Simulating pressurized reservoir flushing in scale models using lightweight sediments

Abstract

The dissertation presents the findings from laboratory experiments conducted to study the pressurised flushing phenomena using lightweight materials as model sediment. The study resulted in four research papers, which are summarized in this thesis and the results are discussed in detail. To speed up the recording of bed levels in the experiments and to produce better quality 3D models of the recorded bed levels, Structure from Motion (SfM) technique was applied. Before adopting to the experiments, different SfM tools available were compared and the suitable one was selected. Then, the applicability of SfM technique with the selected SfM tool was tested in three scale model studies of different scales. Five sets of scaled model experiments on pressurised flushing of non‐cohesive sediment deposit through bottom outlet were carried out. Natural sand and lightweight materials satisfying the scaling criteria were selected to be used as model sediments. The experiments were focused on predicting the dimensions and volume of flushing cones, so two empirical equations were proposed from regression analysis of the experimental data to predict the length and volume of flushing cones. The prediction made by new proposed empirical equations were also compared with the empirical equations proposed by previous laboratory experiments conducted with sand as model sediment. Since the experiments in this study were conducted for variations in different parameters governing the flushing process, the proposed equations performed pretty well for both sand and lightweight materials as model sediment when compared to empirical equations from previous studies.