Heating performance of a large-scale line heater by adding synthesized carbon- nanodots to the heater bath fluid: CFD simulation and experimental study

Abstract

Numerous researchers have recently become interested in nanofluids because of their potential applications in thermal systems. Herein, various concentrations of nanofluid of synthesized carbon nanodots (C-dots) were used to survey the thermal performance of a line heater as a heater bath fluid, and a numerical model was proposed to simulate all of the line heater's components for the first time. C-dots nanoparticles were manufactured with the aid of the hydrothermal method and characterized using FTIR and XRD analysis. In addition, a two-stage approach was used to prepare the nanofluid with a varying concentration of C-dot nanoparticles, ranging from 0.5 to 5 wt%. Nanofluids were also measured and compared to the base fluid in terms of thermophysical properties. Additionally, a numerical model based on the finite element method (FEM) was proposed to simulate fluid flow and heat transfer in the line heater, and validation of the numerical results revealed good agreement with earlier studies. The mesh independence analysis shows that the results are much better and more consistent when mesh number 98,946 is used instead of the others. The results illustrate that temperatures were raised from roughly 300 K near the gas tubes to around 370 K near the fire tubes. In comparison to the situation of employing water as the bath fluid, the maximum heater power consumptions derived from the experiments and numerical findings were 9.7 % and 10.3 %, respectively.