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Transportation and Power Systems

Lagrangian-Eulerian Spark Ignition

LESI Model
LESI is an approach for spark-ignition modeling of complex engine conditions.

Lagrangian-Eulerian Spark Ignition (LESI) is an advanced ignition model developed within the commercial CFD solver CONVERGE via User Defined Functions (UDFs). LESI improves the spark ignition energy deposition process with respect to standard methods, and it does so by combining the accuracy of the Eulerian formulation for energy deposition with the flexibility of the Lagrangian formulation for arc tracking.

In the LESI model, the spark channel is represented by a series of connected particles that are tracked in space and time using the Lagrangian approach and a local velocity field-based algorithm. Typical features such as spark channel elongation, stretch, truncation, and attachment to the electrodes are properly described to maintain a realistic shape of the ignition source during the electrical discharge process. The location of the Lagrangian particles determines the way the energy is deposited in the Eulerian computational grid at any time-step.

LESI is a CFD model that has been developed for automotive applications, nevertheless it can be used for any other applications where the spark-channel evolves in a non-quiescent flow environment. LESI has been tested – and has been validated – for several geometries (constant volume chambers as well as real engines), used in conjunction with any turbulence modeling approach (RANS or LES), and coupled with multiple combustion models (G-equation, Thickened Flame Model, Well-Stirred-Reactor).

Complete this form to register and download the LESI Model. 

Evolution of the spark channel (in yellow) and flame kernel (in red) during an ignition simulation using the LESI model.