Nonhomogeneous Two-Phase Flow in Pipes

Introduction

This type of flow is the most popular in pipes and wellbores. It results from the flowing phases having different in-situ velocities, namely, a nonzero slippage. In the case of gas-liquid flow, slippage is defined as the difference between gas and liquid in-situ velocities as follows,

....................(1)

In this case, the phases arrange in different types of flow patterns. Identifying the existing flow pattern in a pipe segment is the key for pressure drop and temperature profile predictions.

Flow Calculation Procedure For Steady-State Flow

Al-Safran and Brill (2017) summarize the flow calculation procedure for the steady-state case as shown in fig. (1). The inputs for each pipe segment include fluid properties, pipe configuration, and flow conditions. The inputs are fed into the calculation models to identify flow patterns, based on the flow pattern, other calculation models are used to flow characteristics, e.g. liquid holdup and slug properties (if applicable). Then, the pressure gradient is found. In the case of a nonadiabatic flow, an iterative procedure is used to identify the temperature profile.

Figure 1. Nonhomogeneous two-phase flow calculation process (Alsafran and Brill, 2017)