A modeling method for indirect evaporative cooling heat exchanger based on Modelica language

Abstract

The present invention discloses a modeling method for an indirect evaporative cooling heat exchanger model based on the Modelica language, comprising: building a mixed medium model of spray water and outdoor dry air; dividing the heat exchanger using the finite volume method, and setting the number of discrete units based on the Modelica language; constructing a conservation equation for a water film in a wet mode, and heat transfer and mass transfer calculation equations for wet air and water film; and building a conservation equation for each discrete unit based on the geometric structure of the heat exchanger, heat exchange fluids on both sides, heat exchange plate materials, and heat transfer and pressure drop correlation equations; and connecting the outlets of each discrete unit using a connect statement in the Modelica language to obtain an indirect evaporative cooling heat exchanger model based on the finite volume method. The indirect evaporative cooling heat exchanger model can reflect the internal hierarchical structure of the finite volume model of the heat exchanger, reduce the complexity of model construction, simplify the complex model, and improve modeling efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchangers, and in particular to a modeling method of an indirect evaporative cooling heat exchanger model based on the Modelica language. Background Art

[0002] With the development of the information age, data center construction has grown rapidly. Globally, information technology-related carbon emissions account for 5% of total global carbon emissions, while air conditioning systems consume 30% to 50% of this energy. Therefore, optimizing air conditioning systems is crucial for data center energy conservation.

[0003] Indirect evaporative cooling (IEV) air conditioning systems directly utilize the difference between the dry-bulb and wet-bulb temperatures of ambient air to generate cooling capacity, consuming minimal primary energy and causing minimal environmental pollution. They have long been a research hotspot in air conditioning and refrigeration technology. Indirect evaporative cooling systems operate in two modes: dry and wet. In the wet mode, film condensation occurs when moist air contacts the cool wall surface. This water film adheres to the heat exchanger surface, reducing the spacing between the fins and increasing the heat transfer resistance of air passing through the fin channels. Simultaneously, the accumulation of the water film on the fin surface acts as a heat transfer agent similar to that of fins, increasing the heat transfer area. This water film significantly alters the temperature and flow conditions on the heat exchanger wall, disrupting air flow and affecting pressure drop and heat transfer characteristics. Therefore, the heat transfer process of moist air is a complex, irreversible thermodynamic process in which flow, heat, and mass transfer occur simultaneously, with these multiple heat transfer processes coupled and intertwined. Heat exchangers are devices that perform heat transfer between fluids. The core issue in indirect evaporative cooling systems is how to utilize heat exchangers to achieve heat and mass exchange between air and water, and between air and air. Due to the complexity of the process itself, it is very difficult to solve both the physical modeling and the mathematical model, and the establishment of the mathematical model is based on certain assumptions and ideal conditions.

[0004] Modelica is an object-oriented, open-source, non-causal, multi-physics modeling language. It uses non-causal mathematical descriptions and equations to represent system behavior. It supports the modeling of both continuous and discrete physical systems and is widely used in the modeling and simulation of complex physical systems across multiple domains. The connections between model elements satisfy generalized Kirchhoff's laws, enabling coupled modeling and simulation of multiple domains and systems, serving the virtual design and energy-saving optimization of data center cooling systems. Summary of the Invention

[0005] Purpose of the invention: In response to the defects of the prior art, the present invention discloses a modeling method for an indirect evaporative cooling heat exchanger model based on the Modelica language. Based on the Modelica language, the finite volume method is used to divide the heat exchanger, and the conservation equations of the discrete units under the wet mode working condition are constructed. The outlets of each discrete unit are connected by the connect statement of the Modelica language. This can not only reflect the internal hierarchical structure of the finite volume model of the heat exchanger, but also reduce the complexity of model construction, thereby facilitating subsequent research on the internal medium flow of the indirect evaporative cooling heat exchanger.

[0006] Technical solution: In order to achieve the above technical objectives, the present invention adopts the following technical solution.

