A heat exchanger design method based on frequency domain characteristics and heat exchanger

Abstract

The present invention discloses a heat exchanger design method and a transducer based on frequency domain characteristics, belonging to the technical field of heat exchangers; the present invention introduces a control equation based on mechanism modeling into the traditional heat exchanger design process, and takes the control equation as the design basis, not only focusing on the heat exchange efficiency of the heat exchanger, but also proposing an optimization basis for the frequency domain characteristics of the heat exchanger, by combining the heat exchange performance of the heat exchanger with the filtering characteristics, optimizing the design with the static gain as the target to ensure the heat exchange performance of the heat exchanger, and optimizing the design with the disturbance attenuation coefficient as the target to attenuate the disturbance amplitude in a single channel, and optimizing the design with the disturbance diffusion coefficient as the target to reduce the disturbance transfer between channels to achieve the effect of suppressing the disturbance diffusion between bidirectional channels, meeting the requirements of low-frequency range control performance and high-frequency out-of-control range disturbance suppression in ultra-high precision temperature control, and having high control accuracy in the entire frequency range.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat exchangers, and more specifically, relates to a heat exchanger design method and a transducer based on frequency domain characteristics. Background Art

[0002] At present, as processing and manufacturing technology, especially in the field of semiconductor lithography, continues to develop towards ultra-high precision, higher requirements are placed on the stability of working temperature. In the temperature control process, heat exchangers are an indispensable component, so it is of great significance to study the design method of heat exchangers.

[0003] Traditional heat exchanger design focuses more on the heat exchange load and efficiency of the heat exchanger, ignoring its dynamic characteristics, resulting in low control accuracy. To address the above issues, an existing heat exchanger optimization design method uses the heat exchanger's dynamic performance indicator, response time, as a design constraint. Heat exchangers designed using this method have the advantage of fast response and can improve control accuracy to a certain extent. However, there are two shortcomings. First, using only the heat exchanger's response time as a design constraint only improves control accuracy in the low-frequency range. In the field of high-precision temperature control, the accuracy loss in the high-frequency runaway region (the region where control cannot be resolved) caused by disturbances is non-negligible. This cannot meet the requirements of ultra-high-precision temperature control for low-frequency control performance and high-frequency runaway region disturbance suppression, and cannot address a series of characteristics of the heat exchanger in the frequency domain, such as disturbance transmission and disturbance attenuation. Second, the heat exchanger modeling method is crude, using only empirical modeling, simplifying the heat exchanger into a first-order inertia model and hysteresis link, which cannot effectively correspond to the heat exchanger's design parameters. Summary of the Invention

[0004] In response to the above-mentioned defects or improvement needs of the prior art, the present invention provides a heat exchanger design method and transducer based on frequency domain characteristics to solve the technical problem that the prior art cannot simultaneously meet the requirements of low-frequency range control performance and high-frequency out-of-control range disturbance suppression in ultra-high precision temperature control.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a heat exchanger design method based on frequency domain characteristics, comprising the following steps:

[0006] S1. Use the distributed parameter method to model the transducer mechanism and perform discretization to obtain a simulation model; initialize the design parameters of the transducer;

[0007] S2. Substituting the current values ​​of the design parameters and the target frequency into the simulation model for calculation, the corresponding transducer static gain, disturbance diffusion coefficient, and disturbance attenuation coefficient of the target channel are obtained; wherein the disturbance diffusion coefficient is the amplitude-frequency characteristic value of the inter-channel transfer function of the simulation model at the target frequency; and the disturbance attenuation coefficient is the amplitude-frequency characteristic value of the intra-channel transfer function of the simulation model at the target frequency;

[0008] S3, determining whether the static gain, disturbance diffusion coefficient, and disturbance attenuation coefficient are all within the corresponding target ranges; if so, proceeding to step S4; otherwise, adjusting the design parameters and proceeding to step S2;

[0009] S4. Calculate the heat exchanger pressure drop based on the current values ​​of the design parameters and determine whether the heat exchanger pressure drop meets the pressure drop verification requirements. If so, output the current values ​​of the design parameters and the design is completed; otherwise, adjust the design parameters and go to step S2.

