Power conversion system and thermal characteristic modeling analysis method

Abstract

The invention provides a power conversion system and a thermal characteristic modeling analysis method. The power conversion system comprises a compressor, a heat regenerator, a heat pipe pile, an intermediate heat exchanger, a turbine, a motor and a cooler. The compressor is used for receiving the working medium output by the cooler and outputting the working medium to the heat regenerator after pressurizing the working medium; the heat regenerator is used for preheating the pressurized working medium after receiving the pressurized working medium and outputting the preheated pressurized working medium to the intermediate heat exchanger; the heat pipe pile is used for providing heat energy; the intermediate heat exchanger is used for transferring heat energy provided by the heat pipe pile to the preheated pressurized working medium to obtain a high-temperature pressurized working medium and outputting the high-temperature pressurized working medium to the turbine; the turbine is used for doing work based on expansion of the high-temperature pressurized working medium and driving the motor. Through close cooperation among the components, an efficient energy flow link is formed, and the power conversion efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power conversion, and in particular to a power conversion system and a method for modeling and analyzing thermal characteristics. Background Art

[0002] As a unique and highly potential power supply method, the marine nuclear power system plays an important role. In the existing marine nuclear power system, in the conversion process from nuclear energy to mechanical energy and then to the kinetic energy required to finally drive the ship forward, there are many complex steps and sophisticated devices operating in coordination.

[0003] Inside the nuclear reactor, nuclear fuel releases a large amount of heat energy through fission reactions. This heat energy is first transferred to the coolant, and then the coolant takes the heat out of the reactor to heat the working medium, converting it into a high-temperature and high-pressure gaseous form, and then driving the steam turbine to rotate to achieve the conversion of heat energy into mechanical energy.

[0004] In the existing marine nuclear power system during the power conversion process, the power conversion efficiency is not high. How to achieve high-efficiency power conversion is an important issue that the industry urgently needs to solve at present. Summary of the Invention

[0005] The present invention provides a power conversion system and a method for modeling and analyzing thermal characteristics, including: a compressor, a regenerator, a heat pipe stack, an intermediate heat exchanger, a turbine, an electric motor, and a cooler; The input end of the compressor is connected to the output end of the cooler, and the output end of the compressor is connected to the first input end of the regenerator, for receiving the working medium output by the cooler and pressurizing the working medium and then outputting it to the regenerator; The first output end of the regenerator is connected to the input end of the intermediate heat exchanger, for receiving the pressurized working medium, preheating the pressurized working medium, and then outputting the preheated pressurized working medium to the intermediate heat exchanger; The heat pipe stack is connected to the intermediate heat exchanger for providing heat energy; The output end of the intermediate heat exchanger is connected to the input end of the turbine, for transferring the heat energy provided by the heat pipe stack to the preheated pressurized working medium to obtain a high-temperature pressurized working medium, and outputting the high-temperature pressurized working medium to the turbine; The rotating shaft of the turbine is connected to the rotating shaft of the electric motor, and the turbine is used to expand and do work based on the high-temperature pressurized working medium to drive the electric motor.

[0006] According to a power conversion system provided by the present invention, the regenerator further includes a second input end and a second output end; The second input end of the regenerator is connected to the output end of the turbine, and the second output end of the regenerator is connected to the input end of the cooler; The regenerator is further configured to receive the working fluid after work output by the turbine, absorb the heat of the working fluid after work, obtain the working fluid after heat absorption, and output the working fluid after heat absorption to the cooler.

[0007] According to a power conversion system provided by the present invention, the cooler is specifically configured to: After receiving the working fluid after heat absorption output by the regenerator, cool the working fluid after heat absorption.

[0008] According to a power conversion system provided by the present invention, the cooler further includes a heat exchange input end and a heat exchange output end; The heat exchange input end is for seawater to flow in, and the heat exchange output end is for seawater to flow out.

[0009] According to a power conversion system provided by the present invention, the regenerator is obtained by dividing the heat exchange channels on the cold and hot sides of a printed circuit board heat exchanger into multiple nodes.

[0010] According to a power conversion system provided by the present invention, the turbine and the compressor are respectively suspended at both ends of the shaft of the motor, and the compressor, the motor and the turbine are coaxial.

