Dynamics of thermal plumes for large spaces: A comparative study of in-situ smoke test and a CFD model

Abstract

This study focuses on natural convection heat transfer in building heating and ventilation. Amid advancements in natural ventilation and a changing energy landscape, innovative heating methods are crucial. Thermal radiators play a key role in enhancing heat convection and understanding thermal plumes to optimize heating efficiency. This study investigates the use of coloured smoke sources to visualize thermal plume flow fields in real-scale (in-situ), naturally ventilated large spaces, distinguishing itself from most studies that prioritize enhancing thermal efficiency radiator. It offers a way for both qualitative and quantitative validation of a CFD model using passive scalars and experimental images to illustrate thermal plume propagation. This novel approach provides an effective way to visualize and understand thermal plumes in spaces where other experimental techniques are challenging to implement. Experimental results showed high consistency between measured and CFD values for velocity, temperature, and heat exchange, with differences below 10 %. The study unveiled a low impact of initial smoke source ve- locities on plume visualization. Using coloured smoke images to validate the CFD model yielded errors from 2.3 % to 14.5 %, proving the method’s reliability for both qualitative and quantitative analysis of plume propagation, offering valuable insights into air propagation in naturally ventilated spaces.