| AMTEC (Alkali Metal Thermal to Electric Converter) is a promising technology for converting heat energy to electric energy directly. It is characterized by high conversion efficiency, no moving parts and low maintenance requirements. Multi-level Condenser, Capillary Artery and Evaporator (CAV) are most important components of the AMTEC. The working fluid absorbs heat energy and vaporizes in the components, and the capillary force drives the working fluid to move from the low pressure domains to the high pressure domains. So the three components properties will seriously affect the AMTEC performances. The author would research the characteristics of the AMTEC components under different structures using the numerical simulation method.An axisymmetric two-dimensional mathematical model has been developed based on Dacy's law to simulate the Working fluid flow, heat transfer and phase change phenomena in the condenser, Capillary Artery and Evaporator. Source terms have been added in the Continuity equation, Momentum equation and Energy equation to simulate the principle of mass, momentum and energy transfer in the phase change processes. And the Volume of Fluid method has been used to track vapor-liquid interface and Phase Field Method has been used to track liquid-vapor interface. In this paper, it has not only analyzed the inlet temperature on the impact of numerical simulation results, but also studied the capillary pores diameter and porosity on the capillary structure loop performance.The results show that it needs a period of about eight seconds when the condenser achieves a smooth working condition; when the working condition of the condenser changes for some reasons, such as the temperature increasing, it would have great impact on the performances of the condenser, even cause the failure, which is required to care and avoid for the designers. Pores diameter and porosity have a great impact on the performances of the CAV. Comparison of results; the pores diameter has a greater impact on the performance of the CAV. The author has also found that, the CAV inlet temperature only has an influence on the evaporating position, and no obvious effects on the capillary suction force and the flux of the capillary structures. |
