Tuesday, January 11, 2011

COMPUTATIONAL FLUID DYNAMICS-NEW TOOL IN FERMENTATION TECHNOLOGY

In the earlier posts of this blog, we did cover briefly on the importance of the use of coloured dyes to visualize the flow pattern of the fermentation broth in fermentors. This experiment might be suitable for demonstrations to students taking fermentation course only .In that article we also discussed the various limitations of using selected tracers in visualizing the mixing or flow of the broth.
The importance of visualizing the flow is much more than like appreciating the fish in the aquarium. The ability to visualize really help understanding and highlighting problem areas in the fermentation process such as the efficiency of mixing.
Mixing could be improved in order to enhance the fermentation process to the optimum level. After all mixing of the fermentation broth is one of the most important parameters which affect the fermentation process. Mixing also affects other parameters such as mass transfers and heat transfers. Any change in the mixing regime will cause adjustment of the values of other parameters
The most powerful tool now in studying mixing in fermentors is no longer the use of coloured tracers but by the use of computational fluid dynamics (CFD). CFD is more a computer simulation program used to visualize the happenings during mixings It will become a powerful tool in the design and operation of the fermentors
CFD is important especially in trouble shooting the fermentation process and even in the scaling up and scaling down exercise . Areas that could be studied and improved includes fluid dynamics, transport phenomenon, heat transfer, phase transition, and rheology
So how can we visualize the fluid dynamics of a fermentation system? Well we are now aware of various computer programs that execute computational fluid dynamics. In these specialized programs numerical methods and algorithms are applied to solve and analyze problems that involve fluid flows and associated phenomena.
The key to the success of applying CFD depends not only having the right computer programs and computers but the various sensors and interphase that allow the input of the data from the fermentor to the computer. CFD might not be useful if we do not have the proper sensors to detect measure and transmit to the computer
The more important role of CFD in fermentation technology is in prediction of the behavior based on whatever data we have. But the process is not simple as:
1 There is the need to vary the boreactor operating regimes. This is especially so when stirring, volume and pumping have to be changed
2 Effect of a change in one parameter affecting other parameters
3 Secondary effects generated which could be critical such as bubble breakup, and coalescence mechanisms and even effect of shears on microbes
4 Immense data storage is essential when using CFD
Whatever problems faced computer simulation studies using CFD is the future answer in fermentation technology


Type rest of the post here.

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