Research on the structural optimization of ejector nozzle baffle in natural gas transportation systems and the enhancement of ejector performance

Wellhead pressure gradually decreases during natural gas extraction, so it cannot meet the pressure requirements of transportation. Ejectors are often used to solve this problem, but ejectors have low energy transfer efficiency and other problems. Accordingly, from the principle of energy transfer of the ejector, baffles are added at the exit of the existing ejector nozzle structure to analyze the effects of variation of the length and shape on the ejection performance, while its performance is researched under variable operating conditions. The results show that adding a certain length of the baffle can increase the critical back pressure (CBP) value of the ejector by 11.1%, and the breakdown pressure (BDP) value can be increased by 7.9%, which can increase the entrainment ratio (ER) value under the unchoked flow state. However, the existence of the baffle will reduce the ER under the choked flow state; it will be reduced by 3.9%, at most, and investigating the change in the baffle shape can address this problem. Thus, two types of baffle upper sidewall surface profiles are proposed, and the results show that this optimization achieves a joint increase in the back pressure value and the ER.