A bypass ejector geometry with an annular cavity in the nozzle wall was tested for various operating conditions to evaluate the entrainment performance. The results were compared with those of a conventional ejector. The data shows that the primary mass flow rate in the bypass ejector is always about 20% less than that in the conventional ejector. The results show that the bypass ejector is better than the conventional ejector at relatively high primary and secondary flow pressures with a maximum improvement in the entrainment performance of 31.5%. The bypass ejector has better entrainment performance in the critical mode. Since most ejectors operate in the critical mode, this ejector will have many applications requiring more entrainment. (C) 2014 Elsevier Ltd. All rights reserved.