Alternative jet fuels have a high potential to reduce emissions in aviation. A big difficulty for their introduction is the costly and lengthy assessment of fuel effects on combustion performance. In the present work, the evaporation of free-falling droplets of realistic size (D approximate to 80 mu m) in a well- defined vertical laminar heated flow is studied experimentally and numerically. Measurements of droplet diameters and velocities using microscopic double-pulse shadowgraphy are conducted for several single species and systematically chosen conventional and alternative multicomponent jet fuels. The results show that the experiment is fuel-sensitive with respect to evaporation. In this study, special attention is paid to unknown or uncertain boundary and initial conditions, which serve as input in the validation of the numerical models. Therefore, nonintrusive, nondeterministic simulations using polynomial chaos expansion are performed to account for these uncertainties. The uncertainty quantification displays that overall uncertainties are small enough to distinguish between the different fuels and to predict fuel-dependent effects on evaporation. Nevertheless, the uncertainties are not negligible. A sensitivity analysis shows a high sensitivity of the evaporation to the offset of the droplet from the centerline and to the uncertainty of the inflow gas temperature. Reducing the uncertainties of the two abovementioned conditions is most promising in enhancing the validation experiment.