The customer needed to determine the flow split between six cooling towers within a cooling tower arrangement.
Analysis
The six cooling towers were fed from a collector header, which received water through one of three lines. These lines were in turn fed from a second header, supplied by two centrifugal pumps. For optimal cooling tower performance, the flow split between the cooling towers needed to be as even as possible.
A one-dimensional fluid model of the cooling tower layout was generated using the BOSfluids software package. This model included the collector header, filters, and pumps located upstream of the cooling towers. It was observed that the flow to the six cooling towers in the original configuration was unequal, deviating by up to 20% from the mean flow rate.
Results
The project demonstrated that the flow split between the six cooling towers in the original arrangement could be optimized to achieve a more even distribution. By introducing pressure drops using orifice plates, the deviation between cooling towers was reduced to within 10% of the ideal flow split.
The proposed solution required the inclusion of orifice plates in the lines to two of the six cooling towers to create pressure drops. Consideration was given to the best location for the orifice plates, taking into account the customer’s installation requirements. The introduced orifice plates ensured a more even distribution of flow between the cooling towers.
It was shown that the flow splitting remained stable despite changes in flow rates and the number of cooling towers in operation.
By optimizing the flow split using orifice plates, the cooling tower system’s efficiency and performance were significantly improved.
