Control of density wave oscillations in boiling channel

• Numerical studies on the uncontrolled dynamics and the controlled dynamics of boiling flow in the mini-channel.
• Quasi-periodic bifurcation of periodic orbits.
• Performance of NMPC for controlling the oscillations.

The present study reports uncontrolled behavior and controlled behavior of boiling flow in a mini-channel excited by step perturbation and periodic perturbation. It also demonstrates the performance of nonlinear model predictive control (NMPC) in reducing the chaotic oscillations. The control performance significantly varies when the control region is changed from the supercritical bifurcation (stable periodic orbit) region at high inlet subcooling to the subcritical bifurcation (unstable periodic orbit) region at low inlet subcooling. The study also includes the effect of forcing amplitude and forcing frequency on the uncontrolled and controlled dynamics of the channel.