Numerično modeliranje temperature pri elektroporaciji ob prisotnosti pretokov tekočin

Electroporation is a biophysical phenomenon in which high-voltage electric pulses transiently increase cell membrane permeability. Depending on the electric field intensity and exposure duration, this process can result in either reversible or irreversible cell damage, giving it broad applications in food processing and medicine. In pulsed electric field (PEF) food treatments, irreversible electroporation is used to inactivate microorganisms while preserving food quality. In pulsed field ablation (PFA), it enables targeted destruction of cardiac tissue without the collateral thermal damage typical of conventional ablation methods. Although classified as “non-thermal”, the use of high voltages and large numbers of pulses in these applications can cause significant ohmic heating. Understanding the interplay between electrical and thermal effects is therefore essential to improve the safety and efficacy of electroporation-based treatments. This dissertation addresses this challenge by developing and validating two numerical frameworks for PEF and PFA applications. The first framework advances the modeling of continuous-flow PEF treatment chambers. A validated pulse-resolved numerical model was developed that improves upon conventional duty-cycle approximations by simulating each electrical pulse individually. This provides critical insights into transient temperature fluctuations that are otherwise missed, enabling more precise predictions of temperature dynamics. Additionally, a novel particle-level exposure analysis was introduced to evaluate the electrical and thermal doses experienced by individual particles along their trajectories. This analysis reveals the statistical distribution of exposures across the product, offering a direct measure of treatment homogeneity and a link to real-world process outcomes. The second framework focuses on intracardiac PFA through two complementary studies. An in vitro study addressed the key safety concern of bubble formation by developing a numerical model of a bipolar PFA catheter, validated with high-speed camera recordings. The model accurately captured localized heating around sharp electrode edges, allowing it to distinguish between bubble formation from thermal mechanisms (boiling and degassing) and electrochemical reactions. This provided critical insights for designing safer pulse protocols and electrode geometries to minimize gas release. A subsequent comprehensive in vivo study modeled PFA in healthy and infarcted porcine ventricles, incorporating realistic ventricular geometry, cardiac tissue anisotropy, blood flow, and scar tissue distribution. By comparing simulations with cardiac MRI, this work determined the in vivo lethal electric field threshold (LET) for ventricular myocardium for the first time. The models also confirmed the predominantly non-thermal nature of PFA, with less than 2% of the lesion volume attributed to thermal damage, and demonstrated that PFA can effectively ablate through dense scar tissue, a critical insight for treating ventricular arrhythmias. In summary, this dissertation contributes two experimentally validated numerical frameworks that advance the understanding of electroporation-based treatments, providing valuable tools to improve the safety and efficacy of PEF and PFA technologies.