The Types and Equations of Diesel Spray Angle Curve under Cloud Cavitation and Hydraulic Flip

Abstract For the five types of angle profile curve and possible low spray angles in the unsteady state of diesel spray, all the possible corresponding conditions are given and their curve regression equations can be established by experiments and deep learning methods proposed in this paper. The initial pressure rises sharply with the axial velocity difference significant so that we can infer the relatively large radial disturbance is also as an important reason for cloud cavitation formation. At the moment it is difficult to form wall-adherent cavitation and further develop into supercavitation and hydraulic flip and the too large spray angle is formed in the non-steady phase. And the closer to the maximum position the needle valve is, the slower the velocity increases. So there is a significant decline in the later period, which is caused by gradual cloud cavitation weakening. Especially after entering the steady phase, both angle and its variation range are much smaller, indicating that it is mainly affected by the disturbed flow due to the in-nozzle gas under hydraulic flip developing from wall-adherent cavitation. Besides, the experiment the results of cross-sectional, spatial, and three-dimensional detailed distribution under cloud cavitation should also be further developed through X-ray.