Terminology a) compression ratio b) expansion ratio and c) flow ratio?

a) The compression ratio (often symbolised by K) is equal to the discharge pressure of the Ejector divided by its suction pressure. Both pressures have to be expressed in consistent, absolute pressure units.

b) The expansion ratio (often symbolised by E) is equal to the motive pressure of the Ejector divided by its suction pressure. Both pressures have to be expressed in consistent, absolute pressure units.

c) The flow ratio (often symbolised by U) is defined as the suction flowrate divided by the motive flowrate where both are expressed in consistent mass terms. The use of volumetric terms referred to standard conditions (eg. mmscfd) is of course also acceptable.