CFD Review  
Serving the CFD Community with News, Articles, and Discussion
 
CFD Review

User Preferences
Site Sponsorship
Headline Feeds
Mobile Edition
Privacy Policy
Terms of Service
twitter

Submit a CFD Story

Site Sponsors
Siemens PLM Software
Pointwise: Reliable CFD meshing
Software Cradle

Tell a Friend
Help this site to grow by sending a friend an invitation to visit this site.

CFD News by Email
Did you know that you can get today's CFD Review headlines mailed to your inbox? Just log in and select Email Headlines Each Night on your User Preferences page.

 
CFD Used to Troubleshoot Centrifugal Fan Coal Dust Accumulation
Posted Mon January 27, 2003 @02:36PM
Print version Email story Tweet story
Application From the Technology & Innovation Centre,
Larsen & Toubro Limited, Baroda, India

Larsen & Toubro Limited (L&T) is one of the leading engineering, procurement and construction (EPC) players in the refinery and power sectors in Asia. The Technology and Innovation Centre of L&T at Baroda has been using CFX TASCflow extensively for flow and combustion applications to evaluate the reliability of in-house-designed equipment as well as critical out-sourced equipment.

The software has played an important role in understanding, designing and troubleshooting of equipment. Recently, CFX-TASCflow was used to troubleshoot a centrifugal fan used in a coal-dust environment. The fan was accumulating dust unevenly on the impeller vanes, causing severe vibration problems and leading to frequent shutdowns. On visual inspection, it was found that dust was collecting near the tip of the fan vanes, which might be due to the sticky nature of the dust and the high curvature of the vanes near the tip.


Sponsor CFD Review

There was a dilemma as to whether to modify the original impeller or replace it with a new fan of alternative design from the fan manufacturer. To evaluate the options, a flow-modeling study was carried out on the following four variants of impeller design:
  1. The original impeller;
  2. A slight modification of the original impeller with a plate welded near the tip to reduce particle build-up;
  3. A new impeller of shorter size and with less curved vanes, offered by the vendor as a replacement if Option 2 did not work, and
  4. A radial straight impeller, since dust accumulation for this type is very low.

CFX-TASCflow was chosen for the study because of its ability to solve rotating machinery problems with relative ease and to produce reliable solutions. The computational grids for the inlet, impeller and volute were generated with CFX-Build and then imported into CFX-TASCflow. The problem was set-up using CFX-TASCflow's multiple frames of reference, and its particle tracking capabilities were used to simulate the coal dust. Collection of dust on different impellers was then evaluated by calculating the percentage of particles impacting the vanes based on a fixed particle size distribution at the inlet

The analysis revealed that the modified impeller (Option 2) could achieve half the dust accumulation compared to the original design. For the new impeller (Option 3), the results showed this value to be one third of that for the original impeller. The radial straight vane impeller (Option 4) showed no particle build-up, but a much lower efficiency.

These findings were used to finalize the decision to go with the second option and modify the impeller by welding a plate near the tip of the vane. The fan has since been reported to perform satisfactorily with fewer problems. The study helped in the decision to use the modified impeller fan. Meanwhile, the new impeller, provided as an alternative by the fan supplier, has been kept as a standby, thus saving capital cost.

geometry and grid
Centrifugal fan geometry and computational grid.
Image courtesy of Technology & Innovation Centre, Larsen & Toubro Limited, Baroda, India.

velocity vectors
Relative (in the impeller) and absolute (in the diffuser) velocity vectors in the fan.
Image courtesy of Technology & Innovation Centre, Larsen & Toubro Limited, Baroda, India.

particle trajectories
Particle trajectories and build-up profile for the original impeller. The build-up of particles on the vanes occurs in the area highlighted by the black oval.
Image courtesy of Technology & Innovation Centre, Larsen & Toubro Limited, Baroda, India.

[ Post Comment ]

AVL FIRE and SWIFT Training | CFdesign v6.0 Named One of 2002's Top New Products  >

 

 
CFD Review Login
User name:

Password:

Create an Account

Related Links
  • CFX
  • CFX TASCflow
  • Larsen & Toubro Limited
  • More on Application
  • Also by nwyman
  • This discussion has been archived. No new comments can be posted.

    Hope that the day after you die is a nice day. All content except comments
    ©2017, Viable Computing.

    [ home | submit story | search | polls | faq | preferences | privacy | terms of service | rss  ]