Comparison of Flow Boiling Pressure Drop Correlations for Smooth Macrotubes

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

“…9, the empirical Müller-Steinhagen and Heck [25] correlation most accurately predicts the pressure drop outside of the low-x, low-dp fric,exp region. Other authors have found this to be the case over a range of fluids and experimental conditions [18,22,23,26], although they also report deviations of up to 20 % [22]. The Xu and Fang [23] correlation performs similarly well, as Garcia Pabon et al [67] also found to be true for boiling of R1234yf in 3.2-8.0 mm tubes.…”

“…This correlation outperforms the other separated flow models of Grönnerud [17] and Friedel [20]. The Grönnerud [17] correlation was developed specifically for refrigerants, but Turgut et al [18] found it to give accurate results for only a small subset of these fluids. For the experimental data presented here, it underpredicts the pressure drop by approximately 50 %.…”

“…In another approach, the Müller-Steinhagen and Heck [25] method considers the frictional pressure gradients of both phases and performs an empirical interpolation between the two. This method has been found to perform well for a wide range of refrigerants [18] and other fluids [26], as well as across different pipe diameters [22,23]. Mikielewicz [27] modified the Müller-Steinhagen and Heck [25] method for both flow boiling and condensation in minichannels by incorporating the surface tension effect to account for energy dissipation in the flow, and validated this new approach for refrigerants in 2.3 mm tubes [28].…”

“…Lockhart and Martinelli [16] proposed the first separated flow model, but this does not accurately predict two-phase pressure drop and has been subsequently modified by many researchers. Grönnerud [17] expanded this approach further to specifically cover refrigerants, obtaining good results for some fluids and flows [18,19], and his model was, in turn, modified by Friedel [20] based on a large experimental database. This extensive basis for the model means the Friedel [20] method is often found to be one of the most reliable for pressure-drop predictions over a wide range of conditions [21,22].…”