[0011] According to a power conversion system provided by the present invention, the intermediate heat exchanger specifically includes an input end of the intermediate heat exchanger, an upper chamber, an annular heat exchange area, a lower chamber, and an output end of the intermediate heat exchanger; The intermediate heat exchanger is specifically configured to: After receiving the preheated pressurized working fluid at the input end of the intermediate heat exchanger, flow into the annular heat exchange area through the upper chamber to exchange heat and absorb heat; After the preheated pressurized working fluid absorbs heat, converge to the lower chamber and flow out to the output end of the intermediate heat exchanger.

[0012] According to a power conversion system provided by the present invention, the cooler is a shell-and-tube heat exchanger.

[0013] The present invention also provides a method for modeling and analyzing the thermal characteristics of the power conversion system according to any one of the above, including: The compressor receives the working fluid output by the cooler, pressurizes the working fluid and outputs it to the regenerator; After receiving the pressurized working fluid, the regenerator preheats the pressurized working fluid and outputs the preheated pressurized working fluid to the intermediate heat exchanger; The intermediate heat exchanger transfers the heat energy provided by the heat pipe stack to the preheated pressurized working fluid to obtain a high-temperature pressurized working fluid, and outputs the high-temperature pressurized working fluid to the turbine; The turbine expands and does work based on the high-temperature pressurized working fluid to drive the motor.

[0014] According to the thermal characteristic modeling and analysis method provided by the present invention, the thermal parameters of the regenerator nodes are as follows: ; ; where q is the heat transfer amount, H is the heat transfer coefficient, A is the heat transfer area, t is the temperature, the subscript n represents the nth node in the regenerator, h represents the high temperature side, and c represents the low temperature side.

[0015] The power conversion system and the thermal characteristic modeling and analysis method provided by the present invention form an efficient energy transfer link through the close cooperation among various components. The compressor receives the working medium output by the cooler and pressurizes it, providing a high-pressure basis for subsequent energy conversion steps to ensure that the working medium can carry and transfer energy more efficiently. The regenerator preheats the pressurized working medium using its own structure, fully recovering the waste heat inside the system, reducing the need for additional heat energy input, greatly improving the energy utilization rate, and avoiding the waste of heat. The intermediate heat exchanger effectively connects the heat pipe stack and the turbine, realizing the efficient conversion of heat energy into high-temperature pressurized working medium, enabling the working medium to carry sufficient energy to drive the turbine. The design of connecting the turbine and the motor coaxially enables the expansion work of the turbine to directly drive the motor, reducing the loss in the intermediate energy conversion link, converting mechanical energy into electrical energy almost without loss, and improving the overall power output efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 is a schematic structural diagram of the power conversion system provided by the present invention.

[0018] Figure 2 is a schematic working structure diagram of the seawater-based cooler provided by the present invention.

[0019] Figure 3 is a schematic structural diagram of the regenerator provided by the present invention.

[0020] Figure 4 is a schematic structural diagram of the integrated unit provided by the present invention.

[0021] Figure 5 is a schematic structural diagram of the annular heat exchange area provided by the present invention.

[0022] Reference Signs: 110: Compressor; 120: Regenerator; 130: Heat pipe stack; 140: Intermediate heat exchanger; 150: Turbine; 160: Motor; 170: Cooler. Specific embodiments

[0023] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0024] It should be understood that the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0025] The terms "comprising" and "including" indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their combinations.

[0026] Figure 1 is a schematic structural diagram of the power conversion system provided by the present invention. As Figure 1 shown, the present invention provides a power conversion system, which may include: a compressor 110, a regenerator 120, a heat pipe stack 130, an intermediate heat exchanger 140, a turbine 150, a motor 160 and a cooler 170.

[0027] It should be noted that the intermediate heat exchanger 140, the compressor 110, the turbine 150, the regenerator 120 and the cooler 170 form a closed cycle loop. The working fluid circulates in the closed cycle loop to achieve the power conversion process. Among them, the working fluid, that is, the working medium, is the medium used to achieve energy conversion in the energy conversion device. The closed cycle loop can be used in the nuclear power system of a ship.

[0028] The working fluid in the closed cycle loop may specifically be supercritical carbon dioxide. Under the supercritical state, the gas-liquid interface of carbon dioxide disappears, the system properties are uniform, and it is in a fluid state. Its density is close to that of a liquid, its viscosity is close to that of a gas, and the critical state is easy to reach, which is stable, safe and has a low preparation cost.

