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Hydrodynamics in a bubble column at elevated pressures and turbulence energy distribution in bubbling gas-liquid and gas-liquid-solid flow systems

Cui, Zhe
http://rave.ohiolink.edu/etdc/view?acc_num=osu1109956144

Abstract Details

2005, Doctor of Philosophy, Ohio State University, Chemical Engineering.
Bubble columns are widely used as multiphase reactors in chemical industries due to many advantages. The transport behavior in these systems is complex and a comprehensive knowledge of the transport phenomena, including hydrodynamics and turbulence properties are required. The hydrodynamics in a high pressure bubble column is experimentally investigated. The liquid velocities are measured using a LDV (Laser Doppler velocimetry). The Reynolds stresses are obtained. The effect of the pressure on the transition of the flow regime, flow field and the Reynolds stresses are studied. Furthermore, the effects of the liquid properties on the hydrodynamics of the bubble column are discussed. The turbulence energy distributions in the bubble columns are investigated using the LDV and PIV. The energy containing ranges for the bubble-induced and shear-induced turbulence are determined from the power spectra. Experimental results indicate that the bubble-induced turbulence dominates over the shear-induced turbulence under the operating conditions. The bubble-induced turbulence includes the turbulence in the bubble wake and that from the drift velocity change. The interaction between two turbulence field can only be observed when the turbulence in both fields is strong and the interaction tends to enhance the turbulence in both fields. The liquid phase turbulence is enhanced in the presence of particles at high superficial gas velocities while it is attenuated under low superficial gas velocity conditions. A criterion based on the variation of the ratio, Ug( r )/umf is proposed to account for the effect of the solids on the liquid phase turbulence. The prediction based on this criterion matches well with the experimental results. The behavior of a 6 mm mesobubble in an acoustic standing wave field is examined both experimentally and numerically. The acoustic standing waves at 16 kHz and 20 kHz are generated using two Nickel magnetostrictive transducers. The bubble rise velocity is significantly lower than that in the absence of an acoustic field. The behavior of bubble volume contraction and expansion can be accounted for by a 3-D direct numerical simulation of the bubble dynamics and flow field based on the compressible N-S equations coupled with the level-set method.
LiangShih Fan (Advisor)
Engineering, Chemical
BUBBLE COLUMN; TURBULENCE; liquid phase; velocity; liquid; gas velocity

Recommended Citations

Citations

  • Cui, Z. (2005). Hydrodynamics in a bubble column at elevated pressures and turbulence energy distribution in bubbling gas-liquid and gas-liquid-solid flow systems [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1109956144

    APA Style (7th edition)

  • Cui, Zhe. Hydrodynamics in a bubble column at elevated pressures and turbulence energy distribution in bubbling gas-liquid and gas-liquid-solid flow systems. 2005. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1109956144.

    MLA Style (8th edition)

  • Cui, Zhe. "Hydrodynamics in a bubble column at elevated pressures and turbulence energy distribution in bubbling gas-liquid and gas-liquid-solid flow systems." Doctoral dissertation, Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1109956144

    Chicago Manual of Style (17th edition)

osu1109956144
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© 2005, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.