This master's thesis aims to develop robust techniques for inducing extreme conditions in fluids by employing a Pulsed Power Generator (PPG). The project focuses on studying and controlling electrically induced single-wire explosions to efficiently produce shock waves in air and water. An in-depth literature review is conducted, followed by an exploration of the necessary theoretical background to understand the multidisciplinary physical phenomena. A methodology is developed to ensure the safe operation of the PPG, along with defining the Schlieren optical setup and operating procedures for the high-speed camera capable of reaching rates up to 10 million frames per second. The electrical parameters of the PPG are determined through short-circuit experiments and compared to an analogous RLC-like circuit using analytical and numerical simulations. Systematic experimentation is conducted across different copper wire diameters of 150, 400 and 500 micrometres and different initial capacitor voltages up to 23 kV. The optimal explosion conditions are identified, notably with a wire diameter of 400 micrometres in air, resulting in peak pressures in the order of hundreds of bar and Mach numbers up to 21.4. In water, the peak pressures reach tens of kilobar and Mach numbers up to 1.8. The analysis quantifies the transferred electrical energy and initial mechanical energy of the shock waves, reaching power magnitudes in the order of gigawatts and electrical-to-mechanical energy transfer efficiency up to 34%. The results are compared with numerical simulations and existing literature, culminating in a comprehensive report that synthesizes findings from literature review, hands-on experimentation, and analysis.

Electric breakdown in power transformers is preceded by pre-breakdown events such as streamers. The understanding of these phenomena is important in order to optimize liquid insulation systems. Earlier works have derived a model that describes streamers in transformer oil and utilized a finite element method to produce numerical solutions. This research investigates the consequences of changing the numerical method to a finite volume-based solver implemented in OpenFOAM. Using a standardized needle-sphere geometry, a number of oil and voltage combinations were simulated, and the results are for the most part similar to those produced by the previous method. In cases with differing results the change is attributed to the more stable numerical performance of the OpenFOAM solver. A proof of concept for the extension of the simulation from a two-dimensional axial symmetry to three dimensions is also presented. / Elektriska genomslag i högspänningstransformatorer föregås av bildandet av elektriskt ledande kanaler som kallas streamers. En god förståelse av detta fenomen är viktigt vid konstruktionen av oljebaserad elektrisk isolation. Tidigare forskning i ämnet har tagit fram en modell för fortplantningen av streamers. Denna modell har sedan lösts numeriskt av ett beräkningsverktyg baserat på finita elementmetoden. I denna uppsats undersöks konsekvenserna av att byta metod till finita volymsmetoden genom att implementera en lösare i OpenFOAM. En standardiserad nål-sfär-geometri har ställts upp och ett flertal kombinationer av oljor och spänningar har simulerats. De flesta resultaten visar god överensstämmande med tidigare forskning medan resultat som avviker har tillskrivits de goda numeriska egenskaperna hos OpenFOAM-lösaren. En ny typ av simulering har även genomförts där simulationen utökas från en tvådimensionell axisymmetrisk geometri til tre dimensioner.