the external environment.

[0016] Preferably, the system also stores a frequency threshold; the control unit is further configured to: analyze the frequency of interference pulses formed by residual water vapor penetrating the air curtain in the signal of the infrared temperature sensor; and when the frequency of the interference pulses exceeds the frequency threshold, the control unit further increases the intensity of the cold air jet from the micro vortex tube corresponding to the quenching control command when determining the quenching control command.

[0017] Preferably, the phase change energy storage section includes a sandwich structure encapsulating a phase change material, wherein the phase change material is impregnated and composited with a thermally conductive metal skeleton material having a three-dimensional interconnected honeycomb microporous structure.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. This invention establishes a control relationship for predicting and instantly canceling thermal disturbances by setting a reference temperature sensor and a disturbance temperature sensor in series in the upstream section of the flow channel, and using the temperature difference between the two as a feedforward signal to trigger the action of the micro vortex tube in the downstream quenching zone. This approach changes the traditional operating basis of temperature control systems that rely on hysteresis feedback for compensation, so that the system no longer passively responds to the temperature deviation that has already spread, but neutralizes the excess energy carried by the thermal disturbance at the beginning of its formation. This avoids control oscillation and overshoot problems caused by fluid thermal inertia, making the response of the entire temperature control process faster and smoother.

[0020] 2. This invention combines an acoustic sensor located at the exhaust port of a micro vortex tube with control logic for processing its signal to correct the transit time online, forming a passive sensing and adaptive control loop for the internal state of the fluid. It utilizes the exhaust noise generated when the vortex tube is working as an accompanying information, and correlates its acoustic characteristics with the actual flow state of the fluid, which is a key parameter affecting the transit time. Thus, without adding an intrusive flow meter or viscometer, the system can cope with changes in flow velocity caused by fluid aging or changes in operating conditions, ensuring the timing accuracy of the feedforward cancellation action and improving the reliability of the system under long-term operation and complex operating conditions.

[0021] 3. This invention establishes an online self-calibration mechanism for key functional materials by periodically applying brief cold air pulses to the rear-mounted phase change energy storage section using micro-vortex tubes and evaluating the actual working state of the phase change material based on the temperature recovery characteristics collected by the disturbance temperature sensor. This mechanism transforms the potential performance degradation of the phase change material due to physical hysteresis from an invisible risk factor into an internal state parameter that can be quantified and used to adjust the system control gain. This allows the system to self-compensate when the performance of the phase change material fluctuates, maintaining the overall control accuracy and stability. Furthermore, by adding an air guide pipe, the dry cold air generated during the operation of the micro-vortex tube is guided to the front of the infrared temperature sensor lens to form an air curtain. This design not only utilizes the system's own byproducts to solve the engineering problem of external interference in infrared temperature measurement under high humidity conditions, but also uses the residual water vapor interference pulse frequency penetrating the air curtain as an auxiliary judgment criterion for characterizing the severity of system temperature changes. This method of transforming negative interference factors from the external environment into enhancements and supplements to the main control logic through physical isolation and information reinterpretation expands the system's applicability to harsh industrial environments. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the system architecture of a precision temperature-controlled fluid heating system based on vortex tube cooling according to the present invention.

[0023] Figure 2 This is a comparison chart showing the effect of the control strategy of the present invention on suppressing thermal disturbances;

