Simulation Research On Fuel Flow Characteristics And Parameter Optimization Of Nozzle

With the increasing of energy conservation and emissions reduction efforts, the rising of emissions standards requirements, which lead to increasingly high demand on the diesel engine fuel injection system.Fuel injector as the key implementation unit of fuel injection system, its structure parameters directly affect the fuel turbulence and cavitation in orifice internal, and further impact to the fuel spray quality in the cylinders, so as to determine the diesel engine power, economy and emission property. Therefore, the research of the influence law about the nozzle structure parameters acting on fuel flow property in the orifice internal and fuel atomization quality in the cylinders has important application value in engineering, which is also the focus of the work in this paper.First of all, with orthogonal test9scheme was designed based on diesel engine D6114no pressure type nozzle structure parameters:length-diameter ratio(L/D), the round angle-radius to diameter ratio(r/D), orifice angle ratio(λ) and K coefficient. Then the L9(34) orthogonal table was drown. All the Three-dimensional model of the internal nozzle fuel flow field were established with Pro/E software. Then in Gambit each model was divided the grid structure and set the boundary conditions. With the Euler-Euler algorithm of CFD(Computational Fluid Dynamics), Each scheme was simulated and solved calculation on fluid dynamics by setting two phase mixture model and cavitation model. The valid data about fuel cavitation coefficient, velocity, turbulence and mass flow rate has been obtained. The simulated results were analyzed by SPSS(Statistical Product Service Solutions), the influence which the nozzle structure parameters imposed on orifice internal fuel flow characteristics has been summarized. And the effect of various parameters imposing on fuel flow has been analyzed quantitatively. At last, the regular research results have been gotten, there are theoretical guidance value to optimize and improve the structural parameters of injector.Secondly, the influence of fuel flow performance triggered by spray nozzle structure parameters was analyzed.conclusion:As the length-diameter ratio (L/D) decreases, cavitation degree of fuel in the orifice enhances, turbulent kinetic energy decreases, and velocity increases;Along with the round angle-radius to diameter ratio (r/D) increasing, cavitation degree of fuel in the orifice enhances, velocity increases, the turbulent kinetic energy weakens; Along with orifice angle ratio(λ) increasing, cavitation degree of fuel in the orifice strengthens, and the turbulent kinetic energy weakens. From the law point of view, the round angle-radius to diameter ratio is the most important factor in fuel cavitation; In the effect of the mass flow rate, the most significant factor is length-diameter ratio, the second factor is the K coefficient; The influence trend of turbulent kinetic energy&velocity caused by the nozzle structure parameters is similar, the length-diameter ratio is the main factor.Finally, the no pressure type nozzle structure parameters of diesel engine D6114are optimized based on the simulation analysis, the purpose is to increase fuel cavitation in the spray nozzle and diesel beam fracture degree in the cylinder, So as to improve the atomization of fuel quality. In order to enhance the diesel engine emission characteristics under the promise of its power and economy performance.In this paper, a deep research on the influence of fuel flow characteristics in the spray orifice triggered by spray nozzle structure parameters has been done, and the regular theoretical experience was accumulated. These achievements have a guiding significance on the implementation of the fuel injection system component design and related research fields.