[0010] Further preferably, the calculation formula of the disturbance diffusion coefficient is:

[0011] η=ΔT S,f,out / ΔT T,f,in

[0012] Where, ΔT S,f,out is the fluctuation amplitude of the cold fluid output in the cold fluid channel at the target frequency f; ΔT T,f,in is the fluctuation amplitude of the thermal fluid input in the thermal fluid channel at the target frequency f.

[0013] Further preferably, when the target channel is a cold fluid channel, the calculation formula of the disturbance attenuation coefficient is:

[0014]

[0015] When the target channel is a thermal fluid channel, the calculation formula of the disturbance attenuation coefficient is:

[0016]

[0017] Where, ΔT S,f,out is the fluctuation amplitude of the cold fluid output in the cold fluid channel at the target frequency f; ΔT S,f,in is the fluctuation amplitude of the cold fluid input in the cold fluid channel at the target frequency f; ΔT T,f,out is the fluctuation amplitude of the thermal fluid output in the thermal fluid channel at the target frequency f; ΔT T,f,in is the fluctuation amplitude of the thermal fluid input in the thermal fluid channel at the target frequency f.

[0018] Further preferably, the energy converter is a heat exchanger comprising a single-tube flow unit.

[0019] Further preferably, the energy converter includes: a double-tube heat exchanger, a shell and tube heat exchanger, a microchannel heat exchanger and a fin-tube heat exchanger.

[0020] Further preferably, the design parameters of the transducer include: inlet and outlet states of the heat exchanger working fluid, mass flow rate of the heat exchanger working fluid, fin ratio of the heat exchanger, effective heat exchange length of the heat exchanger and flow channel parameters of the heat exchanger.

[0021] Further preferably, the above step S1 includes:

[0022] S1. Use the distributed parameter method to model the transducer mechanism and obtain the partial differential heat transfer control model of the transducer;

[0023] S2. Segment the transducer along the flow channel direction and process the discrete control units obtained by segmentation using a distributed lumping method to discretize the partial differential heat transfer control model, thereby obtaining a discrete difference control equation;

[0024] S3. Establish a state space model for the discrete difference control equation, perform simulation calculation on the state space model, and establish a simulation model; initialize the design parameters of the transducer.

[0025] Further preferably, the Runge-Kutta method is used to perform simulation calculations on the state space model.

[0026] In a second aspect, the present invention provides a heat exchanger, the design parameters of which are determined using the heat exchanger design method provided in the first aspect of the present invention.

[0027] In a third aspect, the present invention further provides a computer-readable storage medium, which includes a stored computer program, wherein when the computer program is executed by a processor, the device where the storage medium is located is controlled to execute the heat exchanger design method provided in the first aspect of the present invention.

[0028] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0029] The present invention provides a heat exchanger design method based on frequency domain characteristics. It introduces a control equation based on mechanism modeling into the traditional heat exchanger design process, and constructs a simulation model based on the control equation as the design basis. It not only focuses on the heat exchange efficiency of the heat exchanger, but also proposes an optimization basis for the frequency domain characteristics of the heat exchanger. By combining the heat exchange performance of the heat exchanger with the filtering characteristics, the optimization design is carried out with the static gain as the target to ensure the heat exchange performance of the heat exchanger. At the same time, the optimization design is carried out with the disturbance attenuation coefficient as the target to attenuate the disturbance amplitude in a single channel, and the optimization design is carried out with the disturbance diffusion coefficient as the target to reduce the disturbance transmission between channels to achieve the effect of suppressing the disturbance diffusion between bidirectional channels. It meets the requirements of low-frequency range control performance and high-frequency out-of-control range disturbance suppression in ultra-high precision temperature control, and has high control accuracy in the entire frequency range. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Flowchart of the heat exchanger optimization design method based on frequency domain characteristics provided in Example 1 of the present invention;

[0031] Figure 2 A schematic diagram of a 4-channel state space simulation model provided in Example 1 of the present invention;

[0032] Figure 3 Schematic diagram of the heat transfer model of the heat exchange unit provided in Example 1 of the present invention;

[0033] Figure 4 Schematic diagram of key parts of a heat exchanger designed according to the heat exchanger optimization design method based on frequency domain characteristics provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0035] Example 1

[0036] The heat exchanger optimization design method based on frequency domain characteristics provided by the present invention is further described below with reference to the accompanying drawings. Figure 1 As shown, the following steps are included:

[0037] S101. According to the layout of the heat exchanger and the flow organization mode, the distributed parameter method is used to model the mechanism of the transducer. Based on the piston flow assumption, a partial differential equation heat transfer control model of the heat exchanger is established.