[0024] Figure 3 This is a functional block diagram of the adaptive feedforward control algorithm of the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0026] The precision temperature-controlled fluid heating system based on vortex tube cooling disclosed in this invention mainly includes a flow channel arranged along the fluid flow direction, a set of temperature sensing units, a quenching zone, and a control unit connected to each component in series along the flow channel; the temperature sensing unit includes a reference temperature sensor located in the upstream section (…). ) and a disturbance temperature sensor located downstream of it ( The quenching zone is equipped with micro-vortex tubes, and the exhaust ports of the micro-vortex tubes are also equipped with acoustic sensors. The operating logic is that the control unit uses the temperature difference collected by the two temperature sensors as a feedforward signal to predict and trigger the instantaneous cooling action of the downstream micro-vortex tubes. Simultaneously, it utilizes the exhaust noise characteristics collected by the acoustic sensors to correct the response timing of the feedforward control online. In some industrial scenarios with high requirements for fluid temperature control accuracy, such as precision injection molding, the instantaneous temperature fluctuations of the heat transfer medium caused by changes in external loads such as mold opening and closing are a key factor affecting product yield. The thermal inertia of the fluid itself makes traditional control methods based on hysteresis feedback difficult to effectively suppress such fluctuations. To address this challenge, this system is configured to execute a thermal disturbance feedforward quenching procedure. The control unit continuously collects data from the reference temperature sensor at high frequency (…). ) and disturbance temperature sensor ( The readings are taken, and the temperature difference between the two is calculated in real time. ,in, and The physical spacing is pre-calibrated to correspond to a preset travel time for the fluid at a nominal flow rate. The system stores a gradient threshold, which is set based on the condition that its value must be higher than the temperature sensor's own measurement noise floor, but lower than the minimum disturbance energy that might cause defects in the final product; for example, it can be set to 0.2°C. When the control unit determines the temperature difference... When the absolute value exceeds the gradient threshold, a thermal disturbance is determined to have passed. and arrived At this time, the control unit will... The occurrence of this signal serves as a feedforward trigger signal, based on which The size of the microvortex tube and a preset initial transit time are used to determine the quenching control command, which is then output to the microvortex tube in the downstream quenching zone. The quenching control command includes an activation command for the microvortex tube and duration information characterizing the duration of its jet of cold air, wherein the duration information is related to the temperature difference. The absolute value is directly proportional. After receiving the command, the vortex tube ejects millisecond-level low-temperature airflow, which cancels out the excess heat carried by the thermal disturbance fluid mass the moment it arrives. In this way, by using the upstream temperature difference change as the feedforward signal of the downstream actuator, the system intervenes in the disturbance propagation path before the thermal disturbance spreads and affects the downstream process, thereby helping to avoid control oscillations and overshoot caused by thermal inertia.

[0027] In industrial operating environments, the physical properties of fluids, especially viscosity, change due to aging or temperature variations. This directly leads to changes in the actual flow rate, causing deviations in the transit time parameters used by the control unit for feedforward prediction, potentially resulting in premature or delayed quenching. Therefore, the system also incorporates an adaptive control loop for passively sensing the fluid state. This loop consists of an acoustic sensor located at the exhaust port of the micro-vortex tube and corresponding control logic. Changes in fluid viscosity affect its heat exchange efficiency with the tube wall. This change is transmitted to the vortex tube and alters its operating back pressure, ultimately causing a regular change in the acoustic characteristics of its exhaust noise. To utilize this physical correlation, the system is configured to synchronously collect the exhaust noise signal from the acoustic sensor each time the vortex tube performs a quenching task. The control unit processes the collected sound pressure signal, for example, calculating its spectral entropy value within a predetermined frequency band as an acoustic characterization of the current fluid state. The selection of the predetermined frequency band can be achieved through offline experiments to calibrate a frequency response range that is sensitive to changes in flow velocity. The system pre-stores a mapping relationship between acoustic characteristics and transit time correction parameters. This mapping relationship can be established through a one-time calibration experiment, i.e., changing the fluid flow velocity under controlled conditions and recording the corresponding spectral entropy value at each flow velocity, thereby generating a lookup table or fitting function. During real-time operation, the control unit determines a transit time correction parameter based on the calculated spectral entropy value by querying the mapping relationship, and uses this correction parameter to adjust the initial transit time. Finally, the control unit generates and issues a quenching control command based on the corrected transit time. Through this mechanism, the system utilizes the accompanying information during actuator operation to perceive changes in the working medium's state, achieving online closed-loop adaptive adjustment of the core timing parameters of the feedforward control, and improving the timing accuracy of the feedforward cancellation action when unknown changes occur in the fluid state.

