UCL Centre for Nature Inspired Engineering


Shuxian Jiang CEP:PI article on fractal injector published

20 July 2022

Shuxian Jiang’s CEP:PI article on fractal injector demonstrates effects beyond fractal dimension on intensification of liquid-liquid processes.


A new article in Chemical Engineering Processing: Process Intensification discusses the “Intensification of liquid mixing and local turbulence using a fractal injector with staggered conformation”. This article is part of a Special Issue to honour Professor KDP Nigam (IIT Delhi), who made seminal contributions in liquid-liquid process intensification using a so-called coiled flow inverter (CFI).

Shuxian Jiang, PhD student at the UCL Centre for Nature-Inspired Engineering (CNIE) and the Department of Chemical Engineering at UCL is the lead author on the article. The work is the result of an excellent collaboration between the NICE Group of Prof Marc-Olivier Coppens (UCL CNIE) and Prof Jiajun Wang at Zhejiang University. Shuxian is a former MSc student from Zhejiang University and current PhD student at UCL. Her research project is funded by Synfuels China.

The CEP:PI article follows a recent paper in Chemical Engineering Science, where the same authors had shown how a fractal injector of intermediate fractal dimension (say, D=2.6) leads to better performance than a planar double-ring sparger (D=2), but also better than a space-filling injector (D=3), for liquid-liquid reactions. This newest work shows how one must look beyond fractal dimension for fluid mechanical and other engineering applications. As in nature, conformation plays a key role too; just think of the changing orientation of tree branches as they split and grow, to catch more sunlight and provide more stability. Staggered and eclipsed branching configurations lead to different spatial packing and, in the case of fluid injection, local interactions between the vortices around the injector openings. Shuxian’s work shows how micromixing is intensified for a (more spaced out) staggered injector configuration, over an eclipsed one (with one injector outlet above another one in the same branching unit). This leads to better reactor performance.

Fractal geometries are oversimplified in most literature, just quoting a non-integer, fractal dimension. We show that one must look beyond, including other descriptors. Nature is subtle, and we must look closely when developing effective, nature-inspired solutions for sustainable development.

Article with citations:

S.Jiang, M.-O.Coppens, J.Wang, 2022, Intensification of liquid mixing and local turbulence using a fractal injector with staggered conformation, Chemical Engineering Processing: Process Intensification, DOI:10.1016/j.cep.2022.109042 [link]