Particle Image Velocimetry (PIV) has been used to investigate flame propagation and unburned gas velocity fields within an optically accessed cylindrical combustion chamber. The flame propagation process and the flame structure of the quiescent and swirling flow inside the chamber is presented. An ionisation probe technique and also a nonintrusive laser refraction technique were used to determine the local flame speed in conjunction with the PIV measurement. The laminar burning velocity of quiescent propane-air mixtures initially at atmospheric condition for different equivalence ratios ranging from 0.7 - 1.4 were measured. These were determined directly from the difference between the local flame propagation speed and the unburned gas velocity immediately ahead of the flame front. Close agreement with other measurements and predicted results was found.