ISSN Online: 2688-7231
ISBN Online: 978-1-56700-478-6
Proceedings of the 24th National and 2nd International ISHMT-ASTFE Heat and Mass Transfer Conference (IHMTC-2017)
DYNAMIC AND STATIC INSTABILITIES IN TWO-PHASE FLOW SYSTEM
Abstract
Two-phase flow or thermal flow instabilities (e.g., pressure
drop oscillations (PDOs)) can affect the safe operating
condition and performance of the system efficiency, leads to
mechanical vibrations and thermal oscillations, and can also
lead to premature critical heat flux. The stability analysis of
PDOs in a two-phase flow system using three equation models
is carried out by MATCONT software. Further, using the same
model, most prominent static instability (Ledinegg type) is
investigated in the two-phase flow system. For analysis of
Ledinegg instability and PDOs, the steady-state internal
pressure drop of the heater channel is obtained by polynomial
fitting. Time evolution of the system is carried out under
perturbation, and following results are observed in the current
system. In the presence of PDOs type instability, sustained
oscillations of mass flow rate and pressure (inlet pressure) are
investigated in the two-phase flow system. An excursion of
equilibrium mass flow rate either to a higher or a lower mass
flow rate dependent on the sign of perturbation are identified in
the system due to Ledinegg type instability. Whereas, the
pressure of surge tank or inlet pressure of heater channel is
almost constant.