[0038] It should be noted that since the centralized parameter method does not contain any structural parameters about the heat exchanger, it cannot be used for parameter design and optimization. Therefore, the present invention adopts the distributed parameter method to model the mechanism of the transducer in order to achieve the purpose of designing the heat exchanger parameters.

[0039] Furthermore, the present invention is applicable to a transducer including a single-tube flow unit, that is, a heat exchanger in the form of a single-tube flow and a heat exchanger that can be simplified to a single-tube flow form, including but not limited to a shell-and-tube heat exchanger, a shell-and-tube heat exchanger, a microchannel heat exchanger, and a fin-and-tube heat exchanger. Taking a shell-and-tube heat exchanger as an example, in common shell-and-tube heat exchangers and similar types, the multi-row tubes and double-sided working fluids of the heat exchanger can be divided into a single-tube heat transfer model coupled with "cold fluid-tube wall-hot fluid" for simplified processing. Other complex arrangements can be understood as series or parallel forms of this simple heat transfer model. In complex flow arrangements such as series flow, it can be understood as a simplified form of multiple downstream and countercurrent single-tube models connected in series and parallel. The difference between downstream and countercurrent is only reflected in the differential process, where downstream is forward differential and countercurrent is backward differential. Therefore, this single-tube model can be used as a simplified form of a complex heat exchanger type for design and calculation. Specifically, if Figure 3 The figure shows a schematic diagram of the heat transfer model of the heat exchange unit; among them, 1 and 3 are the hot end flow channels, and 2 is the cold end flow channel. It should be noted that the hot end and cold end are only used to distinguish the flow channels on both sides, and do not mean that the hot end and cold end fluids must flow through these flow channels in actual design.

[0040] During the actual operation of a heat exchanger, the physical properties of the working fluid change along the flow path and over the operating time. Therefore, the heat transfer coefficient cannot be guaranteed to be constant. When establishing the control equation, it is necessary to consider the changes in the heat transfer coefficient under different input parameters. Designers in this field can determine the flow organization of the heat exchanger based on actual design requirements, whether it is upstream or downstream.

[0041] In the process of modeling the heat exchanger, the parameters involved include the inlet and outlet states of the heat exchanger working fluid, the mass flow rate of the heat exchanger working fluid, the fin ratio of the heat exchanger, the effective heat exchange length of the heat exchanger and the flow channel parameters of the heat exchanger; among them, the inlet and outlet states of the heat exchanger include the inlet and outlet temperatures of the hot end fluid and the inlet and outlet temperatures of the cold end fluid, and the mass flow rate of the working fluid is the uniformed single-tube hot end fluid mass flow rate and cold end fluid mass flow rate; the fin ratio of the heat exchanger is a simplified equivalent form of the finned heat exchanger; the flow channel parameters of the heat exchanger include the hot end fluid flow cross-sectional area, the cold end fluid flow cross-sectional area, the flow pipe diameter, the spacing between multiple rows of tubes and the flow channel form (including straight channel, bend channel, S channel, and airfoil channel).

[0042] The mechanism modeling process includes the mechanism modeling of the total heat transfer coefficient and the mechanism modeling of the heat transfer balance of the flow micro-element. Specifically, the process of establishing the heat exchanger mechanism modeling is as follows:

[0043] For the single-tube model, the heat transfer process is divided into three levels: "cold fluid-tube wall-hot fluid". Since the heat capacity error caused by the tube wall of the heat exchanger is usually much smaller than that of the fluids on both sides, the differential equation at the tube wall level can be ignored. Only the thermal resistance of the tube wall is taken into consideration. The differential equation established for the fluids on both sides is as follows:

[0044]

[0045] Among them, A T is the flow cross-sectional area of ​​the hot side fluid; ρ T is the density of the hot side fluid; c p is the specific heat capacity at constant pressure; T T is the instantaneous temperature of the hot side fluid; Q T is the volume flow rate of the hot side fluid; c pT is the specific heat capacity of the hot side fluid; K is the total heat transfer coefficient of the heat exchanger, Ω L is the heat transfer area per unit length, which needs to be multiplied by the fin ratio when it is reflected in the finned tube; z is the spatial variable along the flow direction; t is the time term. Furthermore, the subscript S represents the corresponding parameter of the cold side fluid, specifically, A S is the flow cross-sectional area of ​​the cold side fluid; ρ S is the density of the cold side fluid; T S is the instantaneous temperature of the cold side fluid; Q S is the volume flow rate of the cold side fluid; Ω S It is the cooling area per unit length, which needs to be multiplied by the fin ratio when it is reflected in finned tubes.

