Spray systems contain a large amount of small droplets, which are responsible for multiple light scattering phenomena. When detected, photons that have been scattered multiple times blur the shape of liquid bodies present in the spray as well as the overall spray structure.
This blurring causes issues with spray visualization and furthermore; multiple light scattering introduces large errors in quantitative measurements from image ratio techniques (e.g. LIF/Mie droplet sizing, two-color LIF thermometry, etc).
The simulation of light propagation and scattering through spray systems is then necessary to understand the effects introduced by multiple scattering and to efficiently tackle the aforementioned issues. A reliable and predictive simulation tool allows for:

* Predicting the amount of multiple light scattering.

* Estimating the errors introduced by multiple scattering in quantitative spray measurements.

* Testing strategies for suppressing the intensity contribution from multiple scattering.

* Optimizing and assisting the development of different spray imaging techniques.

In this article we present an open-access software called “Multi-Scattering”. It is a versatile online Monte Carlo simulation tool where photons are tracked through a cloud of spherical droplets. During the simulations process, each scattering event is described by the Lorenz-Mie theory. The numerical simulation is accelerated with the use of the parallel processing capabilities of modern computer graphics cards, known as general-purpose computing on graphics processing units, making those Monte Carlo simulations potentially in less than a minute. The simulations exemplified here demonstrate the use of Multi-Scattering for spray imaging application. This open access software is freely accessible to any researcher who would like to use it for their own spray application.

This is available at: https://multi-scattering.com