Numerous studies on flow boiling heat transfer in channels
have been performed. Various correlations have been proposed
to predict flow boiling heat transfer by Fang et al. [2], Li and Jia
[3], and Mori [4]. However, these correlations can only provide
satisfactory predictions over a finite range of flow conditions. To
satisfy the demands of engineering applications, many experiments
have been conducted to investigate smooth and rifled tubes.
According to their findings, a rifled tube significantly enhances
heat transfer, and the heat transfer coefficient (HTC) is four times
higher than that in a smooth tube [5]. In addition, heat transfer
deterioration occurs at low vapor quality in a smooth tube and is
delayed effectively by a rifled tube [6]. By contrast, this phenomenon
disappears within the vicinity of critical pressure. Iwabuchi
et al. [7] determined that heat transfer deterioration would
even occur in a subcooled region when pressure approached the
critical value. However, the mechanism of abnormal heat transfer
remains controversial, and additional studies should be conducted
to clarify this mechanism.