Numerical simulation of low pressure natural gas injector

The maximum total recovery from all gas wells are highly desired to be got and the production is to be maintained when the gas well reaches the end of its economic life. Although the injector has been known for about one century, sparse investigations have been performed on the injector of natural gas, and no structural optimization on the natural gas injectors has been reported. In the present paper, the structural parameters of natural gas injectors was optimized numerically with the motive pressure ranging from 2.5 to 3.5MPa, induced pressure ranging from 0.5 to 1.5MPa and discharged pressure being 1.5 MPa. The numerical results showed that the optimal values of diffuser gradient, mixing tube length to diameter ratio, mixing chamber length to diameter ratio and mixing chamber gradient were 40, 5, 0 and 0.25, respectively. The performance of optimized injectors was also investigated numerically. The motive natural gas flowrate increased linearly with increase of motive pressure and was independent of induced pressure. The induced flowrate and entrainment ratio of natural gas were both increased with the increase of induced pressure.