[0028] To further smooth out residual energy fluctuations that may occur after quenching, a passive phase change energy storage section can be set up downstream of the quenching zone. This energy storage section can, for example, employ a sandwich structure encapsulating a phase change material, in which the phase change material is impregnated and composited with a thermally conductive metal skeleton material with a three-dimensional interconnected honeycomb microporous structure to enhance its thermal conductivity. The inherent phase change hysteresis physical characteristics of the phase change material during high-frequency operation may cause its heat absorption and release capacity to decrease at certain times, becoming a potential performance limiting factor. To mitigate this risk, the system is also configured to implement an online calibration mechanism for the working state of the functional material. The control unit is configured to periodically control the micro vortex tube to inject a cold gas pulse of fixed duration and low energy into the phase change energy storage section as a detection signal. Simultaneously, the control unit calculates the temperature recovery rate of the temperature response curve collected by the disturbance temperature sensor adjacent upstream. Because phase change materials in the ideal phase transition region respond slowly to temperature disturbances due to latent heat, while those in the hysteresis failure region respond more rapidly, this temperature recovery rate can reflect the actual operating state of the phase change material at that time; a rate threshold is stored within the system. When the control unit determines the absolute value of the temperature recovery rate When the rate is less than this threshold, i.e. This indicates that the buffering capacity of the phase change material has decreased. At this time, the control unit will automatically increase an internal gain coefficient that it uses to determine the quenching control command, so as to appropriately strengthen the intensity of active quenching and compensate for the temporary attenuation of passive buffering capacity. This design transforms the internal working state of a functional material from an invisible factor into a control parameter that can be quantified and evaluated and used for closed-loop compensation, in order to maintain the overall control accuracy and stability of the system.

[0029] Furthermore, in some applications, infrared temperature sensors can be used for both the reference temperature sensor and the disturbance temperature sensor to achieve non-contact measurement. However, in high-humidity environments, water vapor can interfere with the infrared signal. Therefore, the system can further include a gas guide pipe, one end of which is connected to the cold air outlet of the micro-vortex tube, and the other end opens in front of the lens of the infrared temperature sensor. When the system is running, the dry, cold airflow generated by the vortex tube is guided by this pipe, forming a continuous air curtain in front of the sensor lens. This air curtain physically isolates most of the water vapor in the external environment, ensuring the validity of the temperature measurement signal. Even so, when drastic changes in operating conditions cause a sudden increase in the amount of steam, a small amount of steam may still penetrate the air. The ventilation curtain generates brief interference pulses on the sensor signals. This system further utilizes this interference as usable information. The control unit is configured to analyze the frequency of these interference pulses, as the pulse frequency is related to the intensity of steam generation. The system stores a frequency threshold. When the control unit detects that the frequency of the interference pulse exceeds this threshold, it determines that the system is in a state of severe disturbance. Accordingly, when determining the quenching control command, it further increases the intensity of the cold air jet from the micro vortex tube corresponding to the command. This method of transforming environmental interference into an auxiliary and supplementary function to the main control logic through physical isolation and information reinterpretation expands the system's applicability to specific industrial environments.