[0007] A modeling method for an indirect evaporative cooling heat exchanger model based on the Modelica language includes the following steps:

[0008] S1. Building a mixed medium model of spray water and outdoor dry air: the mixed medium model is used to generate outdoor wet air;

[0009] S2. Use the finite volume method to divide the heat exchanger and set discrete units: The indirect evaporative cooling heat exchanger model includes indoor dry air, outdoor wet air, and a heat exchange wall. Use the finite volume method to divide the heat exchanger's calculation area into a series of non-repeating discrete units. Use the Modelica language to set the number of discrete units.

[0010] S3. Construct conservation equations for each discrete unit: Indoor dry air and outdoor wet air are connected through the heat exchange wall in the middle of the heat exchanger for cross-flow heat exchange. First, construct the condensation, evaporation, energy, and mass conservation equations for the water film. Next, construct heat and mass transfer calculation equations for the wet air and water film. Finally, construct the conservation equations for each discrete unit based on the geometric structure of the heat exchanger, the heat exchange fluids on both sides, the heat exchange plate materials, and the heat transfer and pressure drop correlation equations.

[0011] S4. The connect statement of Modelica language is used to connect each discrete unit, and the connection equation is constructed to obtain the indirect evaporative cooling heat exchanger model based on the finite volume method.

[0012] Preferably, the process of building the mixed medium model in step S1 includes creating boundary conditions for the spray water and outdoor air, adding a volume flow mixing joint to achieve uniform mixing of the spray water and outdoor air to obtain a mixed medium, setting the temperature, relative humidity and volume parameters of the mixed medium in the mixing joint, inputting the energy conservation equation and momentum conservation equation of the mixed medium based on the Modelica language, completing the calculation, and then introducing the mixed medium into the heat exchanger.

[0013] Preferably, the energy conservation equation is:

[0014]

[0015] Among them, H is the enthalpy of the mixed medium, h is the specific enthalpy of the mixed medium, A is the indoor dry air medium, B is the outdoor wet air medium, h A is the specific enthalpy of medium A, h B is the specific enthalpy of medium B, h C is the specific enthalpy of the spray water, m flowC is the mass flow rate of spray water, volume is the volume of the mixed medium, and p is the pressure of the mixed medium;

[0016] The momentum conservation equation is:

[0017]

[0018] Among them, ξ is the moisture content of the mixed medium, A is the moisture content of medium A, ξ B is the moisture content of medium B, ξ C is the moisture content of the spray water, m Gas is the mass of the gas.

[0019] Preferably, the condensation and evaporation mass calculation equations and the energy and mass conservation equations of the water film in step S3 are respectively:

[0020] Calculation equation for the mass of water vapor condensed in moist air:

[0021] m flowCondensate =betaAeff·ρ Gas ·(ζ-ζ Saturation )

[0022] Where betaAeff is the mass transfer coefficient, ρ Gas is the gas density, ζ is the moisture content of the air in the condensed state, Saturation is the humidity content of moist air at saturation temperature, m flowCondensate is the mass flow rate of condensed water in the wet air;

[0023] The calculation equation for the evaporation mass of water in the liquid film is:

[0024] m flowEvaporate =betaAeff·ρ Gas ·(ζ Saturation -ζ)

[0025] The mass conservation equation:

[0026]

[0027] Among them, mFilm is the mass flow rate of water film, Film is the water film, m flowWaterDrain is the amount of water lost, mflowEvaporate is the mass flow rate of evaporated water in moist air;

[0028] Energy conservation equation:

[0029]

[0030] Among them, H Film is the enthalpy of the water film, portN, portW, and portE represent the upper, left, and right outlets of the discrete unit for external heat transfer, and Q flow is the heat transfer from the discrete unit outlet to the outside, h Film is the specific enthalpy of the water film.

