Numerical optimization on the geometrical factors of natural gas ejectors

Increasing production and recovery from mature oil and gas fields often requires a boosting system. Introducing natural gas ejectors can be considered to be a cost-effective way for boosting the production of low-pressure natural gas wells. The CFD technique was employed to investigate the effects of the geometrical factors of natural gas ejectors, the optimal geometrical factors were obtained by numerical simulation to maximize entrainment ratio. Numerical results show that the optimal inclination angle of the mixing chamber was 14 degrees, the optimal diameter ratio of the mixing tube to primary nozzle throat was 1.7, the optimal length to diameter ratio of the mixing tube was 5.0 and the optimal inclination angle of the diffuser was 1.43 degrees. In order to validate the numerical results, a field experiment was carried out. The entrainment ratios obtained by the numerical simulation agreed well with the field data, giving a maximum entrainment ratio up to 93%, proving the optimized geometrical factors of a natural gas ejector. This study may provide a beneficial reference for the design of supersonic ejectors and be helpful for the further applications in boosting natural gas production. (C) 2011 Elsevier Masson SAS. All rights reserved.