Performance evaluation of helical coils as a passive heat transfer enhancement technique under flow condensation by use of entropy generation analysis

Current research focuses on the performance of helically coiled tubes as a passive heat transfer enhancement technique for R134a flow condensation from an entropy generation perspective. Similar to other techniques, helical coils, are accompanied by pressure drop penalty, diminishing their performance, so that these coils lower compared straight where increase in due overcomes decrease enhanced transfer. Unlike previous studies have largely investigated and characteristics regardless this study employs analysis effective method distinguish geometrical conditions at which entropy, i.e. higher tubes. The findings reveal that, both tubes, is tube diameter, mass velocity, vapor quality, wall flux saturation temperature decreases. Additionally, applying within wider ranges velocities can be justified values (≤8.3 mm) coil diameters (≤200 mm), temperatures (≤40 °C), quality (≤0.6), (≥15 kW/m2). These results substantiate employing lieu not justifiable always (for all conditions) although they superior