The two-step method is the most widely used method for preparing nanofluids. Nanofluid is produced using dry powders by chemical or physical methods.

Both methods

Nanofluid is made by mixture of nanoparticles with the base fluids. Nanofluids can be made in a variety of ways, including one-step, two-step, phase transfer, and posttreatment techniques. The stability of the colloidal suspension is critical in the preparation of nanofluids.

https://doi.org/10.1016/B978-0-12-823996-4.00002-1

1.what the physical problem (Determination)

Water+ Al2 O3 or Blood +gold (fluid kind)

2.Definitions of basic concepts like density, viscosity, specific heat, thermal conductivity of fluid and nano particles Cu, Al2O3, gold, ........etc.

3.Mathematical model

4. Solution method

5.Results satisfied the relations between parameters and physical meanings.

sorry, my answer is only How to solve any nan problem in one or two-phase flow

But

Preparation of nano particles is a chemical direction

Both methods

Single-step method combines the synthesis of both nanoparticle and nanofluid. It gives more stable, homogeneous nanofluids compared to nanofluids prepared using two-step method. But it's costly. But Two-step method is the widely used technique among researchers. It consists of two steps 1) nanoparticle synthesis or acquisition 2) dispersion of nanoparticle in the base fluid. Two-step method is cost-effective in wide scale production.

double step