A shell-and-tube heat exchanger exchange system suitable for high pressure working conditions

Abstract

The application relates to the technical field of heat exchangers and discloses a column tube heat exchanger exchange system suitable for high-pressure working conditions, which comprises a multiscale vortex energy dissipation grid arranged at a fluid inlet and a self-adaptive resonance energy absorption assembly integrated with a hollow resonance rod; the energy absorption assembly is passively adjusted by the differential pressure formed by the dissipation grid to adjust the effective mass of the resonance rod, so that the natural frequency of the resonance rod can automatically match the resonance frequency of the tube bundle which drifts due to the change of the working condition; through the cooperative mechanism of the front-end vortex dissipation and the rear-end vibration self-adaptive absorption, the heat exchanger is changed from a rigid body passively bearing the impact into a flexible structure which can actively guide and convert the dynamic energy on site, fatigue damage caused by the vibration energy accumulation in the traditional design is avoided, and effective guarantee is provided for the long-term reliable operation of the equipment under complex working conditions.

Description

Technical Field

[0001] This invention relates to a shell-and-tube heat exchanger system suitable for high-pressure operating conditions, belonging to the field of heat exchanger technology. Background Technology

[0002] Currently, the industry's common design approach to deal with such vibrations is to use rigid reinforced structures, which improve static strength by thickening the pipe walls and strengthening the supports. However, when faced with the aforementioned micro-amplitude resonance, the structural characteristics of this design mean that the vibration energy will not be absorbed, but will be transmitted without attenuation, resulting in stress concentration at places such as pipe welds. At the same time, it will cause fretting wear between the support plate and the heat exchange tube. These effects caused by the accumulation of micro-damage are difficult to detect in advance by conventional monitoring methods, and may eventually lead to fatigue fracture of the equipment.

[0003] Specifically, existing design methods contain an inherent contradiction: the rigidity constructed to resist static pressure becomes the carrier of dynamic destructive energy. Therefore, how to construct an internal structure of a heat exchanger that can actively manage and dissipate this dynamic vibration energy with continuously changing frequency under varying operating conditions, and avoid the accumulation of damage, becomes the technical problem to be solved by this invention. Summary of the Invention

[0004] This invention provides a shell-and-tube heat exchanger system suitable for high-pressure conditions. Its main purpose is to solve the problem that the existing rigid structure of heat exchangers cannot actively manage and dissipate the dynamic vibration energy with frequency changes under varying operating conditions, resulting in the risk of fatigue damage accumulation.

[0005] To achieve the above objectives, the present invention provides a shell-and-tube heat exchanger system suitable for high-pressure operating conditions, comprising a tube bundle, a tube sheet, and at least one support plate for supporting the tube bundle. The system further includes a structured energy flow guidance and adaptive dissipation assembly, which comprises:

[0006] A multi-scale vortex energy dissipation grid is fixed at the fluid inlet of a heat exchanger and is composed of at least two types of perforated plates with different apertures stacked along the fluid direction. The multi-scale vortex energy dissipation grid is configured to break up the mainstream vortex of the inlet fluid step by step.

[0007] An adaptive resonant energy absorption assembly includes a support plate and multiple hollow tubular resonant rods, one end of which is fixed to the support plate and the other end is free. A dynamic pressure acquisition cavity and microchannels connected to the dynamic pressure acquisition cavity are machined within the support plate. The microchannels open onto the upstream and downstream sides of a multi-scale eddy current energy dissipation grid. The open, fixed ends of the hollow tubular resonant rods are connected to the dynamic pressure acquisition cavity. The adaptive resonant energy absorption assembly is configured to utilize the pressure difference created by the fluid flowing through the multi-scale eddy current energy dissipation grid to drive the fluid medium within the heat exchanger into or out of the hollow tubular resonant rods, thereby changing the effective vibration mass of the hollow tubular resonant rods. This allows the natural vibration frequency of the hollow tubular resonant rods to automatically track and match the predetermined resonant frequency of the tube bundle, which changes due to variations in fluid conditions.

[0008] Preferably, the multi-scale eddy current energy dissipation grid includes a first perforated plate, a second perforated plate, and a third perforated plate arranged sequentially along the fluid direction; the first perforated plate has a first aperture, the second perforated plate has a second aperture smaller than the first aperture, and the third perforated plate has a third aperture smaller than the second aperture, and the third aperture is smaller than the minimum spacing between adjacent heat exchange tubes in the tube bundle.

[0009] Preferably, the hollow tubular resonant rod is fixed in the blind hole of the support plate by a combination of interference fit and brazing.

[0010] Preferably, the hollow tubular resonant rod is made of the same metal material as the support plate.

[0011] Preferably, the surface of the hollow tubular resonant rod is provided with an open microgroove array, and the surface of the hollow tubular resonant rod is subjected to a gradient wetting treatment, so that its surface can exhibit a gradual change in properties from hydrophilic to hydrophobic from the fixed end to the free end.

[0012] Preferably, on the support plate, a ring of wedge-shaped microgrooves is provided around the fixing base of each hollow tubular resonant rod. The geometric dimensions of the wedge-shaped microgrooves match the resonance characteristics of the hollow tubular resonant rod, so that the angular velocity of the resonant rod vibration is controlled. and vibration amplitude The determined local pressure fluctuations within the microgroove satisfy the following cavitation initiation conditions: ,in, The static pressure of the fluid in the main flow channel of the heat exchanger. This is the saturated vapor pressure of the fluid under the current operating conditions. For fluid density, It is a critical cavitation number determined by fluid properties and material surface characteristics.

