Validation of Numerically Predicted Shear Stress-dependent Dissipative Losses Within a Rotary Blood Pump

Strauch, Carsten; Escher, Andreas; Wulff, Sebastian; Kertzscher, Ulrich; Zimpfer, Daniel; Thamsen, Paul Uwe; Granegger, Marcus

doi:10.1097/mat.0000000000001488

Cited by 5 publications

(8 citation statements)

References 29 publications

(78 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The importance of establishing confidence in CFD setups was underlined by the initiative of the U.S. Food and Drug Administration (FDA) demonstrating that, despite good agreement of global flow properties between CFD-based computations and in-vitro measurements, local flow may be poorly resolved. [11][12][13] These findings are in line with recent studies indicating the debility of Reynolds-averaged Navier-Stokes (RANS) simulations to fully resolve viscous shear stresses, 11,12 and may imply that global validation is not sufficiently sensitive to draw conclusions about the validity of computed local quantities.…”

supporting

confidence: 85%

“…Experimental validation was performed on a previously developed high-fidelity in-vitro testbench 12,14,16 ( Figure 2C ) that included the torque measuring shaft, the glass for optical access, and the electric drive for pump actuation (Supplementary Section 1, Supplemental Digital Content, http://links.lww.com/ASAIO/B63). A water-glycerol mixture (density: 1,110 ± 0.39 kg·m −3 ; dynamic viscosity: 3 ± 0.057 mPa·s) served as working fluid.…”

Section: Methodsmentioning

confidence: 99%

“…To assess credibility of the CFD setup to accurately resolve shear-stress dependent, dissipative losses, a validated power loss analysis (PLA) was performed for the testbench geometry. 12…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

In-Vitro Flow Validation of Third-Generation Ventricular Assist Devices: Feasibility and Challenges

et al. 2023

View full text Add to dashboard Cite

Computational fluid dynamics (CFD) is a powerful tool for the in-silico evaluation of rotodynamic blood pumps (RBPs). Corresponding validation, however, is typically restricted to easily accessible, global flow quantities. This study showcased the HeartMate 3 (HM3) to identify feasibility and challenges of enhanced in-vitro validation in third-generation RBPs. To enable high-precision acquisition of impeller torques and grant access for optical flow measurements, the HM3 testbench geometry was geometrically modified. These modifications were reproduced in silico, and global flow computations validated along 15 operating conditions. The globally validated flow in the testbench geometry was compared with CFD-simulated flows in the original geometry to assess the impact of the necessary modifications on global and local hydraulic properties. Global hydraulic properties in the testbench geometry were successfully validated (pressure head: r = 0.999, root mean square error [RMSE] = 2.92 mmHg; torque: r = 0.996, RMSE = 0.134 mNm). In-silico comparison with the original geometry demonstrated good agreement (r > 0.999, relative errors < 11.97%) of global hydraulic properties. Local hydraulic properties (errors up to 81.78%) and hemocopatibility predictions (deviations up to 21.03%), however, were substantially affected by the geometric modifications. Transferability of local flow measures derived on advanced in-vitro testbenches toward original pump designs is challenged by significant local effects associated with the necessary geometrical modifications.

show abstract

supporting

confidence: 85%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

In-Vitro Flow Validation of Third-Generation Ventricular Assist Devices: Feasibility and Challenges

et al. 2023

View full text Add to dashboard Cite

show abstract

“…However, in a recent study we found the impeller torque to be reliably resolved in a similar simulation setup. [ 20 ]…”

Section: Discussionmentioning

confidence: 99%

“…To additionally analyze the local distribution of hydraulic losses in both RBPs, local hydraulic power losses were computed in each individual compartment (Figure 2) based on a volumetric integration of both the viscous and turbulent dissipation as previously described. [ 20 ]…”

Section: Methodsmentioning

confidence: 99%

Linking Hydraulic Properties to Hemolytic Performance of Rotodynamic Blood Pumps

Escher

Hubmann

Karner

et al. 2022

Advcd Theory and Sims

Self Cite

View full text Add to dashboard Cite

In rotodynamic blood pumps (RBPs) a substantial proportion of input energy is dissipated into the blood. This energy may propel damaging work on blood constituents. To date, the link between this hydraulic energy dissipation and respective hemolytic action in RBPs remains vastly unknown. In this study, computational fluid dynamics is applied to compute the hydraulic energy dissipation at 9 operating conditions in two RBPs (HM3: HeartMate 3; HVAD: HeartWare Ventricular Assist Device). Respective interrelations with hemolytic pump performance are elucidated by comparing these computations with in silico predicted and in vitro measured hemolysis. Despite different pump geometries, hydraulic loss magnitudes, and distributions, global hydraulic energy dissipation shows strong correlation (r > 0.95) to in vitro hemolysis with scaling factors in the same order of magnitude for both devices (𝝋 HM3 = 0.599 (mL g) (J 100L) -1 ; 𝝋 HVAD = 0.716 (mL g) (J 100L) -1 ). The analytical description of hydraulic energy dissipation reveals to be a function of shear stresses and exposure time, unmasking its analogy to the power-law formulation of hemolysis. This hydraulics-based analysis may denote a step ahead to relate turbomachinery to bioengineering and may provide mechanistic insights into the relation between RBP design, hydraulic properties, and hemolytic performance.

show abstract

Multiobjective Optimization of Rotodynamic Blood Pumps: The Use Case of a Cavopulmonary Assist Device

Escher,

Miric,

Thamsen

et al. 2024

ASAIO Journal

View full text Add to dashboard Cite

Comprehensive optimization of rotodynamic blood pumps (RBPs) requires the consideration of three partially conflicting objectives: size, hemocompatibility, and motor efficiency. Optimizing these individual objectives independently, the potential of multiobjective optimizations often remains untapped. This study aimed at the multiobjective optimization of an RBP for cavopulmonary support accounting for all three objectives simultaneously. Hydraulic and electromagnetic design spaces were characterized using computational fluid dynamics and computational electromagnetics, respectively. Design variables included secondary flow gap widths, impeller diameters, and stator heights. The size objective encompassed the RBP widths and heights, the hemocompatibility objective was a weighted composite measure of well-established metrics, and the motor objective was determined by motor losses. Multiobjective optimization was performed through Pareto analysis. 81 designs were considered, and 21 Pareto-optimal designs were identified. The Pareto analysis indicated that hemocompatibility performance could be improved by 72.4% with a concomitant 1.5% reduction in the baseline pump volume. This, however, entailed an increase in motor losses by 0.2 W, while still meeting design requirements, with maximum local temperature rises remaining below 0.4 K. The multiobjective optimization led to a Pareto front, demonstrating the feasibility to improve hemocompatibility at reduced pump volume, however, at the cost of a diminished yet still acceptable motor performance.

show abstract

Validation of Numerically Predicted Shear Stress-dependent Dissipative Losses Within a Rotary Blood Pump

Abstract: Supplemental Digital Content is available in the text.

Cited by 5 publications

References 29 publications

In-Vitro Flow Validation of Third-Generation Ventricular Assist Devices: Feasibility and Challenges

In-Vitro Flow Validation of Third-Generation Ventricular Assist Devices: Feasibility and Challenges

Linking Hydraulic Properties to Hemolytic Performance of Rotodynamic Blood Pumps

Multiobjective Optimization of Rotodynamic Blood Pumps: The Use Case of a Cavopulmonary Assist Device

Contact Info

Product

Resources

About