[0030] Example 1: In a precision injection molding unit for producing high-precision optical lenses, the technical solution of the present invention is deployed to control the temperature of the heat transfer fluid in the mold cooling channel. When the unit completes a routine maintenance and re-injects a batch of heat transfer fluid with different physical properties from the old fluid, the system operates as follows: Because the actual viscosity of the new fluid at the operating temperature is higher than that of the old fluid, the actual flow rate of the fluid in the pipeline is lower than before maintenance, even with the output pressure of the circulating pump set remaining unchanged. This results in thermal disturbance from the reference temperature sensor. Position flows to disturbance temperature sensor Location, and self The time it takes for the oil to flow to the quenching zone is correspondingly extended; after the injection molding machine performs one mold opening and closing cycle, causing a momentary rise in the temperature of the returning oil, the control unit calculates the temperature difference. The absolute value exceeded the preset gradient threshold, triggering a feedforward quenching task; the control unit, based on this... At the same moment the required quenching energy is calculated and the micro vortex tube is commanded to open, the acoustic sensor located at its exhaust port also begins to collect the acoustic signal of the exhaust noise. Due to the decrease in fluid velocity, the heat transfer conditions of the tube wall are changed, which in turn affects the working back pressure and temperature difference of the vortex tube, resulting in a change in the spectral characteristics of its actual exhaust noise. The control unit obtains an acoustic characteristic reading different from that before maintenance by calculating the spectral entropy value of the sound pressure signal. The control unit then uses this spectral entropy value as an index to find a corresponding transit time correction parameter in the mapping relationship between acoustic characteristics and transit time correction parameters stored in the system. This correction parameter is used to extend the original initial transit time of the system, thereby delaying the issuance of the final quenching control command. This series of online correction calculations and decisions are completed within milliseconds. As a result, the timing of the cold airflow ejected by the micro vortex tube is synchronized with the actual arrival time of the thermally disturbed fluid mass in the quenching zone, thus offsetting the excess heat energy it carries.

[0031] In this process, the system does not rely on independent flow meters or viscometers to sense changes in fluid physical properties. Instead, it uses the acoustic information generated by the actuator of the feedforward quenching action, namely the micro vortex tube, to correct the core timing parameters of the feedforward action itself. A collaborative working loop is formed between the active quenching mechanism and the acoustic adaptive adjustment mechanism. The former provides the latter with a signal source for analysis, while the latter calibrates the timing accuracy of the former when unknown changes occur in the operating conditions. Traditional control methods in this scenario either fail to detect changes in flow velocity, leading to control failure, or require additional sensors to compensate. This technical solution addresses this situation within a single architecture by reusing information within the system. It does not directly measure the fluid velocity variable, but establishes a correlation between noise characteristics and transit time, enabling the system control logic to directly respond to the final impact of changes in flow velocity, i.e., changes in transit time. The internal stress test results of the subsequent batch of optical lenses produced were at the same level as before maintenance, and no defects caused by temperature fluctuations were found.

[0032] Example 2: To objectively verify the adaptability of the technical solution of the present invention in dealing with instantaneous thermal disturbances and changes in the physical properties of the working medium, a closed-loop fluid temperature control test platform was built. The platform includes a standard heat exchange circuit, a controllable power pulse heat source, and the system of the present invention as the test object. A traditional PID controller and an independent heating and cooling unit are configured as control groups. The pulse heat source is used to simulate repeatable step thermal disturbances introduced by rapid load changes in industrial applications. The pulse energy is set to balance the authenticity and distinguishability of the test. The energy value is set to be equivalent to the heat change generated by opening and closing the mold in a typical injection molding cycle, specifically heating with 500W power for 2 seconds. In the test, an independent and calibrated high-precision temperature recorder is set at the final output of the circuit to monitor and record the actual temperature response curves of each group under disturbance.

[0033] The experiment was conducted in two groups. The first group aimed to verify the suppression effect of the thermal disturbance feedforward quenching mechanism, while the second group aimed to verify the role of the acoustic adaptive control loop when the fluid viscosity changed. In the first group of experiments, heat transfer oil of standard viscosity was used. The loop temperature was first stabilized at a reference value of 80.0°C, and then the aforementioned set thermal pulse was injected into the fluid. The outlet temperature changes of the system of the present invention and the conventional PID control system within 60 seconds after the disturbance occurred were recorded respectively. In the second group of experiments, the oil in the loop was replaced with the same type of oil with a viscosity 20% higher, and the above experimental steps were repeated. At the same time, a control group B was added, in which only the feedforward quenching was turned on but the acoustic adaptive control function was turned off, to isolate and verify the effectiveness of the adaptive function. The key values ​​of the collected data are shown in Table 1.

