Generalized dynamic modeling of local heat transfer in bubble columns

Bubble column reactors

“…The heat transfer coefficient has been found to decrease with increasing liquid viscosity in three-phase fluidized systems [26,60,68,92] regardless of particle size. This was actually attributed to lower turbulence attained in the viscous media.…”

“…However, measurements of instantaneous heat transfer coefficients provide more insight into bubble dynamics and mechanism of heat transfer. Chen et al [26] reported that the use of average heat transfer coefficient causes the loss of information related to the effect of instantaneous bubble dynamics on heat transfer. Hence, the authors emphasized the importance of studying the instantaneous heat transfer in bubble columns under wide range of conditions for a comprehensive understanding of the heat transfer mechanism and reliable modeling to improve design and operation.…”

“…This could be explained by the reduced liquid viscosity and enhanced turbulence maintained at higher temperatures. Chen et al [26] investigated the effect of operating pressure on heat transfer characteristics. The authors observed that the heat transfer coefficients increased with increasing pressure.…”

“…Recent research with bubble columns frequently focuses on the following topics: gas holdup studies [4][5][6][7][8][9][10][11], bubble characteristics [3,[12][13][14][15][16], flow regime investigations and computational fluid dynamics studies [1,[17][18][19][20][21], local and average heat transfer measurements [22][23][24][25][26], and mass transfer studies [27][28][29][30][31]. The effects of column dimensions, column internals design, operating conditions, i.e.…”

Heat transfer study in a pilot-plant scale bubble column

“…7 shows a comparison between the radial averaged heat transfer coefficients measured in this work in the fully developed flow region (Z/D = 4.8) and the literatures for both reported values and correlation predictions those were selected for air-water system (Fair et al, 1962;Hikita et al, 1981;Verma, 1989;Saxena et al, 1989Saxena et al, , 1990aSaxena et al, ,b,c, 1992aPrakash, 1997, 1999;Chen et al, 2003). Comparing heat transfer coefficients of this work (0.44 m) with those obtained in smaller column diameter (0.16 m) of Wu et al (2007), it can be seen that heat transfer coefficients in 0.44 m in column diameter is larger than those measured in 0.16 m. This would indicate that the heat transfer coefficients in bubble column increase with the increase in the column diameter, as reported by Saxena et al (1990a).…”