Model of a fuel jet atomization in a diesel engine is elaborated.The jet is assumed to have a shape of Rankines ogive body and the related potential air flow past the body is applied.As a mechanism of jet atomization the model utilizes the concept of quasi-continuous,high-frequency periodic dispersion from the unstable part of the jet surface caused by hydrodynamic instability of the gradient flow in the conjugated(gas – liquid)boundary layers.The theory of gradient instability is applied for quantitative description of the atomization.The Karman – Pohlhousen technique is used to determine the development of the conjugated boundary layers at both sides of the jet surface.The Runge – Kutta method is used to solve the bulky ordinary differential equations for the distributions of the boundary layer thicknesses coupled with equation for the velocity distribution along the gas – liquid interface.The core assumptions and the calculation scheme for the jet atomization process are similar to the considered earlier case of a spherical drop atomization.The lower-level modeling reflects the atomization kinetics,while the upper-level one – spatial aerodynamics of axi-symmetric evaporating mist generated by atomizing jet.The torn-off droplets are assumed to behave as a multi-velocity continuum.The ballistics of an evaporating spray are rendered as equations in dynamic 4-D space and method of CFD is used to investigate the problem.The main regularities of the transient jet atomization kinetics are thus obtained: the torn-off droplet sizes,their size distribution and the total mass efflux rate are calculated.The variance in time of the spatial distributions of the breakaway droplets mass and number densities and also of the vapor density is processed and analyzed.As well,the detailed fields of the droplets mean diameters and polydispersity are obtained.