Utjecaj reoloških modela krvi na strujanje kroz idealiziranu stenozu arterije

Coronary artery disease is a common and serious disease which is a consequence of plaque build-up in the coronary arteries. As a result, the artery cross-sectional area is reduced which restricts the blood flow. In this study, a numerical analysis of the blood flow through an idealised stenosed artery is presented. The effects of rheological models of blood on the flow characteristics is studied. Blood is modeled as a Newtonian, a generalized Newtonian and a viscoelastic fluid. For generalized Newtonian fluid modelling, the Carreau-Yasuda model is used. For viscoelastic fluid modelling, the simplified Phan-Thien-Tanner (sPTT) model is used. Flow is studied as steady and transient for three different stenosis geometries at Reynolds number values of 50 and 200. Results show that the Carreau-Yasuda model predicts the smallest boundary layer size and significantly lesser velocity magnitudes at the artery axis in comparison to the other models. The differences between model predictions are more noticeable when the stenosis is more severe and at higher velocities. Koronarna bolest srca je česta i ozbiljna bolest koja nastaje kao posljedica nakupljanja plaka na koronarnim arterijama. Uzrokuje smanjenje površine poprečnog presjeka arterije što otežava protok krvi. U ovom radu napravljena je numerička analiza strujanja krvi kroz idealiziranu stenotičnu arteriju. Analiziran je utjecaj reološkog modela krvi na strujne karakteristike. Krv je modelirana kao Newtonovski, generalizirani Newtonovski te viskoelastični fluid. Za modeliranje generaliziranog Newtonovskog fluida korišten je Carreau-Yasuda model, a za modeliranje viskoelastičnog fluida korišten je pojednostavljeni Phan-Thien–Tanner (sPTT) model. Proučavano je stacionarno i nestacionarno strujanje za tri različite geometrije stenoze pri vrijednostima Reynoldsovog broja 50 i 200. Rezultati pokazuju da Carreau-Yasuda model predviđa najmanji granični sloj i znatno manje magnitude brzina u osi arterije u usporedbi s ostalim modelima. Razlike između modela su primjetnije kada je stenoza veća te pri većim brzinama strujanja.