Adolph Jr. Manadao Bravo is pursuing his PhD in Earth Sciences at the University of Iceland, where he investigates multiphase flow behavior in high-temperature geothermal fluids with a focus on critical raw material recovery. In his research, he examines how liquid and vapor phases interact under varying pressure, temperature, and salinity conditions, and how these factors influence phase distribution and flow behavior. The interaction between liquid and vapor phases directly affects operational performance in geothermal facilities, particularly pressure losses, flow regime transitions, and mineral deposition. In the context of extracting critical raw materials from geothermal fluids, accurately characterizing these interactions is essential for predicting scaling precipitation along pipelines and wells and refining strategies that support efficient and sustainable resource recovery.
High-temperature geothermal systems naturally contain mixtures of liquid and steam flowing together. This multiphase flow strongly influences how geothermal facilities operate, both underground and at the surface. Despite its importance, most laboratory studies and design tools used in geothermal engineering were originally developed under ambient conditions using oil-gas or air-water systems. Those substitute systems do not truly represent the physical properties and flow behavior of real geothermal fluids. As a result, geoscientist and engineers face uncertainty when applying such tools to operating geothermal fields, which can lead to inaccurate predictions and less efficient production strategies.
Adolph’s PhD project aims to address that gap by using the Geothermal Flow-Loop (GFL) at the University of Iceland, a research facility built through the GeoPro project funded by the European Union’s Horizon 2020 Research and Innovation Programme. The facility was designed to carry out controlled experiments using geothermal brine at temperatures up to 200 °C and pressures up to 40 bar. The GeoPro project has now concluded, but the facility continues to support advanced geothermal research.
Through the CRM-Geothermal project under Horizon Europe, Adolph used the GFL to collect data across a wide range of temperatures relevant to geothermal operations. By closely reproducing conditions found in real geothermal fields, the GFL provides reliable and practical insights into how liquid and gas phases move together. The aim of the project is to develop models that predict the movement of the gas phase through the liquid, identify the flow regimes that occur, and determine how these behaviors influence mineral deposition along wells and pipelines.
Figure: Evolution of flow regime in vertical flow at 140 °C for (a) water-N2 and (b) water-NaCl-N2. The orange arrows indicate the start of bubble coalescence, while the red arrow indicates the formation of fully developed Taylor bubbles (plugs).
Adolph has already published parts of his results in Geothermics, demonstrating the Geothermal Flow Loop’s ability to conduct reliable and field-relevant experiments under geothermal conditions. His ongoing analyses of the collected data, which will be detailed in upcoming publications, show that both temperature and salinity have a significant impact on multiphase flow behavior and the development of different flow regimes. These findings provide important insights for predicting flow patterns and managing mineral deposition in geothermal operations.
