TWO-PHASE FLOW REGIME IDENTIFICATION THROUGH LOCAL TEMPERATURE MAPPING
Two-phase flows underpin some of our most ubiquitous technologies, ranging from micro-scale liquid-liquid
electronics cooling to macro-scale liquid-vapour condensation in Rankine cycle thermoelectric power plants.
Establishing the morphology of a two-phase flow, under a prescribed set of conditions, is considered particularly
important. As the pressure loss and heat transfer characteristics of a two-phase flow are intimately linked
to the fluidic arrangement, knowledge of the prevailing flow topology enhances understanding, and can lead to
the development of flow-specific correlations and/or models. This paper presents a novel, non-invasive experimental
measurement technique for identifying the predominant flow regime of a diabatic flow in a horizontal,
circular tube. Specifically, this paper focuses on condensing flows of steam, at typical Rankine cycle conditions.
However, it is proposed that the arrangement and methodology can be applied to other diabatic cases.
The suggested approach employs a temperature measurement platform, from in-situ instrumentation, to determine
the temperature difference associated with the presence of a liquid film inside the tube. Through analysis
and interpretation of local temperature difference measurements around the inside tube circumference, and
along the tube length, the flow regime can be identified. For the case examined in this paper, the flow regime
was seen to transition from an annular-type profile nearest the tube inlet to a stratified-wavy topology towards
the tube exit.