[0029] Specifically, the input end of the compressor 110 is connected to the output end of the cooler 170, and the output end of the compressor 110 is connected to the first input end of the regenerator 120.

[0030] The main function of the cooler 170 is to reduce the temperature of the working fluid, so that it can be restored from a relatively high temperature state to a relatively low temperature level close to the initial state. When the cooler 170 completes cooling of the working fluid, the working fluid flows out in a low temperature and low pressure state.

[0031] At this time, the compressor 110 begins to work. The compressor 110 uses a mechanical device, such as a reciprocating compressor through the reciprocating motion of the piston in the cylinder, or a centrifugal compressor with a high-speed rotating impeller, to apply external force to the incoming low-temperature and low-pressure working fluid. In this process, the distance between the working fluid molecules is compressed closer, which reduces the volume of the working fluid and increases the pressure, thereby obtaining a pressurized working fluid. The compressor 110 outputs to the regenerator 120 through the channel between the output end of the compressor 110 and the input end of the regenerator 120.

[0032] The first output end of the regenerator 120 is connected to the input end of the intermediate heat exchanger 140 , and is used for receiving the pressurized working fluid, preheating the pressurized working fluid, and outputting the preheated pressurized working fluid to the intermediate heat exchanger 140 .

[0033] The working principle of the regenerator 120 is based on the principle of heat exchange, that is, heat transfer is performed by using the temperature difference between fluids of different temperatures. When the working fluid after the turbine has done work enters the regenerator 120, it still contains a relatively high amount of heat. A heat exchange surface is designed inside the regenerator 120 to promote heat transfer of the working fluid.

[0034] The high-temperature working fluid output by the turbine undergoes heat exchange in the regenerator 120. The high-temperature working fluid releases its remaining heat to the low-temperature fluid, causing the temperature of the low-temperature fluid to rise. After the heat exchange, the temperature of the high-temperature working fluid output by the turbine decreases and becomes a working fluid after heat absorption. This part of the working fluid is then output to the cooler for further cooling. The recovered heat can be used to preheat the working fluid, thereby improving the energy utilization efficiency of the entire system.

[0035] Specifically, the pressure and energy state of the working fluid after being pressurized by the compressor 110 are significantly improved. The reason why the pressurized working fluid is transported to the regenerator 120 is that the regenerator 120 can make full use of the internal waste heat. In the regenerator 120, the exhaust gas discharged from the turbine and other components still carries a certain amount of heat, which can be used to preheat the working fluid that is about to enter the subsequent links such as the heater. After the pressurized working fluid output by the compressor 110 enters the regenerator 120, it exchanges heat with the exhaust gas carrying waste heat, absorbs the heat of the exhaust gas, and further increases its own temperature. This not only reduces the energy input demand of the subsequent intermediate heat exchanger 140 and improves the thermal efficiency of the entire system, but also enables the working fluid to have a better energy state when entering the next cycle link, laying the foundation for the continuous and efficient operation of the system.

[0036] The heat pipe reactor 130 is a new type of reactor system that combines heat pipe technology with a nuclear reactor. The heat pipe reactor uses nuclear fuel fission to generate heat energy, and conducts this heat energy efficiently through heat pipes.

[0037] The heat pipe reactor 130 is connected to the intermediate heat exchanger 140, and is used to transfer the heat of the heat pipe reactor 130 to the preheated pressurized working fluid in the intermediate heat exchanger 140, so that the preheated pressurized working fluid reaches a preset temperature.

[0038] The output end of the intermediate heat exchanger 140 is connected to the input end of the turbine 150, and is used to transfer the heat energy provided by the heat pipe reactor 130 to the preheated pressurized working fluid to obtain a high-temperature pressurized working fluid, and output the high-temperature pressurized working fluid to the turbine 150.

[0039] In the intermediate heat exchanger 140, the heat energy from the heat pipe reactor exchanges heat with the preheated pressurized working fluid, so that the temperature of the preheated pressurized working fluid further rises to the preset temperature to obtain a high-temperature pressurized working fluid. The intermediate heat exchanger 140 transfers the high-temperature pressurized working fluid to the turbine 150 through the channel between the output end of the intermediate heat exchanger 140 and the input end of the turbine to do work.

