| Abstract |
An ejector is a static device that uses a high-pressure fluid to induce fluid flow from a low-pressure source, resulting in a combined flow with an intermediate outlet pressure. In 2021, the power company Landsvirkjun tested a rudimentary subsonic ejector at its Theistareykir Geothermal Power Plant in Iceland to use the high-pressure fluid from well ThG-11 to induce flow from the low-pressure well ThG-15. The tests showed that entrainment from well ThG-15 was achieved. However, well ThG-11 operated at less than half its normal operating conditions, as it was disconnected from the plant during testing. In 2024, we designed and built a supersonic ejector with a convergent-divergent nozzle to evaluate its performance under normal pressure operating conditions of well ThG-11, but at 10% of its usual mass flow. Differential pressure sensors, absolute pressure sensors, temperature gauges, and orifice plates were used to measure pressure, temperature, enthalpy, and mass flow in different setup parts. The results confirmed that the ejector successfully entrained fluid from well ThG-15 when the pressure difference between wells ranged from 9.9 to 26.3 bar, achieving a maximum entrainment ratio of 0.38. This corresponded to a 3.4 bar pressure gain in the secondary flow and an additional exergy rate of 269.2 kW, representing a 9.1% increase in the exergy delivered from well ThG-11. Scaling to the full mass flow capacities of both wells indicates a potential additional exergy rate of approximately 1.96 MW for the power plant. |