Abstract
A uniform spray burner was developed to perform a fundamental study on partially-prevaporized spray combustion. A laminar stream of partially-prevaporized spray was generated by the condensation method using rapid expansion of a saturated ethanol vapor-air mixture. A coaxial nozzle burner of 8 mm in inner nozzle exit diameter was applied to the uniform spray burner. Microgravity experiments were performed for large droplet streams because large droplets fall down during the spray generation process at normal gravity. Ethanol was used as a liquid fuel. The mean droplet diameter was able to be varied within the range of 3-120 μm and was stable during an experiment under normal and microgravity conditions. Spray streams were laminar and fuel droplets were uniformly dispersed. The mean droplet diameter and the droplet diameter distribution were constant during spray stream generation. A fiat flame was realized successfully in a laminar spray stream with a stagnation plate. Spray flames of 0.9 in the total equivalence ratio are thicker and brighter than that of fuel vapor-air premixture with the same equivalence ratio.
