>> A case study of aided design of CFD on OA ducting system

author R&D Lin Shi Chung

L&K engineering company introduced CFD (Computational Fluid Dynamics) application tools into engineering fields since year 2002.  We experienced unfamiliarity, learning, site validation and it’s a long way for practicing it on any kinds of engineering applications.  And nobody knows when the payback will come back for such kinds of investment.

In this issue, we would like to share with you our real application on a G7.5 TFT industry via the aided design of CFD to save initial and operation cost for customers and ourselves.  And more important thing is we found we also solved the OA ducting system problem while customers’ mass production starting.

 

>> Preface

Preface

It is a very popular way to use a common chamber to share and distribute outside fresh air to each zones of cleanroom in OA ducting system for semiconductor and TFT/LCD industries.  But what is the best way to use the concept of common chamber? Is it a good way to overemphasize the applications of common chamber?  Here a case study combined with engineering validation and CFD tool could be as your reference to provide you some insight about this.

 

>> Original Design

Original Design

Two common chambers in series (common chamber-1 and common chamber-2) were proposed by consultant as shown below.

The grid of CFD modeling is as shown below,

>> Simulation Result

Simulation Result

Please refer to the following figures for the simulation results,

 

 

 

>> Discussions

Discussions

1. We can find the common chamber-2 will add additional 280Pa contribution of pressure drop on the whole ducting system and it will be difficult to make air balance in the future if following the original design of one side with common chamber(common chamber-2) and another side without common chamber.

2. Considering about the functions of common chamber-2 in details, it seems nothing.  It could get the savings of initial and operation cost if common chamber-2 could be cancelled.

>> Validation

Validation

Under the verification of CFD simulation, we successfully convinced customers to remove the original design of common chamber-2 and got the win-win of costdown for customers and ourselves.

The strategy to cancel that common chamber was validated correct after finishing all engineering work and pilot run because of smooth operation of OA system and low power consumption compared to other FABs at different floors which followed the original design.

 

>> Conclusions

Conclusions

We succeeded to fulfill and construct a complex OA ducting system via CFD and assisted customers to save initial and operation cost.