Method for automatically identifying diesel spray crushing process and automatically realizing spray continuous calculation

A crushing process and automatic identification technology, which is applied in the testing of engines, engine components, fuel injection devices, etc., can solve the problems of not being able to dynamically change the interval position, not suitable for changing the working state, and greatly affecting the calculation accuracy.

CN110848065AActive Publication Date: 2020-02-28BEIJING UNIV OF TECH
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2020-02-28

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Abstract

The invention discloses a method for automatically identifying a diesel spray crushing process and automatically realizing the spray continuous calculation. The method automatically judges the processthat a liquid film is crushed into liquid drops in the diesel injection process, and realizes a SD-ELSA algorithm of the spray continuous calculation. The SD-ELSA algorithm is characterized in that the sphericity degree and the average particle diameter of liquid phases in grids are calculated and taken as judgment bases, the information of particles in a flow field are calculated through a Lagrangian method, the information of the grids belonging to continuous liquid phases in the grid node information in the full-flow field is calculated by using an Euler model, and Euler block masses meeting two bases for determination are converted into particles and re-calculated through the Lagrangian method. According to the method, dynamic converting coupling of the Euler-Lagrangian model is realized, the complete information of discrete phases and continuous phases in the flow field can be automatically obtained and subjected to iterative computation, three stages of a liquid column, primarycrushing and secondary crushing of the diesel injection are obtained, and the diesel spray process is completely represented.
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Description

technical field

[0001] The invention belongs to the research field of diesel engine spray characteristics and relates to a simulation calculation method of spray characteristics. Background technique

[0002] The high-pressure diesel oil enters the cylinder of the diesel engine through the nozzle jet flow. During the jet flow process, the diesel oil will firstly form a liquid film on the periphery of the liquid column from the continuous liquid column state at the outlet, and further develop with the jet flow, the liquid film breaks and begins to produce droplets. These The droplets are further broken and developed, and finally atomized. This is a process along the direction of the jet, where there is a continuous liquid phase region, a transition region where the continuous phase and the discrete phase are mixed, and a full droplet region where all the discrete phases are present. The cost of existing optical testing methods is high, and simulation calculation simulation i...

Examples

Embodiment Construction

[0030] Enter the entire flow field calculation domain from the outlet of the nozzle, calculate the flow field grid at the first step, and use the large eddy simulation method for the atomization flow field, and in order to simplify the calculation amount, use the RANS equation for near-wall processing, free shear The layer is simulated by LES. In order to reduce the calculation amount under the premise of ensuring the calculation accuracy, the sub-model of the large eddy equation is calculated using WNLES S-Omega, the near-field VOF model is calculated using the Explicit method, and the far-field DDM model is calculated using the KH-RT fragmentation model calculate.

[0031] The simulation boundary conditions and calculation model parameters are as follows: inlet pressure 100Mpa, back pressure 1Mpa, nozzle diameter 0.3mm, aspect ratio 5, fluid diesel, wall temperature 298.15K, fluid density 850kg / m3, surface tension coefficient 0.031N / m, the air is a compressible gas, the air...