Enhanced prediction of pressure drops in pressurized systems with sudden contractions from circular to annular cross sections

In pressurized systems, sudden contractions in flow cross sections often lead to significant pressure drops, which can affect system performance and efficiency. Current pressure drop models are known to have limitations, particularly in accurately predicting pressure changes for transitions from circular to annular cross sections. This paper reviews existing pressure drop models and evaluates their predictive accuracy using a comprehensive dataset. The investigation focuses on pressure gradients during transitions from circular to annular cross sections, considering various contraction ratios and Reynolds numbers. The study introduces a new pressure drop model based on momentum conservation, which incorporates all relevant boundary effects. The results show that pressure drop losses due to sudden contraction are inversely proportional to the contraction ratio and directly proportional to the Reynolds number. The proposed model's predictions exhibit a close match with experimental data, achieving an absolute average relative error of 14.32%. The newly developed model significantly improves the predictive accuracy of pressure drops for sudden contractions from circular to annular cross sections. By addressing the limitations of existing models, this research provides a more reliable tool for designing and analyzing pressurized systems, particularly for macro pipelines.