Local instantaneous heat transfer characteristics around a rising single Taylor bubble and the temperature response of relatively thick pipe wall under local constant heat flux

A novel non-intrusive thermal diffusion measurement (TDM) method is proposed to measure the flow rate of gas-liquid two-phase flows under the slug flow state in our previous research. To improve the measurement accuracy of TDM by clarifying the real-time correspondence between wall temperature change and Taylor bubble (TB) location, the local instantaneous heat transfer characteristics around a rising single TB and the corresponding temperature response of the pipe wall are further investigated in detail by using the CFD tool in this paper. During the passage of TB, the local heat transfer between the pipe wall and fluid was analyzed based on the dynamic velocity field and temperature boundary layer, and the temperature on the fluid-solid interface presents the opposite trend with the heat transfer coefficient. For the zone upstream of the heat flux center, the lag time and increase of the wall temperature become large and weak along the radial direction, respectively, whereas the lag time is independent of the axial location, TB velocity, and TB length. Meanwhile, the increase in wall temperature shows an upward trend with the TB length for short TBs but is the same for long TBs.