Diesel Spray Ultra-High Injection, Paper Numerical Validation, ANSYS Fluent Tutorial

Project Description

The present problem simulates fuel injection through an injector into a chamber by ANSYS Fluent software.

This simulation is based on the information in the article “Spray-induced air motion in single and twin ultra-high injection diesel sprays” and its results are compared and validated with the results in the article.

The fuel used in this model is diesel and its properties include density equal to 830 kg/m3, specific heat capacity equal to 1680 j/kg.K, droplet surface strain equal to 0.0255 n/m and viscosity equal to 0.0027888 kg/m.s.

An injection process is also defined to define the fuel injection process. Thus, the fuel flow is injected into the chamber with a flow rate of 14 g/s, a velocity of 850.23 m/s and a temperature of 298 K.

The diameter of the fuel particles is considered to be 0.00016 m and the type of fuel injection into space is defined as single. The duration of the injection process in the time interval is equal to 0.001 s.

The present 3-D model is designed using Design Modeler software. The meshing of the model has been done using ANSYS Meshing software and the mesh type is structured. The element number is 675000.

Diesel Spray Methodology

In this project, the discrete phase model (DPM) is used. The behavior of discrete phase particles in the unsteady state is also defined and it is also assumed that the behavior of the particles is affected by the continuous flow (interaction with the continuous phase).

The physical states defined for the discrete phase model include stochastic collision, which means that fuel particles collide with each other, coalescence, which means that fuel particles combine with each other, and breakup, which means the decay of fuel particles.

Diesel Spray Conclusion

At the end of the solution process, the results of the present numerical study are compared and validated with the results of the laboratory (experimental results)of the mentioned article.

Validation is based on Figure 3 of the article. Since the present simulation was performed at a time interval of 0.5 ms, the results of the numerical work were compared only in the first 0.5 ms.

This simulation was performed at an injection pressure of 300 MPa, which according to the Bernoulli principle, the particle injection rate is considered to be 850.23 m/s.

Also after the solution process, two-dimensional and three-dimensional contours related to velocity, DPM density, discrete phase model number and volume, and particle tracking in terms of residence time and diameter size are obtained for better understanding.