The analysis of residual stress in glass-to-metal seals for solar receiver tube

The solar receiver tube is a key component in the parabolic trough solar thermal power system. Breakage of glass-to-metal sealing is main cause for damages of receivers in existing power plants. The residual stresses that are generated during the cooling process of the seal can decrease the seal strength and induce the breakage of the glass-to-metal sealing. Residual stresses were simulated by finite element software ANSYS and measured experimentally by photoelastic techniques. In order to lower the seal failure probability, the effects of the component dimensions were analyzed using finite element method. The simulation results agreed with the measurement results. The dangerous tensile stresses occur not only at the glass–metal interface but also on the outer surface of glass tube near the sealing area. When the depth of metal embedded into glass increases, the magnitude of residual stress decreases and the sealing strength will increase. The results of this study have important implications on the optimization of seal configuration in the solar receiver tubes.