Analytical and Experimental Modeling of Internal Erosion in Porous Media

• Author / Creator

  Azadbakht, Saman

• Constitutive law is a key component in the development of numerical models to simulate erosion of solid particles in a porous medium. In combination with the principle of conservation of mass, these models allow the estimation of internal erosion rate as a function of various parameters such as fluid velocity and time. This research aims at enhancing the existing constitutive laws describing the internal erosion phenomenon.
  Using the principles of dimensional analysis, we developed a mathematical relation between the internal erosion rate, fluid velocity and a proportionality constant called erosion coefficient. An equation is derived which indicates that the erosion coefficient is a function of grain density, particle Reynolds number and porosity variation during the erosion. Results of a series of erosion experiments were used to calibrate and validate the proposed constitutive law. The model is able to explain decreasing erosion rate over time. Further, the comparison between experimental data and analytical predictions show that the proposed model is able to predict the experimental results with reasonable accuracy.
  An experimental apparatus was designed and set up to perform a series of internal erosion tests on unconsolidated sand packs with different grain size distributions (GSD). The tests were conducted at different hydraulic gradients. During the testing, inflow pressure, fluid flow rate and turbidity of outflow stream were monitored and recorded. In this way, the mass of eroded particles was estimated as a function of time for different GSD’s.
  Based on the observations from the experimental results, we developed another constitutive law to model internal erosion as an exponential decay process. This model is an enhancement to the model that we developed using dimensional analysis technique. The proposed constitutive law was calibrated using the test results we gathered in our experimental program and some experimental data that we obtained from the literature. The results of this analysis show that internal erosion is, indeed, an exponential decay phenomenon. This erosion constitutive model has two calibration parameters, namely, final value of porosity, φf, and decay coefficient, λ. We developed, using dimensional analysis technique, relationships to predict φf and λ using material and test parameters. The proposed relationships were calibrated and validated using experimental data and the validation results show that the proposed relationships can predict final porosity and decay coefficient with reasonable accuracy.

• Subjects / Keywords

  • Analytical Modeling
  • Experimental Modeling
  • Internal Erosion

• Graduation date

  Fall 2015

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R37P8TN2C

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.