[0013] Preferably, at least one hollow tubular resonant rod has an armored thermocouple integrated at its free end as a temperature sensor. The system also includes a state diagnostic unit configured to: continuously acquire the output electrical signal of the temperature sensor; perform fast Fourier transform processing on the output electrical signal to obtain the spectrum formed under the excitation of the inherent thermal noise of the heat exchanger system; and identify the resonance peak corresponding to the natural frequency of the hollow tubular resonant rod from the spectrum, and then output a diagnostic data characterizing the position of the center frequency of the resonance peak.

[0014] Preferably, the second perforated plate has hexagonal holes, the first perforated plate has circular holes, and the central axis of the hexagonal holes of the second perforated plate is offset from the central axis of the circular holes of the first perforated plate in a plane perpendicular to the direction of fluid flow.

[0015] Preferably, the status diagnosis unit is further configured to generate and output a warning signal when the center frequency position of the resonance peak represented by the diagnostic data output by it drifts more than a health status threshold relative to an initial calibration frequency position of the resonance peak.

[0016] Preferably, the cantilever length and wall thickness of the hollow tubular resonant rod are determined in advance by finite element analysis based on the expected variation range of the Karman vortex street shedding frequency induced by fluid flow within the target operating conditions of the heat exchanger design.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 1. This invention provides a structured energy conduction and dissipation method, avoiding the limitations of traditional designs that rely solely on increasing structural rigidity to resist vibration stress. By setting a multi-scale vortex energy dissipation grid at the fluid inlet, the disordered large-scale vortices in the high-pressure fluid can be broken up and dissipated in stages before impacting the heat exchange tube bundle. This changes the initial conditions of vibration excitation. Furthermore, the adaptive resonant energy absorption assembly working in conjunction with the grid automatically adjusts the effective mass of the resonant rod by utilizing the pressure difference formed by the change in the fluid conditions, so that its natural frequency can always be locked at the resonant frequency point of the tube bundle, thereby forming a continuous targeted absorption channel for vibration energy. This collaborative mechanism of first conducting and then absorbing energy transforms the system from a rigid body that passively withstands vibration impact into a flexible structure that can actively manage and convert dynamic energy on-site. This makes the long-term operational reliability of the equipment under extreme conditions no longer solely dependent on the accumulation of material strength.

[0019] 2. By integrating a hollow tubular resonant rod onto a support plate and constructing a dynamic pressure acquisition cavity and microchannel connected to it, an adaptive tuning system without any external energy or active control was established. This system transforms the pressure difference generated by the multi-scale eddy current energy dissipation grid during flow equalization—an energy loss byproduct—into a real-time fluid condition change sensing signal. This signal directly drives the fluid medium to exchange inside and outside the resonant rod, thereby changing its effective vibration mass and automatically matching the changing trend of its natural frequency with the fluid excitation frequency. This design internalizes the unpredictability of dynamic operating conditions—an external challenge—into the driving force for the system's self-optimization. This expands the vibration protection capability from fixed-point defense at a single static frequency point to tracking coverage of the entire dynamic operating range, providing structural safety assurance for the heat exchanger during the entire process of real industrial operations such as start-up, shutdown, and load changes.

[0020] 3. By setting wedge-shaped microgrooves around the base of the resonant rod, the function of the resonant rod, which was originally used to absorb and dissipate vibration energy, is extended, making it a microscale online self-cleaning actuator. When the resonant rod resonates at high frequency, its concentrated energy is converted in situ into a violent compression and rarefaction effect on the local fluid through the specific geometry of the wedge-shaped microgrooves, thereby inducing a controllable cavitation effect. This process uses the microjets generated by the collapse of cavitation bubbles to continuously peel off and crush any dirt that tries to adhere to the surface of the support plate, thereby avoiding the risk of reduced heat transfer efficiency and under-deposit corrosion caused by scaling. This method of unifying the two long-standing independent technical issues of structural dynamic stability and surface heat transfer enhancement through a single passive microstructure design allows the structure to peel off dirt from the surface of the support plate during equipment operation using a controllable cavitation effect.

[0021] 4. By integrating a temperature sensor and configuring a corresponding condition diagnostic unit on the resonant rod, a passive online health monitoring mechanism is established for the core protective components of the heat exchanger. This mechanism utilizes the fluid thermal noise that is ubiquitous and unavoidable in heat exchanger systems as a natural, continuous, broadband micro-disturbance excitation source. By analyzing the spectrum of the temperature sensor signal, the structural health status of the resonant rod is inverted. When the resonant rod suffers damage such as micro-cracks due to fatigue or corrosion, its natural frequency will inevitably drift. This change will be directly reflected in the position of the resonance peak monitored by the diagnostic unit. This approach avoids the traditional monitoring scheme that relies on external excitation sources and complex vibration sensors. In a near-zero-cost manner, an invisible silent failure risk is transformed into a manageable maintenance event that can be predicted in advance, realizing the transformation from post-failure maintenance to pre-failure predictive maintenance. Attached Figure Description

[0022] Figure 1This is a structural and functional block diagram of a shell-and-tube heat exchanger system suitable for high-pressure conditions according to the present invention.

[0023] Figure 2 This is a flowchart illustrating the design and calibration process of the adaptive resonant energy absorption assembly of the present invention.

