Inlet Duct Treatment is a state-of-the-art method of surge margin enhancement for centrifugal compressors, allowing significant extension of turbocharger operating range.


The operating range of a turbocharger is limited by the compressor, which experiences surge – an aerodynamic instability of the entire air system – at low flow rates. This impacts both turbocharger-engine matching and wastegate operation, leading to non-optimal performance. IDT introduces a novel blockage-based geometry upstream of the compressor, located close to the blade tips to improve aerodynamic stability and delay the inception of surge.

IDTExperimental testing at Imperial College of an optimised IDT geometry has delivered a 32.4% improvement to compressor surge margin and a 27.5% increase in operating map width (in comparison to no surge enhancement), under unsteady (pulsating) flow conditions.


Inlet Duct Treatment provides surge margin improvement to all turbochargers where near-surge operation is significant.


The development of this technology is currently being supported by the Industry Partnerships and Commercialisation Engineering team at Imperial College London. A business development manager has been engaged to attract and negotiate with potential licensees for the technology.

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