Objective To optimize the supporting structure of the heart to increase the suspension force and reduce hemolysis.
Methods The suspension support structure of a new centrifugal heart pump was designed, the fan-shaped opening was designed near the diversion cone and the auxiliary blade was designed at the bottom of the suspension bearing. The suspension force and hemolysis performance of the heartpump before and after optimization were compared by using the computational fluid dynamics method.
Results After improvement, the inlet and outlet pressure difference of the heart pump decreased with the increase of the flow rate, and increased with the increase of the impeller speed. It was the same as the flow pressure difference of the heart pump in the fluid, and the pressure difference of the heart pump was within the allowable range. The maximum blood velocity in the impeller was less than the rate of hemolysis (6 m/s). Structural improvement was feasible. The pressure difference between the upper and lower surfaces of the impeller decreased with the increase of flow rate, and the axial upward suspension force increased, the suspension force of the impeller increased, and the suspension performance was improved. At the suspension gap of the hydraulic bearing, the average fluid velocity increased, the maximum shear stress and the proportion of high shear stress in the bottom region of the heart pump were relatively reduced, and the hemolysis indexes at the suspension gap and the bottom region of the hydraulic bearing was decreased, and the hemolysis indexes of the heart pump was reduced by 12% after the improved structure compared with that before the improvement.
Conclusion The suspension performance of the optimized heart pump is improved and the hemolysis indexes are reduced. The improved suspension structure can also be applied to other centrifugal heart pumps, which has practical value in increasing the suspension force of the heart pump and reducing hemolysis in the suspension bearing clearance.
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