[0024] Figure 3 This is a schematic diagram of the working state transition of the switching system of the present invention;

[0025] Figure 4 This is a schematic diagram of the overall structure of the switching system of the present invention;

[0026] Figure 5 This is a partial structural schematic diagram of the adaptive resonant energy absorption assembly of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0028] In a specific scenario applied to the core regenerator of a supercritical carbon dioxide power generation system, a shell-and-tube heat exchanger system suitable for high-pressure conditions is configured with a structured energy flow guidance and adaptive dissipation assembly. This assembly consists of a multi-scale eddy current energy dissipation grid located at the fluid inlet of the heat exchanger and a support plate integrating an adaptive resonant energy absorption assembly. The multi-scale eddy current energy dissipation grid functions to systematically break down and dissipate the large-scale eddy current energy carried by the high-pressure fluid at the inlet before it contacts the heat exchange tube bundle. The adaptive resonant energy absorption assembly utilizes the inherent pressure difference formed by the grid during eddy current dissipation to establish a passive tuning mechanism, enabling it to continuously absorb and convert the structural vibration energy generated by the tube bundle under fluid excitation, with a frequency that varies with the operating conditions. The synergistic effect of the two allows the heat exchanger structure to guide and convert internal dynamic energy on-site, changing its passive vibration impact characteristics.

[0029] Furthermore, in the initial stage of high-pressure fluid entering the shell side of the heat exchanger, the large-scale, high-energy vortices present in the main fluid flow channel pose a technical challenge. If these vortices directly impact the heat exchange tube bundle, they will induce severe and multi-frequency flow-induced vibrations. To address this challenge, a multi-scale vortex energy dissipation grid is fixed at the fluid inlet of the heat exchanger and is composed of at least two types of perforated plates with different apertures stacked along the fluid direction. In one specific implementation, the grid consists of three layers of perforated plates, with the first perforated plate serving as the flow-facing surface and having circular holes of the first aperture machined on it, for example... Its size is set to be able to break up the largest mainstream vortex at the inlet first. The second perforated plate has a second aperture smaller than the first aperture, and its aperture shape is hexagonal, for example... Furthermore, the central axis of the hexagonal hole in the second perforated plate is offset from the central axis of the circular hole in the first perforated plate in a plane perpendicular to the fluid flow direction. This structural combination causes strong interference and energy loss in the secondary vortices formed by the first layer's breakup as they pass through the second layer. The third perforated plate has a third aperture smaller than the second aperture, for example... Furthermore, the third aperture is smaller than the minimum spacing between adjacent heat exchange tubes in the tube bundle. This procedure refines the turbulence scale of the fluid that ultimately flows through the grid to a scale that cannot effectively impact the tube bundle, thereby achieving orderly channeling of the initial fluid kinetic energy at the source of vibration.

[0030] Even if the inlet fluid is calmed, the shedding of the Karman vortex street generated by the fluid flow around the heat exchanger tube bundle will still induce continuous flow-induced vibration. Furthermore, the characteristic frequency of this vibration will drift with adjustments to the system load, i.e., changes in the fluid mass flow rate. This phenomenon poses a continuous challenge to the dynamic safety of the structure. Therefore, the adaptive resonant energy absorption assembly in this technical solution is configured to address this challenge. This assembly includes a support plate and multiple hollow tubular resonant rods. One end of each resonant rod is fixed to a blind hole in the support plate via a combination of interference fit and brazing, while the other end is a closed end that freely extends in the fluid. Its cantilever length and tube wall thickness are based on the Karman vortex street induced by the fluid flow within the target operating conditions of the heat exchanger design. The expected range of frequency variation of the street shedding is pre-calculated using the finite element method. To achieve adaptive frequency tracking, a dynamic pressure acquisition cavity is machined within the support plate. This cavity is connected to the main flow channel of the heat exchanger via microchannels. The microchannels open onto the upstream and downstream sides of the multi-scale vortex energy dissipation grid. The open fixed end of the hollow tubular resonant rod is connected to the dynamic pressure acquisition cavity. With this configuration, when changes in heat exchanger operating conditions lead to an increase in fluid flow rate, the pressure difference generated by the multi-scale vortex energy dissipation grid also increases. This increased pressure difference drives the fluid medium in the main flow channel through the microchannels and the dynamic pressure acquisition cavity into the interior of the hollow tubular resonant rod. According to the principles of vibration dynamics, the effective vibration mass of the resonant rod... Increase, leading to its inherent vibration frequency (and The pressure difference decreases proportionally to the flow rate; conversely, when the flow rate decreases, the pressure difference decreases, some fluid flows out of the rod, and the effective mass... Decrease, natural frequency The natural frequency of the resonant rod can be increased by designing the volume of the hollow resonant rod and the flow resistance of the microchannel. This trend of change matches the trend of the von Karman vortex street shedding frequency as the excitation source changing with the flow rate, thus forming a targeted channel that can continuously lock in and absorb the resonant energy of the tube bundle.

[0031] To achieve positive tracking matching where the natural frequency of the resonant rod increases with the flow rate, a helical guide vane is integrally formed along the length of the hollow tubular resonant rod. When the fluid is under pressure difference... When the fluid enters the rod and flows through the spiral guide vanes, it forms a high-speed rotating internal vortex. The centrifugal force of this vortex exerts radial tension on the thin wall of the resonant rod, thus creating a numerical value and pressure difference. Equivalent hydrodynamic stiffness proportional to the square of The specific relationship is as follows: ,in, It is a hydrodynamic stiffness coefficient uniquely determined by the geometry of the helical guide vanes, such as the pitch and blade angle; therefore, the total natural frequency of the resonant rod under fluid coupling is... Its natural frequency and hydrodynamic stiffness are jointly determined by the following relationship: ,in, For the stiffness of the rod structure. For the mass of the rod structure. Adding mass to the fluid inside the rod, while the hydrodynamic stiffness coefficient The final value is determined by performing a joint finite element and computational fluid dynamics simulation of the rod-fluid coupled system during the design phase, using the total natural frequency within the target operating range. rate of change rate of change of the von Kármán vortex street shedding frequency The convergence objective is to achieve a goodness of fit of 0.95 or higher between the two values, and the final output result is obtained through iterative calculation.

