Laminar flame speeds of cyclic hydrocarbon fuels: Effect of unsaturation

•Laminar flame speeds of five six-carbon cyclic hydrocarbons were determined.•Differences among laminar flame speeds of the cyclic hydrocarbons were identified.•The thermal, diffusional and chemical effects were discussed.•Model performance in predicting laminar flame speeds of the cyclic fuels were evaluated.•The refined JetSurf model could well predict laminar flame speeds of all cyclic fuels except benzene.