[0034] Table 1: A comparison of temperature response data under different control methods and operating conditions.

[0035]

[0036] As shown in Table 1, under standard viscosity oil conditions, the outlet temperature of control group A exhibited a peak overshoot exceeding 2°C after disturbance, accompanied by continuous oscillations, and failed to stabilize within the 60-second observation period. This phenomenon is consistent with the characteristics of PID control based on hysteresis feedback compensation. In contrast, the temperature fluctuation of the experimental group was suppressed to within 0.3°C and stabilized within seconds. This result corresponds to the operation of the thermal disturbance feedforward quenching mechanism, i.e., by controlling the temperature difference... The signal prediction cancels out the energy carried by the thermal disturbance before it reaches the outlet. After switching to a high-viscosity oil, the peak temperature fluctuation of control group B increased to 1.2°C, indicating that the fixed transit time parameter was inconsistent with the actual situation due to the slowed flow rate, which caused the feedforward quenching pulse to fail to synchronize with the thermal disturbance. In contrast, the temperature fluctuation of the experimental group under this condition was not significantly different from that under the standard viscosity. The reduction in this difference is attributed to the intervention of its acoustic adaptive control loop. Through online analysis of the exhaust sound of the vortex tube, the change in fluid state was determined and the transit time parameter was compensated, thereby maintaining the timing accuracy of the feedforward control.

[0037] Example 3: This example combines Figures 1 to 3 This describes a precision temperature-controlled fluid heating system based on vortex tube cooling, such as... Figure 1 As shown, the system's workflow begins with fluid input, and the fluid flows sequentially through a reference temperature sensor located upstream. With disturbance temperature sensor ,in Used to measure inlet reference temperature The temperature difference signal generated by the two sensors is used to identify thermal disturbances from upstream. The feedforward trigger signal is sent to the control unit, which performs thermal disturbance feedforward quenching and adaptive adjustment based on the signal, and generates a quenching control command. This command includes activation and duration information to control the micro vortex tubes in the downstream quenching zone to perform instantaneous cooling to counteract thermal disturbances. When the micro vortex tubes are working, the acoustic sensor at their exhaust port collects the exhaust noise and transmits the noise-related information to the control unit. The control unit extracts acoustic features such as spectral entropy values ​​to correct the transit time parameters online, thereby ensuring the timing accuracy of the quenching action. The fluid after being processed in the quenching zone flows further through a passive phase change energy storage section. This energy storage section utilizes the latent heat effect of the phase change material to further smooth residual temperature fluctuations. The control unit also periodically detects pulses and analyzes their temperature recovery rate. The system evaluates the state of the phase change material and adjusts the control gain online. Ultimately, the system obtains a fluid with stable temperature control from the output.

[0038] like Figure 2 As shown in the figure, the horizontal axis represents time (seconds), and the vertical axis represents temperature (°C). The three curves represent the temperature changes of the solid line of the system of this invention, the long dashed line of the traditional PID control, and the line without a control reference point, respectively. As can be seen from the figure, when the initial temperature is stable at 80.0°C, the same thermal disturbance is applied. The system without a control reference will experience a sharp rise in temperature followed by a slow natural cooling. The traditional PID control system exhibits significant lag and overshoot, with its temperature peak reaching approximately 82.1°C and subsequently producing continuous oscillations. It has not fully stabilized even after an observation period of more than 60 seconds. In contrast, the temperature response of the system of this invention shows minimal fluctuations. Its peak temperature is effectively suppressed to approximately 80.3°C and rapidly recovers to the set temperature within approximately 4.5 seconds without significant oscillations. This verifies that the present invention, through a combination of feedforward quenching and adaptive adjustment, can effectively avoid the control oscillation problem caused by thermal inertia.

