Flow and Heat Transfer Analysis of Polyacrylamide Nanofluid in Sudden Expansion Tube With Spherical Protrusions

ABSTRACT Polyacrylamide has great potential in improving the performance and stability of photovoltaic systems due to its excellent thermal conductivity and thermal stability. This study focuses on the flow and heat transfer analysis of polyacrylamide‐aluminum oxide nanofluids in a sudden expansion tube containing spherical protrusions and analyzes its influence on the cooling effect of photovoltaic panels. By configuring polyacrylamide‐aluminum oxide nanofluids, its thermal conductivity is measured using a thermal conductivity meter, and the thermal conductivity formula is fitted. The Maxwell constitutive equation is used to describe the viscoelastic properties of polyacrylamide nanofluid. The constitutive equation and thermal conductivity formula are imported into the solver through user‐defined functions to simulate and analyze the influence of different physical parameters and pipeline structure design on the performance of the photovoltaic system. The results show that the structural design of the sudden expansion tube and spherical protrusions enhances the heat exchange effect by increasing the contact area and disrupting the thermal boundary layer along the pipe wall, and reduces the generation of local hot spots on the surface of the photovoltaic panel. Reducing the inlet diameter can simultaneously increase the fluid velocity and heat exchange efficiency, and increase the Nusselt number.