Numerical investigation and modelling of the venous injection of sclerosant foam

Sclerosant foam, a mixture of a surfactant liquid and air, is injected directly into varicose veins as a treatment that causes the vein to collapse. This investigation develops a model that will allow the medical specialist to visualise how the sclerosant foam will interact with the blood and behave within the vein. The process is simulated using a multiphase computational fluid dynamics model with the sclerosant foam considered as a two-phase non-Newtonian power law viscosity liquid. The governing multiphase equations are solved using an Eulerianâ –â Eulerian approach coupled with a population balance model to predict the bubble size distribution within the flow field. The computational results demonstrate similar flow characteristics and flow features to an available set of experimental results. The model predicts the mixing layers between the sclerosant foam and the ambient fluid, and the sclerosant liquid and the ambient fluid, as well as the sclerosant liquid coverage on the vein wall and the bubble size distribution within the vein. These quantities are of interest to medical specialists allowing them to assess the treatment feasibility and safety before treating the patients. References S. Ali Mirjalili, J. C. Muirhead, and M. D. Stringer. Redefining the surface anatomy of the saphenofemoral junction in vivo. Clin. Anat., 27(6):915–919, 2014. doi:10.1002/ca.22386. E. Cameron, T. Chen, D. E. Connor, M. Behnia, and K. Parsi. Sclerosant foam structure is strongly influenced by liquid air fraction. Eur. J. Vasc. Endo. Surg., 46:488–494, 2013. doi:10.1016/j.ejvs.2013.07.013. P. Coleridge-Smith. Saphenous ablation: Sclerosant or sclerofoam? Semin. Vasc. Surg., 18:19–24, 2005. doi:10.1053/j.semvascsurg.2004.12.007. J.-J. Guex. Complications and side-effects of foam sclerotherapy. Phlebology, 24:270–274, 2009. doi:10.1258/phleb.2009.009049. Ansys Inc. ANSYS FLUENT 12.0 population balance module manual. ANSYS, 2010. URL https://www.afs.enea.it/project/neptunius/docs/fluent/html/popbal/main_pre.htm. F. Ren, N. A. Noda, T. Ueda, Y. Sano, Y. Takase, T. Umekage, Y. Yonezawa, and H. Tanaka. CFD-PMB coupled simulation of a nanobubble generator with honeycomb structure. volume 372 of IOP Conference Series: Materials Science and Engineering, page 012012, June 2018. doi:10.1088/1757-899X/372/1/012012. P. Souroullas, R. Barnes, G. Smith, S. Nandhra, D. Carradice, and I. Chetter. The classic saphenofemoral junction and its anatomical variations. Phlebology, 32(3):172–178, 2017. doi:10.1177/0268355516635960. A. H. Syed, M. Boulet, T. Melchiori, and J. M. Lavoie. CFD simulations of an air-water bubble column: Effect of Luo coalescence parameter and breakup kernels. Front. Chem., 5(68):1–16, 2017. doi:10.3389/fchem.2017.00068. T. Wang and J. Wang. Numerical simulation of gas-liquid mass transfer in bubble column with a CFD-PBM coupled model. Chem. Eng. Sci., 62:7107–7118, 2007. doi:10.1016/j.ces.2007.08.033. M. R. Watkins. Deactivation of sodium tetradecyl sulphate injection by blood proteins. Euro. J. Vasc. Endo. Surg., 41(4): 521–525, 2011. doi:10.1016/j.ejvs.2010.12.012. K. Wong. Experimental and numerical investigation and modelling of sclerosant foam. PhD thesis, University of Sydney, 2018. K. Wong, T. Chen, D. E. Connor, M. Behnia, and K. Parsi. Basic physiochemical and rheological properties of detergent sclerosants. Phlebology, 30(5):339–349, 2015. doi:10.1177/0268355514529271. K. C. Wong, T. Chen, D. E. Connor, M. Behnia, and K. Parsi. Computational fluid dynamics of liquid and foam sclerosant injection in a vein model. Appl. Mech. Mater., 553:293–298, 2014. doi:10.4028/www.scientific.net/AMM.553.293