Hydrodynamic cavitation for intensifying multiphase processes: state of the art, challenges, and path forward
Professor Vivek Ranade
Abstract
Multiphase processes are used in a wide range of applications and are of great economic and ecological importance. Hydrodynamic cavitation is a phenomenon of formation, growth and collapse of vapour-filled cavities. It generates highly localised extreme conditions
- temperatures > 103 K, pressures > 102 MPa
- energy dissipation rates > 107 m2/s3
- highly oxidising radicals
Harnessing such localised extreme conditions hold tremendous promise for intensifying a wide range of multiphase processes. Thereby enhancing resource efficiency and facilitating decarbonisation throughout the value chain and across the economy. In recent years, hydrodynamic cavitation has been used for intensifying many applications, including:
- wastewater treatment
- microbial disinfection
- desulphurisation of fuels
- biomass pre-treatment
- food and beverage production
- multiphase reactions
- crystallisation
Despite the intense research and several start-up companies, the full potential of hydrodynamic cavitation is not yet realised. One of the key reasons for this is inadequate understanding of inception. Another is the resulting physico-chemical effects of cavitation. Systematic methodology for designing hydrodynamic cavitation devices and generalised framework for development, scale-up and optimisation of hydrodynamic cavitation processes is still not adequately established.
In this talk, I will critically review the state of the art on applications of hydrodynamic cavitation. This will include types and performance of different cavitation devices. Also, I will review the current state of fundamental understanding of complex physico-chemical processes occurring in hydrodynamic cavitation. In light of personal experience of application, I will discuss various prevailing approaches for modelling of hydrodynamic cavitation. This includes empirical, phenomenological, and multi-scale models. Key challenges and potential ways of overcoming these challenges will be highlighted. At the end, I will share some thoughts on the path forward and prospects.
I believe that hydrodynamic cavitation has a great potential to beneficially impact resource efficiency, new products, and decarbonisation across many sectors. I hope that the talk will stimulate further research on hydrodynamic cavitation and facilitate wider applications of hydrodynamic cavitation to realise its true potential.
