[Paper Review] A Practical Computational Hemolysis Model Incorporating Biophysical Properties of the Red Blood Cell Membrane

Nico Dirkes, Marek Behr|arXiv (Cornell University)|Jan 27, 2026

Blood properties and coagulation0 citations

TL;DR

The paper presents a practical Eulerian hemolysis model that combines viscoelastic red blood cell membrane behavior with pore-formation-based hemoglobin release, showing accurate predictions in FDA benchmark cases using a simple strain-based approach. It compares strain-based and stress-based RBC models and two release mechanisms in CFD workflows.

ABSTRACT

Purpose: Hemolysis is a key issue in the design of blood-handling medical devices. Computational prediction of this phenomenon is challenging due to the complex multiscale nature of blood. As a result, conventional approaches often fail to predict hemolysis accurately, commonly showing deviations of multiple orders of magnitude compared to experimental data. More accurate models are typically computationally expensive and thus impractical for real-world applications. This work aims to fill this gap by presenting accurate yet simple and efficient computational hemolysis models. Methods: Hemolysis modeling relies on two key components: a red blood cell model and a hemoglobin release model. In this work, we compare three red blood cell models: a common stress-based model (Bludszuweit), a simple strain-based model based on the Kelvin-Voigt constitutive law, and a more complex tensor-based model (TTM). Further, we compare two hemoglobin release models: the widely used power-law approach and a biophysical pore formation model. Results: We evaluate these models in two benchmark cases: the FDA blood pump and the FDA nozzle. In both benchmarks, the simple strain-based model combined with the pore formation model achieves absolute predictions of hemolysis within the standard deviation of experimental measurements. In contrast, stress-based power law models deviate by several orders of magnitude. Conclusion: The strain-based pore modeling approach takes into account the biophysical properties of red blood cell membranes, in particular their viscoelastic deformation behavior and hemoglobin release through membrane pores. This leads to significantly improved hemolysis predictions in a framework that can easily be integrated into common CFD workflows.

Motivation & Objective

• Motivate improved, computationally efficient hemolysis prediction for blood-handling devices.
• Incorporate biophysical membrane properties (viscoelastic deformation) into an Eulerian framework.
• Evaluate hemoglobin release via pore formation against empirical power-law approaches.
• Provide a modular modeling framework easily integrated into CFD workflows.

Proposed method

• Use incompressible Newtonian blood flow as the CFD base and extract velocity and velocity gradient fields.
• Compare three RBC deformation models: Bludszuweit (stress-based), Kelvin-Voigt (KV) viscoelastic strain-based, and Tank-Treading Model (TTM).
• Adopt two hemoglobin release models: a power-law empirical model and a biophysical pore formation model (Vitale et al. simplified).
• Compute an effective shear rate G_eff from RBC models to drive hemolysis metrics independent of viscosity.
• Formulate hemolysis using IH and MIH as global measures, with MIH integrating IH over device outlet fields.
• Implement in Eulerian form (Dφ/Dt = F(φ, ∇u)) with boundary conditions and initial conditions suitable for 3D flows.

Experimental results

Research questions

• RQ1 Can a strain-based viscoelastic RBC model combined with a pore-formation release mechanism predict hemolysis more accurately than stress-based and purely empirical approaches?
• RQ2 How do 3D stress states and RBC orientation (TTM) affect predicted hemolysis compared to simplified shear-only formulations?
• RQ3 Is the proposed model accurate across representative FDA benchmarks (e.g., rotary blood pump and nozzle) when integrated into standard CFD workflows?
• RQ4 What are the sensitivities of predictions to the choice of RBC model and release mechanism?

Key findings

• The strain-based KV model combined with the pore formation release model achieves absolute hemolysis predictions within the experimental standard deviation in FDA benchmark problems.
• Stress-based power-law models show deviations by orders of magnitude from experimental data in the same benchmarks.
• In extensional flow, the tank-treading model predicts greater deformation than KV, highlighting three-dimensional stress effects.
• The approach integrates biophysical RBC membrane properties into a computationally efficient Eulerian framework suitable for large-scale CFD simulations.
• Pore formation-based release, tied to G_eff and membrane strain, provides a mechanistic link between RBC deformation and Hb release.
• The framework is designed to be easily implementable in existing CFD solvers and applicable to general 3D flows.