Fractal grids

Our efforts to enhance the jet-stabilized combustion framework—well known for its fuel versatility and minimal soot and NOx emissions with gaseous fuels—face challenges when transitioning to compact liquid fuel operated designs. The main obstacle is the absence of suitable injection systems, leading to increased emissions and hindering scalability in micro gas turbine systems.

The Challenge is to provide an excellent homogeneous fuel-air mixture to the combustion process within short timescales. This can be achieved by prompt and robust primary atomization into very small droplets that exhibit a short vaporisation timescale. Such a development requires deep understanding of the multilateral interactions between gas, liquid, and chemistry phases.

Our Approach is to modulate the primary atomization process, promote the formation of smaller droplets and enhance their turbulent dispersion.  For example, we experimentally modulate the turbulent flow field using space filling cross fractal grids (CFG). These grids generate multiscale turbulence with enough energy in scale that can impact the PS sheet and/or airblast fuel film. As illustrated in the accompanying figure, we achieve well-developed droplet distribution and surfaces without losing the high jet momentum. By applying fractal grids, we have successfully reduced droplet sizes to below 10 μm downstream.

If you are interested in our project, have further questions, or would like to support us through student work, internships, or thesis projects, we would be delighted to hear from you via email or phone. Contact details can be found below.