Multi-stage vortex-heat conduction combined type heat exchanger

Abstract

According to the multi-stage vortex-heat conduction combined type heat exchanger, the multi-stage vortex generation systems arranged in series are adopted, the system starts from guiding large-scale spiral flow and transits to generate longitudinal vortexes with a strong shearing effect, and finally an optimized field-coordinated detached vortex is formed, so that multi-scale disturbance is achieved, and the heat conduction efficiency is improved. Heat transfer is enhanced, and solid particles are difficult to stably deposit. An advanced on-line monitoring and self-diagnosis system is integrated, the system can estimate key unmeasurable scaling thermal resistance on line in real time through multi-sensor fusion and an extended Kalman filtering algorithm, and the limitation that only macroscopic parameters can be observed in traditional monitoring is broken through; and furthermore, a support vector machine classification model and comprehensive health indexes are combined, so that early, accurate and quantitative diagnosis of a fault mode is realized, and a piezoelectric ceramic micro-vibration online cleaning maintenance strategy can be triggered in a linkage manner. And the device is particularly suitable for high-sand-content and easy-to-scale oil field crude oil conveying working conditions, and the reliability, the economical efficiency and the intelligent level of equipment operation can be greatly improved.

Description

Technical Field

[0001] This invention relates to the field of petrochemicals, and in particular to a multi-stage eddy current-heat conduction composite heat exchanger. Background Technology

[0002] Spiral plate heat exchangers have long been widely used in the preheating and transportation of crude oil in oilfields due to their compact structure, high heat transfer efficiency, and certain self-cleaning capabilities. However, as oilfield exploitation enters its later stages, the water content of crude oil increases, and the associated sediment content also increases significantly, posing a severe challenge to the long-term stable operation of heat exchange equipment.

[0003] In existing technologies, such as the "vortex and centrifugal sand removal interface device for spiral plate heat exchangers" disclosed in CN104236378A, the core idea is to add an independent vortex separation device before the heat exchanger inlet. This device causes the crude oil to rotate through tangential feeding and internal spiral guide channels, using centrifugal force to achieve preliminary separation of oil and sand. The settled silt is collected by the conical cylinder at the bottom and discharged periodically. The main purpose of this design is "anti-clogging," that is, to prevent silt from entering the core heat exchange area as much as possible through pretreatment. However, this solution has the following inherent limitations: First, as an independent interface device, it does not alter the flow field and heat transfer characteristics within the spiral plate heat exchange channel itself. It is ineffective against fine particles already inside the heat exchange channel or silt that is periodically suspended due to flow velocity fluctuations, and the problem of heat exchange efficiency decaying over time persists. Second, this solution is a passive, intermittent sand removal method, relying on gravity settling and periodic manual cleaning. It cannot achieve real-time sensing and online intervention of the heat exchanger's performance during operation, let alone predict the scaling state. When the crude oil flow rate is too low or its composition changes, silt will still slowly accumulate in the heat exchange channel, eventually leading to a reduction in flow area, an increase in pressure drop, and a deterioration in heat transfer, until shutdown for physical cleaning is necessary, severely impacting production continuity and increasing maintenance costs.

[0004] In addition to the aforementioned technical approaches focusing on inlet separation, other common solutions exist in this field to address fouling on heat exchange surfaces and enhance heat transfer. For example, corrugated plates, threaded pipes, and other irregularly shaped surfaces are used to disturb the flow field, or static mixers are installed. However, these methods often only provide disturbance at a single scale, and their anti-fouling and heat transfer enhancement effects are limited and non-adjustable for high-viscosity, multiphase flow crude oil media. Another approach is to develop online monitoring systems, but existing monitoring systems are mostly limited to simple threshold alarms for macroscopic parameters such as inlet and outlet temperatures and pressures. They cannot deeply quantify the critical internal conditions of the equipment (such as real-time fouling thermal resistance), have weak diagnostic capabilities, high false alarm rates, and cannot provide accurate decision-making basis for preventative maintenance.