[0032] To improve the operational stability of the system in complex media environments, it is necessary to address the technical challenge of altered damping characteristics of the resonant rod caused by changes in fluid viscosity. This issue affects the resonant rod's resonance efficiency. To address this, the surface of the hollow tubular resonant rod is equipped with an open microgroove array, and the surface undergoes a gradient wetting treatment. This results in a gradual change in surface characteristics from hydrophilic to hydrophobic from the fixed end to the free end. When handling low-viscosity fluids, the fluid's flowability allows it to fill the microgrooves, forming a stable liquid film and ensuring effective coupling between the resonant rod and the fluid. However, when handling high-viscosity fluids, the fluid's flowability makes it difficult for the fluid to completely fill the microstructure, and surface tension in the hydrophobic regions locks in tiny cavities. These cavitation cavitation cavitation cavitation forms an interface between the resonant rod and the fluid, reducing the viscous damping effect of the fluid on the rod. This passively compensates for the damping changes caused by variations in fluid viscosity, maintaining the energy absorption efficiency of the resonant rod. Simultaneously, to address the issue of fouling during long-term heat exchanger operation, a ring of wedge-shaped microgrooves is provided around the fixed base of each hollow tubular resonant rod on the support plate. When the resonant rod is excited to generate high-frequency resonance, the concentrated vibration energy at its root drives the inner wall of the wedge-shaped microgrooves, producing a rapid alternating compression and rarefaction effect on the local fluid within the grooves. The geometry of the wedge-shaped microgrooves matches the resonance characteristics of the hollow tubular resonant rod, ensuring that the vibration angular velocity of the resonant rod... and vibration amplitude The determined local pressure fluctuations within the microgroove satisfy the following cavitation initiation conditions: ,in, The static pressure of the fluid in the main flow channel of the heat exchanger. This is the saturated vapor pressure of the fluid under the current operating conditions. For fluid density, The critical cavitation number is determined by the fluid properties and the surface characteristics of the material. When this condition is met, the fluid in the trench will generate controlled cavitation. The generation and collapse of cavitation bubbles produce microjets that continuously act on the surface of the support plate to peel off the attached dirt particles, thereby achieving an online self-cleaning function.

[0033] To ensure the long-term effectiveness of the resonant rod's structural integrity, it is necessary to monitor for potential damage such as microcracks or corrosion under operating conditions. Therefore, the system also includes a condition diagnostic unit. At the free end of at least one representative hollow tubular resonant rod, an armored thermocouple is integrated as a temperature sensor. This condition diagnostic unit is configured to continuously acquire the output electrical signal of the temperature sensor and perform a Fast Fourier Transform (FFT) on the signal to obtain the signal spectrum generated under the excitation of fluid thermal noise, which is inherent to the heat exchanger system and serves as a broadband excitation source. A healthy resonant rod will exhibit a certain frequency at its designed natural frequency. A clear resonance peak is identified by the condition diagnostic unit from the spectrum. The unit then outputs diagnostic data representing the center frequency position of this resonance peak. When the condition diagnostic unit detects that the drift of the center frequency position of the resonance peak relative to an initial calibration frequency position exceeds a health status threshold, it generates and outputs a warning signal, thus providing a basis for predictive maintenance of the equipment. The signal acquisition and parameter determination of the condition diagnostic unit follow a complete set of engineering calibration procedures. The armored thermocouple integrated at the free end of the resonant rod outputs an electrical signal... It contains a slowly varying DC component determined by temperature. This is modulated by a high-frequency AC component generated by the periodic micro-strain of the thermocouple sheath material due to the piezoresistive effect caused by the high-frequency vibration of the resonant rod. The signal processing front end of the status diagnostic unit is equipped with a fourth-order Butterworth high-pass filter with a cutoff frequency of 100Hz to filter out... Without distortion The AC signal is then amplified by a low-noise amplifier with a gain of 60 dB, and its output is fed into a fast Fourier transform processor to obtain the spectrum; while the benchmark model used to determine the blockage of the multi-scale eddy current energy dissipation grid... coefficients in The unique value is obtained by applying a continuously varying flow rate from zero to the maximum design flow rate to the grid on a clean test bench, while simultaneously recording the pressure difference and flow data, and then fitting the obtained data point set using the least squares method. In addition, the specific geometric contour and depth of the wedge-shaped microgroove used to trigger the self-cleaning function are calculated based on the calibrated resonant rod resonant angular velocity ω and amplitude A, substituting the cavitation initiation conditions and combining the target fluid physical parameters, through microscopic flow field simulation calculations, with the optimization goal of generating shear stress on the support plate surface to reach more than twice the dirt adhesion force.

[0034] Example 1: In a core regenerator of a supercritical carbon dioxide power generation system, the exchange system is deployed to handle rapid load increases by the unit. Under these conditions, the mass flow rate of the supercritical carbon dioxide fluid entering the shell side of the heat exchanger increases rapidly, causing a change in the energy state within the flow field. This not only intensifies the mainstream vortex at the inlet but also causes the Karman vortex street shedding frequency of the heat exchange tube bundle to drift to a higher frequency range due to the increased flow velocity. This frequency drift range covers the inherent resonant frequency of the tube bundle, thus affecting the structural integrity of the equipment. This presents a significant challenge; in this process, the multi-scale vortex energy dissipation grid installed at the fluid inlet of the heat exchanger first processes the flow field. Its stacked perforated plate structure gradually breaks up the large-scale vortices at the inlet, which are exacerbated by the increased load. This reduces the turbulence scale and energy of the fluid entering the core region of the heat exchanger before it contacts the tube bundle. As a result, a stable pressure difference that changes synchronously with the mass flow rate is formed upstream and downstream of the grid. This pressure difference drives the fluid medium into the interior of the hollow tubular resonant rod through the dynamic pressure acquisition chamber and microchannels, increasing the effective vibration mass of the resonant rod. to make its natural frequency As the frequency decreases, the way this frequency change matches the trend of the Karman vortex street shedding frequency increasing due to the increase in flow velocity, so that the energy absorption band of the resonant rod can be aligned with the dangerous resonant frequency point of the tube bundle. This constitutes a cooperative mechanism, in which the flow field smoothing effect of the front grid provides a driving signal for the adaptive frequency adjustment of the rear resonant rod, while the targeted energy absorption of the rear resonant rod keeps the structural vibration load on the front grid at a low level.

