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Investigation of the Liquid Viscosity Effect on the Rising Bubble Motion (Effect of Ethylene Glycol Concentration on Terminal Velocity)

Asadi Zeidabadi, Fateme | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 49370 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Bastani, Dariush; Lotfi, Marzieh
  7. Abstract:
  8. Surface phenomena is one of the fundamental branches of science that has many applications in industries related to multiphase processes. One of the most important issues of this knowledge is inter-phase transport phenomena in contacting gas - liquid and liquid – liquid systems. Multiphase systems generally include dispersions such that in many cases are associated with the relative motion between the continuous and dispersed phase. One of the most widely used inter-phase flow systems is dispersion of gas bubbles in the bulk of liquid. The overall efficiency of these systems is often determined by the characteristics of the gas phase. In order to understand the dynamic behavior of such systems measurable variables such as bubble motion velocity and shape deviations are noticed. Rising bubbles into the liquid bulk consist of many complex behaviors. These complexities are increased when impurities and additives with surface activity abilities are present in the system. Various investigations have been performed in the case of rising bubbles, but there are generally many uncertainties in the quantitative investigations of inter-phase non-equilibrium behavior under dynamic conditions and refreshing of interface (such as rising bubble). The purpose of this thesis is investigation of viscosity effect on the behavior of rising bubbles in continuous liquid bulk in the presence and absence of surface-active substances. In this regard, bubble motion in continuous phase of solution with different concentration of non-ionic surface-active substances are initially investigated in order to obtain the critical concentration of surface active substance. Then, the motion of bubbles in the solutions with different concentration of water and ethylene glycol was respectively examined in the absence and presence of surface-active substance in its critical concentration. In these experiments, the terminal velocity of rising air bubbles for 0, 15, 27.7, 46, 70, 80 and 100 mass percent ethylene glycol solutions in the absence of surface-active substance were respectively 35.72, 32.46, 25.76, 20.21, 13.78, 12.8 and 7 cm/s, and in the presence of surface-active substance were 15.067, 13.78, 13.29, 12.48, 12.37, 11.59 and 6.99 cm/s. As it is so clear, with increasing the viscosity of solution and also in the presence of surface-active substances, bubble terminal velocity dramatically decreased. Along these steps, bubbles’ shape deviation from spherical shape was also investigated. As a result, by increasing in the solution viscosity and in the presence of surface-active substance, these deviation is decreased and shape of bubbles are inclined to sphere
  9. Keywords:
  10. Viscosity ; Rising Bubble ; Surface Active Elements ; Surfactants ; Ethylen Glycol ; Surface Phenomenas ; Limit Velocity

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