Numerical investigation on heat transfer performance of the segmented cementing coaxial heat exchanger

The segmented cementing coaxial heat exchanger is proposed in this paper, where different thermal conductivity cementing layers are used. Based on field tests, its numerical model is established, and results show that it consistently demonstrates better heat transfer performance compared to conventional coaxial heat exchanger and high thermal conductivity cementing coaxial heat exchanger, regardless of whether higher or lower inlet temperature and flow rate. Additionally, the influencing factors such as the thermal conductivity of the cementing layer, segmented point, flow rate, and inlet fluid temperature on the thermal performance of the segmented cementing coaxial heat exchanger is analyzed, which indicates that the thermal performance of heat exchanger reaches its maximum only when the segmented point of the cementing layer coincides with the thermal equilibrium point. And it is recommended that the thermal conductivity of the enhanced heat transfer cementing layer should not be less than 1.5 W/(m·K). Finally, the influencing factors of the thermal equilibrium point position are investigated to find that it is significantly affected by the inlet fluid temperature and flow rate, while its response to the operating time is not pronounced.