Improved natural convection in a vertical cylinder using smart fluid for solar heating and off-place cooking applications

The poor thermal conductivity of conventional base fluids limits their widespread applications and causes significant heat and mass losses. The thermal conductivity of traditional base fluids can be dramatically improved by suspending metal nanoparticles. The resultant nanofluids have excellent thermal conductivity than classical base fluids. Herein, the natural convection phenomenon in two vertical metallic cylinders at the same constant heat flux (180 W) containing silver nanofluid and deionized water (DI) has been experimentally investigated. The one-step method was used to prepare the silver nanofluid without using any surfactant. The prepared silver nanofluid is characterized by various modern scientific tools to assess its stability, evenness, and size distribution. The size of the prepared silver nanoparticles is observed in the range of 2 nm to 6 nm. The zeta potential analysis reveals a high value of zeta potential of − 38.5 mV, suggesting the superior stability of the prepared nanofluid. Furthermore, the variation in the silver nanofluid and DI water temperature with time, along the length of the cylinder, density, and the Grasshof number in two separate vertical fluid columns is also studied, and the results are compared. The experimental results show that the process of natural convection is highly improved in a vertical column containing silver nanofluid, encouraging rapid and optimized heat transfer applications in an inclined (45 °C) heat exchanger. This work will pave the way to further explore nanofluids for thermal applications.