[0046] The overall heat transfer coefficient of the heat exchanger is calculated as follows:

[0047]

[0048] Where h o 、h i are the convection heat transfer coefficients of the fluids on both sides of the tube wall; δ is the tube wall thickness, and λ is the thermal conductivity of the tube wall.

[0049] For the fluids on both sides of the tube wall, the convective heat transfer coefficient is calculated by the following formula:

[0050]

[0051] Nu is the Nusselt number; λ is the thermal conductivity of the fluid; and d is the equivalent diameter of the fluid flow. Specifically, for a certain forced flow in a tube, d is the tube diameter; while for forced flow between tube gaps, d is usually taken as:

[0052]

[0053] A is the cross-sectional area of ​​the fluid, and P is the wetted perimeter of the fluid. The calculation of Nu varies depending on the flow state. In laminar flow, Nu has the following calculation formula:

[0054]

[0055] In the case of turbulent flow, Nu is determined by the Reynolds number Re and the Prandtl number Pr of the fluid:

[0056]

[0057]

[0058] Nu=BRe C Pr D

[0059] Where v is the fluid flow velocity; μ is the dynamic viscosity coefficient of the fluid; in the Nu number calculation formula, the values ​​of B, C, and D can all be given by the value range of the fluid Re and Pr and the empirical calculation formula for different bending angles.

[0060] S102, dividing the heat exchanger along the flow channel direction, and using a distributed lumping method for each discrete control unit obtained by dividing, that is, replacing the differential with the differential for the partial differential equation heat transfer control model.

[0061] In an optional embodiment, after establishing the partial differential equation, the heat exchanger is divided into equal distances along the flow direction. After the division, the uniform temperature or average boundary temperature can be taken as the qualitative temperature of the microelement according to the lumped parameter method to establish a discrete ordinary differential equation model. Specifically, taking the uniform temperature as the qualitative temperature of the microelement to establish a discrete ordinary differential equation model as an example, the difference is replaced by the differential in the z space domain, and the heat exchanger is divided into N segments along the z direction. In principle, the larger the value of N, the closer it is to the actual heat exchanger model. The actual selection can be made by designers in this field based on computer performance and heat exchanger requirements. The endpoints of each segment are represented by z(i), i=0~N, z(0)=0, z(N)=L, then the length of the i-th segment Δz(i)=z(i)-z(i-1), which can be obtained:

[0062]

[0063]

[0064] The fluids on both sides are discretized and lumped, respectively. The selection of the qualitative temperature within the micro-segment is crucial. For a specific micro-segment, using a lumped model, the spatial temperature distribution is ignored, and the average temperature T(z,i) is considered the micro-segment temperature. It should be noted that the countercurrent arrangement employed in the heat exchanger embodiments of the present invention does not necessarily imply that the invention is applicable only to countercurrent arrangements; this is determined by the design professionals in the field. The only difference between forward and reverse flow is that the differential process uses forward and reverse differentials.

[0065] After the heat exchanger of the embodiment provided by the present invention is discretized, the discrete equation can be obtained as follows:

[0066]

[0067] S103. Establish a state space model for the above differential equations, use the Runge-Kutta method to perform simulation calculations on the state space model, and establish a simulation model.

[0068] The above difference model can be transformed into the following state space model:

[0069]

[0070] in,

[0071] X=[T T,1 …T T,N T S,1 …T S,N ] T

[0072] U=[T T,in T S,in ] T

[0073] Y=[T T,out T S,out ] T

[0074] Wherein, the A, B, and C matrices can be obtained by simply transforming the form of the discretized equation. Thus, the partial differential model is transformed into the form of an ordinary differential equation. When solving the ordinary differential equation, attention should be paid to the selection of the integral solver. Algorithms such as the Euler method and the Runge Kutta method can be used for solving. In the embodiment provided by the present invention, the Runge Kutta method is used for integral solution, which uses Taylor expansion for solution. The fourth-order Runge Kutta method has very high solution accuracy.

