The radioisotope batteries have drawn extensive attention due to the high energy density. Nowadays, the radioisotope thermophotovoltaic systems are one of the most promising radioisotope batteries. In this work, the crystal emitter design and the associated performance of the radioisotope thermophotovoltaic generators are investigated. First, the design of photonic crystal emitter together with the adoptions of both the multi-layer insulation and supporting materials are discussed. In order to optimize the system efficiency, the effects of the area of emitters are mainly investigated. We have analyzed the efficiency of system using GaSb cells and Si cells, respectively. With Si cells, the system efficiency can computationally reach about [Formula: see text] with an output power of 7 W. When GaSb cells are employed, the system performance is estimated to an efficiency of [Formula: see text] with 61.6 W output.

Nuclear reactor fuel assemblies are mainly composed of cylinders bundle(CB), calculating the dynamics characteristics of CB under axial flow can lay a foundation for predicting fretting wear and vibration fatigue. In the paper, the CB coupling dynamic model of forced vibration under pulsating flow is established. And the stability analysis and natural frequency calculation of the CB system under steady flow are compared with the existing results to verify the model. Finally, the Runge-Kutta method is applied to solve the forced vibration equation of the CB under pulsating flow. The influence of the pulsating parameters m, w0,  on the amplitude-frequency characteristics and the motion trajectory of the midspan cross section of the CB under forced vibration are analyzed and discussed. The results show that the pulsating parameters have an important influence on the vibration of the CB system.

No abstract