[0031] Preferably, the heat and mass transfer calculation equations of the humid air and water film in step S3 are:

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039] Where Nu is the Nusselt number, Le is the Lewis number, α is the convective heat transfer coefficient, L is the characteristic length, λ is the thermal conductivity of moist air, C, m, and n are coefficients, and different flow conditions have different values; Re is the Reynolds number, Sh is the Sherwood number, β is the mass transfer coefficient of moist air, D is the characteristic coefficient of water vapor solubility in moist air, Sc is the Schmidt number, v is the kinematic viscosity, μ is the dynamic viscosity, ρ is the fluid density, Pr is the Prandtl number, and C p is the specific heat capacity at constant pressure, a is the thermal conductivity, β idealGas is the mass transfer coefficient of an ideal gas.

[0040] Preferably, the discrete element conservation equations in step S3 include a mass conservation equation, an energy conservation equation, and a momentum conservation equation, specifically:

[0041] The mass conservation equation:

[0042] m flowA +m flowB -m flowCondensate +m flowEvaporate =0

[0043] Among them, m flowA is the mass flow rate of indoor dry air medium, m flowB is the mass flow rate of outdoor wet air medium, m flowCondensate is the mass flow rate of condensed water in wet air, m flowEvaporate is the mass flow rate of water evaporation in wet air, A is the indoor dry air medium, and B is the outdoor wet air medium;

[0044] Energy conservation equation:

[0045] Q flow +m flowA ·h A +m flowB ·h B +h Film ·(m flowCondensate -m flowEvaporate )=0

[0046] Among them, Q flow The heat generated by the dynamic changes of evaporation and condensation of water film due to the mixture of wet air, dry air and water film. A is the indoor dry air medium, B is the outdoor wet air medium, and h A is the enthalpy of medium A, h B is the enthalpy of medium B, h Film is the enthalpy of the water film;

[0047] Momentum conservation equation:

[0048] p A -p B =dp

[0049] Among them, p A is the pressure of medium A, p B is the pressure of medium B, and dp is the pressure difference.

[0050] Beneficial effects: The present invention is based on the Modelica language, adopts the finite volume method to divide the heat exchanger, constructs the conservation equations of discrete units under wet mode conditions, and connects the outlets of each discrete unit through the connect statement of the Modelica language. It can not only reflect the internal hierarchical structure of the finite volume model of the heat exchanger, but also reduce the complexity of model construction, which is convenient for subsequent research on the internal medium flow of the indirect evaporative cooling heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 is a flow chart of the method of the present invention;

[0052] Figure 2 Schematic diagram of the hybrid model of the present invention;

[0053] Figure 3Schematic diagram of the internal structure of the discrete unit of the heat exchanger of the present invention;

[0054] Figure 4 Schematic diagram of the geometric structure of the heat exchanger of the present invention;

[0055] Figure 5 This is a schematic diagram of the connection of discrete units of the heat exchanger of the present invention;

[0056] Figure 6 This is a schematic diagram of the indirect evaporative cooling heat exchanger model of the present invention. DETAILED DESCRIPTION

[0057] This invention provides a modeling method for an indirect evaporative cooling heat exchanger based on the Modelica language. This method can implement air-water and air-air heat and mass exchange in an indirect evaporative cooling system, thereby providing the necessary technical support and implementation path for model-based energy-saving optimization of data center cooling systems. The invention will be described in detail below with reference to the accompanying drawings and examples.

[0058] As attached Figure 1 As shown, the modeling method of the indirect evaporative cooling heat exchanger model based on the Modelica language of the present invention is mainly implemented by the following steps. Modelica is a general simulation language supported by software such as Dymola, Mworks, OpenModelica, and Jmodelica. In this embodiment, the process implemented in the Dymola software is given. It should be noted that the method described in the present invention can be implemented in other simulation software supporting the Modelica language. The following five steps are implemented in the Dymola software:

[0059] Step 1: Build a mixed medium model of spray water and outdoor dry air. The mixed medium model is used to generate humid air for heat exchange in wet mode. The spray water is turned off in dry mode. Create boundary conditions for spray water and outdoor air in Dymola, add a volume flow mixing joint, and achieve uniform mixing of spray water and outdoor air to obtain a mixed medium, as shown in the attached figure. Figure 2 As shown, parameters such as the temperature, relative humidity, and volume of the mixed medium are set in the mixing joint. The energy and momentum conservation equations for the mixed medium are input using the Modelica language to complete the calculations. The mixed medium is then introduced into the heat exchanger to build the mixed medium model.

