A General Correlation for Condensation Heat Transfer in Micro-Fin for Herringbone and Dimple-Texture Tubes
An experimental investigation was performed to evaluate the condensation characteristics inside smooth, herringbone and dimple-texture (Vipertex® 1EHT) tubes with the same outer diameter (12.7 mm) using R22 and R410a refrigerants, for a mass flux range from 81 to 178.5 kg/m²s. The condensation saturation temperature is 47℃; with an inlet quality of 0.8 and an outlet vapor quality of 0.2. Results indicate that the condensation heat transfer coefficient of the herringbone tube was approximately 3 times that of the smooth tube for R22 and a factor of 2.3 for R410a. Multipliers for the dimple tube heat transfer coefficient is approximately 2 times that of a smooth tube for R22 and 1.8 for R410a. Four previously reported correlations are used to compare heat transfer coefficient measurements in the plain tube; while a new equation is proposed to predict the heat transfer coefficient in the herringbone tube.
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