Estimating mechanical blood trauma in a centrifugal blood pump: laser Doppler anemometer measurements of the mean velocity field.
A laser Doppler anemometer (LDA) was used to obtain the mean velocity and the Reynolds stress fields in the inner channels of a well-known centrifugal vaneless pump (Bio-pump). Effects of the excessive flow resistance against which an occlusive pump operates in some surgical situations, such as cardiopulmonary bypass, are illustrated. The velocity vector field obtained from LDA measurements reveals that the constraint-forced vortex provides pumping action in a restricted area in the core of the pump. In such situations, recirculating zones dominate the flow and consequently increase the damage to blood cells and raise the risk of thrombus formation in the device. Reynolds normal and shear stress fields were obtained in the entry flow for the channel formed by two rotating cones to illustrate the effects of flow disturbances on the potential for blood cell damage.
Pinotti
M
M
Departamento de Energia, Faculdade de Engenharia Mecânica, UNICAMP, Campinas SP, Brazil.
Paone
N
N
D001783:Blood Flow Velocity / Q000502:physiology*; D002315:Cardiopulmonary Bypass / Q000009:adverse effects / Q000592:standards; D002498:Centrifugation; D004912:Erythrocytes / Q000166:cytology / Q000473:pathology*; D018495:Fluid Shifts; D006353:Heart-Assist Devices / Q000009:adverse effects*; D017078:Laser-Doppler Flowmetry / Q000379:methods*; D008433:Mathematics; D013314:Stress, Mechanical