[0039] like Figure 3 As shown, firstly, the temperature sensing unit , Provides real-time temperature readings, from which module 1.0 calculates the disturbance temperature difference. ;Should The signal is transmitted to module 2.0, which is responsible for generating a feedforward quenching command and sending it to the micro-eddy current tube, which acts as the actuator. The generation of this command depends not only on... The magnitude of the quenching command also depends on a core timing parameter, namely the transit time parameter stored in database D1. To ensure the accuracy of this timing parameter, the system introduces an adaptive correction loop. The exhaust noise signal collected by the acoustic sensor is sent to module 3.0. This module calculates the transit time correction parameter by analyzing the signal characteristics and uses this parameter to update the transit time in database D1 online. This allows module 2.0 to generate the quenching command based on the more accurate corrected transit time. At the same time, the system also includes a calibration loop for the passive phase change energy storage section, namely module 4.0. This module evaluates the current operating state of the phase change energy storage section by analyzing the temperature response curve and generates an updated gain coefficient based on the evaluation result. This updated gain coefficient is used to update the current gain coefficient stored in database D2. This updated gain coefficient is also called by module 2.0 to adjust the intensity of the quenching command, thus forming a dual closed-loop adaptive control system that can simultaneously adapt to changes in fluid state and fluctuations in the performance of functional materials.

[0040] Example 4: Before a newly constructed fluid heating system for polymer extrusion molding is put into formal operation, its control system needs to undergo offline parameter calibration and model building to ensure that its feedforward control logic matches the physical conditions of this specific application scenario. The passive phase change energy storage section used in this system encapsulates industrial-grade paraffin wax with a melting point of 85°C as the phase change material. This paraffin wax is impregnated in a three-dimensional interconnected open-cell copper foam skeleton, utilizing the high thermal conductivity of copper to improve the response rate of the phase change material. Before calibration, the system circulates the fluid at the nominal flow rate without turning on any heating or cooling units, and continuously collects readings from the reference temperature sensor and the disturbance temperature sensor for 300 seconds. The control unit calculates the standard deviation of the sensor signal noise during this period. The gradient threshold required to trigger the thermal perturbation feedforward is set to three times this standard deviation, i.e., 3. .

[0041] To establish the mapping relationship between the acoustic characteristics of the vortex tube exhaust noise and the fluid transit time correction parameter, the system was connected to a calibration loop equipped with a precision adjustable-speed pump and an external high-precision flow meter. After the calibration program was started, the adjustable-speed pump was controlled to drive the fluid at a series of discrete and increasing flow rate points, covering the range from 80% to 120% of the nominal flow rate. At each stable flow rate point, the control unit performed a preset quenching operation, and the acoustic sensor collected the exhaust noise signal of the vortex tube to calculate the corresponding spectral entropy value. Simultaneously, a tiny thermal pulse is injected downstream of the perturbation temperature sensor, and its arrival time in the quenching zone is recorded by an additional fast-response thermocouple, thus obtaining the actual transit time at that flow rate. The control unit will record this actual transit time. The transit time is compared with the initial transit time of the system at the nominal flow rate to obtain the transit time correction parameter corresponding to that flow rate point. By traversing all preset flow rate points, the system obtains a set containing multiple data pairs. , The set of acoustic features, which is stored in the non-volatile memory of the control unit in the form of a lookup table, constitutes the core mapping relationship from acoustic features to transit time correction.

[0042] After completing all the above calibration steps, the adjustable speed pump and external flow meter in the calibration loop are removed, and the system is reconnected to its standard working pump set. At this point, the system has completed the parameter setting and model building for the current hardware configuration and fluid type. In subsequent online operation, its control unit can obtain the corresponding transit time correction parameters by querying the internally stored lookup table based on the real-time acquired spectral entropy value, without relying on any external measuring equipment. The entire calibration process transforms the key parameters and internal model that may have previously relied on experience into an engineering data set that can be determined through standardized experimental procedures, providing a foundation for the system's operation in practical applications.