[0075] The general form of simulation calculation model is as follows Figure 2 shown.

[0076] S104. Substituting the current values ​​of the design parameters and the target frequency into the simulation model for calculation, to obtain the corresponding transducer static gain, disturbance diffusion coefficient, and disturbance attenuation coefficient of the target channel; wherein the disturbance diffusion coefficient is the amplitude-frequency characteristic value of the inter-channel transfer function of the simulation model at the target frequency; and the disturbance attenuation coefficient is the amplitude-frequency characteristic value of the intra-channel transfer function of the simulation model at the target frequency;

[0077] Specifically, before the first iteration, initial design parameters and boundary values ​​are determined and substituted into the simulation model for iterative calculations. The boundary values ​​for the iterative process are the heat exchanger structural constraints, including overall length, width, and height limits, as well as the working fluids on both sides of the heat exchanger, the heat exchanger design temperature difference, the heat exchanger design pressure, and the allowable pressure drop across the heat exchanger.

[0078] The above-mentioned design parameters may include the inlet and outlet states of the heat exchanger working fluid, the mass flow rate of the heat exchanger working fluid, the heat exchanger fin ratio, the effective heat transfer length of the heat exchanger, the heat exchanger flow path parameters, and the number of units in the heat exchanger tube bundle. A detailed explanation of each parameter is provided in S101.

[0079] The boundary values ​​of the above iterative process include the structural limitations of the heat exchanger, including the total length, width, and height limitations of the heat exchanger. In addition, they also include the properties of the working fluid on both sides of the heat exchanger, the design temperature difference of the heat exchanger, the design pressure of the heat exchanger, the allowable pressure drop of the heat exchanger, etc.

[0080] The static gain G of the target channel of the heat exchanger measures the heat transfer load of the heat exchanger. Its value can be obtained from the target working fluid temperature output / input in the simulation results. The heat transfer load under a given temperature difference is:

[0081] Q=(1-G)T T,in c P Q m

[0082] Where Q is the heat transfer load of the heat exchanger; T T,in is the hot end input temperature; c p is the specific heat capacity at constant pressure; Q m is the hot end mass flow rate.

[0083] The heat exchanger's perturbation diffusion coefficient, η, measures the transmission and attenuation characteristics of inter-channel fluctuations. This metric is particularly important in the field of precision temperature control. If the target fluid needs to be heated, this metric measures the extent to which the temperature fluctuations of the hot fluid in a specified frequency domain affect the cold fluid side. η is derived based on the amplitude-frequency characteristics of the inter-channel transfer function in the simulation model (deriving the amplitude-frequency characteristics from the simulation model requires inputting a sinusoidal signal of a specific frequency; the details of this method are beyond the scope of this invention and will not be elaborated on here). Specifically, the formula for calculating η for fluctuations is as follows:

[0084] ΔT S,f,out =ΔTT,f,in ·η

[0085] Where ΔT S,f,out is the fluctuation amplitude of the cold fluid output at the target frequency f; ΔT T,f,in is the fluctuation amplitude of the thermal fluid input at the target frequency f.

[0086] Heat exchanger disturbance attenuation coefficient The attenuation characteristics of the fluid temperature fluctuation after the fluid in the channel flows through the heat exchanger are measured based on the amplitude-frequency characteristics of the transfer function in the fluid channel on the same side of the above model; specifically, The calculation formula for volatility is as follows:

[0087]

[0088]

[0089] Specifically, for the cold fluid channel, the calculation formula of the disturbance attenuation coefficient is:

[0090]

[0091] For the thermal fluid channel, the calculation formula of the disturbance attenuation coefficient is:

[0092]

[0093] Where ΔT S,f,out is the fluctuation amplitude of the cold fluid output in the cold fluid channel at the target frequency f; ΔT S,f,in is the fluctuation amplitude of the cold fluid input in the cold fluid channel at the target frequency f; ΔT T,f,out is the fluctuation amplitude of the thermal fluid output in the thermal fluid channel at the target frequency f; ΔT T,f,in is the fluctuation amplitude of the thermal fluid input in the thermal fluid channel at the target frequency f.

[0094] S105. Determine whether the static gain, disturbance diffusion coefficient, and disturbance attenuation coefficient are all within the corresponding target ranges. If not, adjust the design parameters and re-iterate the calculation according to steps S104-S105 based on the adjusted parameters until the static gain, disturbance diffusion coefficient, and disturbance attenuation coefficient are all within the corresponding target ranges.