[0005] In summary, existing technologies generally employ a single strategy of "blocking" or "post-event handling" to address the problems faced by oilfield crude oil heat exchangers, failing to integrate proactive, multi-scale flow and heat transfer enhancement mechanisms with model-based algorithm-based intelligent state perception and decision-making systems. Therefore, developing an intelligent heat exchanger that can adapt to crude oil operating conditions, proactively suppress sediment deposition, maintain continuous high-efficiency heat transfer, and provide real-time health monitoring and predictive maintenance has become a pressing technical challenge in this field. Summary of the Invention

[0006] The purpose of this invention is to provide a multi-stage eddy current-thermal conduction composite heat exchanger to solve the problems existing in the prior art.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] This invention provides a multi-stage eddy current-thermal conduction composite heat exchanger, comprising: The shell is a cylindrical structure with tube sheets at both ends. The shell has a crude oil tangential inlet and a crude oil outlet, forming a shell-side channel. The heat exchange tube bundle consists of multiple parallel threaded tubes, each end of which is fixed to a tube sheet at both ends to form a tube-side channel. A multi-stage vortex generator assembly is disposed within the shell-side channel and located in the inter-tube region of the heat exchange tube bundle, for sequentially generating vortices of different scales in the shell-side channel; the multi-stage vortex generator assembly includes a first-stage helical guide, a second-stage adjustable vortex generator, and a third-stage field synergistic enhancer arranged sequentially along the fluid direction; An online monitoring and self-diagnosis system is used to monitor the performance status of the heat exchanger in real time and perform fault diagnosis. It includes temperature sensors, pressure sensors, and differential pressure sensors installed at the inlet and outlet of the shell-side channel and the tube-side channel, an ultrasonic thickness probe installed inside the shell-side channel, and an edge computing controller connected to all sensor signals. The edge computing controller has a built-in algorithm model for estimating fouling thermal resistance and diagnosing fault types in real time based on sensor data.

[0009] Preferably, the primary spiral guide includes a continuous spiral blade fixedly welded to the inlet section of the inner wall of the housing, the spiral angle of the continuous spiral blade being 25°-35°, and its length accounting for 10%-20% of the total length of the housing.

[0010] Preferably, the secondary adjustable eddy current generator includes a central shaft, which is rotatably disposed at the center of the housing, and multiple sets of delta wing eddy current generating units are fixedly installed on the side of the central shaft; the angle of attack of the delta wing eddy current generating units is adjustable in the range of 20°-50°; one end of the central shaft extends to the outside of the housing and is connected to a drive actuator.

[0011] Preferably, a piezoelectric ceramic actuator is integrated inside the central shaft. The piezoelectric ceramic actuator is electrically connected to the edge computing controller and is used to receive commands to generate high-frequency micro-amplitude vibrations.

[0012] Preferably, the three-stage field synergistic intensifier includes multiple elliptical cylinders, which are longitudinally welded between adjacent heat exchange tube bundles. The surface of the elliptical cylinders is provided with wavy fins, and the height of the wavy fins varies in a gradient along the fluid direction.

[0013] Preferably, the algorithm model in the online monitoring and self-diagnosis system performs the following steps: Acquire and preprocess temperature, pressure, differential pressure and ultrasonic signals from various sensors; An extended Kalman filter model with outlet temperature and fouling thermal resistance as state variables is constructed to estimate the current overall heat transfer coefficient and fouling thermal resistance online in real time. A comprehensive health index is constructed based on the estimated fouling thermal resistance, measured pressure drop, and calculated heat transfer efficiency. The feature vectors, including comprehensive health indicators and scaling thermal resistance growth rate, are input into a pre-trained support vector machine classification model to perform qualitative identification of fault modes. If the fault is identified as a scaling-related fault, the scaling layer thickness is calculated based on the mechanism model, and corresponding maintenance instructions are triggered according to the comprehensive health index threshold and fault mode.

[0014] Preferably, the maintenance instructions include: triggering the piezoelectric ceramic actuator to work when the comprehensive health index reaches a first threshold and the fault mode is mild scaling; and outputting an alarm and recommending manual descaling when the comprehensive health index reaches a higher second threshold and the fault mode is severe scaling.

[0015] Preferably, the surface of the heat exchange tube bundle is coated with a polytetrafluoroethylene coating.

[0016] Preferably, the tangential direction of the crude oil tangential inlet is consistent with the initial rotation direction of the first-stage spiral guide.

