Imperial College London


Faculty of EngineeringDepartment of Mechanical Engineering

Associate Dean Industry Partnerships,Prof of Turbomachinery



+44 (0)20 7594 7241r.botas Website




611City and Guilds BuildingSouth Kensington Campus






While at Imperial College Ricardo developed the area of unsteady flow aerodynamics of small turbines, with particular application to the turbocharger industry. The contributions to this area centre on the application of unsteady fluid mechanics, instrumentation development and computational methods. My personal group has become a recognised centre of turbocharger turbine aerodynamics, and more particularly in the application experimental methods and one dimensional calculation procedures.

The specific contributions and impact in relation to the work in turbocharger aerodynamics are summarised here:

  • Development of air management strategies to enable engine technologies harnesses the available exhaust energy in reciprocating engines. The state of the art in design and engine air management only makes use of the steady turbomachinery component maps, thus forcing the design, matching and eventual installation along lines of quasi-steady operation. Critically, such an approach does not harness the full energy potential contained in an unsteady flow and implies sub-optimal component choices (leading to higher environmental overall impact).
  • Development of a high speed dynamometer for turbocharger research. This novel machine allows the research to go beyond the current procedures by enabling the extension of the performance map by three fold. It provides a better understanding of the turbine performance well away from design point. This development contributes very directly to understanding turbocharger flow conditions and it is a unique feature of my group.
  • The aerodynamic investigations have lead to a new concept: Active Flow Control Turbocharger (ACT). This development has been the basis of an EPSRC grant, a Carbon Trust Incubator award and it is currently supported by Imperial College Innovations. In this patented technology, Variable Geometry Turbine turbocharger system is tuned to follow the engine generated exhaust pulse by means of a fast actuated nozzle. It aims to make better use of the exhaust gas energy of the engine than in current turbochargers.
  • Development of modelling strategies for improved turbocharger selection and matching. The need to provide reduced order and yet accurate models for optimisation of components is well recognised. My group has contributed to this area by development of accurate boundary conditions for unsteady flow simulations. The availability of detailed unsteady flow experimental data clearly allows validation of methods. The results have made their way into the design codes from industry.