[0060] Conservation equation for mixed media:

[0061] Conservation of Energy:

[0062]

[0063] Where H is the enthalpy of the mixed medium, h is the specific enthalpy of the mixed medium, A is the indoor dry air medium, and B is the outdoor wet air medium; h A is the specific enthalpy of medium A, h B is the specific enthalpy of medium B, h C is the specific enthalpy of the spray water, m flowC is the mass flow rate of spray water, volume is the volume of the mixed medium, and p is the pressure of the mixed medium;

[0064] Conservation of momentum:

[0065]

[0066] Among them, ξ is the moisture content of the mixed medium, A is the moisture content of medium A, ξ B is the moisture content of medium B, ξ C is the moisture content of the spray water, m Gas is the mass of the gas.

[0067] Step 2: Set the discrete units of the heat exchanger. Divide the space of the heat exchanger into a system of non-repetitive discrete units. Each discrete unit contains different states, and heat exchange connections are made between discrete units to facilitate monitoring of the flow state of the medium during the heat exchange process. The indirect evaporative cooling heat exchanger model consists of three parts: two media and a heat exchange wall. The two media refer to indoor dry air and outdoor wet air. According to the principle of the finite volume method, the calculation area of ​​the heat exchanger is divided into a series of non-repetitive discrete units. Each discrete unit is set to have a discrete point, called a node. The number of discrete units is set in the parameter setting nCells of the heat exchanger in Dymola.

[0068] Step 3: Build the conservation equations for each discrete unit, including the conservation equations for the wet air medium + heat exchange wall + dry air medium, which are divided into three parts: the conservation equation for the water film; the heat transfer and mass transfer calculation equations for the wet air and water film; and the energy conservation equation for the entire discrete unit. Figure 3 The structure diagram of the discrete unit is shown in Figure 1. The indoor and outdoor media are connected by cross-flow heat exchange through the middle heat exchange wall. a is the indoor dry air flow channel, b is the outdoor wet air flow channel, and flow channel b is the wet air heat exchange wall. First, consider the condensation and evaporation of the water film attached to the heat exchange plate, and construct the mass and energy conservation equations of the water film; secondly, construct the heat and mass transfer process of the wet air and water film; finally, consider the geometric structure of the heat exchanger (such as Figure 4 As shown in the figure), the heat exchange fluids on both sides, the heat exchange plate materials, the heat transfer and pressure drop correlation formula, and the energy conservation equation of the entire discrete unit are constructed.

[0069] Water film conservation equation:

[0070] Calculation equation for the mass of water vapor condensed in moist air:

[0071] m flowCondensate =betaAeff·ρ Gas ·(ζ-ζ Saturation )

[0072] Where betaAeff is the mass transfer coefficient, ρ Gas is the gas density, ζ is the moisture content of the air in the condensed state, Saturation is the humidity content of moist air at saturation temperature, m flowCondensate is the mass flow rate of condensed water in the wet air;

[0073] The calculation equation for the evaporation mass of water in the liquid film is:

[0074] m flowEvaporate =betaAeff·ρ Gas ·(ζ Saturation -ζ)

[0075] The mass conservation equation:

[0076]

[0077] Among them, mFilm is the mass flow rate of water film, Film is the water film, m flowWaterDrain is the amount of water lost, m flowEvaporate is the mass flow rate of evaporated water in moist air;

[0078] Energy conservation equation:

[0079]

[0080] Among them, H Film is the enthalpy of the water film, portN, portW, and portE represent the upper, left, and right outlets of the discrete unit for external heat transfer, and Q flow is the heat transfer from the discrete unit outlet to the outside, h Film is the specific enthalpy of the water film;

[0081] Heat and mass transfer calculation equations for moist air and water film:

[0082]

[0083]

[0084]

[0085]

[0086]

[0087]

[0088]

