Experimental and numerical characterization of particle-laden air flow in a horizontal pipe

  • Ying Dai

Student thesis: Master's Thesis

Abstract

One of the major challenges gas industries are facing is contaminants in sales gas called Black Powder. It causes erosion failure and lowers the performance of equipment. It is difficult to determine the severity of black powder contaminant inside pipeline networks, which is needed in order to guide cleaning operations. It requires detailed understanding of the black powder transport behavior. This work aims to investigate the pickup and deposition mechanisms of particle-laden air flow in a horizontal circular pipe. One part of the experimental characterization is conducted with various stationary particles bed heights and pipe diameters, focusing on the determination of critical pickup velocity of the solid particles from the stationary bed. Critical pickup velocity is determined by extrapolating the weight loss curves plotted as a function of corrected velocity above the sand layer. Another part of the experimental characterization is carried out with different particle injection rates and air flow rate, to analyze the particle deposition patterns in terms of geometric parameters and transportation velocity using image analysis. Numerical simulation using FLUENT code is conducted to predict the free-flight length using an Eulerian-Lagrangian approach. The calculations are compared with experimental measurements. Experimental results show significant effects of layer height and pipe diameter on the pickup velocity. Critical pick up velocity of solid particles is found to increase with increasing blockage ratio and pipe diameter. A correlation has been developed. Sand particles pickup rate is found to decrease with time as a consequence of decreasing layer height. It is also found that the geometric parameters are affected by the combination of particle injection rates and air velocities. The particles carrying capacity of air has a linear increasing relationship with particle loading. The numerical simulation on free-flight length shows the same increasing trend as experimental measurements with air velocities for each injection rate, where the discrepancies might be caused by the assumptions on force balance and the different physical properties of particles and the different particle interaction conditions.
Date of Award2015
Original languageAmerican English
SupervisorMohamed Al Shehhi (Supervisor)

Keywords

  • Applied sciences
  • Critical pickup velocity
  • Deposition patterns
  • Particle laden air flow
  • Pneumatic conveying
  • Mechanical engineering
  • 0548:Mechanical engineering

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