‘Knock on nanocellulose’: Approaching the laminar burning velocity of powder-air flames

•Laminar burning velocity of nanocellulose-air mixtures was determined experimentally.•A value of 20cms−1 is proposed for the laminar burning velocity of nanocellulose.•Tests performed in a semi-open tube a modified 20L sphere give consistent results.•Linear and nonlinear correlations between flame stretching and velocity were compared.•These results are useful as inputs to CFD models of dust explosion on a larger scale.