Specific energy dissipation rate for super-high-rate anaerobic bioreactor

2011 ◽  
Vol 86 (5) ◽  
pp. 749-756 ◽  
Author(s):  
Xiaoguang Chen ◽  
Zheng Ping ◽  
Shuang Ding ◽  
Chongjian Tang ◽  
Jing Cai ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Specific Energy ◽  
Dissipation Rate ◽  
Energy Dissipation Rate ◽  
High Rate ◽  
Anaerobic Bioreactor

Comparison of specific energy dissipation rate calculation methodologies utilising 2D PIV velocity measurement

2015 ◽  
Vol 137 ◽  
pp. 752-767 ◽  
Author(s):  
Mohammad Mainul Hoque ◽  
Mayur J. Sathe ◽  
Subhasish Mitra ◽  
Jyeshtharaj B. Joshi ◽  
Geoffrey M. Evans
Keyword(s):  
Energy Dissipation ◽  
Specific Energy ◽  
Velocity Measurement ◽  
Dissipation Rate ◽  
Energy Dissipation Rate ◽  
Rate Calculation

Micromixing Characteristics in an Aerated Stirred Tank with Half Elliptical Blade Disk Turbine

2014 ◽  
Vol 12 (1) ◽  
pp. 231-243
Author(s):  
Wanbo Li ◽  
Xingye Geng ◽  
Yuyun Bao ◽  
Zhengming Gao
Keyword(s):  
Energy Dissipation ◽  
Specific Energy ◽  
Dissipation Rate ◽  
Gas Flow ◽  
Liquid Surface ◽  
Energy Dissipation Rate ◽  
Reaction Scheme ◽  
Stirred Tank ◽  
Wall Region ◽  
Superficial Gas Velocity

Abstract The parallel-competing iodide-iodate reaction scheme was used to investigate the micromixing efficiency in an aerated stirred tank of 0.30 m diameter agitated by a half elliptical blade disk turbine. The mean specific energy dissipation rate Pm ranged from 0.5 to 2.2 W/kg, while the superficial gas velocity VS ranged from 0.015 to 0.047 m/s. Four sub-surface feed positions were considered. When the tank is fed just under the liquid surface or in the near-wall region, the micromixing efficiency can be enhanced by introducing gases with superficial gas velocities higher than 0.031 m/s. The effects of gas on the micromixing performance become complicated, while the tank is fed in the impeller discharging region. The increase of gas flow rate does not always have good effects on the micromixing performance. Moreover, the way to feed sulfuric acid can strongly affect the efficiency of the reaction scheme. For a single liquid phase, the micromixing time tm according to the incorporation model varies from 5 × 10−3 to 3 × 10−2 s. The dimensionless local specific energy dissipation rate Φ near the liquid surface is almost independent of Pm, while Φ in the impeller discharging area decreases with increasing Pm.

The evolution of turbulent bursts: the b—ε model

1994 ◽  
Vol 5 (4) ◽  
pp. 537-557 ◽  
Author(s):  
M. Bertsch ◽  
R. Dal Passo ◽  
R. Kersner
Keyword(s):  
Partial Differential Equations ◽  
Energy Dissipation ◽  
Energy Density ◽  
Differential Equations ◽  
Dissipation Rate ◽  
Turbulent Energy ◽  
Energy Dissipation Rate ◽  
Self Similar ◽  
Similar Solutions ◽  
Semi Empirical

We study the semi-empirical b—ε model which describes the time evolution of turbulent spots in the case of equal diffusivity of the turbulent energy density b and the energy dissipation rate ε. We prove that the system of two partial differential equations possesses a solution, and that after some time this solution exhibits self-similar behaviour, provided that the system has self-similar solutions. The existence of such self-similar solutions depends upon the value of a parameter of the model.

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