[0089] Where Nu is the Nusselt number, Le is the Lewis number, α is the convective heat transfer coefficient, L is the characteristic length, λ is the thermal conductivity of moist air, C, m, and n are coefficients, and different flow conditions have different values; Re is the Reynolds number, Sh is the Sherwood number, β is the mass transfer coefficient of moist air, D is the characteristic coefficient of water vapor solubility in moist air, Sc is the Schmidt number, v is the kinematic viscosity, μ is the dynamic viscosity, ρ is the fluid density, Pr is the Prandtl number, and C p is the specific heat capacity at constant pressure, a is the thermal conductivity, β idealGas is the mass transfer coefficient of an ideal gas.

[0090] The conservation equations of the entire discrete element include the mass conservation equation, energy conservation equation, and momentum conservation equation, specifically:

[0091] Conservation of mass:

[0092] m flowA +m flowB -m flowCondensate +m flowEvaporate =0

[0093] Among them, m flowA is the mass flow rate of indoor dry air medium, m flowB is the mass flow rate of outdoor wet air medium,

[0094] Conservation of Energy:

[0095] Q flow +m flowA ·h A +m flowB ·h B +h Film ·(m flowCondensate -m flowEvaporate )=0

[0096] Among them, Q flow The heat generated by the dynamic changes of evaporation and condensation of the water film when wet air, dry air and water film are mixed. A is the enthalpy of medium A, h B is the enthalpy of medium B, h Film is the enthalpy of the water film;

[0097] Conservation of momentum:

[0098] p A -p B =dp

[0099] Among them, p A is the pressure of medium A, pB is the pressure of medium B, dp is the pressure difference;

[0100] Step 4: Connect discrete units based on the connect statement of Modelica language. Figure 5 As shown, in each discrete unit, the outdoor wet air medium is connected horizontally, and the medium flow b, that is, the outdoor wet air flows from the discrete unit outlet A through the n discrete units connected horizontally and output to the discrete unit outlet B, and its heat is transferred to the indoor dry air medium through the heat exchange wall unit, that is, the medium flow a of each discrete unit, and the heat of the indoor dry air medium is then aggregated to the total outlet of the indoor dry air medium (outlet A and outlet B), ensuring the cross-flow heat transfer form of the flow channel in the heat exchanger. Each discrete unit has its own conservation equation. The connect statement connects each discrete unit, which can transfer flow variables such as heat flow and volume flow, as well as potential variables such as heat and pressure. At the discrete unit connection point, the sum of the flow variables is zero, and the potential variable values ​​are equal, so that the energy of each discrete unit connection point is conserved, ensuring the transfer of material properties in each discrete unit. Then it is connected to the mixed medium connection port, and finally the indirect evaporative cooling heat exchanger model based on the finite volume method is obtained, as shown in the attached figure. Figure 6 As shown, one end of the mixed medium connection port is connected to the spray port, one end is connected to the outdoor air side, and one end is connected to the discrete unit outlet A, that is, the attached Figure 5 The heat exchanger discrete unit connections in the attached Figure 6 In, attached Figure 5 Exit A and Exit B are attached. Figure 6 The two indoor air sides, attached Figure 5 The discrete unit outlet B is attached Figure 6 The right side of the outdoor air.

[0101] The Modelica language organizes and encapsulates data using classes as its core. It supports building models using a component connection mechanism, with connectors defining flow and potential variables. Modelica connectors create connection equations between discrete elements, reflecting the conservation of momentum, mass, and energy between discrete element connections in a real-world heat exchanger.

[0102] The Modelica language utilizes acausal modeling. When declaring equations, no solution direction is specified. The solution direction is ultimately determined automatically by the simulation solver based on the data flow environment of the equation system, making heat exchanger modeling easier. The fundamental phenomena of the heat exchanger's discrete elements are described using equations, and the interactions between these discrete elements are represented as acausal connections, significantly reducing the modeling workload.

