Unstable Transients Affecting Flow Assurance during Hydraulic Transportation of Granular Two-Phase Slurries

Predicting density wave amplification of settling slurries using a 1D Driftux model

“…Research by [1][2][3][4] laid the foundation for understanding density wave amplification for horizontal pipelines, caused by an inverse relationship between sedimentation and erosion of sand deposits in a pipeline when the pipeline operates close to the deposit limit velocity. This is referred to the "erosion and sedimentation imbalance", and as a result high concentration zones of a slurry erode deposits and low concentration parts form deposits [3,5]. As such, a spatial redistribution occurs with sediment redistributing from low density parts to high density parts of the flow.…”

“…As such, a spatial redistribution occurs with sediment redistributing from low density parts to high density parts of the flow. Density wave amplification in horizontal pipelines can be avoided by remaining well above the deposit limit velocity, preferably with a safety margin to compensate for inaccuracies in deposit limit velocity predictive models and to account for velocity variations due to pipeline-pump dynamics [5].…”

“…The amplification rate seemed to depend on the particle size, the average volumetric concentration and the mixture velocity relative to the deposit limit velocity (more details in chapter 3.1). The origins of the mechanism behind amplification was explored by [5] and was thought to be caused by a different and new mechanism as opposed to the erosion and sedimentation imbalance. The authors of [5] hypothesized that amplification can be caused by a reduction of the particle velocity when particles flow from vertical to horizontal pipes resulting in an increase in concentration, referred to as "transient accumulation."…”

A multispecies 1D concentration distribution model for coarse‐particle slurries

“…In the area of online monitoring and instrumentation, recent publications describe noninvasive measurements of solids accumulation, and stationary bed formation, [ 3 ] inline slurry flow measurements using artificial intelligence tomography, [ 4 ] and high‐concentration measurements using novel 2D gamma‐ray tomography. [ 5 ] The importance of process understanding for slurry pipeline process optimization is covered in the excellent review by Pullum et al [ 6 ] illustrated in the analysis of often‐overlooked transient density‐waves [ 7,8 ] and the application of computational fluid dynamics (CFD) modelling to slurry flows is thoroughly discussed in the review of Messa et al [ 9 ]…”

“…In the area of online monitoring and instrumentation, recent publications describe noninvasive measurements of solids accumulation, and stationary bed formation, [3] inline slurry flow measurements using artificial intelligence tomography, [4] and high-concentration measurements using novel 2D gamma-ray tomography. [5] The importance of process understanding for slurry pipeline process optimization is covered in the excellent review by Pullum et al [6] illustrated in the analysis of oftenoverlooked transient density-waves [7,8] and the application of computational fluid dynamics (CFD) modelling to slurry flows is thoroughly discussed in the review of Messa et al [9] Common among the aforementioned subjects is the importance of the spatial concentration of the solids phase within the flow domain-often referred to as the solids concentration distribution-which in horizontal or inclined flows, shows a noticeable asymmetry around the pipe axis. While 2D distributions over the pipe cross-section can now be measured [4,5,10] or reasonably well predicted using CFD simulations, [11] historically, 1D chord-averaged measurements as illustrated in Figure 1 have been made.…”