The heat transfer in the cooling process of subsea oil and gas pipeline is a key factor of the flow assurance in offshore petroleum industry

such as wax

hydrate etc. In this study

capacitance probe

thermocouple and resistance thermometer were used to measure the flow and heat transfer characteristics of oil-gas slug flow in different cooling conditions and the effect of flow parameters on heat transfer of slug flow was analyzed. It was demonstrated that the convective heat transfer coefficient of oil-gas slug flow is mainly affected by the liquid superficial velocity. While the temperature of the outer cooling fluid is decreased

the viscosity of the inner thermal fluid at the bottom of the tube will increase and the thickness of the thermal boundary layer will be increased

therefore the heat transfer will be deteriorated. Also the convective heat transfer coefficient of oil-gas is much lower than that of water-gas due to the different viscous force and boundary layer. The local convective heat transfer coefficient is increasing from the top to the bottom of the tube along the circumferential direction. Moreover

the correlation and heat transfer model of oil-gas slug flow under cooling condition were presented.