Experimental study of refrigerant condensation heat transfer and pressure drop in horizontal tubes with full and partial coiled wire inserts (CWIs)

• Published in: International journal of heat and mass transfer 2023-12, Vol.216, p.124577, Article 124577
• Main Authors: Rajabi, Vahid, Mansoori, Zohreh, Rahimzadeh, Hassan, Nasrfard, Hamed, Ahmadi, Goodarz
• Format: Article
• Language: English
• Subjects: Coiled wire insert (CWI); Condensation; Heat transfer coefficient (HTC); Pressure drop
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2023.124577

•The effect of full and partial coiled wire inserts (CWIs) on the condensation heat transfer was studied.•The performance of CWIs was evaluated at different mass fluxes and vapor qualities.•The predictions of well-known correlations were assessed for smooth and fully inserted tubes.•The heat transfer coefficient (HTC) increases exponentially by partial CWIs length.•Three new accurate correlations were developed for different tubes. The condensation heat transfer coefficient (HTC) and pressure loss in the horizontal smooth and wire-inserted tubes were investigated experimentally. Three different coiled wire inserts (CWIs) of the full length of 1000 mm and partial lengths of 100 mm and 200 mm with 0.8 mm wire thickness and 9.5 mm pitch were studied. The main condenser was a heat exchanger of double pipe type with an 8 mm inner diameter for the refrigerant and an active length of 1 m cooled by water circulating in the annulus. The experiments were conducted for different refrigerant mass velocities within 90–400 kg/m2s and low vapor mass fraction (x