A Review of Supersonic Compressor Development

The aerodynamics of a baseline supersonic throughflow fan rotor

“…Experimental research on supersonic compressors began in the late-middle 1930's and was actively pursued by the NACA during the 1940's and 1950's at the Lewis Flight Pro pulsion Laboratory and the Langley Aeronautical Laboratory, as they were then named. Historical information summarizing much of the NACA research at the two facilities can be found in References 20 and 21, and a review of supersonic compressor development in general, up to the year 1961, has been presented by Klapproth [22]. One of the primary motivations behind the development of the supersonic compressor was the potential for high work-input per stage thus allowing the possibility of reducing the number of axialflow stages in multi-stage compressors.…”

“…Furthermore, high mass flows per fan frontal area, approaching the maximum possible, would be achievable with this type of fan. It was held, and not without justification, that if the total-pressure losses were maintained at reasonable levels then fairly high adiabatic efficiencies were still possible, even with a normal shock and separated blade-boundary-layers [22], due to the large total-pressure increases. The modern transonic fan, the development of which is recognized as a major success in the field of aircraft gas turbine engines, demonstrates the practicality of this concept.…”

“…^ Total-pressure ratios of up to 9.6 have been obtained across a single, axial-flow rotor blade row [22].…”

“…Supersonic rotor operation with (relative) subsonic flow at the rotor exit involves the effects of a normalshock compression to achieve most of the work interaction. This mode of operation, con ventionally referred to as shock-in-rotor [20][21][22], is typically associated with a relatively high stage-reaction due to the resulting large static pressure (or enthalpy) rise through the rotor shock. Conversely, operation of a supersonic rotor at low back-pressure, often with axial-supersonic exit flow, involves little or no static-pressure rise through the rotor, and may even involve a substantial decrease in static pressure.…”

“…Conversely, operation of a supersonic rotor at low back-pressure, often with axial-supersonic exit flow, involves little or no static-pressure rise through the rotor, and may even involve a substantial decrease in static pressure. A rotor designed to operate in this so-called impulse-type [21][22] manner accomplishes the work input mostly through flow turning rather than compression, with an accompanying increase in the kinetic energy of the fluid.…”