[0040] A turbine 150 is a machine that converts the energy contained in a fluid working medium into mechanical work, also known as a turbine, and is a commonly used power machine.

[0041] After the high-temperature pressurized working fluid enters the turbine of the turbine 150, it expands and does work in the turbine, pushes the impeller of the turbine to rotate, converts the heat energy of the working fluid into mechanical energy, and drives the motor 160 to operate.

[0042] The power conversion system provided by the present invention forms an efficient energy transfer link through the close cooperation between components. The compressor receives the working fluid output by the cooler and pressurizes it, providing a high-pressure basis for subsequent energy conversion steps to ensure that the working fluid can carry and transfer energy more efficiently. The regenerator preheats the pressurized working fluid using its own structure, fully recovers the waste heat inside the system, reduces the need for additional heat energy input, greatly improves the energy utilization rate, and avoids the waste of heat energy without reason. The intermediate heat exchanger effectively connects the heat pipe reactor and the turbine, realizing the efficient conversion of heat energy into a high-temperature pressurized working fluid, enabling the working fluid to carry enough energy to drive the turbine to operate. The design of the coaxial connection between the turbine and the motor enables the expansion work of the turbine to directly drive the motor, reducing the loss of the intermediate energy conversion link, and converting mechanical energy into electrical energy almost without loss, improving the overall power output efficiency.

[0043] In one embodiment, the regenerator further includes a second input end and a second output end; the second input end of the regenerator is connected to the turbine output end, and the second output end of the regenerator is connected to the input end of the cooler; the regenerator is further configured to receive the working fluid after work output from the turbine output end, absorb the heat of the working fluid after work, obtain the working fluid after heat absorption, and output the working fluid after heat absorption to the cooler.

[0044] After the high-temperature pressurized working fluid enters the turbine to do work, the working fluid often still contains a certain amount of heat. If this part of the heat is directly discharged into the environment, it will be a waste. To improve the energy utilization efficiency, the regenerator is designed to absorb this part of the heat.

[0045] Specifically, the regenerator further includes a second input end and a second output end. The second input end of the regenerator is connected to the turbine output end, and is configured to, after the turbine does work, the working fluid output is connected to the second input end of the regenerator through a pipeline.

[0046] After the regenerator absorbs the heat of the working fluid output from the turbine, it outputs the working fluid after heat absorption to the cooler through its second output end for further cooling.

[0047] The working principle of the regenerator is based on the heat exchange principle, that is, heat transfer is carried out by using the temperature difference between fluids at different temperatures. When the working fluid after the turbine does work enters the regenerator, it still contains relatively high heat. The regenerator is internally designed with a heat exchange surface to promote the heat transfer of the working fluid.

[0048] The high-temperature working fluid output from the turbine undergoes heat exchange in the regenerator. The high-temperature working fluid releases its remaining heat to the low-temperature fluid, causing the temperature of the low-temperature fluid to rise. After heat exchange, the temperature of the high-temperature working fluid output from the turbine decreases and becomes the working fluid after heat absorption. This part of the working fluid is then output to the cooler for further cooling. The recovered heat can be used to preheat the working fluid, thereby improving the energy utilization efficiency of the entire system.

[0049] The power conversion system provided by the present invention, by setting a regenerator, preheats the pressurized working fluid using its own structure, fully recovers the waste heat inside the system, reduces the demand for additional heat energy input, greatly improves the energy utilization rate, and avoids the waste of heat without reason.

[0050] In one embodiment, the cooler is specifically configured to: after receiving the working fluid after heat absorption output by the regenerator, cool the working fluid after heat absorption. The cooler further includes a heat exchange input end and a heat exchange output end; the heat exchange input end is for seawater to flow in, and the heat exchange output end is for seawater to flow out.

[0051] Specifically, for the cooler, a shell-and-tube heat exchanger can be selected as the cooler. The shell-and-tube heat exchanger mainly consists of components such as a shell, a tube bundle, a tube sheet, and a head. Among them, the tube bundle is the core component of the heat exchanger, which is composed of many tubes arranged in parallel and fixed on the tube sheets at both ends. These tubes can be plain tubes or fin tubes, threaded tubes, or other special-shaped tubes used to enhance the heat transfer effect.

