Problem Statement:

A leading engineering company in the energy and environmental sector received a requirement for the Design of Cooling Tower Fan Support Structure, aimed at optimizing its structural components while resolving noise and vibration issues. The existing design featured a frame made of I-beams, supporting a fan weighing about 1 tonne and a motor gearbox weighing another 2 tonnes. As part of the project, NVH testing of industrial structures was performed using field vibration data, including velocities and displacements, collected from an existing cooling tower installation. This data was used as a benchmark for developing a new, optimized design.

At analyzer, we used this field data to validate our FEA model of the existing system. As this structure was part of a bigger assembly of a cooling tower, we adjusted different parameters in the FEA model to tune the model with field data.

Challenges:

The Design of Cooling Tower Fan Support Structure was evaluated under simultaneous vibratory forces at different frequencies. Performing a full transient dynamic analysis to capture all these loads was time-consuming due to the wide frequency range involved. To improve efficiency, we adopted a faster approach by combining multiple harmonic analyses at different frequencies and accordingly validated the model. Since the operating frequency of the fan was very close to the natural frequencies, a forced response analysis was carried out on the validated model for the new optimized frame. As part of the process, NVH testing of industrial structures was undertaken, and ISO 1940 was followed to calculate dynamic excitation forces generated by the motors, fan, and gearbox, based on their respective balancing grades.

Results:

The weight of the Frame structure was reduced by about 30% with a better estimated NVH characteristic than that of the original frame by using analysis-based design modifications.

Other Projects Executed in Analysis of Structures (for details please contact us), in addition to the Design of Cooling Tower Fan Support Structure:

• Noise and Vibration Analysis
• Static & Dynamic Analysis of Centrifuge support structure for the chemical industry
• Dynamic & Seismic Analysis of Pumps Motor systems support
• Troubleshooting of excessive vibrations in paint emulsifier unit
• Root Cause Analysis of Fuel filter mounting bracket failure
• Buckling Analysis of Vertical support structure for process vessel
• Lifting Analysis of pressure vessel & big shelters for BEL