1-D thermo-fluidynamic model of a cardiac cryoballoon catheter

The objective of this work has been to develop a 1-D numerical model of a cryoballoon catheter for cardiac ablation. The continuity, energy and momentum equations are written under steady-state conditions. Models for the two-phase flow and the critical efflux through small orifices have been addressed. A suitable model for single and two-phase heat exchange has been considered to simulate the heat transfer between the flows in the cryoprobe. The system of ordinary differential equations has been discretized by applying the finite volume approach, and the resulting system of non-linear equations has been solved using the Newton–Raphson iterative procedure. The developed numerical model has been validated experimentally with reference to a tailor-made cryoprobe layout. Finally, the performances of a commercial cryoballoon have been simulated and the numerical results have been compared with those available in the literature.