Numerical Analysis of Convection Heat Transfer for Subsea Xmas Tree Assembly

This study aims to investigate the convection heat transfer of a horizontal subsea Xmas tree assembly at a high spatial resolution. Such study is important for increasing the structural reliability design and flow assurance level of subsea Xmas tree. Computational fluid dynamics (steady Reynolds-averaged Navier-Stokes) is adopted to evaluate the forced convective heat transfer of the subsea Xmas tree assembly. The temperature, the convection heat loss and the convective heat transfer coefficient (CHTC) at the surfaces of the subsea Xmas tree assembly are numerically obtained with low-Reynolds number modeling (LRNM). The numerical results show that the outer surface temperatures of the subsea tree are close to that of the ambient cold sea water with the exception of the pipeline. The components along the internal production tubes are typical “hot spots,” which have high CHTHs and cause a great deal of heat loss. Under the designed water depth, the effects of installation orientation and sea water velocity on convective heat transfer are investigated. The overall average CHTCs and the local CHTC distribution of the subsea Xmas tree assembly are depended on the installation orientation. Meanwhile, with the increase of the sea water velocity, the growth rates of the CHTCs for individual components show great difference. Ultimately, for selected installation orientation, the CHTC-sea water velocity correlation is derived by using a power-law CHTC-U_in correlation.