[0017] Preferably, the edge computing controller is also communicatively connected to a cloud server to upload performance degradation trend data and dynamically optimize the alarm threshold of the comprehensive health index through a reinforcement learning algorithm.

[0018] The present invention achieves the following beneficial technical effects compared to the prior art: This invention provides a multi-stage vortex-thermal conduction composite heat exchanger, which effectively overcomes the shortcomings of existing technologies through the deep integration of innovative structural design and intelligent monitoring algorithms. Firstly, structurally, this invention creatively designs a multi-stage vortex generation system arranged in series. This system starts by guiding a large-scale helical flow, transitions to generating longitudinal vortices with strong shearing effects, and finally forms a detached vortex with optimized field coordination. This achieves multi-scale perturbation of the shell-side fluid from macroscopic to microscopic levels with progressive intensity, significantly enhancing heat transfer. More importantly, it makes it difficult for solid particles to deposit stably, achieving active and continuous anti-fouling throughout the entire heat exchange process. Secondly, this invention integrates an advanced online monitoring and self-diagnostic system. This system, through multi-sensor fusion and extended Kalman filtering algorithms, can estimate key, unmeasurable scaling thermal resistance online in real time, overcoming the limitations of traditional monitoring which can only observe macroscopic parameters. Furthermore, by combining a support vector machine classification model with comprehensive health indicators, it achieves early, accurate, and quantitative diagnosis of fault modes such as "mild scaling" and "severe sludge buildup," and can trigger an online cleaning and maintenance strategy using piezoelectric ceramic micro-vibration, truly realizing the transformation from "periodic maintenance" to "predictive maintenance." In summary, this invention features high heat transfer efficiency, strong anti-scaling ability, transparent operating status, and intelligent maintenance decision-making. It is particularly suitable for crude oil transportation conditions in oilfields with high sand content and prone to scaling, significantly improving the reliability, economy, and intelligence level of equipment operation. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A schematic diagram of the multi-stage eddy current-thermal conduction composite heat exchanger provided by the present invention; Figure 2 The flowchart illustrates the online monitoring and self-diagnosis system for the multi-stage eddy current-thermal conduction composite heat exchanger provided by this invention. Detailed Implementation

[0021] Unless otherwise specified, the terms "connection" and "linkage" used in this application include both direct and indirect connections (linkages). In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0022] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] The purpose of this invention is to provide a multi-stage eddy current-thermal conduction composite heat exchanger to solve the problems existing in the prior art.

[0025] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Example 1: Please see Figure 1 and Figure 2 This invention provides a multi-stage eddy current-heat conduction composite heat exchanger, the core of which is to integrate active multi-stage eddy current enhanced heat transfer, surface anti-fouling technology and intelligent online monitoring system based on model algorithm into an integrated design, thereby achieving efficient, stable and predictable heat exchange operation under high sand content crude oil conditions.

[0027] like Figure 1As shown, the heat exchanger body of the present invention includes a cylindrical shell 1. Tube sheets 2 are fixed to both ends of the shell 1 by welding, forming a sealed pressure-bearing space. A crude oil tangential inlet 11 and a crude oil outlet 12 are provided on the side wall of the shell 1, located at opposite ends of the shell, allowing the crude oil to flow axially within the shell. The design of the crude oil tangential inlet 11 ensures that the fluid acquires an initial tangential velocity component upon entering the shell, laying the foundation for subsequent rotational flow. Multiple heat exchange tubes are arranged in parallel within the shell, forming a heat exchange tube bundle 3. These heat exchange tubes are preferably reinforced heat transfer tubes with threads machined on their outer surface, and their ends are fixed to the tube sheets 2 at both ends by expansion joints or welding, forming tube-side channels for introducing heating or cooling media. The surface of the heat exchange tube bundle 3 is coated with a dense polytetrafluoroethylene coating. This coating has extremely low surface energy, excellent hydrophobic and oleophobic properties, and good chemical inertness. It can effectively reduce the initial adhesion of polar substances and waxes in crude oil to the pipe wall, reduce the tendency to scale, and form a synergy with the subsequent eddy current anti-scaling mechanism.