[0103] The Modelica language supports declarative physical modeling, focusing solely on the model's statement—that is, how to express the behavior of the simulated object through mathematical equations—without having to consider the detailed implementation of the model solution. This paper uses the Modelica language's connect statement to connect the outlets of each discrete element. This not only reflects the internal hierarchical structure of the heat exchanger's finite volume model, but also reduces the complexity of model construction, facilitating subsequent research on the internal medium flow of indirect evaporative cooling heat exchangers.

[0104] The heat exchanger simulation modeling of the indirect evaporative cooling system air conditioner of the present invention uses the finite volume method to discretize the heat exchanger space. Based on the finite volume method, the heat exchanger is divided into a series of non-repetitive discrete units, each of which is represented by a node. Within each discrete unit, the geometric structure of the heat exchanger itself, the heat exchange fluids on both sides, the heat exchange plate materials, the heat exchange and pressure drop correlation are considered, and the continuous control equations in the heat exchanger solution area are converted into discrete equations representing the relationship between the function values ​​to be solved at the unit nodes. Each discrete equation is an expression of the conservation of a certain physical quantity on a finite volume. Solving the established representative equation to obtain the node value of the continuous function greatly reduces the difficulty of solving the mathematical model. The indirect evaporative cooling heat exchanger model constructed based on the Modelica language can well simulate the dry and wet modes of the indirect evaporative cooling air conditioning system; the dry mode is the most basic simulation form, using outdoor dry air as the medium. On this basis, the mixture of spray water and outdoor dry air is added to construct a simulation model under the wet mode, and the influence of water film precipitation in the wet air on the heat exchange process is considered. The model has strong reusability and fast calculation, which improves modeling efficiency.

[0105] The evaporation and condensation of the water film attached to the heat exchanger plate are fully considered under wet working conditions. The water film heat transfer model is constructed from the following points: (1) The wet air heat exchange wall is used for calculation in the water film modeling, and the wet air, water film and heat exchange wall are integrated into one model. The energy conservation, mass conservation and momentum conservation equations are constructed between the wet air, water film and heat exchange wall. (2) The Lewis number is used to describe the scale of the wet air heat and mass transfer process. When the Lewis number is 1, the Nusselt number and the Sherwood number have the same value, and the scale of heat and mass transfer in the boundary layer is similar. It can also be corrected in this subsequent calibration process. (3) In the model options, it is defined whether to process water film condensation and consider the dynamic conservation of water film.

[0106] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A modeling method for an indirect evaporative cooling heat exchanger model based on the Modelica language, characterized by: The following steps are involved: S1. Building a mixed medium model of spray water and outdoor dry air: the mixed medium model is used to generate outdoor wet air; S2. Use the finite volume method to divide the heat exchanger and set discrete units: The indirect evaporative cooling heat exchanger model includes indoor dry air, outdoor wet air, and the heat exchange wall. Use the finite volume method to divide the heat exchanger's calculation area into a series of non-repeating discrete units. Use the Modelica language to set the number of discrete units. S3. Construct conservation equations for each discrete unit: Indoor dry air and outdoor wet air are connected through the heat exchange wall in the middle of the heat exchanger for cross-flow heat exchange. First, construct the water film condensation and evaporation mass calculation equations and the energy and mass conservation equations. Next, construct the heat and mass transfer calculation equations for the wet air and water film. Finally, construct the conservation equations for each discrete unit based on the heat exchanger's geometric structure, the heat exchange fluids on both sides, the heat exchange plate materials, and the heat transfer and pressure drop correlation equations. The discrete element conservation equations in step S3 include mass conservation, energy conservation, and momentum conservation equations, specifically: The mass conservation equation: m flowA +m flowB -m flowCondensate +m flowEvaporate =0 Among them, m flowA is the mass flow rate of indoor dry air medium, m flowB is the mass flow rate of outdoor wet air medium, m flowCondensate is the condensation mass of water film in humid air, m flowEvaporate is the mass of water evaporated from the water film; Energy conservation equation: Q flow +m flowA ·h A +m flowB ·h B +h Film ·(m flowCondensate -m flowEvaporate )=0 Among them, Q flow is the heat transfer from the discrete unit outlet to the outside, h A is the specific enthalpy of medium A, h B is the specific enthalpy of medium B, h Film is the specific enthalpy of the water film; Momentum conservation equation: P A -P B =dp Among them, P A is the pressure of medium A, P B is the pressure of medium B, dp is the pressure difference; S4. The connect statement of Modelica language is used to connect each discrete unit, and the connection equation is constructed to obtain the indirect evaporative cooling heat exchanger model based on the finite volume method.

