Single- and two-phase pressure losses in a horizontal mini-size impacting tee junction with a rectangular cross-section

► Experiments were conducted with a mini-size impacting tee junction. ► The junction was horizontal with a rectangular cross-section. ► Data on the flow regimes and pressure drop were obtained. ► New correlations for single- and two-phase pressure drop were developed. An experimental study was conducted in order to investigate the single- and two-phase pressure drops in a mini-size, horizontal, impacting tee junction with a rectangular cross-section (1.87-mm height×20-mm width). The single-phase experiments covered a wide range of Reynolds number using either air or water as the test fluid, while the two-phase experiments used air-water mixtures at 200kPa (abs) and room temperature with various inlet flow regimes. The results include the fully-developed pressure gradients in the three sides of the junction, as well as the pressure drops due to flow in the junction for both the single- and the two-phase cases. These results were validated by comparisons with exact analytical solutions, existing empirical correlations, or new numerical results. The new correlations developed for the pressure drop at the junction under single- and two-phase flow conditions can be valuable in the design of compact heat exchangers.