Pressure drop and heat transfer augmentation due to coiled wire inserts during laminar flow of oil inside a horizontal tube

• Published in: International journal of thermal sciences Vol. 49; no. 2; pp. 373 - 379
• Main Authors: Akhavan-Behabadi, M.A., Kumar, Ravi, Salimpour, M.R., Azimi, R.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Masson SAS 01.02.2010; Elsevier
• Subjects: Applied sciences; Coiled wire insert; Coiling; Devices using thermal energy; Energy; Energy. Thermal use of fuels; Engines; Enhancement; Exact sciences and technology; Fanning friction factor; Heat exchangers (included heat transformers, condensers, cooling towers); Heat transfer; Heating; Horizontal; Inserts; Tubes; Turbulence promoter; Wire; Fanning friction factor; Enhancement; Coiled wire insert; Heat transfer; Turbulence promoter; Twisted shape; Countercurrent flow; Experimental study; Wire; Insert; Turbulence generator; Oil; Laminar flow; Pressure drop; Heat exchanger; Horizontal tube; Tubular heat exchanger
• ISSN: 1290-0729; 1778-4166
• DOI: 10.1016/j.ijthermalsci.2009.06.004

An experimental investigation has been carried out to study the enhancement in heat transfer coefficient by coiled wire inserts during heating of engine oil inside a horizontal tube. The test-section was a double-pipe counter-flow heat exchanger. The engine oil flowed inside the internal copper tube, while saturated steam, used for heating the oil, flowed in the annulus. First of all, the data were acquired for the heating of engine oil while flowing in the plain tube. Later, seven coiled wires having pitches of 12–69 mm and wire diameters of 2.0 mm and 3.5 mm were put one by one in the oil-side of test-section. The effects of Reynolds number and coiled wire geometry on the heat transfer augmentation and fanning friction factor were studied. Finally, two empirical correlations have been developed for predicting the heat transfer enhancement of these coiled wire inserts. These correlations predict the experimental Nusselt number in an error band of ±20 percent.