[0028] One of the core innovations of this invention is a multi-stage vortex generator assembly installed in the shell-side channel, in the region between the three tubes of the heat exchanger bundle. This assembly is not a simple static mixer, but a three-stage structure carefully designed and arranged in series along the fluid direction, designed to perform multi-scale control of the shell-side crude oil flow field from macroscopic guidance to microscopic disturbances with progressive intensity.

[0029] The first stage is a single-stage helical guide 4, which consists of a continuous helical metal plate fixedly welded to the inlet section of the inner wall of the shell 1. The helix angle of this helical plate is preferably 30°, and its axial length accounts for approximately 15% of the total length of the shell. Its inlet end is connected to the tangential crude oil inlet 11, and the initial helix direction is consistent with the tangential direction of the inlet, ensuring a smooth transition of the fluid from tangential flow to controlled helical flow. The main function of this stage is to regulate the incoming flow into a large-scale, organized helical flow, achieving uniform distribution of the fluid in the circumferential direction, avoiding localized low-velocity zones caused by the inlet "jet" effect, and creating stable and orderly flow field conditions for the subsequent generation of vortices.

[0030] Downstream of the primary helical guide 4 is the secondary adjustable vortex generator 5. This generator includes a central shaft 51 arranged along the axis of the housing. The central shaft 51 is rotatably supported within the housing 1 by bearing seats at both ends, with one end passing through the housing and sealed, extending externally to connect to a drive actuator 53, such as a servo motor. On the side of the central shaft 51, multiple sets of delta-air-shaped vortex generating units 52 are fixedly installed axially and circumferentially. The angle of attack of these delta airfoils can be adjusted, allowing for overall adjustment within the range of 20° to 50°. When crude oil with helical motion flows through these delta airfoils, a pair of small longitudinal vortices with opposite rotation directions are induced in the wake region of each delta airfoil. These longitudinal vortices have strong three-dimensionality and shearing effect, capable of penetrating deeply and strongly disturbing the fluid boundary layer on the surface of the heat exchange tubes, significantly improving local turbulence and heat transfer coefficient. By externally adjusting the angle of attack, it is possible to adapt to crude oil conditions with different viscosities and flow velocities, achieving a dynamic optimal balance between flow resistance and heat transfer enhancement. In addition, a piezoelectric ceramic actuator 54 is integrated inside the central shaft 51. Its power supply and control signal lines are arranged and led out along the inside of the shaft and connected to the edge computing controller described later. This actuator can generate high-frequency, low-amplitude mechanical vibrations when it receives a specific electrical signal, and transmits the vibrations to the entire secondary generator structure through the shaft.

[0031] The third stage is the three-stage field synergistic enhancer 6, located in the downstream heat exchange region. It consists of multiple elliptical cylinders 61, which are longitudinally welded between adjacent heat exchange tubes. Each elliptical cylinder 61 has wavy fins 62 welded to its surface. The presence of the elliptical cylinders themselves generates periodic, smaller-scale detached vortices behind them. The gradient-changing wavy fins further refine the flow field near the tube wall, its core function being to optimize the "field synergy" principle: by designing the fin shape and gradient, the spatial distribution of the fluid velocity vector field and the temperature gradient field becomes more synergistic, thereby further enhancing the heat transfer process at the molecular diffusion level. This stage structure refines and optimizes the vortices of the first two stages, aiming to tap into the potential for deep heat transfer.

[0032] Another core innovation of this invention lies in the integration of an online monitoring and self-diagnosis system. For example... Figure 1 and Figure 2 As shown, the system includes sensor arrays positioned at key physical locations and an edge computing controller for data processing. The sensors include: temperature and pressure sensors installed at the shell-side crude oil inlet and outlet; temperature sensors installed at the tube-side medium inlet and outlet; differential pressure sensors installed before and after the secondary adjustable eddy current generator 5 and the tertiary field co-enhancer 6; and an ultrasonic thickness probe installed inside the shell, pointing towards the heat exchange tube bundle, for non-contact measurement of possible deposit thickness on the outer wall of the tubes. All sensors are signal-connected to the edge computing controller.