[0035] Traditional heat exchangers employ rigid reinforcement methods to resist high static pressure. However, under such dynamic conditions, they face a technical challenge: the higher the structural rigidity, the higher the efficiency of vibration energy transmission, which can easily lead to energy accumulation at weak points and cause fatigue damage. This technical solution provides a solution to this problem by integrating an adaptive resonant energy absorption assembly on a rigid support plate. When the vibration wave generated by the tube bundle due to resonance is transmitted through the support plate, the energy is not transmitted without attenuation, but is absorbed by a hollow tubular resonant rod array with a frequency matched to it. The vibration of the resonant rod converts mechanical energy into heat energy and dissipates it through the internal damping of its material, enabling the structure to maintain static strength while possessing the ability to dissipate dynamic energy.

[0036] Throughout this load increase operation, the system's response to flow-induced vibration did not rely on structural rigidity, but rather on its internal energy management mechanism. The pressure difference generated by the flow through the multi-scale vortex energy dissipation grid, a physical phenomenon traditionally considered an energy loss, was used here as a passive, real-time flow change characterization signal. This directly drove the frequency tuning of the hollow tubular resonant rod, transforming the previously destructive fluid kinetic energy into a self-regulating driving force for the system. This transformed vibration protection from a passive structural strength issue into an active energy management problem that could be actively managed and converted. After the unit completed the load increase operation, the heat exchanger entered a new steady-state operating condition. The spectrum of the output electrical signal from the armored thermocouple integrated on the resonant rod, collected and analyzed by the condition diagnosis unit, showed that the center frequency of the resonant rod's resonance peak stabilized at a new frequency point matching the current operating condition, with no significant changes in its peak value and shape. This indicates that the structural integrity of the resonant rod was maintained throughout the dynamic adjustment process, and the vibration amplitude of the heat exchanger tube bundle was consistently suppressed within the design allowable range.

[0037] Example 2: To objectively verify the effect of this technical solution on suppressing flow-induced vibration under dynamic operating conditions, a high-pressure fluid dynamics test platform was built. This platform includes a high-pressure pump capable of programmatically adjusting the fluid mass flow rate, and a test section with a built-in replaceable heat exchanger tube bundle module. Two heat exchanger tube bundle modules were set up: a control group and a prototype of this invention. The control group used a traditional rigid structure with a solid support plate, while the prototype of this invention integrated a complete structure including a multi-scale eddy current energy dissipation grid and an adaptive resonant energy absorption assembly. Both tests used a non-contact laser Doppler vibration meter to continuously monitor the vibration displacement of the heat exchanger tubes at the same location in the central region of the tube bundle in the fluid normal direction. The core parameter of the test, namely the fluid flow rate variation protocol, was set to simulate the Karman vortex street shedding frequency during heat exchanger operation under varying load. The sweep frequency resonance caused by the change requires a balance between the severity of the simulated operating conditions and the stability of the measurement data. Therefore, the test procedure was determined as follows: the fluid velocity is linearly increased over 60 seconds using programmed control of a high-pressure pump, and the corresponding Karman vortex street shedding frequency is determined. From the first-order natural frequency of the tube bundle 0.8 times ( Smoothly transition to 1.2 times ( This ensures that the excitation frequency can completely sweep through the resonant region of the tube bundle; for the first-order natural frequency... The tube bundle, calibrated to 250Hz by modal testing, had its fluid excitation frequency linearly swept from 200Hz to 300Hz.

[0038] After the experiment was started, the above-described frequency sweep excitation procedure was executed on both the control group and the sample group of the present invention. The maximum vibration amplitude recorded at the center measuring point of the tube bundle showed significant differences. In the initial stage of the frequency sweep, when the excitation frequency... At 200Hz, the vibration amplitudes of both the control group and the sample group of this invention were at relatively low levels, at 0.05mm and 0.04mm respectively; when the excitation frequency approached the resonance region, for example at... At 237.5 Hz, the vibration amplitude of the control group had risen to 0.45 mm, while the amplitude of the sample group of the present invention was only 0.07 mm. At the 250 Hz resonance point, where the excitation frequency perfectly matches the natural frequency of the tube bundle, the vibration amplitude of the control group reached a peak of 1.25 mm. In contrast, the maximum vibration amplitude of the sample group of the present invention was suppressed to 0.08 mm under the same conditions. As the excitation frequency passed the resonance point and continued to rise to 300 Hz, the vibration amplitude of the control group quickly dropped back to 0.06 mm, while the vibration amplitude of the sample group of the present invention remained below 0.08 mm throughout the entire frequency sweep range, without showing a significant resonance peak. The reason for this difference in data trends is that the adaptive resonant energy absorption assembly of the sample group of the present invention played a role during the experiment. The increase in the flow rate led to an increase in the pressure difference across the multi-scale eddy current energy dissipation grid, which passively adjusted the effective mass of the hollow tubular resonant rod, enabling its energy absorption frequency point to continuously track the changing excitation frequency. This allows the accumulated resonance energy to be absorbed and dissipated locally, preventing the vibration amplitude from amplifying. In contrast, the control group, lacking this mechanism, experienced a sharp increase in vibration energy due to the accumulation of vibration energy at the resonance point. The test results show that, compared with heat exchangers using traditional rigid support structures, the heat exchanger system equipped with the structured energy flow guidance and adaptive dissipation assembly of this invention can suppress the vibration amplitude of the tube bundle to a significantly lower range under dynamic operating vibration conditions with varying excitation frequencies. This result confirms that the technical solution can effectively address the resonance risk caused by changes in operating conditions, providing technical support for improving the structural reliability of equipment under complex operating conditions.