[0095] The iterative optimization calculation results must meet the following conditions: the static gain G meets the design requirement value range, η and At the target frequency f required by the design, the given design target range is met.

[0096] Specifically, the static gain parameter is used to describe the heat transfer load characteristics of the heat exchanger. This parameter is the open-loop gain of the transfer function within the simulation model channel and is related to the working fluid input state. In some embodiments of the heat exchanger provided in this application, the static gain of the hot end is 0.90-0.95. The disturbance diffusion coefficient is used to describe the fluctuation transfer characteristics of the hot and cold ends of the heat exchanger. This parameter is the amplitude-frequency characteristic of the transfer function between the simulation model channels. The frequency domain is related to the working fluid input state. In some embodiments of the heat exchanger provided in this application, the disturbance diffusion coefficient is within the 5mHz-10mHz frequency domain and the design value is 0.1-0.3. The disturbance attenuation coefficient is used to describe the fluctuation attenuation characteristics of the cold or hot end of the heat exchanger. This parameter is the amplitude-frequency characteristic of the transfer function within the simulation model channel and is related to the frequency domain and the working fluid input state. In some embodiments of the heat exchanger provided in this application, the disturbance attenuation coefficient is within the 5mHz-10mHz frequency domain and the design value is 0.5-0.75.

[0097] Furthermore, when adjusting the design parameters, it is necessary to meet the structural limitations of the heat exchanger, including the total length, width, and height limitations of the heat exchanger.

[0098] S106. Obtain the heat exchanger pressure drop according to the heat exchanger design parameters.

[0099] In some embodiments of the present application, the heat exchanger pressure drop is determined by calculating the heat exchanger length, heat exchanger fluid flow rate, and equivalent diameter of the heat exchanger flow channel in the design parameters using the following formula:

[0100]

[0101] Where ΔP is the pressure drop; f is the Fanning friction coefficient; L is the length of the heat exchanger flow channel; D is the flow equivalent diameter; ρ is the fluid density; v is the fluid velocity. For fluids with different flow states, the value of f is different. For laminar flow:

[0102]

[0103] In turbulent flow, the value of f varies depending on the design of the flow channel. In some embodiments of the present application, the formula for the value of f in a straight flow channel is:

[0104] f=0.05776Re -0.2192

[0105] For the values ​​of f for other flow channels, designers in this field can calculate them based on empirical formulas.

[0106] S107. Perform a pressure drop check on the heat exchanger to determine whether the pressure drop of the heat exchanger meets the pressure drop check requirements, that is, whether it is greater than or equal to the allowable pressure drop of the heat exchanger. If the pressure drop check requirements are met, the current values ​​of the design parameters are output and the design is completed. If not, the design parameters are iteratively calculated again until the pressure drop check requirements are met.

[0107] Design requirements are the pre-determined requirements for heat exchanger parameters set by designers in this field, such as the heat transfer load, allowable pressure drop, target range of the heat exchanger's disturbance diffusion coefficient, and target range of the heat exchanger's disturbance attenuation coefficient. Designers in this field can determine the design requirements based on their needs.

[0108] Example 2

[0109] This embodiment provides a heat exchanger, whose design parameters are determined by the heat exchanger design method provided in Example 1 of the present invention. The schematic diagram of the key parts of the designed heat exchanger is shown in FIG. Figure 4 As shown. During the design process, the static gain, disturbance diffusion coefficient, and disturbance attenuation coefficient of the heat exchanger are determined using the scheme described in Example 1. Therefore, the heat exchanger not only meets the requirements of the heat exchange load, but also has optimized frequency domain characteristics, taking into account both the heat exchange load and frequency domain filtering characteristics, and meets the requirements of ultra-high-precision temperature control for low-frequency range control performance and high-frequency runaway range filtering performance, while achieving the effect of suppressing disturbance diffusion between bidirectional channels.

[0110] The ultra-high-precision temperature control series products designed based on the heat exchanger provided in this example can ultimately achieve a control accuracy of ±0.002K to ±0.005K under a flow rate environment of 20L / min to 50L / min. This is an order of magnitude higher than the conventional ±0.01K to ±0.02K in the industry, and has higher control accuracy.

[0111] The relevant technical solutions are the same as those in Example 1 and will not be described in detail here.

