ISSN Online: 2377-424X
ISBN Print: 0-89116-909-1
International Heat Transfer Conference 9
PREDICTION OF HEAT TRANSFER FOR TWO-PHASE FORCED FLOW IN CHANNELS OF DIFFERENT ORIENTATION
Abstract
Heat transfer prediction technique for two-phase forced flow in channels of different orientation with fully wetted perimeter is presented. All the mechanisms of subcritical heat transfer, i.e. nucleate boiling, vaporization, single-phase liquid forced convection, have been taken into account. Correlation previously derived by one of the authors mainly on the basis of data for vertical channels was taken as a reference one. Basing on the analysis of hydrodynamic situation in the channel, a new dimensionless parameter, characterizing the degree of non-uniformity of local heat transfer coefficient around the circumference, is introduced. To identify wetting conditions around the perimeter a new flow pattern map for heated horizontal channels is proposed. This map has a single boundary curve, separating regimes with fully wetted and partially (periodically) wetted perimeter. It is also applicable for rotating channels if gravitational acceleration is replaced by centrifugal one.