ISSN Online: 2377-424X
International Heat Transfer Conference 3
SYSTEM-INDUCED INSTABILITIES IN FORCED CONVECTION FLOWS WITH SUBCOOLED BOILING
Abstract
This study of system-induced instabilities of
forced-convection flows with boiling was restricted
to the case of water flow in small (< 1/4") circular
channels, high L/D ratios (25-200), moderate
temperature and pressure (Tin ~ 70°F; Pex < 60 psia) and primarily directed toward subcooled
boiling (hex. < hsat.liq.).
Both excursive and oscillatory instabilities were analyzed using a linearized, lump-parameter model, characterized by steady-state quantities. The energy storage mechanism for the oscillatory behavior were fluid inertia and system compressibility. The stability criteria were found to be dependent on a critical slope of the pressure drop-flow rate curve.
The analytical predictions were checked on a single tube apparatus with controlled compressibility and good agreement was obtained. Similar agreement was found in comparisons with stability data in the literature.
Both excursive and oscillatory instabilities were analyzed using a linearized, lump-parameter model, characterized by steady-state quantities. The energy storage mechanism for the oscillatory behavior were fluid inertia and system compressibility. The stability criteria were found to be dependent on a critical slope of the pressure drop-flow rate curve.
The analytical predictions were checked on a single tube apparatus with controlled compressibility and good agreement was obtained. Similar agreement was found in comparisons with stability data in the literature.