[0033] The edge computing controller incorporates an intelligent algorithm model that integrates physical mechanisms and data-driven approaches. Its workflow is as follows: Figure 2 As shown, the specific execution steps are as follows: Step S1: Synchronous Acquisition and Preprocessing of Multi-Source Data. The controller synchronously acquires raw data from all sensors at a fixed frequency. For slowly varying signals such as temperature and pressure, a sliding time window averaging filter is used to eliminate random noise. For ultrasonic thickness signals, which are susceptible to fluid noise and bubble interference, a discrete wavelet transform based on the Symlets 8 wavelet basis is used for noise reduction. A soft threshold function is used to filter out high-frequency noise components, retaining the low-frequency effective signal that reflects the true thickness change, which can significantly improve the signal-to-noise ratio.

[0034] Step S2: Real-time estimation of fouling thermal resistance based on extended Kalman filtering. This is crucial for achieving online state awareness. First, a discrete-time state-space model of the system is established.

[0035] The state vector is defined as: ; in, for The temperature at the crude oil outlet of the shell side at any given time. The outlet temperature of the medium in the tube. The total fouling thermal resistance on the shell side is to be estimated.

[0036] The measurement vector is: ; in, for The shell-side crude oil outlet temperature measured at all times. for The tube-side medium outlet temperature is measured at all times. for The total pressure drop across the shell side measured at any given time.

[0037] The equation of state is constructed based on the dynamic energy balance and heat transfer equations: ; in, Given the known inputs, including the inlet temperatures and mass flow rates of both the shell and tube sides, This is process noise. (Function) The core is to simultaneously solve the dynamic energy equations for the shell and tube sides: ; ; in, The total heat capacity of the shell-side fluid. The mass flow rate of the shell-side crude oil. The specific heat capacity at constant pressure of the shell-side crude oil. The total heat capacity of the fluid in the tube. The mass flow rate of crude oil in the pipeline. The specific heat capacity at constant pressure of crude oil in the pipeline. The overall heat transfer coefficient is based on the current state. For the total heat transfer area, This represents the logarithmic mean temperature difference between the shell and tube sides. The relationship between the overall heat transfer coefficient and the heat transfer coefficient in the clean state and the fouling thermal resistance is as follows: ; in, The overall heat transfer coefficient of the heat exchanger under clean conditions. This is the additional thermal resistance caused by dirt.

[0038] The measurement equation is: ; in, For the observation matrix, For measuring noise.

[0039] The EKF algorithm iterates on this model, recursively obtaining the optimal estimate of the state vector by fusing real-time measurement data, thereby directly outputting the fouling thermal resistance and the implicit overall heat transfer coefficient at the current moment. This step realizes online "soft measurement" of key state variables that cannot be directly measured.

[0040] Step S3: Construction of a Comprehensive Health Index. To comprehensively assess the health status of the heat exchanger, a comprehensive health index is constructed. This index is a weighted sum of multiple normalized performance degradation indices: ; in, This is the current measured value of the total pressure drop. This is the instantaneous heat transfer efficiency calculated based on the current inlet and outlet temperatures. , and These represent the set critical values ​​for fouling thermal resistance, pressure thresholds, and heat transfer performance under clean conditions, respectively. Weighting coefficients. , , The parameters are pre-set based on their impact on operational safety and economy (e.g., values ​​of 0.5, 0.3, and 0.2 respectively). The comprehensive health index quantifies the degree of equipment performance degradation from three dimensions: heat transfer performance, flow resistance, and efficiency. The closer the value is to 1, the worse the health condition.

[0041] Step S4: Fault Mode Recognition Based on Support Vector Machine (SVM). The current feature vectors, combined with health indicators, the rate of change of scaling thermal resistance, the deviation of the current pressure drop from the baseline pressure drop in the clean state, and the local deposition thickness measured ultrasonically, are input into a pre-trained multi-class SVM model for qualitative fault mode identification. The SVM model is trained offline using historical operating data to learn the distribution patterns of these feature vectors under different fault modes. In online applications, this model can accurately distinguish typical fault modes such as "normal state," "light particulate scaling," "severe viscous fouling," and "localized flow blockage."

