Goyal, Ameeta2018-07-262018-07-262014-04https://hdl.handle.net/11299/198395University of Minnesota Ph.D. dissertation. April 2014. Major: Mechanical Engineering. Advisor: EPHRAIM SPARROW. 1 computer file (PDF); xviii, 191 pages.Cryosurgery has served as an alternative to scalpel-based surgery for over fifty years. A significant amount of research has been performed to improve the procedure. The goal of this research is to quantify the fluid mechanic, thermodynamic, and heat transfer processes which take place within two cryosurgical devices: a cryoprobe and a cryoballoon. A cryoprobe is a long, thin, cylindrical concentric tube which is inserted directly onto the cancerous tissue to be necrosed. A cryoballoon is a device that is deployed in a deflated state and is later inflated using a cryofluid that changes phase to cause low temperatures on the outer wall of the balloon to cause necrosis. Of the two aforementioned modalities, a heavy research focus has been seen on the study of the cryoprobes. However, it appears that the literature is void of any reported investigation that encompasses the entirety of all the participating physical processes. With respect to the cryoballoon, the literature appears to be without significant research publications. An extensive and in-depth analysis of cryoprobe fundamental mechanisms like the Joule-Thomson (J-T) effect, compressibility driven high-speed flow, shocks, expansion waves, 180-degree turns, and heat transfer between the spent and virgin cryofluid. A rigorous, assumption-free in-probe and ex-probe phenomenological model was created here and implemented by synergistic use of numerical simulation and experimentation. The experiments were designed to verify the fidelity of the simulation model, and comparisons between the outcomes of the simulation and the experimentation were highly favorable. The capacity of a cryoprobe to extract heat from surrounding tissue has, for the first time, been demonstrated to be predictable from first principles alone, thereby, enabling logic-based design of cryoprobes. A similarly first-principles model, devoid of empiricism and simplifying assumptions, was created for the study of cryoballoon-based necrosis. This investigation involved change of phase of liquid nitrous oxide to vapor. The available incremental experimental data was used for comparison and provided excellent verification. It is believed that the models created and implemented here are sufficiently well supported to be regarded as universal approaches to be used when other cryosurgical devices are to be evaluated and quantified.enThesis or Dissertation