Zinc coating is similar to a welding process. Two zinc electrodes, under high electrical voltage, are brought close together. Above a certain distance, an arc is created, causing the zinc to melt. The resulting droplets are propelled onto the product by nozzles. The droplets harden, forming a solid protective layer on the workpiece.
To guarantee optimal coating, the heat exchanger strips are sprayed over a large area, causing some of the zinc droplets to flow past them. This ‘overspray’ is captured by an extraction system. As part of an expansion in production capacity, this extraction system is also to be optimised. The design goal for the system is to minimise the escape of overspray into the factory hall without zinc depositing inside the system, hardening, and clogging it. This would reduce cleaning intervals and thus maximise production capacity.
To verify the functionality of the facility to be developed before actual installation, FlowMotion was required to perform a simulation of the extraction system. The primary objective was to map the trajectory of the zinc droplets for various droplet sizes and different system settings. An accurate model was created, encompassing not only the extraction system but also the nozzles and the moving heat exchanger strips.
Analysis of the simulation results provided deeper insight into the fluid-mechanical mechanisms, which contributed to a more effective implementation of the new extraction system.
