Sensing solutions for assessing and monitoring of nuclear power plants (NPPs)

The effect of inlet flow conditions upon thermal mixing and conjugate heat transfer within the wall of a T-Junction

“…Thermal cycling is due to the fluctuation of the interface between thermally stratified fluids. It can be caused by an operational transient event or the interaction between turbulence and thermally stratified layers in the component [4,5]. Thermal striping is defined as the fluctuating temperature field imposed on a surface when the cold and hot flow mix in the vicinity of the structure surface [6,7].…”

Mean Flow, Turbulent Structures, and SPOD Analysis of Thermal Mixing in a T-Junction with Variation of the Inlet Flow Profile

“…The interaction between the two fluids is often highly turbulent and can result in an incomplete mixing and, on a larger scale, can lead to damage to the pipe structure induced by thermal fatigue [2][3][4]. The key factors that can cause thermal fatigue near the T-junction are (1) thermal cycling, which is the process of cycling of the interface of thermally stratified fluids [5], and (2) thermal striping, which is defined as a quasirandom temperature fluctuation produced by the incomplete mixing of fluids [6,7]. Several pipe failures and leakage incidents in NPPs have been attributed to thermal striping and fatigue [8][9][10], which highlights the need to better understand the flow physics underlying thermal fatigue for plant safety and long-term component reliability, as well as plant aging assessment and life extension (PLEX) [11,12].…”