Abstract: A method of and devices for avoiding rotor instability thereby increasing the dynamic power limit of rotary fluid machines such as turbines and compressors which have contact free seals in the gaps between the rotating and nonrotating elements of the machine in which the rotary flow of fluid in the gap is modified as by axial baffles in the gap or by introducing a fluid medium into the gap thereby to decrease, eliminate, or even reverse the force component acting on the rotating element and disposed 90.degree. ahead of the oscillation deflection of the rotating element.

Abstract: A fuel injector for internal combustion engines in which an axially slidable nozzle needle is provided which is capable of being lifted off its seat by the pressure of the fuel against the thrust of one or a plurality of springs and is formed with a pointed tip below the valve seat with at least one spray hole being provided in the nozzle body at an acute angle relative to the nozzle axis. The tip of the nozzle needle is shaped and enters the spray hole or injection bore in such a way that the free cross-sectional area at the injection bore is less than the free cross-sectional area at the seat in nearly all positions of the nozzle needle.