Experimental Study on R245fa Condensation Heat Transfer in Horizontal Smooth Tube and Enhanced Tube

An experimental study of the thermohydraulic characteristics of flow boiling in horizontal pipes: Linking spatiotemporally resolved and integral measurements

“…The most consistent correlation, and most accurate overall with MARD = 23 %, across the data set, is that of Shah [30] which despite being one of the earliest enhancementfactor correlations has been reported to give reasonable predictions for both boiling [32] and condensation [33] of R245fa in smaller tubes. The Kandlikar [34] correlation is a further development of that Shah [30] and performs similarly well (MARD = 28 %) overall despite larger deviations at x < 0.05.…”

“…Overall, the experimental heat transfer coefficient is not well-predicted by pool boiling correlations, particularly at low values of h exp . This suggests that convective heat transfer cannot be neglected at these conditions and superposition approaches, such as that of Liu et al [33] as investigated in Figs. 11 and 12 are more appropriate.…”

“…Some models employ an enhancement-factor approach, whereby h is based on the dominant heat transfer mechanism. An early example of this is the Shah [30] correlation which offered an improvement on that of Chen [31] for horizontal tubes and has been reported to give good predictions for R245fa boiling [32] and condensation [33]. Kandlikar [34] further developed the Shah [30] model, simplifying the implementation and modifying the nucleate to convective boiling transition criteria.…”