[0042] Step S5: Maintenance Decision and Execution. Based on the failure modes identified by SVM and the values ​​of comprehensive health indicators, the system executes a tiered maintenance strategy: If the scale is identified as "light particulate fouling" and the overall health indicators exceed a preset first threshold, the system determines it to be early-stage fouling that can be intervened online. The edge computing controller then sends a drive signal to the piezoelectric ceramic actuator 54, causing it to operate for a period of time. The high-frequency micro-amplitude vibration generated by the actuator is transmitted to the entire secondary adjustable eddy current generator 5 and its delta wing, which can effectively loosen the loose particulate deposits attached to the heat exchange tubes and generator surface, allowing them to be carried away by the mainstream, thus achieving online micro-cleaning without shutting down the system.

[0043] If the system identifies the problem as "severely viscous fouling" or "localized flow blockage," and the overall health indicators exceed a higher second threshold, it indicates severe performance degradation, and online micro-cleaning may be ineffective. In this case, the system will issue a high-level audible and visual alarm through the human-machine interface and clearly display the diagnostic conclusion, the suggested estimated scale thickness, and a maintenance work order recommending manual cleaning on the monitoring screen. Operators can use this accurate warning to plan shutdowns and perform manual descaling operations such as high-pressure water jetting or chemical cleaning, thereby avoiding unplanned downtime and production interruptions.

[0044] Furthermore, the edge computing controller can upload long-term comprehensive health indicator trends, thermal resistance change curves, and other performance degradation data to the cloud server via the network. The cloud uses reinforcement learning algorithms to analyze the performance degradation patterns under different crude oil characteristics and operating conditions, dynamically optimizing the alarm thresholds sent to the edge controller. This makes maintenance strategies more adaptive and achieves optimal lifecycle costs.

[0045] The specific working process of this invention is as follows: The heating medium (such as hot water) flows into the heat exchange tube bundle 3 from the tube-side inlet and flows out from the tube-side outlet. High-sand crude oil enters the shell-side space of the shell 1 tangentially from the crude oil tangential inlet 11. The fluid first passes through the first-stage helical guide 4 and is regulated into a rotating and rising helical flow. Then it enters the region of the second-stage adjustable vortex generator 5, where a large number of high-intensity longitudinal vortices generated by the delta fins strongly disturb the fluid and the tube wall boundary layer, thereby enhancing heat transfer and preventing sediment deposition. At the same time, based on the crude oil property information fed back by the online monitoring system, the angle of attack of the delta fins can be adjusted by the drive actuator 53 to adapt to changes in operating conditions. Next, the fluid enters the region of the third-stage field synergistic enhancer 6, where, under the action of the elliptical cylinder and gradient fins, a more complex vortex system is generated and the synergy between the velocity field and the temperature field is optimized for deep heat transfer. Finally, the heat-exchanged crude oil flows out from the crude oil outlet 12. Throughout the process, the online monitoring and self-diagnosis system works continuously to assess the equipment status in real time and automatically initiates online micro-cleaning of piezoelectric ceramics or provides early warning prompts for manual cleaning when necessary, thereby ensuring that the heat exchanger operates in a highly efficient and stable state for a long time.

[0046] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0047] It should be noted that the components mentioned in the above embodiments are all general standard parts or components known to those skilled in the art. Their structures and principles can be learned by those skilled in the art through technical manuals or conventional experimental methods.

[0048] This invention has illustrated its principles and implementation methods using specific examples. The descriptions of these embodiments are merely illustrative of the method and its core ideas; furthermore, those skilled in the art will recognize that modifications may be made to the specific implementation methods and application scope based on the principles of this invention. Therefore, the content of this specification should not be construed as limiting the invention.