[0043] Example 5: When a system of the present invention that has been running continuously for more than 2000 hours needs to undergo an online internal status self-check and parameter verification, the control unit can be placed in a preset maintenance mode; in this mode, the rate threshold of the passive phase change energy storage section is verified. The system first heats the energy storage section to a temperature above its phase change point, causing the internal phase change material to completely melt. Then, a standardized pulse of cold gas is injected, and the absolute value of its temperature recovery rate is recorded. Subsequently, the system cools the energy storage section to a state below its phase transition point, causing it to completely solidify, and repeats the pulse injection and rate recording steps described above to obtain the absolute value of its temperature recovery rate in the solid state. The control unit then sets the rate threshold. Set as the arithmetic mean of these two measurements, i.e. The calculated threshold will then be used to determine the working status of the phase change material in subsequent online assessments.

[0044] Next, to verify the long-term effectiveness of the mapping relationship between acoustic characteristics and transit time correction parameters, an external and calibrated flow meter was temporarily connected in series in the fluid loop. With the assistance of the flow meter, the fluid velocity was adjusted to the nominal velocity most commonly used in production. Under this stable operating condition, a quenching operation was triggered by the control unit, and the spectral entropy value of the exhaust noise of the vortex tube at this moment was recorded. The control unit will use this real-time measured spectral entropy value The original spectral entropy value stored during the initial system calibration and corresponding to the same nominal flow rate. The two are compared. If the deviation is less than a tolerance set based on the statistical dispersion of the initial calibration data, it proves that the original mapping relationship is still valid. If the deviation exceeds the tolerance, it indicates that the acoustic characteristics of the system may have drifted. At this time, the control unit will generate a maintenance alarm and record an event log, prompting that a complete offline recalibration process is required. After the online verification procedure is completed, the external flow meter is removed and the system returns to normal operation mode.

[0045] Example 6: Before deploying the system of the present invention in the temperature control loop of a biopharmaceutical reactor using a novel coolant, an on-site installation, configuration, and control parameter tuning are required; firstly, to determine the reference temperature sensor... With disturbance temperature sensor The physical spacing between the components is determined by injecting a series of standardized thermal pulses into the fluid on a test tube section with multiple reserved sensor mounting ports. The control unit records the calculated temperature difference at different mounting distances. The signal-to-noise ratio and waveform characteristics of the signal are ultimately selected to enable... The spacing that achieves the maximum signal-to-noise ratio and minimum waveform spread is used as the fixed installation distance for this application. After determining the spacing, the gain of the quenching control command is calibrated. The control unit injects a series of thermal disturbances of known energy levels into the fluid through a pulsed heat source. The temperature difference generated by each level of thermal disturbance is determined. The system attempts different quenching durations in an incremental manner. The system records the temperature deviation at downstream monitoring points after each quenching until a quenching duration that minimizes the temperature deviation is found. By iterating through all thermal disturbance levels, the system constructs a graph characterizing the temperature difference. With quenching time An internal data table showing the functional relationships between them.

[0046] After completing the above parameter calibration, the system executes a self-check procedure for the actuator status to address boundary conditions where the vortex tube may fail due to gas source pressure fluctuations or its own malfunction. The control unit is configured to simultaneously analyze the total signal energy from the acoustic sensor at the exhaust port of the micro vortex tube when issuing any quenching control command. During the initial system startup, a standard test spray is performed to record the baseline acoustic energy value under normal operating conditions. In subsequent operation, if the control unit fails to receive an acoustic energy signal exceeding a specific percentage of the baseline value from the acoustic sensor within a short time window after issuing a quenching command, it determines that the actuator or its gas source has malfunctioned. Once a malfunction is determined, the control unit will immediately suspend the thermal disturbance feedforward quenching function to avoid erroneous control outputs, generate an alarm requiring manual intervention on the human-machine interface, and switch the system to a preset backup operating mode that relies on the main heating unit for baseline temperature maintenance. This series of procedures provides assurance for the system's performance configuration and operational reliability in specific application scenarios.