[0039] Example 3: This example combines Figures 1 to 4 This document describes the implementation of a shell-and-tube heat exchanger system suitable for high-pressure operating conditions. Figure 1As shown, the diagram is divided into two levels: the physical domain and the information domain. In the physical domain, the high-pressure fluid first flows through a multi-scale vortex energy dissipation grid located at the inlet, and then enters the core area of ​​the heat exchanger. This core area integrates tube bundles, support plates, and an adaptive resonant energy absorption assembly. Finally, the fluid is processed and flows out. During the processing of the fluid, the multi-scale vortex energy dissipation grid generates a pressure difference signal at both ends, which is transmitted to the adaptive resonant energy absorption assembly. In the information domain, a status diagnostic unit acts as the core. It receives electrical signals from the temperature sensor of the adaptive resonant energy absorption assembly in the physical domain, as well as the pressure difference signal at both ends of the grid. It also receives a signal from an external flow meter. Through comprehensive analysis of these input signals, the status diagnostic unit finally outputs diagnostic data and necessary warning signals.

[0040] like Figure 2 As shown, the diagram begins with step 1.0, where the geometric dimensions of the resonant rod are initially determined through iterative calculations using finite element analysis (FEA) based on the design objectives and physical properties, such as the target resonant frequency and the Young's modulus of the material. Step 2.0 then proceeds to experimentally calibrate the dynamic tuning characteristics of the resonant rod. This involves applying a controllable pressure difference to the resonant rod on a specialized test bench and measuring its corresponding frequency. The calibration results are stored in a database, forming an experimental calibration curve. In step 3.0, this experimental calibration curve is compared with a demand curve representing the operating conditions for parameter comparison and optimization decisions. The goodness of fit between the two is evaluated. If the goodness of fit is not met, the process returns to adjusting the microchannel parameters and repeating the experimental calibration in step 2.0 until the comparison results meet the design requirements. At this point, the geometric dimensions of the resonant rod and the microchannel are solidified as the final design parameters.

[0041] like Figure 3 As shown in the diagram, the system exhibits a core online operating composite state, along with auxiliary states such as offline / static and maintenance / calibration. When a system startup or fluid injection event occurs, the system transitions from the offline / static state to the online operating state. In this state, the system continuously performs frequency adaptive tuning, meaning the fluid mass within the rod passively adjusts its natural frequency according to changes in operating conditions. The safeguard condition is that the natural frequency successfully matches the excitation source, thereby achieving targeted resonance energy absorption of vibration energy. If a change in operating conditions or an excitation frequency drift event occurs, the system will self-adjust within the online state. When the health monitoring unit determines that the frequency drift exceeds a threshold, it indicates potential structural damage, and the system will trigger an early warning. Furthermore, the system can return to the offline / static state via a system shutdown event or switch to the maintenance / calibration state via a maintenance mode entry event to perform operations such as parameter updates and baseline recalibration.

[0042] like Figure 4As shown in the figure, the fluid enters from the fluid inlet 1 and first passes through a multi-scale eddy energy dissipation grid, which consists of a large-aperture plate 2a, a medium-aperture plate 2b, and a small-aperture plate 2c arranged sequentially along the fluid direction. Then, the fluid enters the core area of ​​the heat exchanger, which consists of end tube sheets 3, heat exchange tube bundles 5 for heat exchange, and at least one support plate 4 as a tube bundle support structure. Finally, the fluid flows out from the fluid outlet 6. The figure also shows the adaptive resonant energy absorption assembly 7 integrated on the support plate 4, as well as the upstream microchannel 9 and the downstream microchannel 10 for collecting the pressure difference signal at both ends of the grid 2. Both microchannels are connected to the dynamic pressure acquisition chamber 8 located inside the support plate 4.

[0043] like Figure 5 As shown, Figure 5 This is a structural schematic diagram for local magnification of the adaptive resonant energy absorption assembly 7. The diagram shows in detail: the dynamic pressure acquisition cavity 8 disposed inside the support plate 4, and the upstream microchannel 9 and downstream microchannel 10 respectively connected to the cavity; the diagram also shows a hollow tubular resonant rod 11 with an open fixed end 14 at one end and connected to the dynamic pressure acquisition cavity 8, the other end of the resonant rod 11 being a free end 13, and a ring of wedge-shaped microgrooves 12 disposed around the fixed base of the resonant rod 11.

[0044] Example 4: In an engineering design and calibration scenario, the task is to determine the geometry and operating parameters of the structured energy flow conduction and adaptive dissipation assembly within a shell-and-tube heat exchanger with a known tube bundle structure and operating parameters that processes fluids of a specific viscosity. The technical challenge lies in transforming a passive adaptive tuning mechanism from a theoretical description into an engineering procedure with predictable and verifiable performance. The initial step of this procedure is to determine the reference geometry of the hollow tubular resonant rod, with the input condition being the principal resonant frequency of the heat exchanger tube bundle determined by finite element analysis under the target operating conditions. The model incorporates the Young's modulus and density of the metallic material used in the resonant rod. Based on these inputs, a cantilever beam model of the resonant rod is established using finite element simulation software. The cantilever length and wall thickness of the model are iteratively calculated and adjusted until the natural vibration frequency and target resonance frequency in a vacuum environment are found. The convergence of this process determines the reference geometry of the resonant rod.

