Experimental Investigations of Single Bubble Rising in Static Newtonian Fluids as a Function of Temperature Using a Modified Drag Coefficient

Abstract

In the oil production industry, it is of significance to measure and predict the form of multi-phase flow and gas flow that are present within petroleum production and processing pipelines. One component which has received little attention is the characteristics of bubbly flow around production pipelines. Rising bubble behavior in a wellbore changes with various factors, of which temperature leading to variations of liquids properties is one of the important factors. Herein, using an improved drag coefficient model to investigate bubble rising behavior at different temperatures is considered to calculate bubble flow velocities for drilling design, operation and wellbore pressure control. Firstly, a series of simulated laboratory experiments were conducted at 5–100 °C in four Newtonian fluids to obtain liquid properties and bubble parameters, such as bubbles shape, terminal velocity and trajectory. Then, compared with terminal velocities obtained by using the drag coefficients models CD = 0.95, which was considered to be constant by many literature at high Reynolds region (Re > 135), the modified drag coefficient model CD = 1.227 yielded better satisfactory prediction results for bubbles terminal rising velocity. Additionally, a new correlation using Reynolds number, Eotvos number, Weber number is proposed to predict bubble terminal velocity at low Reynolds number (Re < 135) based on experimental data and the Schiller–Naumann model. The results showed excellent agreement with the experimental data, with standard error of 5.32%.