Effect of heat flux on pressure drop in low pressure flow boiling in a horizontal tube

There has been a lack of research specifically examining the effect of heat addition on frictional pressure drop in two-phase flow systems. The work presented is a result of a series of experiments using a low pressure steam-water loop to investigate this effect. It was found that the application of constant heat flux results in a significant increase in frictional pressure drop at certain qualities. It was also found that increasing mass flux or decreasing system pressure shifts the maximum pressure drop towards lower qualities. The observed phenomenon is believed to be the result of liquid-vapour interactions at the slug-annular flow regime transition. This has been confirmed by flow pattern analysis using Mandhane's flow map. (author)