[0052] In addition to including an input end for the inflow of the working medium after heat absorption and an output end for the outflow, the cooler also includes a heat exchange input end and a heat exchange output end. The heat exchange input end is used for the inflow of seawater, and the heat exchange output end is used for the outflow of seawater, so that the seawater cools the working medium after heat absorption in the cooler.

[0053] Specifically, based on the layout of the inlet and outlet of the hot and cold fluids of the seawater cooler as Figure 2 shown in the working structure schematic diagram of the cooler based on seawater provided by the present invention, the seawater flows out from the heat exchange input end to the heat exchange output end, the working medium after heat absorption flows in from the input end of the cooler and flows out from the output end of the cooler, the hot and cold fluids are arranged in countercurrent, and the tubes in the cooler are arranged in an equilateral triangle staggered arrangement.

[0054] In one embodiment, the recuperator is obtained by dividing the heat exchange channels on both the hot and cold sides of the printed circuit board heat exchanger into multiple nodes.

[0055] Specifically, the recuperator uses a printed circuit board heat exchanger (PCHE). The printed circuit board heat exchanger (PCHE) is a new type of high-efficiency and compact heat exchanger, and its core component is a metal plate. Microchannels are processed by an etching method. These plates are assembled into unit modules by diffusion welding to form hot and cold fluid channels. The advantages of PCHE include high heat transfer efficiency, strong pressure-bearing capacity, high compactness, and high weld strength.

[0056] The structural schematic diagram of the recuperator can be as Figure 3 shown in the structural schematic diagram of the recuperator provided by the present invention. The heat exchange channels on both the hot and cold sides of the printed circuit board heat exchanger are divided into N nodes, and the length of each node is taken as a smaller length unit dL to solve the problem of drastic change in physical properties along the way. The constructed recuperator needs to meet the following conditions: The total mass flow rate is evenly distributed in each channel; The temperature distribution of the heat exchanger is periodic like that of the hot and cold channels; The temperature in the circumferential direction of the channel is the same; The area of heat conduction is equal to the area of convective heat transfer in the channel; The distance of heat conduction between adjacent hot and cold channels is equal to the spacing between the hot and cold channels.

[0057] Furthermore, the thermodynamic parameters of each node of the heat exchanger can be obtained as: ; ; where q is the heat transfer amount, H is the heat transfer coefficient, A is the heat transfer area, t is the temperature, the subscript n represents the nth node in the regenerator, h represents the high-temperature side, and c represents the low-temperature side.

[0058] In one embodiment, the compressor is respectively suspended at both ends of the shaft of the motor, and the compressor, the motor and the turbine are coaxial. This layout is beneficial to achieve efficient power transmission.

[0059] The coaxial design means that the rotational power generated by the motor can be directly and efficiently transmitted to the compressor and the turbine, reducing the energy loss during the transmission process. The coaxial arrangement makes the volume of the entire system more compact and occupies less space, which is particularly important for application scenarios with limited space.

[0060] The turbine and the compressor are key components in the power conversion system to achieve the pressurization of the working medium and the expansion power generation. It includes three parts: the turbine, the compressor and the generator. The generator is in the middle, and the turbine and the compressor are respectively suspended at both ends of the shaft of the motor, as Figure 4 shown in the structural schematic diagram of the integrated unit provided by the present invention.

[0061] Specifically, the work consumed by the compressor can be expressed as: ; where Hco is the actual outlet enthalpy of the compressor, H co,s is the isentropic compression enthalpy of the compressor, Hci is the inlet enthalpy of the compressor, and η c is the isentropic efficiency of the compressor.

[0062] The work done by the turbine expansion can be expressed as: ; where H to is the outlet enthalpy of the turbine, H to,s is the isentropic expansion enthalpy of the turbine, H ti is the inlet enthalpy of the turbine, and η t is the isentropic efficiency of the turbine.

[0063] In one embodiment, the intermediate heat exchanger specifically includes an upper chamber, an annular heat exchange region and a lower chamber; the intermediate heat exchanger is used for the preheated pressurized working medium to enter the upper chamber, then flow into the annular heat exchange region to exchange heat and absorb heat; after the preheated pressurized working medium absorbs heat, it converges to the lower chamber and flows out.

