Comparison of Ejection Plant Variants Under Conditions of Natural Gas Pumping Pressure Reduction

In the process of gas main transportation, repair work is periodically required with cutting off the extended section and emptying the internal cavity of the pipeline. According to the established practice, gas from the cut-off section is released into the atmosphere. Ejectors may be involved in gas scavenging, but due to pressure reduction in the cut-off area, it is necessary to ensure high efficiency of the gas ejection unit. It is proposed to compare different configurations of ejectors at reduction of pumping gas pressure (single-stage ejector, ejector with inner cone, two-stage ejector). The ejector parameters are defined using the ANSYS Fluent CFD package. For each version of ejection unit, a graph is drawn on the dependence of the intake gas flow rate on the intake gas pressure, the inner cone position in the nozzle and the active gas pressure in the first stage of the ejector.