A thermal phantom control method based on porous media

Abstract

The invention belongs to the field of thermal technology, in particular to a thermal phantom control method based on porous media. The method of the present invention combines Fourier's law and Darcy's law to describe the process of heat conduction and heat convection; utilizes the consistency of the equation form of thermal conductivity and permeability under steady state conditions, and obtains the expression of equivalent permeability based on effective medium theory ; Afterwards, the pressure field and temperature field are established to generate heat convection and diffusion, and the simple core-shell structure is used to realize thermal transparency, heat accumulation and thermal invisibility cloak by adjusting the radial and tangential values ​​of the permeability and thermal conductivity of the shell. This thermal phantom function does not change the distribution of the temperature field and heat flow field before the background. Compared with other thermal phantom control methods in the heat convection diffusion process, the method of the invention has a simple structure, is more flexible and feasible, and solves the singularity and non-uniformity of materials, so it is more practically applicable.

Description

technical field

[0001] The invention belongs to the field of thermal technology, and in particular relates to a thermal phantom control method based on a thermal convection diffusion process based on a porous medium. Background technique

[0002] Transformation heat has been widely studied since 2008, and has made great breakthroughs and rich results in the process of heat conduction. Many metamaterials and novel devices have been designed and realized theoretically and experimentally, such as thermal invisibility cloaks, thermal concentrating and thermal spinning functional devices, etc. Transformation theory provides a powerful method for thermal regulation on a macroscopic scale. However, materials designed by transformation theory have singularities and inhomogeneities, such as thermal cloaks, which require a radial thermal conductivity of 0. These materials do not exist in nature. To solve this problem, people use effective medium theory and multilayer composites The ...

Examples

Embodiment Construction

[0045] The present invention will be described in detail below with reference to specific embodiments and accompanying drawings, but the present invention is not limited thereto. In this example, the system size and side length are 10 -5 m order of magnitude, the temperature difference is 40K, the pressure difference is 400Pa, and the fluid velocity is controlled at 10 -3 -10 -2 m / s magnitude. The fluid is chosen to be water, and its density is 10 3 kg / m 3 , the heat capacity is 4.2×10 3 J kg -1 K -1 , the viscosity is 10 -3 Pa s, thermal conductivity 0.6Wm -1 K -1 . The permeability of porous media is 10 -12 m 2 magnitude. The system is in steady state.

[0046] figure 1 The left and right are the schematic diagrams of the structures where the applied temperature field and pressure field are perpendicular or parallel to each other. The temperature field is in the x direction. This method considers that the fluid is incompressible and the fluid density is cons...

technical field

[0001] The invention belongs to the field of thermal technology, and in particular relates to a thermal phantom control method based on a thermal convection diffusion process based on a porous medium. Background technique

[0002] Transformation heat has been widely studied since 2008, and has made great breakthroughs and rich results in the process of heat conduction. Many metamaterials and novel devices have been designed and realized theoretically and experimentally, such as thermal invisibility cloaks, thermal concentrating and thermal spinning functional devices, etc. Transformation theory provides a powerful method for thermal regulation on a macroscopic scale. However, materials designed by transformation theory have singularities and inhomogeneities, such as thermal cloaks, which require a radial thermal conductivity of 0. These materials do not exist in nature. To solve this problem, people use effective medium theory and multilayer composites The ...

Examples

Embodiment Construction

[0045] The present invention will be described in detail below with reference to specific embodiments and accompanying drawings, but the present invention is not limited thereto. In this example, the system size and side length are 10 -5 m order of magnitude, the temperature difference is 40K, the pressure difference is 400Pa, and the fluid velocity is controlled at 10 -3 -10 -2 m / s magnitude. The fluid is chosen to be water, and its density is 10 3 kg / m 3 , the heat capacity is 4.2×10 3 J kg -1 K -1 , the viscosity is 10 -3 Pa s, thermal conductivity 0.6Wm -1 K -1 . The permeability of porous media is 10 -12 m 2 magnitude. The system is in steady state.

[0046] figure 1 The left and right are the schematic diagrams of the structures where the applied temperature field and pressure field are perpendicular or parallel to each other. The temperature field is in the x direction. This method considers that the fluid is incompressible and the fluid density is cons...

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