Studies of Thermal-Hydrodynamic Flow Instability : 1st Report: Theoretical Analysis of Parallel Channel Flow Instability

For the purpose of predicting flow instability in sodium heated steam generators, a theoretical model was presented for boiling flow oscillations in parallel channel systems, and a computer code was developed. The propagation of thermal-hydrodynamic disturbances was described with a matrix transfer function, and the modes of proper oscillations were obtained by solving a characteristic equation, in which the boundary conditions were imposed on the transfer function. Eigenvalues and patterns of the properscillations determined for instability revealed that the frequency given by the eigenvalues is in good agreement with that observed in the performance of a small size steam generator.