In thermal isolation applications the need for uniform flow conditions is imperative. Therefore the shape of the flow passage, its inlet and exit have a major impact on the flow rate and resulting flow field.
The impact of laser drilling parameters on the hole geometry, flow discharge was studied.
An image of an exotic metal after laser drilling is shown. Visible is the non-uniform hole shape and dross buildup at the exit.
Below an image from a scanning electron microscope (SEM) highlighting the irregular nature of a typical flow passage.
By varying drilling parameters, ESI was able to record volume flow rate changes up to 100%.