Analytical Simulation of Annular Two-Phase Flow Considering the Four Involved Mass Transfers

Abstract

Efficiently employing two-phase flows for cooling objectives requires comprehensive knowledge of their behavior in different conditions. Models, capable of predicting heat transfer and fluid flow trends in this area, are of great value. Numerical/analytical models in the literature are one-dimensional models involving with many simplifying assumptions. These assumptions in most cases include neglecting some mechanisms of mass transfer in two-phase flows. This study is devoted to developing an analytical two-dimensional model for simulation of fluid flow and mass transfer in two-phase flows considering the all mass transfer mechanisms (entrainment, evaporation, deposition and condensation). The correlation employed for modeling entrainment in this study, is a semiempirical correlation derived based on physical concept of entrainment phenomenon. Emphasis is put on the annular flow pattern of liquid vapor two-phase flow since this regime is the last encountered two-phase regime and has a higher heat transfer coefficient among other two-phase flow patterns. Attempts are made to employ the least possible simplification assumptions and empirical correlations in the modeling procedure. The model is then verified with experimental models of Shanawany et al., Stevanovic et al. and analytical model of Qu and Mudawar. It will be shown, considering pressure variations in both radial and axial directions along with applying our semiempirical entrainment correlation has improved the present analytical model accuracy in comparison with the accuracy of available analytical models.

Investigating the effect of nanofluids of aluminum oxide and titanium dioxide on the heat transfer of the engine cooling coil by considering the boiling phenomenon

“…The most important heat transfer mechanism for dissipating the generated heat in the engine is the boiling mechanism, which can cool down about 90% of the generated heat. The two‐phase regime has a higher heat transfer coefficient compared with other regimes 1 . The boiling regime inevitably occurs in the vehicle engine, 2 so this type of heat transfer must be considered to be precise in the calculations.…”

“…The two-phase regime has a higher heat transfer coefficient compared with other regimes. 1 The boiling regime inevitably occurs in the vehicle engine, 2 so this type of heat transfer must be considered to be precise in the calculations. To predict the boiling phenomenon, several relationships have been proposed by the researchers, each of which has its own limitations and advantages.…”

Analytical Simulation of Flow and Heat Transfer of Two-Phase Nanofluid (Stratified Flow Regime)

“…Baniamerian et al [4] analytically modeled annular twophase flow considering the four involved mass transfers. They employed empirical correlation to simulate heat transfer in annular flow regime and proposed correlations for pressure drop and mass transfer contributions individually.…”

A simple model for predicting the pressure drop and film thickness of non-Newtonian annular flows in horizontal pipes

“…The two-phase flows are commonly found in power plants, chemical processes, nuclear reactors, and petroleum related industries. The three most important hydrodynamic features of gas-liquid flows in engineering applications, including the flow pattern, the void fraction, and the pressure drop of two-phase flows, have been studied experimentally and theoretically (Al-Kizwini et al, 2013;Al-Sarkhi et al, 2012;Baniamerian et al, 2012;Cioncolini and Thome, 2012;Okawa et al, 2010;Ren et al, 2012;Tai and Chung, 2010;Wang et al, 2012;Xiao et al, 2011). An annular flow, which occurs at relatively high gas flowrates, is defined with a gas core in the center of the channel and an annular liquid film adjacent to the channel wall.…”