[0047] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A precision temperature-controlled fluid heating system based on vortex tube cooling, characterized in that, The system includes a flow channel and a control unit arranged along the fluid flow direction; a reference temperature sensor located in the upstream section of the flow channel and a disturbance temperature sensor located downstream of the reference temperature sensor; a quenching zone located downstream of the disturbance temperature sensor, the quenching zone being equipped with a micro vortex tube; and an acoustic sensor located at the exhaust port of the micro vortex tube. The control unit is connected to a reference temperature sensor, a disturbance temperature sensor, a micro eddy tube, and an acoustic sensor. The system stores gradient thresholds and the initial transit time characterizing the thermal disturbance from the location of the disturbance temperature sensor to the location of the quenching zone. The control unit is configured to calculate the temperature difference between the temperature readings of the reference temperature sensor and the disturbance temperature sensor; Based on the acoustic characteristics of exhaust noise collected by acoustic sensors, the transit time correction parameters are determined. When the absolute value of the temperature difference exceeds the gradient threshold, the control unit determines the quenching control command based on the temperature difference, the initial transit time, and the transit time correction parameter, and outputs the quenching control command to the micro eddy current tube.

2. The precision temperature-controlled fluid heating system based on vortex tube cooling according to claim 1, characterized in that, The system stores the mapping relationship between acoustic features and transit time correction parameters; The control unit is configured to determine transit time correction parameters based on the acoustic characteristics of exhaust noise collected by acoustic sensors, including: the control unit collects the sound pressure signal of exhaust noise in a predetermined frequency band and calculates the spectral entropy value of the sound pressure signal as an acoustic feature; The control unit determines the transit time correction parameter corresponding to the spectral entropy value based on the mapping relationship.

3. The precision temperature-controlled fluid heating system based on vortex tube cooling according to claim 1, characterized in that, A passive phase change energy storage section is also provided downstream of the quenching zone; the system also stores a rate threshold; the control unit is also configured to: periodically control the cold air pulse with a fixed duration of injection from the micro vortex tube to the phase change energy storage section; and calculate the temperature recovery rate of the temperature response curve based on the temperature response curve collected by the disturbance temperature sensor after the cold air pulse injection. And when the absolute value of the temperature recovery rate is less than the rate threshold, i.e. The control unit increases the gain coefficient it uses to determine the quenching control command; among which, This represents the absolute value of the temperature recovery rate. This is the rate threshold.

4. The precision temperature-controlled fluid heating system based on vortex tube cooling according to claim 1, characterized in that, The quenching control commands include the activation command of the micro vortex tube and the duration information characterizing the duration of its jet of cold air.

5. A precision temperature-controlled fluid heating system based on vortex tube cooling according to claim 4, characterized in that, When determining the duration information, the control unit recognizes that the duration information is directly proportional to the absolute value of the temperature difference.

6. The precision temperature-controlled fluid heating system based on vortex tube cooling according to claim 1, characterized in that, The miniature vortex tube connects to a compressed air pipeline, which is connected to an existing compressed air source at the location of the industrial equipment carrying the system.

7. The precision temperature-controlled fluid heating system based on vortex tube cooling according to claim 1, characterized in that, Both the reference temperature sensor and the disturbance temperature sensor are infrared temperature sensors.

8. A precision temperature-controlled fluid heating system based on vortex tube cooling according to claim 7, characterized in that, The system also includes an air duct, one end of which is connected to the cold air outlet of the micro vortex tube, and the other end is opened in front of the lens of the infrared temperature sensor to form an air curtain that isolates water vapor from the external environment.

9. A precision temperature-controlled fluid heating system based on vortex tube cooling according to claim 8, characterized in that, The system also stores frequency thresholds; the control unit is also configured to: analyze the frequency of interference pulses formed by residual water vapor penetrating the air curtain in the signal of the infrared temperature sensor; and when the frequency of the interference pulses exceeds the frequency threshold, the control unit further increases the intensity of the cold air jet from the micro vortex tube corresponding to the quenching control command when determining the quenching control command.

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