Experimental and Model-Based Characterization of a Xanthan Gum Solution as a Blood-Mimicking Fluid at Body Temperature

In biomedical engineering, reliable blood-mimicking fluids that accurately replicate the thermophysical properties of human blood are essential for in vitro flow experiments and Computational Fluid Dynamics simulations, particularly those involving heat transfer mechanisms. This study experimentally characterizes the temperature-dependent viscosity and density of non-Newtonian dilute Xanthan gum aqueous solutions (0.06% and 0.12% w/w) across a clinically relevant range of 15°C to 40°C. Measurements were performed using a Rudolph Research Analytical density meter, and the data were modeled using a physiological reference-based exponential decay function for viscosity and a Boussinesq-based linear equation of state for density. The findings revealed that the 0.12% (w/w) solution exhibited high conformity to healthy adult human blood rheology, yielding a dynamic viscosity of 3.78 mPa·s at the physiological temperature of 37°C. The proposed viscosity model, anchored at 37°C, operated with 0% error at the reference point, although deviations up to 19.15% were observed at the lower thermal boundary due to hysteresis. Thermodynamic analysis indicated a flow activation energy of 18.76 kJ mol⁻¹, reflecting stable, plasma-like flow characteristics. Crucially, the calculated Prandtl numbers for the 0.12% solution ranged from 24.43 to 45.64, closely aligning with human blood values. This confirms that momentum transfer is more dominant than thermal diffusion and demonstrates that the thermophysical data obtained using the proposed formulation provide a comprehensive basis for future CFD and PIV studies involving convection-limited haemodynamic applications and requiring precise thermo-rheological coupling.