Asst. Prof. Dr. Hayder Mohammad Jaffal Ministry of Higher Education &scientific Research Mustansiriyah University College of Engineering Mechanical Engineering Department Two- phase flow pressure drop caused by sudden expansion and contraction (Section 6) Asst. Prof. Dr. Hayder Mohammad Jaffal

Two- phase flow pressure drop caused by sudden expansion and contraction Flow of two phase mixtures through sudden expansion and contractions are typically seen between the connection pipes as well as in the case for many applications such as chemical reactors and petrochemical plants. Frictional pressure drop can be noticed in sudden expansion and contraction of the tubes. This pressure drop can be added to the total pressure drop of the flow through the tubes.

1- Pressure drop through sudden expansion Figure (1) Definition of pressure drop subject to the influence of sudden expansion

For the two-phase pressure change across sadden expansion is :   Flow cross-sectional area contraction ratio can be calculated as:   For homogenous flow, the two-phase pressure change across sadden expansion is :  

where    

2- Pressure drop through sudden contraction Figure (2) Definition of pressure drop subject to the influence of sudden contraction

  Where   For two-phase flow, the frictional pressure drop due to sudden contraction can be estimated using a homogeneous flow model as: