Beta 1


Title Two-phase flow in ammonia risers
Author Atlason, Guðmundur Freyr
Supervisor Elmegaard, Brian (Termiske Energisystemer, Institut for Mekanisk Teknologi, Danmarks Tekniske Universitet, DTU, DK-2800 Kgs. Lyngby, Denmark)
Kærn, Martin Ryhl (Termiske Energisystemer, Institut for Mekanisk Teknologi, Danmarks Tekniske Universitet, DTU, DK-2800 Kgs. Lyngby, Denmark)
Reinholdt, Lars (Dansk Teknologisk Institut)
Institution Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark
Thesis level Master's thesis
Year 2009
Abstract Models simulating two-phase flow of ammonia in a vertical riser have been made along with a model simulating a refrigeration system with a flooded evaporator. Simulations using five frictional pressure loss correlations and four void fraction correlations were made using the program Engineering Equations Solver. These correlations are explained briefly and their pressure drop results compared. The correlations are then compared with data collected from a test setup. This setup was built by DTI in Århus, Denmark to simulate two-phase ammonia flow in various riser diameters. A literature search suggests that El-Boher & Lesin correlation is most suitable for modeling void fraction for vertical flow with large diameters. Comparing the considered correlations with data from the test setup shows that Müller, Steinhagen & Heck correlation for frictional pressure drop predicts the measured data the best. Various literatures suggest that minimum pressure loss is achieved within the annular flow regime. It was shown that gravitational pressure drop has a steeper pressure drop gradient than frictional one. Further experiments would be ideal to better test the validity of the models in this project. Constructing a flow map using the test setup in Århus would be of great interest as such a map has not been made for vertical ammonia flow. The map could then be used to test the validity of flow pattern models.
Imprint Technical University of Denmark (DTU) : Kgs. Lyngby, Denmark
Fulltext
Original PDF report.pdf (2.45 MB)
Original PDF Appendix.pdf (0.20 MB)
Admin Creation date: 2009-11-05    Update date: 2010-10-28    Source: dtu    ID: 252042    Original MXD