Experiments were carried out to study the atomisation characteristics of superheated liquid( water ) jet injected into the atmosphere through the single-hole nozzle. In present experimental range superheated liquid jet was observed to be atomised in two-phase effluent type: that is, spray formed by the bubble nucleation in the nozzle. In case of liquid injection through a long nozzle ( L/D = 29.09 ), the critical superheat for occurrence of two-phase effluent atomisation can be determined from sudden change of spray angle. Sauter mean diameter of the spray droplets decreases as the degree of superheat increases. For the short nozzle, mean diameter increases with the injection pressure, whereas inverse case occurs for the long nozzle. Also, for the long nozzle the effect of injection pressure is not significant compared with the case of the short nozzle. For the short nozzle the uniformity of drop size distribution increases with increasing the degree of superheat. but for the long nozzle the effect of superheat on the uniformity is negligible except for the low injection pressure.
