Electro-static precipitators (ESP) are very effective in the removal of fine mists and fine particles from gas streams. Atmospheric dust concentration measurement is also achieved by employing electro-static precipitators. A typical electrostatic precipitator is comprised of ductwork and a diffuser section. Electro-statically charged filters are located in the diffuser section. Effective performance of an ESP requires uniform flow in the diffuser section. The upstream ductwork can have a significant impact on the flow entering the diffuser and hence its performance. These devices are several meters in dimensions and are difficult to prototype. Expensive experimental setups may be constructed to study the flow fields in such devices. The other option is numerical simulation of the flow field. This option is relatively inexpensive and can be completed on a smaller time scale. Computational Fluid Dynamics (CFD) methods are routinely employed to examine ESP performance.
In the example shown below CFD is applied to examine the effect of various distributor plate configurations on the uniformity of flow entering the diffuser section of an ESP. The original design employs a grid- type distributor plate (Figure 1). The flow entering the diffuser is not uniformly distributed and continues as a jet in the core of the diffuser section. This leads to a large recirculation region in the ESP.
Figure 1 - Original Configuration
In an attempt to introduce more uniform flow in the diffuser the effect of a four plate splitter was examined (Figure 2). The velocity field indicates that the recirculation region is reduced but not eliminated.
Figure 2 - Intermediate Design - Results of Addition of Four-Plate Splitter
Finally the effect of a grid employing three vertical and three horizontally placed splitter plates is examined (Figure 3). As can be seen in the velocity vector plot in this figure, the uniformity of the velocity field in the ESP is significantly improved by this change.
Figure 3 - Final Design - Results of Addition of Three-by-Three Splitter Plate Grid
CFD methods can be rapidly applied to examine the effect of various geometric and flow parameters on the overall flow behavior in an ESP. These techniques can not only be applied for trouble-shooting and improving the performance but also for rapid prototyping.
The Company | Office Locations | Online Resources
Employment Opportunities | Request More Information | Email SES
| Copyright © 2007 Stress Engineering Services, Inc. |