[0064] Specifically, as the inlet of the preheated pressurized working fluid, the upper chamber is responsible for receiving and initially accommodating these working fluids. Its design usually takes into account the uniform distribution of the fluid and reduces the impact of the fluid on the heat exchange area to ensure the smooth progress of the heat exchange process.

[0065] The annular heat exchange area is the core part of the intermediate heat exchanger and is responsible for completing the heat exchange between the preheated pressurized working fluid and the heat source. The annular design helps to increase the heat exchange area and improve the heat exchange efficiency. At the same time, enhanced heat transfer technologies such as finned tubes and threaded tubes can be used in this area to further enhance the heat exchange effect.

[0066] After the preheated pressurized working fluid completes the heat exchange, they will converge to the lower chamber. The lower chamber, as the outlet, is responsible for outputting the heated working fluid to the next process step.

[0067] The working principle of the intermediate heat exchanger is based on the principle of heat conduction. When the preheated pressurized working fluid enters the upper chamber, they will flow into the annular heat exchange area. Here, the working fluid and the heat source exchange heat through the tube wall. The heat source transfers heat to the working fluid, increasing its temperature. After completing the heat exchange, the heated working fluid will converge to the lower chamber and flow out from the outlet.

[0068] For the intermediate heat exchange area, its structure can be as Figure 5 shown in the schematic diagram of the annular heat exchange area structure provided by the present invention. The annular heat exchange area mainly includes the heat tube wall, helium gas in the gap, the sleeve, supercritical CO2 fluid in the annular channel and the matrix. The heat exchange methods involved include conduction, convection and radiation heat exchange, and the flow resistance model of the fluid is also considered. Through three-dimensional fine modeling and simulation calculations, the heat transfer coefficient and friction coefficient under this structure are as follows: ; ; where Re is the Reynolds number, Nu is the Nusselt number, Pr is the Prandtl number, f is the resistance coefficient, Tw is the wall temperature, and Ts is the fluid temperature.

[0069] Assuming that supercritical CO2 is an incompressible fluid, a single-channel model is used to simulate the flow and heat transfer in each channel. The mass equation and momentum equation are general equations and will not be elaborated here. Its energy equation considers the convective heat transfer with the matrix and sleeve on both sides: ; where A is the heat exchange area, ρ is the density, cp is the specific heat capacity at constant pressure, T is the temperature, w is the flow rate, U is the wetted perimeter, h is the convective heat transfer coefficient, and the subscripts s, w, and t refer to the supercritical CO2 fluid, the matrix wall and the sleeve wall respectively.

[0070] In one embodiment, the cooler is a shell-and-tube heat exchanger.

[0071] The shell-and-tube heat exchanger mainly consists of components such as a shell, a tube bundle, tube sheets, and tube heads. Among them, the tube bundle is the core component of the heat exchanger, which is composed of many tubes arranged in parallel and fixed on the tube sheets at both ends. These tubes can be plain tubes or finned tubes, threaded tubes, or other special-shaped tubes used to enhance the heat transfer effect.

[0072] In one embodiment, the working fluid is supercritical carbon dioxide.

[0073] At the supercritical state, the gas-liquid interface of carbon dioxide disappears, the system properties are uniform, and it is in a fluid state. Its density is close to that of a liquid, and its viscosity is close to that of a gas. The critical state is easily achieved, and it is stable, safe, and has a low preparation cost.

[0074] The power conversion system constructed based on the above components forms an efficient energy transfer link through the close cooperation between components. The compressor receives the working fluid output by the cooler and pressurizes it, providing a high-pressure basis for subsequent energy conversion steps to ensure that the working fluid can carry and transfer energy more efficiently. The recuperator preheats the pressurized working fluid using its own structure, fully recovering the waste heat inside the system, reducing the need for additional heat energy input, greatly improving the energy utilization rate, and avoiding the waste of heat. The intermediate heat exchanger effectively connects the heat pipe stack and the turbine, realizing the efficient conversion of heat energy into high-temperature pressurized working fluid, enabling the working fluid to carry enough energy to drive the turbine. The design of coaxial connection between the turbine and the motor allows the turbine to expand and do work to directly drive the motor, reducing the loss in the intermediate energy conversion link, converting mechanical energy into electrical energy almost without loss, and improving the overall power output efficiency.

