Measurement of the heat transfer coefficient of a nanofluid based on water and copper oxide particles in a cylindrical channel

The heat transfer coefficient of a nanofluid in a cylindrical channel under constant heat flux density at the walls is measured experimentally. The studied fluid was prepared based on distilled water and $\mathrm{CuO}$ nanoparticles with an average size of $55$ nm. To stabilize the nanofluid, a biopolymer was used. The volume concentration of nanoparticles was in the range from $0.25$ to $2\%$. It is shown that the nanofluid is Newtonian at the lowest concentration of nanoparticles, and in all other cases, its rheology is described well by the model of a power-law fluid. A correlation of the dependence of the parameters of this model on the concentration of nanoparticles is obtained. It is found that the presence of nanoparticles greatly intensifies the heat transfer.