Claims

1. A multi-stage eddy current-thermal conduction composite heat exchanger, characterized in that, include: The shell (1) is a cylindrical structure with tube sheets (2) at both ends. The shell (1) is provided with a crude oil tangential inlet (11) and a crude oil outlet (12) to form a shell-side channel. The heat exchange tube bundle (3) is composed of multiple parallel threaded tubes, with its two ends fixed to the tube sheets (2) at both ends to form tube-side channels. A multi-stage vortex generator assembly is disposed in the shell-side channel and located in the inter-tube region of the heat exchange tube bundle (3) for generating vortices of different scales in the shell-side channel in sequence; the multi-stage vortex generator assembly includes a first-stage spiral guide (4), a second-stage adjustable vortex generator (5), and a third-stage field synergistic enhancer (6) arranged in sequence along the fluid direction. An online monitoring and self-diagnosis system is used to monitor the performance status of the heat exchanger in real time and perform fault diagnosis. It includes temperature sensors, pressure sensors, and differential pressure sensors installed at the inlet and outlet of the shell-side channel and the tube-side channel, an ultrasonic thickness probe installed inside the shell-side channel, and an edge computing controller connected to all sensor signals. The edge computing controller has a built-in algorithm model for estimating fouling thermal resistance and diagnosing fault types in real time based on sensor data.

2. The multi-stage eddy current-thermal conduction composite heat exchanger according to claim 1, characterized in that, The primary spiral guide (4) includes a continuous spiral blade fixedly welded to the inlet section of the inner wall of the housing (1). The spiral angle of the continuous spiral blade is 25°-35°, and its length accounts for 10%-20% of the total length of the housing (1).

3. The multi-stage eddy current-thermal conduction composite heat exchanger according to claim 1, characterized in that, The secondary adjustable eddy current generator (5) includes a central shaft (51), which is rotatably disposed at the center of the housing (1). Multiple sets of delta wing eddy current generating units (52) are fixedly installed on the side of the central shaft (51). The angle of attack of the delta wing eddy current generating unit (52) is adjustable from 20° to 50°. One end of the central shaft (51) extends to the outside of the housing (1) and is connected to a drive actuator (53).

4. The multi-stage eddy current-thermal conduction composite heat exchanger according to claim 3, characterized in that, The central shaft (51) integrates a piezoelectric ceramic actuator (54), which is electrically connected to the edge computing controller and is used to receive commands to generate high-frequency micro-amplitude vibration.

5. The multi-stage eddy current-thermal conduction composite heat exchanger according to claim 4, characterized in that, The three-stage field synergistic enhancer (6) includes multiple elliptical cylinders (61), which are longitudinally welded between adjacent heat exchange tube bundles (3). The surface of the elliptical cylinders (61) is provided with wavy fins (62), and the height of the wavy fins (62) varies in a gradient along the fluid direction.

6. The multi-stage eddy current-thermal conduction composite heat exchanger according to claim 5, characterized in that, The algorithm model in the online monitoring and self-diagnosis system performs the following steps: Acquire and preprocess temperature, pressure, differential pressure and ultrasonic signals from various sensors; An extended Kalman filter model with outlet temperature and fouling thermal resistance as state variables is constructed to estimate the current overall heat transfer coefficient and fouling thermal resistance online in real time. A comprehensive health index is constructed based on the estimated fouling thermal resistance, measured pressure drop, and calculated heat transfer efficiency. The feature vectors, including comprehensive health indicators and scaling thermal resistance growth rate, are input into a pre-trained support vector machine classification model to perform qualitative identification of fault modes. If the fault is identified as a scaling-related fault, the scaling layer thickness is calculated based on the mechanism model, and corresponding maintenance instructions are triggered according to the comprehensive health index threshold and fault mode.

7. The multi-stage eddy current-thermal conduction composite heat exchanger according to claim 6, characterized in that, The maintenance instructions include: when the comprehensive health index reaches the first threshold and the fault mode is mild scaling, triggering the piezoelectric ceramic actuator (54) to work; when the comprehensive health index reaches a higher second threshold and the fault mode is severe scaling, outputting an alarm and suggesting manual descaling.

8. The multi-stage eddy current-thermal conduction composite heat exchanger according to claim 1, characterized in that, The surface of the heat exchange tube bundle (3) is coated with a polytetrafluoroethylene coating.

9. The multi-stage eddy current-thermal conduction composite heat exchanger according to claim 1, characterized in that, The tangential direction of the crude oil tangential inlet (11) is consistent with the initial rotation direction of the first-stage spiral guide (4).

10. The multi-stage eddy current-thermal conduction composite heat exchanger according to any one of claims 1-9, characterized in that, The edge computing controller is also communicatively connected to a cloud server to upload performance degradation trend data and dynamically optimize the alarm threshold of the comprehensive health index through reinforcement learning algorithms.

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