Advancing nanofluid numerical modelling: A novel Euler–Lagrange method with experimental validation

We present a novel approach to numerical modelling of thermal nanofluids based on the Euler–Lagrange method. This approach overcomes the challenge of extremely fine temporal discretization, which previous Euler–Lagrange nanofluid numerical models struggled to address, while also avoiding the need for too many Lagrangian nanoparticles. A numerical uncertainty assessment method is adapted for the proposed approach. The model is validated with a simple verification case and applied to simulate a closed natural circulation loop heat exchanger operating with heating power ranging from 10 W to 50 W and nanoparticle volume fractions of 0.5% to 2%, using an Al 2 O 3 –water nanofluid. Results are compared with experimental temperature measurements and an Euler–Euler implementation of the same nanofluid. The model is also applied to simulate the natural convection inside a vertical enclosure, studied experimentally by other authors. The proposed novel approach demonstrates agreement with both experimental data and the Euler–Euler implementation, effectively capturing the overall behaviour of nanofluids. We establish, that the interplay of multiple transport phenomena, that occur in nanofluid operated devices, can be difficult to completely reproduce numerically within the framework of current modelling assumptions. • A heat exchanger is built and operated with Al 2 O 3 – water nanofluid. • Al 2 O 3 – water nanofluid thermophysical properties are measured. • Mathematical correlations are obtained from the measurements. • The modified Lagrangian particle tracking method is implemented to simulate nanofluids. • The model is mathematically verified and validated against experiments. • Numerical uncertainty analysis is performed for the novel approach.