| Title | Numerical model analysis of supersonic ejector for geothermal wells at the Theistareykir Geothermal Power Plant |
|---|---|
| Authors | Christine Groves |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | Supersonic ejector, geothermal energy, numerical model, CFD simulations |
| Abstract | An ejector is a flow device with no moving parts. A high-pressure fluid is accelerated through a converging-diverging nozzle to induce flow from a low-pressure fluid. The two flows combine in a constant area mixing chamber and are discharged at an intermediate pressure. In 2024, a supersonic ejector was built and tested at the Theistareykir Geothermal Power Plant in Iceland to see if it can entrain the secondary fluid flow from well ThG-15 using the high-pressure fluid flow from well ThG-11. To have a working model for future modifications, different computational fluid dynamic (CFD) models were created to compute the internal flows of the supersonic two-phase industrial-scale steam ejector using ANSYS Fluent. The supersonic ejector was modelled with three different turbulence models (standard ? − ?, RNG ? − ?, realizable ? −?). The standard ? −? model had the lowest error for the entrainment ratio compared to the experimental data and was subsequently used to test additional data points after reaching mesh independence. The CFD entrainment ratio was consistently overestimated compared to the experimental data, with good experimental agreement during periods of stable data collection, with errors ranging from 4% to 71%. These models provide a reasonable estimate of supersonic two-phase ejector behavior and will be developed further to improve the design of the ejector. |