Fluid to fluid modeling scaling factors of R134A-water for critical heat flux

A series of calculations of the critical heat flux (CHF) fluid to fluid modeling scaling factors were performed to obtain relative data between R134a and water for CHF modeling method. The pressure range of R134a used in calculation was 0.15-3.59Mpa (liquid-gas density ratio 172.45-2.88), water-equivalent pressure range 1-20Mpa. Based on Ahmad model and Y. Katto model, four modeling scaling factors F_L, F_P, F _Hand F_G were determined. According to the thermophysical properties of saturated R134a and saturated water, data near triple point and critical point temperature were discarded. The middle values were obtained by using a data interpolation or data fitting method, and 23 pairs of data in total were used in the whole calculation process. From the analysis of the calculation results, it was determined that the difficulty in performing CHF experiments would be drastically reduced by 70%-80% and costs reduction by about 80%, using R134a as modeling fluid. Considering the difference between the two kinds of F_G derived by Ahmad model and Y. Katto model, an average method was developed to apply for modeling technique, which works well for CHF prediction at higher mass flux conditions in helically-coiled tubes.