[0075] To further improve the efficiency of the system, it can also start from multiple aspects. At the material level, new materials with excellent thermal conductivity are selected to make heat exchange components such as heat exchangers and heat pipe stacks, reducing the thermal resistance, accelerating heat transfer, reducing heat loss during the transfer process, and enabling heat energy to be absorbed and utilized by the working fluid more efficiently. Optimize the impeller design of the compressor and its matching with the motor to reduce mechanical friction loss during compression, improve the compression efficiency, and ensure that the working fluid enters the subsequent process in a more ideal state. For the recuperator, improve the internal heat exchange structure, increase the heat exchange area, and enhance the waste heat recovery efficiency to make the preheating effect more significant. In the turbine part, optimize the blade shape and layout with the help of advanced fluid mechanics simulation technology to reduce air flow disturbance and friction loss, enabling the expansion work efficiency of high-temperature pressurized working fluid to reach a higher level, and then comprehensively improving the operating efficiency of the entire power conversion system and enhancing the power performance of the ship.

[0076] The present invention also provides a method for modeling and analyzing the thermodynamic characteristics of the power conversion system described in any one of the above, including: The compressor receives the working fluid output by the cooler, pressurizes the working fluid, and then outputs it to the recuperator; After the recuperator receives the pressurized working fluid, it preheats the pressurized working fluid and outputs the preheated pressurized working fluid to the intermediate heat exchanger; The intermediate heat exchanger transfers the thermal energy provided by the heat pipe stack to the preheated pressurized working fluid to obtain a high-temperature pressurized working fluid, and outputs the high-temperature pressurized working fluid to the turbine; The turbine expands and does work based on the high-temperature pressurized working fluid to drive the motor.

[0077] Specifically, the main function of the compressor is to pressurize the working fluid (usually gas or steam) output from the cooler. This process is achieved through the internal working mechanism of the compressor, such as the reciprocating motion of the piston or the rotation of the rotor. As the pressure increases, the temperature and density of the working fluid also increase accordingly. The pressurized working fluid output by the compressor is then sent to the recuperator.

[0078] The recuperator receives the pressurized working fluid from the compressor. Its main function is to preheat the pressurized working fluid to increase its temperature before entering the intermediate heat exchanger. The preheating process is achieved by using the low-temperature but partially cooled working fluid returned from other parts of the system (such as the evaporator). This heat exchange not only increases the temperature of the pressurized working fluid but also helps to recover the thermal energy in the system, thereby improving the overall efficiency. The preheated pressurized working fluid is sent to the intermediate heat exchanger.

[0079] The intermediate heat exchanger receives the preheated pressurized working fluid from the recuperator and transfers the thermal energy provided by the heat pipe stack to the working fluid through heat exchange with the heat pipe stack. The heat pipe stack is an efficient thermal energy conversion device that can convert thermal energy into energy available for driving equipment such as turbines. In the intermediate heat exchanger, the preheated pressurized working fluid absorbs the thermal energy released by the heat pipe stack, and the temperature further increases to form a high-temperature pressurized working fluid. This process provides the necessary energy for the subsequent expansion and work of the turbine.

[0080] After the high-temperature pressurized working fluid enters the turbine, it expands and does work by utilizing its high-temperature and high-pressure characteristics. The internal working mechanism of the turbine (such as the rotating blades) converts the thermal energy of the working fluid into mechanical energy. During this process, the rotational motion of the turbine drives the motor to operate, thereby converting mechanical energy into electrical energy or other forms of available energy. The operation of the motor not only provides power for the system but also realizes the conversion and utilization of energy.

[0081] In one embodiment, the structure of the recuperator is to divide the heat exchange channels on both the hot and cold sides of the printed circuit board heat exchanger into N nodes, and the length of each node is taken as a smaller length unit dL to solve the problem of drastic changes in physical properties along the way. The constructed recuperator needs to meet the following conditions: The total mass flow rate is evenly distributed in each channel; The temperature distribution of the heat exchanger is periodic like that of the hot and cold channels; The temperature in the circumferential direction of the channel is the same; The area of heat conduction is equal to the convective heat transfer area inside the channel; The distance of heat conduction between adjacent hot and cold channels is equal to the spacing between the hot and cold channels.

