An Aerodynamic Method for Control and Range Improvement of Rotary Compressors

An aerodynamic method is proposed to replace the variable inlet guide vanes used for imparting compressor inlet prewhirl. High pressure jets are injected obliquely into the inflow, from orifices spaced around the periphery of the inlet pipe. A mathematical model of the flow situation was developed, which considers an unbounded axisymmetric jet ejected obliquely at various angles into a cross flow. The solution for the trajectory and growth of the jet was found to be in good agreement with relevant published experimental data. Prewhirl producing jet arrangements were designed and the flow deflection resulting from the combined action of the jets was measured for a range of jet velocities and cross flow velocities.