[0045] The subsequent steps aimed to experimentally calibrate the dynamic tuning characteristics of the adaptive resonant energy absorption assembly. To this end, a hollow tubular resonant rod, fabricated according to reference geometry, was integrated onto a simulated support plate and mounted on a fluid testing bench capable of applying a controllable pressure differential to the interfaces connected to both ends of the microchannels on the support plate. The calibration process is as follows: First, measure and record the internal structure of the resonant rod when it is empty ( The natural frequency of the dry mold at that time And the wet mold natural frequency when fully filled with the test fluid. These two values ​​define the frequency adjustment range that the resonant rod can achieve; then, the pressure difference is gradually increased in predetermined steps of 0.01 MPa. At each stable pressure differential step point, after the fluid filling inside the rod reaches equilibrium, the current natural frequency of the resonant rod is measured and recorded again. This process is repeated until the pressure difference reaches the maximum pressure difference predicted by computational fluid dynamics simulation at the highest design flow rate of the heat exchanger, thereby obtaining a natural frequency of the resonant rod characterizing this specific microchannel size. With driving pressure difference The changing experimental calibration curve.

[0046] The calibration curve of this experiment, and the actual operation of the heat exchanger, are determined by the Karman vortex street shedding frequency. The demand curve, formed by the change in flow rate, is compared. If the matching degree between the two does not reach the goodness of fit required by the design throughout the entire working range, the aperture or length of the microchannel in the support plate is adjusted to change its flow resistance, and the aforementioned experimental calibration process is repeated. Through one or more iterations, until the trend and range of the experimental calibration curve and the demand curve reach the preset goodness of fit, the determined microchannel geometry is solidified as the final design parameters. This procedure transforms the frequency adaptation problem of the resonant rod into an engineering problem that can be calibrated through a standardized experimental process. Based on the determined parameters of the resonant rod and microchannel, the parameters of other functions of the system are determined. For the self-cleaning function, the vibration angular velocity of the calibrated resonant rod at resonance is determined. and vibration amplitude Substitute the cavitation initiation condition as input. The local pressure fluctuations required to induce cavitation are calculated by combining fluid property parameters. Based on this, the cross-sectional shape and depth of the wedge-shaped microgrooves that can generate these pressure fluctuations are determined through microscopic flow field simulation. For the condition diagnosis function, the center frequency of the resonance peak obtained by processing the thermocouple signal of the calibrated and healthy resonant rod under rated operating conditions through fast Fourier transform is recorded as the initial calibration frequency. The health condition threshold required for alarm (such as...) The determination of the frequency drift threshold is based on the material fatigue theory. When the frequency drift reaches the threshold, the corresponding change in structural stiffness is close to the critical point of microcrack initiation. This procedure provides a quantifiable monitoring basis for the reliable operation of the entire system.

[0047] Example 5: In a chemical production process, a heat exchanger system of this technical solution that has been installed and is running needs to have its processing medium changed from material A to a new material B with different density and viscosity characteristics due to production plan adjustments. In order to ensure that the adaptive resonant energy absorption assembly and condition diagnosis unit of the system can continue to maintain their working performance in subsequent operation, a field parameter update and baseline recalibration procedure needs to be performed before the system resumes full-load operation after the formal material change.

[0048] After the procedure is initiated, the known physical properties of the new material B, including its density at the operating temperature, will be determined first. With saturated vapor pressure The data is input into a monitoring system connected to the condition diagnostic unit. Subsequently, new material B is briefly circulated into the heat exchanger at a stable low flow rate below the normal operating range. During this period, the condition diagnostic unit is placed in calibration mode. This unit uses the fluid noise under this stable low flow rate as an excitation source to continuously collect and analyze the signal of the armored thermocouple integrated on the hollow tubular resonant rod. Through fast Fourier transform processing, the wet mode resonance peak of the resonant rod in the new material B environment is identified, and its center frequency is determined as the new baseline reference frequency. Based on this new baseline reference frequency and the input material B property parameters, the monitoring system updates its internal cavitation initiation conditions for solving the self-cleaning function and the drift algorithm model for evaluating the health status of the resonant rod, thereby completing the adaptive adjustment of the entire system to the new medium environment.

[0049] Example 6: In the design verification phase before the deployment of a heat exchanger system for a specific industrial installation, the task is to determine the optimal geometric parameters of a multi-scale vortex energy dissipation grid for the application environment with a defined inlet pipe diameter and maximum fluid Reynolds number. A baseline reference model is also established for online monitoring of the grid's health status to address the risk of flow channel blockage caused by foreign impurities during operation. This phase first optimizes the aperture of the multi-scale vortex energy dissipation grid through computational fluid dynamics simulation. The goal is to find a set of aperture parameters that minimizes a comprehensive performance evaluation function. This function considers both the turbulent kinetic energy of the downstream mainstream vortex and the total pressure drop generated by the grid itself—two mutually constraining performance indicators. Through iterative simulation calculations of various combinations of the first, second, and third apertures of the grid, a set of aperture parameters that converges the aforementioned evaluation function to the optimal solution is finally determined. The pressure difference across this optimized structure under clean conditions is then calculated. With fluid mass flow rate Functional relationship between It is determined, among which the coefficients These constants, which are related to the optimized grid geometry and fluid properties, constitute the baseline reference model characterizing the health status of the grid.

