TY - JOUR

T1 - Bubbly free and impinging jets under forced flow conditions

T2 - Experimental study by means of PIV/PFBI

AU - Nichik, Mikhail Yu

AU - Pervunin, Konstantin S.

AU - Markovich, Dmitriy M.

PY - 2017/9/27

Y1 - 2017/9/27

N2 - Jet flows are extensively used in various practical applications. Presently, the development of technical equipment where jets are employed is connected with the improvement and optimization of different methods of flow control. In the paper, an experimental investigation of the turbulent structure of forced bubbly free and impinging jets was carried out by means of PIV and PFBI techniques. PIV was applied to measure velocity distributions and turbulent characteristics in the continuous phase, while PFBI approach was applied to visualize bubbles in the flow and evaluate their sizes. The flow was studied at the Reynolds number of 12,500 and three void fractions β = 0, 1 and 2% for forced conditions St = 0.5. The mean air bubble diameter was estimated to be roughly 0.8 mm for all β. It was revealed that in the free jet the air bubbles and flow pulsations reduces substantially the longitudinal dimension of the jet core. In two-phase flow with forcing distribution of turbulence kinetic energy was similar to one-phase case but maximum value was two and a half times higher then for one-phase unforced jet. In the impinging jet flow, the bubbles produced a maximum of the turbulence kinetic energy near the wall, which increased two and a half times in forced conditions.

AB - Jet flows are extensively used in various practical applications. Presently, the development of technical equipment where jets are employed is connected with the improvement and optimization of different methods of flow control. In the paper, an experimental investigation of the turbulent structure of forced bubbly free and impinging jets was carried out by means of PIV and PFBI techniques. PIV was applied to measure velocity distributions and turbulent characteristics in the continuous phase, while PFBI approach was applied to visualize bubbles in the flow and evaluate their sizes. The flow was studied at the Reynolds number of 12,500 and three void fractions β = 0, 1 and 2% for forced conditions St = 0.5. The mean air bubble diameter was estimated to be roughly 0.8 mm for all β. It was revealed that in the free jet the air bubbles and flow pulsations reduces substantially the longitudinal dimension of the jet core. In two-phase flow with forcing distribution of turbulence kinetic energy was similar to one-phase case but maximum value was two and a half times higher then for one-phase unforced jet. In the impinging jet flow, the bubbles produced a maximum of the turbulence kinetic energy near the wall, which increased two and a half times in forced conditions.

UR - http://www.scopus.com/inward/record.url?scp=85033779012&partnerID=8YFLogxK

U2 - 10.1088/1742-6596/899/3/032016

DO - 10.1088/1742-6596/899/3/032016

M3 - Article

AN - SCOPUS:85033779012

VL - 899

JO - Journal of Physics: Conference Series

JF - Journal of Physics: Conference Series

SN - 1742-6588

IS - 3

M1 - 032016

ER -