Drop dispersion and coalescence in a direct contact thermal energy storage

In this work drop dispersion of disintegrating jets for a liquid–liquid system in a direct contact thermal energy storage pilot was investigated experimentally. The coalescence behavior of the dense packed emulsion layer was linked to the size of drops. It was found that coalescence rates were strongly affected by the drop sizes, where a three-fold increase was achieved by increasing the drop sizes. By varying the number and size of injection nozzles, drop sizes from < 1 to > 10 mm were produced. Drop size distributions were studied and described in terms of the inlet jet breakup behavior, which was quantified by the Ohnesorge and Reynolds numbers. • Drop dispersion in DC-TES depend on the inlet jet Reynolds and Ohnesorge number. • Drop sizes were shown to have a large impact on phase separation. • A three-fold increase in the coalescence rate was achieved by increasing drop sizes. • Jet velocity and flow per nozzle are determining factors for drop size.