Computational Fluid Dynamics-Enabled Modelling and Optimisation of Coolant Flow through Helical Channels

Computational Fluid Dynamics (CFD) is used to investigate the effect of geometry and flow parameters on liquid flow in helical channels for conditions relevant to coolant flow in twist drilling applications. CFD predictions of pressure drop in circular and triangular channels are compared against three important experimental correlations and it is shown that the correlation due to Yamamoto et al. [1] is accurate for both circular and triangular channels. Numerical results show how pressure drop varies with pitch, torsion and arc length and how the regions of high velocity flow can be manipulated through helical orientation. A parametrisation of triangular channels is presented and a meta-model for pressure drop created which demonstrates clearly how this depends on corner radius and orientation. Results also show how the larger pressure drop associated with triangular channels, for a given target flow rate, can be reduced towards those for equivalent flows in circular channels by increasing cross-sectional area whilst reducing flow velocities accordingly.