Condensing heat transfer coefficients of R134a in smooth and grooved multiport flat tubes of automotive heat exchanger: An experimental investigation

• Published in: International journal of heat and mass transfer 2019-05, Vol.134, p.366-376
• Main Authors: Ammar, Syed Muhammad, Abbas, Naseem, Abbas, Saleem, Ali, Hafiz Muhammad, Hussain, Iftikhar, Janjua, Muhammad Mansoor, Sajjad, Uzair, Dahiya, Anurag
• Format: Article
• Language: English
• Subjects: Automotive heat exchanger; Condensation; Flattened tube; Heat exchangers; Heat flux; Heat transfer; Heat transfer coefficient; Heat transfer coefficients; Pure two-phase vapor; R134a; Saturation; Temperature; Tubes
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2019.01.047

•Finding condensation heat transfer coefficient for smooth and grooved flat tubes using R134a.•Investigating the effect of mass flux, saturation temperature and heat flux on heat transfer coefficient.•Comparison of heat transfer coefficient data with well-known correlations.•Improving Aker et al. heat transfer correlation [21] for the current experimental data. Condensation heat transfer coefficient of R134a was obtained in multi-port micro channel smooth and grooved flat tubes of automotive heat exchanger. The test consisted of two smooth and one grooved tube. The test range covered mass flux 490–1600 kg/m2 s, heat flux 5.5–19 kW/m2 and saturation temperature 51–68 °C. Results revealed that condensation heat transfer coefficient increased with an increment of mass flux, vapor quality and decreased with the increase of saturation temperature. The effect of heat flux on heat transfer coefficient was negligible. The grooved tube showed larger heat transfer coefficient than that of smooth tubes. A comparison of the present data of flat tube with existing correlations revealed that the heat transfer coefficient was not reasonably predicted, therefore new correlation was developed for heat transfer coefficient that predicted 86% data within ±30% with a mean error of 16%.