Measurement of Liquid Film Thickness during Upward Annular Air-Water Flow in Vertical Pipe Using Planar Laser-Induced Fluorescence (PLIF) Technique

• Author / Creator

  Mamedulanov, Doszhan

• Experimental investigation of vertical annular two phase flow is the main scope of this thesis. Flow parameters such as pressure drop, temperature and film thickness were recorded and analyzed at low liquid and moderate gas flow rates. Film thickness measurement was done using Planar Laser Induced Fluorescence (PLIF) technique. Liquid film thickness in annular gas-liquid flow is of significant importance for mechanistic modeling of this flow regime. It is required for calculation of gas core diameter, distribution of dynamic interfacial roughness which affects interfacial shear and the pressure drop in annular two-phase flow. The current experimental study examined the variation of film thickness in annular air-water flow in one-inch vertical clear acrylic tube. Planar laser-induced fluorescence (PLIF) technique combined with high magnification imaging was used for visualisation of the liquid film. Average film thickness distribution was found to increase with increase of liquid flow rate and decrease with increase of gas flow rate. Visualization of liquid film was performed in two steps. First, recording of flowing film was done with laser aligned with the center of the pipe at low liquid flow rates of 20, 25, 30 liters per hour. Second, laser position was moved away from pipe center closer to camera in order to reduce obstruction of imaging path by air bubbles at liquid flow rates from 20 to 60 liters per hour. The film thickness was obtained from digital images by converting them into binary images using threshold level. Correction number was acquired by comparing images from two setups at low liquid flow rates of 20, 25, 30 liters per hour. Further calculations of liquid film thickness at higher liquid flow rates gave inconsistent results due to increasing concentration of air bubbles in liquid phase that made it challenging to distinguish liquid film edge. Results were compared against mechanistic models of Hughmark (1973), Henstock and Hanratty (1976) and Ansari (1994) and experiments with similar geometry and conditions.

• Subjects / Keywords

  • Film thickness
  • Upward annular air-water flow
  • Planar Laser-Induced Fluorescence

• Graduation date

  Fall 2016

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R32N4ZP3J

• 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.