HyperVapotrons are two-phase water-cooled heat exchangers able to receive high heat fluxes (HHF) byemploying a cyclic phenomenon called the "Vapotron Effect". HyperVapotrons have been used routinelyin HHF nuclear fusion applications. A detailed experimental investigation on the effect giving rise to theability to sustain steady state heat fluxes in excess of 10 MW/m 2 has not yet been possible and hence thephenomenon is not yet well understood. The coolant flow structures that promote the effect have been amajor point of interest, and many investigations based on computational fluid dynamic (CFD) simulationshave been performed in the past. The understanding of the physics of the coolant flow inside the devicemay hold the key to further optimisation of engineering designs. However, past computational investi-gations have not been experimentally evaluated. Isothermal flow velocity distribution measurements ofthe fluid flow in HyperVapotron optical models with high spatial resolution are performed in this paper.The same measurements are subsequently calculated via commercial CFD software. The isothermal CFDcalculation is compared to the experimental velocity measurements to deduce the accuracy of the CFDinvestigations carried out. This unique comparison between computational and experimental results inHyperVapotrons will direct future efforts in analysing similar devices.