Two phase flow heat transfer analysis at different flow patterns in the wellbore

Liquid gas two phase flow in the wellbore is a common phenomenon in oil and gas engineering. Flow patterns such as bubble flow, slug flow and annular-mist flow may significantly affect the heat transfer process. In this paper, heat transfer process in different flow patterns is studied by employing the thermal boundary theory. The Dittus-Boelter equation is modified by including the concept of gas volume fraction based on experimental data and new expressions for the heat transfer coefficient in different flow patterns has been proposed. It is found the heat transfer coefficient changes differently for different flow patterns. For bubble flow, the heat transfer coefficient increases with gas volume fraction. For slug flow, the heat transfer coefficient fluctuates largely and decreases as gas volume fraction increases. For annular mist flow, the heat transfer coefficient rapidly decreases as gas volume fraction increase. In comparison with experimental data, the error range of the new expressions for heat transfer coefficient falls in 20% which is good for field application. (C) 2017 Elsevier Ltd. All rights reserved.