1. The prediction of multiphase flow patterns at elevated pressures is still not fully investigated in literature, and current prediction tools lack validation at high pressure conditions.
2. Upscaling models based on small diameter and low pressure experimental data to large diameter and high pressure conditions is important in multiphase flow application and research studies.
3. A similitude approach using dimensional analysis can be used for upscaling single-phase gas flow pressure gradient, and the Lockhart-Martinelli approach can be applied for upscaling two-phase flow pressure gradient and liquid holdup at high-pressure conditions.
The article discusses the challenges of predicting multiphase flow patterns at elevated pressures and the importance of upscaling models based on small diameter and low pressure experimental data to large diameter and high pressure conditions. The authors propose a new method for predicting pressure gradient and liquid holdup in gas-liquid flow at high-pressure conditions using dimensional analysis.
The article provides a comprehensive review of previous studies on two-phase flow behavior in large diameter pipes under high-pressure conditions. However, the authors do not provide a clear explanation of their methodology for upscaling models based on small diameter and low pressure experimental data to large diameter and high pressure conditions. They simply state that they use the similitude method, which is well-known in single-phase flow but has never been used in two-phase flow.
The authors also claim that current multiphase flow prediction tools lack methods and techniques validated at elevated pressure, but they do not provide evidence to support this claim. They only cite examples of wrong selection of flow pattern at high pressure, which can result in erroneous prediction of pressure drop and liquid holdup.
Furthermore, the article lacks exploration of counterarguments or alternative approaches to upscaling models for high-pressure conditions. The authors only present their own method without discussing potential limitations or drawbacks.
Overall, while the article provides valuable insights into the challenges of predicting multiphase flow patterns at elevated pressures, it lacks clarity in its methodology and evidence to support some of its claims. Further research is needed to fully understand the complexities of two-phase flow behavior under high-pressure conditions.