Numerical hydrothermal analysis of water-Al 2 O 3 nanofluid forced convection in a narrow annulus filled by porous medium considering variable properties: Application to cylindrical heat pipes

摘要: A study on the flow and heat transfer characteristics of nanofluid forced convection in an annular porous medium, as the main part of a cylindrical heat pipe, is numerically carried out to investigate the effect of nanoparticles on hydrothermal performance of a cylindrical heat pipe. The Al2O3-water mixture is considered as working fluid and a single-phase approach with variable properties adopted to formulate it. The influence of heat load and particle concentration level on thermophysical properties, velocity, pressure, and temperature fields, thermal performance of heat pipe is evaluated. It is found that the use of nanoparticles presents a better wall temperature uniformity. The values of velocity in wick structure decreases as more nanoparticles are added in base fluid. The profiles of pressure drop for low and middle particle concentration levels are nearly similar to each other, while the pressure drop …