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In silico fluid dynamic comparison of piston-equipped and piston-free prototypes of cassette system for automated peritoneal dialysis machine.

Lorenzo Rolfo

In silico fluid dynamic comparison of piston-equipped and piston-free prototypes of cassette system for automated peritoneal dialysis machine.

Rel. Umberto Morbiducci, Diego Gallo, Giuseppe De Nisco, Elena Torta. Politecnico di Torino, Corso di laurea magistrale in Ingegneria Biomedica, 2021

Abstract:

Peritoneal dialysis is a treatment for kidney failure, using the peritoneum, i.e., the lining of the abdomen, to filter blood (e.g., removing excess fluid, correcting electrolyte problems, and removing toxins) in end-stage renal disease patients. The treatment might be quite easily done overnight at patient home by using a device for Automated Peritoneal Dialysis (APD). The latter, called cycler, consists of a pumping system filling and emptying patient’s belly three to five times during the night. This study aimed at evaluating the fluid dynamic performance of two prototypes of diaphragm pumps for APD cassette system. The first model, named Pump 2, consisted of an elliptical chamber limited on the top by a membrane and equipped with a piston allowing for fluid motion. The second one, named Pump 4, was a piston-free model with an almost circular chamber. For each prototype, two working conditions were modeled: (1) the diaphragm completely deformed and the chamber almost empty, and (2) the diaphragm in resting position and the chamber full of dialysate. Each model was discretized to build the computational grid, and the finite volume method was used to solve the Navier-Stokes equations. Twenty steady-state computational fluid dynamic simulations were performed by imposing five different values of inflow rate (from 50 to 400 mL/min). Gauge pressure was prescribed at models’ outlet. The post-processing analysis was focused on pressure and wall shear stress acting on the diaphragm, and velocity field developing in the chamber. Results from this study suggested the higher hydrodynamic efficacy of Pump 4 with respect to Pump 2. In detail, the piston-free model was characterized by lower pressure and WSS values at the inner surface of the membrane, and higher chamber volume than piston-equipped one. Finally, Pump 4 required a lower pressure gradient both to fill the chamber and drain the fluid out, than Pump 2.

Relatori: Umberto Morbiducci, Diego Gallo, Giuseppe De Nisco, Elena Torta
Anno accademico: 2020/21
Tipo di pubblicazione: Elettronica
Numero di pagine: 105
Informazioni aggiuntive: Tesi secretata. Fulltext non presente
Soggetti:
Corso di laurea: Corso di laurea magistrale in Ingegneria Biomedica
Classe di laurea: Nuovo ordinamento > Laurea magistrale > LM-21 - INGEGNERIA BIOMEDICA
Aziende collaboratrici: NON SPECIFICATO
URI: http://webthesis.biblio.polito.it/id/eprint/19670
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