Centrifugal Left Ventricular Assist Devices (LVADs) are a major development in mechanical circulatory assistance for severe heart failure patients. This implantable device continuously pumps blood from the left ventricle to the aorta, increasing cardiac output and organ perfusion. Centrifugal LVADs create continuous blood flow with a revolving impeller, improving durability, size, and energy efficiency over pulsatile devices. In our current study, “ Numerical simulation of centrifugal and hemodynamically levitated LVAD for performance improvement,” the reference paper leads us to make the most accurate assumptions.

Figure 1: Schematic of centrifugal LVAD device

Simulation Process

Besides drawing different parts of the geometry model, producing a qualified mesh grid regarding thin blood paths that compound the process is the greatest challenge. However, by using 12021305 elements that are meticulously distributed, we could solve it. The blood behaves like a non-Newtonian fluid. Thus, it requires a proper viscosity model. Indeed, we have come up with a user-defined function (UDF) that relates shear stress to viscosity. For the rotational motion of the LVAD impeller, a Multi-reference Frame (MRF) module is adopted.

Figure 2: A section view of centrifugal LVAC, given in the reference paper

Post-processing

A gradient from high pressure near the impeller’s edge to low pressure in the center is visible in the pressure distribution visualization, which suggests the centrifugal pumping action. An essential tool for determining possible blood damage is the wall shear stress study, which shows areas of higher stress close to the blade tips and reduced stress in the center region. Higher velocities are shown at the outlet and along the blade surfaces in the stationary frame’s velocity profile, illustrating the intricate flow patterns inside the device. The computed pressure head of 0.56345358, along with these flow characteristics, indicates that the LVAD design is successfully converting rotational energy into fluid momentum. However, more optimization might improve efficiency and lessen areas of possible stagnation or excessive shear. In order to optimize the therapeutic efficiency of LVADs and reduce the risk of thrombosis and hemolysis in clinical settings, a thorough investigation of these parameters is crucial.