[0082] Furthermore, the thermodynamic parameters of each node of the heat exchanger can be obtained as follows: ; ; where q is the heat transfer quantity, H is the heat transfer coefficient, A is the heat transfer area, t is the temperature, the subscript n is the nth node in the regenerator, h is the high-temperature side, and c is the low-temperature side The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative labor.

[0083] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence, or the part that contributes to the prior art can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of each embodiment of the present invention.

Claims

1. A power conversion system, characterized in that, Including: A compressor, a recuperator, a heat pipe stack, an intermediate heat exchanger, a turbine, an electric motor, and a cooler; The input end of the compressor is connected to the output end of the cooler, and the output end of the compressor is connected to the first input end of the recuperator, for receiving the working medium output by the cooler, and pressurizing the working medium and then outputting it to the recuperator; The first output end of the recuperator is connected to the input end of the intermediate heat exchanger, for receiving the pressurized working medium, preheating the pressurized working medium, and outputting the preheated pressurized working medium to the intermediate heat exchanger; The heat pipe stack is connected to the intermediate heat exchanger, for providing heat energy; The output end of the intermediate heat exchanger is connected to the input end of the turbine, for transferring the heat energy provided by the heat pipe stack to the preheated pressurized working medium to obtain a high-temperature pressurized working medium, and outputting the high-temperature pressurized working medium to the turbine; The rotating shaft of the turbine is connected to the rotating shaft of the electric motor, and the turbine is used for expanding and doing work based on the high-temperature pressurized working medium to drive the electric motor.

2. The power conversion system according to claim 1, characterized in that, The recuperator further includes a second input end and a second output end; The second input end of the recuperator is connected to the output end of the turbine, and the second output end of the recuperator is connected to the input end of the cooler; The recuperator is further used for receiving the working medium after doing work output by the turbine, and absorbing the heat of the working medium after doing work to obtain the working medium after heat absorption, and outputting the working medium after heat absorption to the cooler.

3. The power conversion system according to claim 2, characterized in that, The cooler is specifically used for: After receiving the working medium after heat absorption output by the recuperator, cooling the working medium after heat absorption.

4. The power conversion system according to claim 3, characterized in that, The cooler further includes a heat exchange input end and a heat exchange output end; The heat exchange input end is for seawater to flow in, and the heat exchange output end is for seawater to flow out.

5. The power conversion system according to claim 1, wherein The recuperator is obtained by dividing the heat exchange channels on the cold and hot sides of a printed circuit board heat exchanger into multiple nodes.

6. The power conversion system according to claim 1, wherein The turbine and the compressor are respectively suspended at both ends of the shaft of the electric motor, and the compressor, the electric motor, and the turbine are coaxial.

7. The power conversion system according to claim 1, wherein The intermediate heat exchanger specifically includes an input end of the intermediate heat exchanger, an upper chamber, an annular heat exchange area, a lower chamber, and an output end of the intermediate heat exchanger; The intermediate heat exchanger is specifically used for: After receiving the preheated pressurized working medium at the input end of the intermediate heat exchanger, flowing into the annular heat exchange area through the upper chamber to exchange heat and absorb heat; After the preheated pressurized working medium absorbs heat, converging to the lower chamber and flowing out to the output end of the intermediate heat exchanger.

8. The power conversion system according to claim 1, characterized in that, The cooler is a shell-and-tube heat exchanger.

9. A method for modeling and analyzing the thermal characteristics of a power conversion system according to any one of claims 1-8, characterized in that, Including: The compressor receives the working medium output by the cooler, pressurizes the working medium and then outputs it to the recuperator; The recuperator receives the pressurized working medium, preheats the pressurized working medium, and outputs the preheated pressurized working medium to the intermediate heat exchanger; The intermediate heat exchanger transfers the heat energy provided by the heat pipe stack to the preheated pressurized working medium to obtain a high-temperature pressurized working medium, and outputs the high-temperature pressurized working medium to the turbine; The turbine expands and does work based on the high-temperature pressurized working medium to drive the electric motor.

10. The thermal characteristic modeling and analysis method according to claim 9, characterized in that, The thermodynamic parameters of the recuperator nodes are: ； ； Among them, q is the heat transfer amount, H is the heat transfer coefficient, A is the heat transfer area, t is the temperature, the subscript n represents the nth node in the regenerator, h represents the high-temperature side, and c represents the low-temperature side.

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