Доступ предоставлен для: Guest

ISSN Online: 2379-1748

8th Thermal and Fluids Engineering Conference (TFEC)
March, 26-29, 2023, College Park, MD, USA


Get access (open in a dialog) pages 1695-1704
DOI: 10.1615/TFEC2023.ref.046091


Grooved, or microfin tubes are widely used in industry due to superior heat transfer performance. Significant work has been done on characterizing the thermal-hydraulic performance of microfin tubes; however, research on void fraction prediction is limited. Experimental data available in the literature was collected for R134a and R410A, tube diameters between 7.25 and 8.93 mm, helix angles of zero (axial), 18° and 25°, 50 − 70 fins, constant fin height of 0.18 mm, 75 − 700 kg/m2-s mass flux range, 0-10 kW/m2 heat flux range, inlet temperatures of 5°C and 35°C, and 0.1 − 0.85 quality range. This data was used to develop a correction factor which was then applied to the best performing existing void fraction correlation. The improvement in prediction accuracy was very significant for 25° helix tubes, but not for axial and 18° helix tubes. Heat exchanger level analysis was carried out to assess the effect of the correction factor on overall charge prediction. It was found that the correction factor had a significant impact of up to 40% compared to existing correlations on charge prediction of a heat exchanger having 25° helix angle tubes. Lastly, the limitations of the new correlation are discussed which is due to the lack of experiment data for microfin tubes which can be addressed in the future.