[0050] Based on the aforementioned health status baseline model, an online blockage diagnosis logic is further configured in the system's status diagnosis unit. This diagnosis unit, in addition to collecting the actual pressure difference across the grille used to drive the adaptive resonant energy absorption assembly, also... In addition, it is configured to acquire a signal characterizing the current real-time mass flow rate from an independent flow meter outside the heat exchanger. During system operation, the diagnostic unit will monitor the real-time flow rate. Substituting the values ​​into the established baseline reference model, a theoretical pressure difference prediction is calculated. and compared it with the actual measured value of the pressure difference. Perform continuous comparison; when there are multiple consecutive sampling periods, All values ​​are greater than a dynamic threshold set based on the predicted value, thus satisfying the condition. At that time, among them, As a tolerance coefficient characterizing the allowable deviation, the system judges that the multi-scale eddy current energy dissipation grid has been blocked in a way that is sufficient to affect its function, and generates a corresponding early warning signal, thus providing a basis for operators to intervene in a timely manner.

[0051] 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.

[0052] 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 shell-and-tube heat exchanger system suitable for high-pressure operating conditions, comprising a tube bundle, a tube sheet, and at least one support plate for supporting the tube bundle, characterized in that, The system also includes a structured energy flow guidance and adaptive dissipation assembly, which includes: A multi-scale vortex energy dissipation grid is fixed at the fluid inlet of a heat exchanger and is composed of at least two types of perforated plates with different apertures stacked along the fluid direction. The multi-scale vortex energy dissipation grid is configured to break up the mainstream vortex of the inlet fluid step by step. An adaptive resonant energy absorption assembly is integrated onto a support plate and includes multiple hollow tubular resonant rods, each with one end fixed to the support plate and the other end free. The support plate contains a dynamic pressure acquisition cavity and microchannels connected to the dynamic pressure acquisition cavity. The microchannels open onto the upstream and downstream sides of a multi-scale eddy current energy dissipation grid. The open, fixed ends of the hollow tubular resonant rods are connected to the dynamic pressure acquisition cavities. The adaptive resonant energy absorption assembly is configured to utilize the pressure difference created by the fluid flowing through the multi-scale eddy current energy dissipation grid to drive the fluid medium within the heat exchanger into or out of the hollow tubular resonant rods, thereby changing the effective vibration mass of the hollow tubular resonant rods. This allows the natural vibration frequency of the hollow tubular resonant rods to automatically track and match the predetermined resonant frequency of the tube bundle, which changes due to variations in fluid conditions. The cantilever length and wall thickness of the hollow tubular resonant rod are determined in advance by finite element analysis based on the expected variation range of the Karman vortex street shedding frequency induced by fluid flow within the target operating conditions of the heat exchanger design.

2. The shell-and-tube heat exchanger system suitable for high-pressure conditions according to claim 1, characterized in that, The multi-scale eddy current energy dissipation grid includes a first perforated plate, a second perforated plate, and a third perforated plate arranged sequentially along the fluid direction; the first perforated plate has a first aperture, the second perforated plate has a second aperture smaller than the first aperture, and the third perforated plate has a third aperture smaller than the second aperture, and the third aperture is smaller than the minimum spacing between adjacent heat exchange tubes in the tube bundle.

3. A shell-and-tube heat exchanger system suitable for high-pressure conditions according to claim 1, characterized in that, The hollow tubular resonant rod is fixed in the blind hole of the support plate by a combination of interference fit and brazing.

4. A shell-and-tube heat exchanger system suitable for high-pressure conditions according to claim 1, characterized in that, The hollow tubular resonant rod is made of the same metal material as the support plate.

5. A shell-and-tube heat exchanger system suitable for high-pressure conditions according to claim 1, characterized in that, The surface of the hollow tubular resonant rod is provided with an open microgroove array, and the surface of the hollow tubular resonant rod is treated with gradient wettability, so that its surface can exhibit a gradual change in properties from hydrophilic to hydrophobic from the fixed end to the free end.

6. A shell-and-tube heat exchanger system suitable for high-pressure conditions according to claim 1, characterized in that, On the support plate, a ring of wedge-shaped microgrooves is provided around the fixed base of each hollow tubular resonant rod. The geometry of the wedge-shaped microgrooves matches the resonance characteristics of the hollow tubular resonant rod, so that the angular velocity of the resonant rod vibration is controlled. and vibration amplitude The determined local pressure fluctuations within the microgroove satisfy the following cavitation initiation conditions: ,in, The static pressure of the fluid in the main flow channel of the heat exchanger. This is the saturated vapor pressure of the fluid under the current operating conditions. For fluid density, It is a critical cavitation number determined by fluid properties and material surface characteristics.

7. A shell-and-tube heat exchanger system suitable for high-pressure conditions according to claim 1, characterized in that, At least one hollow tubular resonant rod has an armored thermocouple integrated at its free end as a temperature sensor. The system also includes a state diagnostic unit, which is configured to: continuously acquire the output electrical signal of the temperature sensor; perform fast Fourier transform processing on the output electrical signal to obtain the spectrum formed under the excitation of the inherent thermal noise of the heat exchanger system; and identify the resonance peak corresponding to the natural frequency of the hollow tubular resonant rod from the spectrum, and then output a diagnostic data characterizing the position of the center frequency of the resonance peak.

8. A shell-and-tube heat exchanger system suitable for high-pressure conditions according to claim 2, characterized in that, The second perforated plate has hexagonal holes, and the first perforated plate has circular holes. The central axis of the hexagonal holes of the second perforated plate is offset from the central axis of the circular holes of the first perforated plate in a plane perpendicular to the direction of fluid flow.

9. A shell-and-tube heat exchanger system suitable for high-pressure conditions according to claim 7, characterized in that, The status diagnostic unit is also configured to generate and output a warning signal when the center frequency position of the resonance peak represented by the diagnostic data output by it drifts more than a health status threshold relative to an initial calibration frequency position of the resonance peak.

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