Heat transfer measurements for oil–water flow of different flow patterns in a horizontal pipe

• Heat transfer of oil–water flow in a horizontal pipe was studied experimentally.
• Heat transfer coefficient was strongly dependent on the flow patterns.
• A heat transfer correlation for some flow patterns was proposed.

Flow patterns and local heat transfer coefficients were measured for oil–water flow in a horizontal pipe. The test section was an 11 mm ID copper pipe with L/D ratio of 164. In this study, water and diesel fuel (2.49 mPa s viscosity and 798 kg/m3 density) were selected as immiscible liquids and high speed photography technique was used for the flow pattern identification. Measurements were made for superficial Reynolds numbers in the range of 1350–13700 for water and 300–3700 for oil. Experimental results demonstrated that the heat transfer to flowing immiscible mixtures is strongly flow pattern dependent. In addition, a heat transfer correlation was developed for two flow patterns: stratified flow with mixing at the interface (STMI) and dispersion of water in oil and oil in water (Dw/o & o/w). The proposed correlation predicted the data with an average deviation of −2.768% and a standard deviation of 12.84%.