Numerical and Experimental Investigation on Environmental Air Exchange in a Museum Showcase

The air exchange rate (AER) is a significant parameter to quantify the environmental air exchange phenomenon in museum showcases. A 3D transient CFD model is established to characterize the environmental air exchange phenomenon in a museum showcase in Chongqing China Three Gorges Museum. In order to validate the CFD model established, a set of CO
2
decay experiment and corresponding simulation are performed under the same condition. Comparisons show that the model has reasonable prediction accuracy, with a relative prediction error for AER of 7.6%. Visualizations are realized with the model for CO
2
concentration and air flow velocity distributions in the showcase, which help to explain the air exchange phenomenon. The model is then applied to simulate the CO/NO decay processes in the showcase, and regressions are performed to calculate corresponding AERs of the showcase. The AERs got with CO
2
/CO/NO as tracer gases are compared and discussed. The AER values with CO or NO as the tracer gas are close to each other, but both higher than that with CO
2
as the tracer gas, which could be explained by the difference in molecular mass of tracer gases. This work proves CFD to be a useful tool to characterize the environmental air exchange phenomenon in museum showcases.