مدلسازي سه بعدي جريان خون درون قلب مصنوعي با حلزوني دوگانه به روش مش متحرك

3D Blood Flow Simulation in Artificial Heart with Double Volute using Dynamic Mesh Method

جريان خون در پمپ گريز از مركز با 16 پرۀ شعاعي، دبي 5 ليتر بر دقيقه و سرعت دوران پروانه 2000 دور بر دقيقه در حالت‌هاي دو و سه‌بعدي به كمك روش‌هاي دستگاه مختصات چندگانه، مش لغزان و مش متحرك با تكنيك حجم محدود شبيه‌سازي‌شده ‌است. نتايج نشان داد كه حلزوني دوگانه، موجب ايجاد توزيع متقارن فشار‌ و الگوي جريان در كانال‌هاي عبور سيال از بين پره‌ها مي‌شود. محاسبه شد كه تنش برشي ديواره اطراف دماغه و صفحۀ جداكننده و لبه‌هاي پشتي پره‌ها حداكثر است كه اين نواحي را در معرض خطر تخريب ياخته‌ها و هموليز قرار مي‌دهد.

The two dimensional and three dimensional numerical simulation of blood flow in a centrifugal pump with 16 radial blades placed on a magnetically suspended impeller have been presented. The results of simulation for the pump of model Kyoto-NTN have been obtained using multi-reference frame (MRF), sliding mesh, and dynamic mesh methods. With the assumption of incompressible flow and Newtonian fluid, the blood flow is simulated in an unsteady turbulent manner using collocated finite volume method over unstructured grids. The results showed that with the rotational speed of 2000 round per minute, the capacity and pressure difference of pump are 5 l/min and 15.1 kPa, respectively. Results including the pressure distribution, the velocity vectors, the flow pattern, the shear stress contours, and the pump characteristics illustrated that using the double spiral shaped volute leads to the symmetrical pressure distribution around the surface of impeller, and consequently, the reduction of radial thrust. The maximum wall shear stress is observed near the cutwater splitter leading edge and blade leading edges. So, these regions are highly at the risk of Hemolysis. Finally, the results of simulation obtained from two and three dimensional modeling with various moving boundary capturing methods have been presented and compared.