Effect of Motive Pressure on Ejector Entrainment Capacity

This article analyzes the influence of motive fluid pressure in a gas ejector on its entrainment capacity, which is determined by the friction force between gas layers and is proportional to the coefficient of dynamic viscosity. Accordingly, the analysis is based on investigating the dependence of gas viscosity on its pressure across various ranges. It is shown that at low pressures (up to 3–6 MPa for various gases), gases obey Maxwell's equation, and their viscosity remains constant as pressure increases. When the gas significantly deviates from ideal behavior, its state is described by the Van der Waals equation, and its viscosity increases linearly with a specific proportionality factor dependent on the gas molecular characteristics. This conclusion was confirmed experimentally using a custom-built setup featuring a gas ejector. Graphs, not previously presented in the literature, are provided showing the dependence of the entrained flow rate on the motive flow pressure as its values increase up to 1 MPa, which demonstrate the constant value of the entrained flow rate. This established independence of the ejector's entrainment capacity from the motive flow pressure within the investigated range makes it possible to simplify the design of ejector systems and reduce the energy consumption required for motive gas compression.