Turbomachine with a vaneless rotating diffuser and nozzle

A turbomachine comprising at least one of a radial turbine and a centrifugal radial compressor, said turbine comprising a rotor mounted to rotate in a casing about an axis of rotation, the rotor comprising a disk that can rotate about its axis which is coincident with the axis of rotation, and of which a face facing in a downstream direction with respect to a direction of flow of a fluid let into the turbine is fitted with blades, the radial turbine being supplied with fluid by a plain radial inlet nozzle rotating freely and coaxially with respect to the turbine rotor and surrounding the turbine rotor, said centrifugal radial compressor comprising a rotor rotating about said axis of rotation in the casing, the compressor rotor comprising a rotary disk of which a face facing in an upstream direction with respect to the direction of flow of a fluid let into the compressor is equipped with blades compressing the fluid toward a plain radial exhaust diffuser rotating freely, the compressor exhaust diffuser surrounding the compressor rotor and being surrounded by a fluid flow uptake volute wherein a torque to rotate at least one of the plain, freely rotating compressor radial exhaust diffuser and the plain, freely rotating turbine inlet nozzle, is derived from fluid friction from the fluid flow through at least one of said plain, freely rotating compressor radial exhaust diffuser and said plain, freely rotating turbine inlet nozzle.