**5. Conclusions and future perspectives**

**Reactor configuration Fluid agitator/application Experimental** 

68 Laboratory Unit Operations and Experimental Methods in Chemical Engineering

purification

Axial impeller/water purification

Rushton turbine/ bio-flocculation

particle deagglomeration

Marine impeller/cell cultivation

impellers/cell culture

impellers/autoclave

protein synthesis

flocculation

Rectangular flocculator Axial impeller/water

Cylindrical stirred tank Pitched turbine blade/silica

Cylindrical bioreactor Rushton, scaba and paddle

Cylindrical tank Turbine, anchor and oblique

Cylindrical bioreactor Marine impeller/recombinant

Cylindrical bioreactor Rushton turbine/anaerobic

Cylindrical tank Turbine impeller/

Cylindrical tank Rushton impeller/cell

Cylindrical tank Rushton turbine/cell

Cylindrical tank Rushton turbine and

Cylindrical crystallizer Rushton impeller/

Cylindrical Photobioreactor

process reactors.

digestion

cultivation

inactivation

precipitation

culture

propellers/cell culture

Rotating cylinder/algal

polymerization

Cylindrical tank R1342-type impeller/

Cylindrical sedimentation

Cylindrical Jar testing

Cylindrical flocculation

Cylindrical stirred bioreactor

tank

device

reactor

**validation method**

Paddle stirrer/flocculation LDA Fluent/MRF k-ε, k-ω, RSM

Laser diffraction/

PIDS

Cylindrical tank Rushton impeller/cell culture Optical sensor CFX/MRF k-ε [93]

Cylindrical tube reactor Impeller/bacterial inactivation 2D PIV CFX/MRF RSM [2]

Gas

chromatography

Droplet size measurements

X-ray/laser diffraction

**Table 4.** Selected studies on CFD characterization of hydrodynamics and physicochemical processes in field-assisted

Tracer and dynamic method

Cylindrical flocculator Paddle mixer/flocculation LDA, 2D PIV CFX/MRF k-ε, RSM [84]

**Numerical code/modeling approach**

2D PIV Fluent/MRF k-ε [85]

Laser diffraction CFX/MRF k-ε [86]

LDV Fluent/MRF k-ε [89]

Image analysis Fluent/MRF k-ε [92]

Optical density Fluent/MRF k-ε [94]

Tracer injection Fluent/MRF k-ε [95]

Dynamic method Fluent/MRF k-ε [99]

PIV Fluent/MRF k-ε [100]

Dynamic method Fluent/MRF RSM [101]

Optical density Fluent/SRF k-ω [103, 104]

PIV Fluent/MRF k-ε [91, 96]

Fluent/MRF k-ε [90]

Fluent/MRF k-ε [91]

Fluent/MRF k-ε [97]

Fluent/MRF k-ε [98]

Fluent/MRF k-ε [102]

**Turbulence models**

[7, 87, 88]

A review of recent advances in the experimental analysis and numerical modeling of physicochemical processes in stirred tanks and agglomeration reactors have been presented. This review briefly summarizes important findings and major contributions from numerous publications in this field. This short review of the developments in this field clearly shows that significant progress has been made over the past decade in the understanding of complex physicochemical phenomena that are vital for many industrial and environmental processes, especially from experimental and theoretical perspective. However, there is still a gap in knowledge especially in the suitability of the existing mathematical models to accurately predict the reactor performance in a wide range of existing and emerging processes. This clearly calls for a numerical code programming and development to form an integral part of the engineering training and curriculum in future. The successful design, development and optimization of agglomeration units depend on the robustness of the experimental data, mathematical models and simulation tools. This short review is by no means an exhaustive one, and readers are advised to consult other multitudes of scientific publications on the subject matter. In conclusion, numerical modeling along with robust experimental data will continue to be highly indispensable well into the foreseeable future.
