Digital twin of a fluidic system for industrial processing of prosthetic heart valves

Worldwide, heart valve malfunction-related diseases are among the leading causes of surgery and/or death every year, along with myocardial infarction. Diseases such as stenosis and incompetence affect the mitral and aortic valves, resulting in reduced efficiency of the heart and additional stress and strain. The main treatments of these heart valve diseases are valve surgical repair and valve replacement with the implantation of a heart valve prostheses. This demand has led to the development of biocompatible industrial processes that can guarantee the effectiveness and structural integrity of the medical device, while ensuring safe implantation. Besides, an efficient cleaning industrial process is of crucial importance when utilizing reusable instruments. In this context, chemical reagents, may be pumped through the industrial system. Computational Fluid Dynamics (CFD) represents a powerful tool to rigorously characterized the performance of specific industrial processes, providing qualitative and quantitative information on flow variables and structures inside the industrial system. CFD analysis may point out limitations and critical issues of the industial process and support the optimization of procedures and/or instrumentation designs. In this scenario, the aim of this thesis is to use CFD to (i) characterize the fluid dynamics of an industrial system unit used for several process phases, and (ii) analyse the impact of medium inflow rate on the process performance. The unit consisted of a jar-like chamber, a hermetic cap, and an inflow and outflow conduit through which the medium, is pumped. Starting from the industrial unit CAD model, the investigating domain was meshed, and the finite volume method was used to solve the governing equation of fluid motion, using the k-ω approach to model turbulence. Four unsteady state simulations were performed by imposing a constant inflow rate corresponding to four different Reynolds numbers. Reference pressure was prescribed at the outlet. An industrial process interval of 0.5 s was simulated with a time-step size of 1ms. Simulation results were analysed in terms of velocity, vorticity and Q-criterion distribution. The percentage volume of the industrial unit characterized by low velocity was quantified. Overall, two main vortex structures generate in the chamber. Their dimension depends on the inflow rate value (larger vortex with higher inflow rate). Two evident regions of low velocity emerged on the opposite sides of the outlet and inlet conduits at the bottom and top of the chamber, respectively. As confirmed by low velocity volume percentage, the amplitude of such regions decreases with the increase of inflow Reynolds number. Our findings suggest that a higher inflow rate ensures better performance of the industrial process. This study represents a preliminary investigation on the inflow rate impact on medium-based industrial process, further investigations are needed to complete the characterization of the industrial system.