A general thermal stratification criterion for single and two-phase flows in a pipe after subcooled injection. (April 2018)

• Record Type: Journal Article
• Authors: Gaillard, P.; Rodio, M.G.
• Is Part Of: International journal of multiphase flow. Volume 101(2018)
• Page Start: 1
• Page End: 10
• Publication Date: 2018-04
• Subjects: Thermal stratification -- Two-phase flows -- Injection Froude criterion -- TOPFLOW -- COSI -- LSTF -- CREARE; Multiphase flow -- Periodicals; Écoulement polyphasique -- Périodiques; Multiphase flow; Periodicals; 620.1064
• DOI: 10.1016/j.ijmultiphaseflow.2017.12.004
• Languages: English
• ISSNs: 0301-9322

Abstract

Highlights: Analysis of thermal stratification in the liquid layer for single and two-phase flows. Criterion development for identifying thermal stratification in single and two-phase flows. Innovation points of the development: two-phase condition, condensation hypothesis and no-zero flow velocity in the pipe. The criterion results are in accordance with the experimental results for 124 on 129 test cases. Abstract: This paper aims to define a general criterion in order to predict the thermal stratification in a pipe induced by a subcooled injection. The mixing of two fluids with different temperatures yields a density difference, which could induce a thermal stratification between two liquids or two gases. Well-established criteria exist in literature for predicting the thermal stratification in single phase flows. However, experimental observations detected thermal stratification in two-phase flows as well, i.e. when a liquid-gas (or liquid-vapor) flow and a liquid flow at different temperature are mixed together. When a second phase exists, the mechanisms facilitating (or not) a thermal stratification are more complex to determine. In this paper, we propose a general criterion, able to identify the conditions for which a thermal stratification appears in both single and two-phase flows. We focus on the case of a liquid cold injection in a pipe, filled up with hot liquid or hot liquid/vapor flows. This criterion is then validated on a relevant experimental database that includes several fluid conditions.