Experimental validation of the CFD model of heat losses from the horizontal rectangular flue gas duct exposed to wind and solar radiation

Abstract

The article presents the experimental validation of a numerical model of heat losses from a horizontal rectangular flue gas duct situated outside a heating plant building. The duct is insulated with mineral wool mats and protected with galvanised sheet metal. The model was developed in ANSYS Fluent 2024 R2, incorporating the effects of wind velocity and solar radiation. The computational domain is defined as encompassing the duct and the surrounding airspace. A sensitivity analysis of the mesh on the simulation results was performed. The validation experiment was conducted at an operational coal-fired heating plant under various wind and sunlight conditions. The measurement of the heat flux density was conducted by means of heat flux sensors. The validation indicators, that is to say, the process validation metric and the relative root mean square error, confirm the consistency between the simulation results and the heat flux density measurements on the bottom and side walls. The numerical model that has been utilised is capable of being employed in analyses of flue gas duct modernisation, with the objective of reducing heat losses from flue gases flowing through the duct.