Boiling onset oscillation: A new type of dynamic instability in a forced-convection upflow boiling system

This work presents a new type of dynamic instability; namely, boiling onset oscillations, found in a single-channel, high-pressure, forced-convection, upflow boiling system using water as working fluid. Experiments with various pressure levels, mass flow rates, inlet subcoolings, heat inputs, and exit restrictions have been conducted to investigate the effects of these parameters on the occurrence, amplitudes, and periods of the boiling onset oscillations. Their mechanism is discussed. Comparisons are made to show the difference between this new type of oscillation and others that have been encountered in this experimental study. A table that illustrates the regions of different types of oscillations is also given.