2. The modeling method of an indirect evaporative cooling heat exchanger model based on the Modelica language according to claim 1, characterized in that: The process of building the mixed medium model in step S1 includes creating boundary conditions for the spray water and outdoor air, adding a volume flow mixing joint to achieve uniform mixing of the spray water and outdoor air to obtain a mixed medium, setting the temperature, relative humidity, and volume parameters of the mixed medium in the mixing joint, inputting the energy conservation equation and momentum conservation equation of the mixed medium based on the Modelica language, completing the calculation, and then introducing the mixed medium into the heat exchanger.

3. The modeling method of an indirect evaporative cooling heat exchanger model based on the Modelica language according to claim 2, characterized in that: The energy conservation equation of the mixed medium input based on the Modelica language is: Among them, H is the enthalpy of the mixed medium, h is the specific enthalpy of the mixed medium, A is the indoor dry air medium, B is the outdoor wet air medium, h A is the specific enthalpy of medium A, h B is the specific enthalpy of medium B, h C is the specific enthalpy of the spray water, m flowA is the mass flow rate of indoor dry air medium, m flowB is the mass flow rate of outdoor wet air medium, m flowC is the mass flow rate of spray water, volume is the volume of the mixed medium, and p is the pressure of the mixed medium; The momentum conservation equation of the mixed medium input based on Modelica language is: Among them, ξ is the moisture content of the mixed medium, A is the moisture content of medium A, ξ B is the moisture content of medium B, ξ C is the moisture content of the spray water, m Gas is the mass of the gas.

4. The modeling method of an indirect evaporative cooling heat exchanger model based on the Modelica language according to claim 1, characterized in that: The condensation and evaporation mass calculation equations and the energy and mass conservation equations of the water film in step S3 are specifically: The calculation equation for the condensation mass of water film in humid air is: m flowCondensate =betaAeff·ρ Gas ·(z-z Saturation ) Where betaAeff is the mass transfer coefficient, ρ Gas is the gas density, ζ is the moisture content of the air in the condensed state, Saturation is the humidity content of moist air at saturation temperature, m flowCondensate is the condensation mass of water film in humid air; The calculation equation for the evaporation mass of water in the water film is: m flowEvaporate =betaAeff·ρ Gas ·(g Saturation -g) The mass conservation equation of the water film is: Among them, mFilm is the mass flow rate of water film, Film is the water film, m flowWaterDrain is the amount of water lost, m flowEvaporate is the mass of water evaporated from the water film; Energy conservation equation of water film: Among them, H Film is the enthalpy of the water film, portN, portW, and portE represent the upper, left, and right outlets of the discrete unit for external heat transfer, and Q flow is the heat transfer from the discrete unit outlet to the outside, h Film is the specific enthalpy of the water film.

5. The modeling method of an indirect evaporative cooling heat exchanger model based on Modelica language according to claim 1, characterized in that: The heat transfer and mass transfer calculation equations of the wet air and water film in step S3 are specifically: Where Nu is the Nusselt number, Le is the Lewis number, α is the convective heat transfer coefficient, L is the characteristic length, λ is the thermal conductivity of moist air, C, m, and n are coefficients, and different flow conditions have different values; Re is the Reynolds number, Sh is the Sherwood number, β is the mass transfer coefficient of moist air, D is the characteristic coefficient of water vapor solubility in moist air, Sc is the Schmidt number, v is the kinematic viscosity, μ is the dynamic viscosity, ρ is the fluid density, Pr is the Prandtl number, and C p is the specific heat capacity at constant pressure, a is the thermal conductivity, β idealGas is the mass transfer coefficient of an ideal gas.

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