Ultrasonic measurements of sand particle erosion in gas dominant multiphase churn flow in vertical pipes

Solid particle erosion can result in major pipeline failures, economic losses and more importantly safety and environmental issues. Erosion in multiphase flow is not widely understood and previous work has mostly focused on cases where the carrier fluid is single phase. There are different multiphase flow regimes, and amid them, churn flow appears frequently in piping systems such as risers, jumpers and flow spools. Furthermore, elbows have broad applications in the oil and gas industry, and they are subject to sand particle erosion damage. Therefore, the study of erosion in elbows, while the superficial velocities of the carrier fluids are in the range so that the flow pattern is churn flow, is of utmost importance. Experimental tests were carried out in order to investigate sand particle erosion in a 76.2 mm ID standard vertical-horizontal (V-H) elbow. A novel non-intrusive ultrasonic device was implemented to attain erosion patterns under different flow conditions. The effects of superficial gas and liquid velocities, particle size and liquid viscosity on erosion rate were investigated. The results are compared to the available data of erosion rates in a horizontal-horizontal (H-H) elbow with the same size of the elbow employed here. The most striking outcome to emerge from the comparisons is that erosion rates in the V-H elbow are significantly higher than those in the H-H elbow.