| Summary: | 碩士 === 國立成功大學 === 機械工程學系碩博士班 === 101 === Using natural material cannot effectively manipulates the directional distribution of heat conduction. Accordingly, this study applies the mathematics method of transformation optics in controlling the heat transfer. In addition, a thermal metamaterial simulation is used to realize the novel thermal devices.
First, the present study analyzes the invisibility cloak of thermal conductivity (thermal cloak) proposed by former research. The former thermal cloak has a lot of limitations on design, and is not easily achieved. Therefore, two new methods for thermal conduction cloaking are proposed. In the first method, a thermal carpet cloak is proposed theoretically using a layered metamaterial, which is composed of homogeneous silicon layer and a phononic crystal silicon layer. The thermal cloaking effect is demonstrated using COMSOL Multiphysics Finite Element software. Great cloaking performance is achieved when a thermal insulator is well hidden under the thermal carpet cloak. In addition, the thermal carpet cloak can homogenize the temperature on irregular surface. Thermal carpet cloak can be easily realize because of its simple material composition. The second method design a mesh-like thermal conductivity cloak by means of thermal resistance network simulations. Compared to the solid multi-layered cloaks, the proposed cloak comprises a mesh-like array of discrete conductance components. The thermal shielding performance of the proposed cloak is compared with that of a layered cloak by means of COMSOL Multiphysics Finite Element software. In addition, simulations are performed to determine the optimal design of the mesh-like web in terms of the number, dimensions and conductivity of the discrete conductance components. In general, the results presented in this study show that the proposed mesh-like cloak not only achieves a better thermal shielding effect than a layered cloak, but also has a smaller physical size, a cheaper cost, and a greater design versatility.
On the other hand, other transformed thermal devise, thermal concentrator, is also designed and simulated using COMSOL Multiphysics Finite Element software. As a result, it provides a promising solution for various thermal manipulating applications in the microelectronics, national defense, green energy field etc..
|
|---|
