A number of studies in recent years have confirmed that cavitation inside a fuel injector plays an important role in the characteristics of the injected fuel spray.However,effects of nozzle inlet roundness and nozzle length on cavitation and the discharged liquid jet are not clearly understood.The present study proposes a set of correlations to predict the characteristics of cavitation and liquid jet discharged through various two-dimensional nozzles.In order to understand the detailed process and the mechanism of the cavitating flow in a nozzle and the jet deformation induced by cavitation,a number of two-dimensional nozzles with various combinations of curvature radius R of the inlet corner and nozzle length L were made to visualize their cavitation and jet.The nozzle width W was fixed to be 4.00 mm,R/W and L/W were varied(R = 3,30,40,120,260,500,530 and 800 μm,R/W = 0.1%– 20%,L/W = 2,4 and 6).Cavitation length Lc and cavitation thickness Wc were obtained by image analysis,from which contraction coefficient Cc was measured.The analysis confirmed that Cc depends not on L/W but only on R/W.From the experiment results,a correlation was proposed for cavitation length Lc as a function of the modified cavitation number σc based on Cc.Finally,a correlation was derived for total jet angle θ,which is given as the sum of the jet angle θ0 at non-cavitating and the additional jet angle θcav induced by cavitation.By using the combination of these correlations,the cavitation length and jet angle for various twodimensional nozzles can be roughly estimated.The proposed approach can be applied to various complex injectors,if the contraction coefficients could be known.