[0112] Example 3

[0113] A computer-readable storage medium includes a stored computer program, wherein when the computer program is executed by a processor, the device where the storage medium is located is controlled to execute the heat exchanger design method provided in Example 1 of the present invention.

[0114] The relevant technical solutions are the same as those in Example 1 and will not be described in detail here.

[0115] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A heat exchanger design method based on frequency domain characteristics, characterized in that: The following steps are involved: S1. Use the distributed parameter method to model the transducer mechanism and perform discretization to obtain a simulation model; initialize the design parameters of the transducer; S2. Substituting the current values ​​of the design parameters and the target frequency into the simulation model for calculation, obtaining the corresponding transducer static gain, disturbance diffusion coefficient, and disturbance attenuation coefficient of the target channel; wherein the disturbance diffusion coefficient is the amplitude-frequency characteristic value of the inter-channel transfer function of the simulation model at the target frequency; and the disturbance attenuation coefficient is the amplitude-frequency characteristic value of the intra-channel transfer function of the simulation model at the target frequency; S3, determining whether the static gain, disturbance diffusion coefficient, and disturbance attenuation coefficient are all within the corresponding target ranges; if so, proceeding to step S4; otherwise, adjusting the design parameters and proceeding to step S2; S4. Calculate the heat exchanger pressure drop based on the current values ​​of the design parameters and determine whether the heat exchanger pressure drop meets the pressure drop verification requirements. If so, output the current values ​​of the design parameters and the design is completed; otherwise, adjust the design parameters and go to step S2.

2. The heat exchanger design method according to claim 1, characterized in that: The calculation formula of the disturbance diffusion coefficient is: η=ΔT S,f,out / ΔT T,f,in Where ΔT S,f,out is the fluctuation amplitude of the cold fluid output in the cold fluid channel at the target frequency f; ΔT T,f,in is the fluctuation amplitude of the thermal fluid input in the thermal fluid channel at the target frequency f.

3. The heat exchanger design method according to claim 1, characterized in that: When the target channel is a cold fluid channel, the calculation formula of the disturbance attenuation coefficient is: When the target channel is a thermal fluid channel, the calculation formula of the disturbance attenuation coefficient is: Where ΔT S,f,out is the fluctuation amplitude of the cold fluid output in the cold fluid channel at the target frequency f; ΔT S,f,in is the fluctuation amplitude of the cold fluid input in the cold fluid channel at the target frequency f; ΔT T,f,out is the fluctuation amplitude of the thermal fluid output in the thermal fluid channel at the target frequency f; ΔT T,f,in is the fluctuation amplitude of the thermal fluid input in the thermal fluid channel at the target frequency f.

4. The heat exchanger design method according to any one of claims 1 to 3, characterized in that: The transducer is a heat exchanger comprising a single-tube flow unit.

5. The heat exchanger design method according to claim 4, characterized in that: The energy converters include: a shell-and-tube heat exchanger, a shell-and-tube heat exchanger, a microchannel heat exchanger and a fin-and-tube heat exchanger.

6. The heat exchanger design method according to any one of claims 1 to 3, characterized in that: The design parameters of the energy converter include: the inlet and outlet states of the heat exchanger working fluid, the mass flow rate of the heat exchanger working fluid, the heat exchanger fin ratio, the heat exchanger effective heat exchange length and the heat exchanger flow channel parameters.

7. The heat exchanger design method according to any one of claims 1 to 3, characterized in that: The above step S1 includes: S11. Use the distributed parameter method to model the transducer mechanism and obtain the partial differential heat transfer control model of the transducer; S12, dividing the transducer along the flow channel direction, and processing the divided discrete control units using a distributed lumping method to discretize the partial differential heat transfer control model, thereby obtaining a discrete difference control equation; S13. Establish a state space model for the discrete difference control equation, perform simulation calculation on the state space model, and establish a simulation model; initialize the design parameters of the transducer.

8. The heat exchanger design method according to claim 7, characterized in that: The Runge-Kutta method is used to simulate the state space model.

9. A heat exchanger, characterized in that: Its design parameters are determined by the heat exchanger design method described in any one of claims 1-8.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium includes a stored computer program, wherein when the computer program is executed by a processor, the processor controls the device where the storage medium is located to execute the heat exchanger design method according to any one of claims 1 to 8.

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