Modeling and analysis of supercritical flow instability in parallel channels

With a view to better utilizing and further expanding the experimental results recently obtained on supercritical flow instability, an in-house code has been developed applying time-domain approach. Different ways of geometrical modeling of the test section in the experiments are studied. Comparison between the numerical and experimental results shows that the numerical code is capable to predict well the stability boundaries. Based on the validated code, the geometrical simplification is further discussed and a relatively simple as well as common geometrical configuration is proposed. Discussions also indicate that the entrance and riser sections cannot be eliminated with respect to numerical modeling of flow stability. Effects of inlet temperature and total mass flow rate are numerically analyzed. Results show that the inlet temperature has a non-monotonic effect on the threshold power, while the threshold power is roughly proportional to the total mass flow rate no matter the system is symmetrical or not. Moreover, the results indicate that it would be more difficult to perform flow instability experiments at higher inlet temperature or total mass flow rate.