Biography

Research interests

My research interests are in the area of interfacial fluid mechanics and multiphase flow with industrial applications and a particular interest in the effect of surfactant on the dynamics of thin liquid films (or multi-layers) and slender liquid threads and jets (which may be single or compound). A variety of situations is considered in which these films that may have complex rheology are driven by capillarity, marangoni stresses (due to the presence of surfactant concentration and/or temperature gradients), surface and bulk diffusion of chemicals, antagonistic intermolecular forces, gravitational modulation (due to vibration) and electric fields on smooth or patterned substrates, which may be rigid or flexible, impermeable or porous. Examples of our work are given below:

• Spinning disc reactors for pharmaceuticals and fine chemicals manufacture. Here, the thin liquid film overlying a rapidly spinning disc is subjected to large shear rates resulting in the formation of large amplitude waves with an associated dramatic increase in the rates of heat and mass transfer. This enhancement in mixing conditions can relieve intrinsically fast reactions, which arise naturally in the pharmaceutical and fine chemicals industry that would have otherwise been inhibited by poor mixing conditions in a standard batch operated agitated vessel reactor. This activity can therefore lead to an alternative, small-scale technology, which is of direct relevance to the manufacture of pharmaceuticals and fine chemicals.
• The spreading of surfactants on thin liquid films of Newtonian and non-Newtonian liquids and focuses on understanding the physical mechanisms responsible for a novel fingering instability that accompanies the spreading process. This instability gives rise to highly non-uniform surface coverage and its understanding is central to coating flows, surfactant replacement therapy, ink-jet printing, oil-spill clean-up and enhanced oil recovery.
• Phase inversion of concentrated emulsions. This activity is of direct relevance to pipeline transportation of crude oils, during which abrupt and significant changes can occur in the frictional pressure drop and the rheology of the liquid-liquid dispersion near the phase inversion point, which must be prevented. It is also relevant to the manufacture of spreads in the food industry wherein phase inversion constitutes an essential processing step.

Links

• UG Courses Undergraduate courses in the department. 
• IC Alumni Imperial College London Alumni homepage 
• ICHEME Institution of Chemical Engineers 
• APS American Physical Society