Study On Internal Flow Of The Small Room Of Ventilation By Numerical Simulation And PIV

In this dissertation, the internal flow fields within a small ventilation room wereanalyzed using both Particle Image Velocimetry (PIV) and numerical simulation acrossa variety of airflow distributions. The numerical simulation results were compared withthe PIV measurements to provide a basis for further numerical simulation research onsimilar problems of air flow field distribution within a confined space.Firstly, we designed three scenarios regarding the position of air inlet and outlet. Inthe first scenario air was supplied from the upperpart and returned from the lowerparton the same side. In the second scenario, air was supplied from the upperpart andreturned from the lowerpart on the opposite side. In the third scenario, air was suppliedfrom the top and returned from the lowerpart. In addition, for each scenario, two airsupply velocities were tested: low speed and high speed. Therefore, in total, sixconditions were tested. For each of the six conditions, we used PIV to measure thevelocity field and plot the contours of velocity magnitude on one internal plane.Secondly, for each of the six conditions, computational fluid dynamics was used tocalculate the internal flow field; the CHEN model and the standardk-turbulencemodel were both tested during the numerical simulations. Finally, the datacorresponding to the PIV measurement plane was extracted from the numericalsimulation results. This was done in order to compare the character of the flow field, theposition of the vortex centers and the velocity field.It was found that both the CHEN model and the standard turbulence modelcould describe the basic characteristics of the flow field in the small ventilation roomacross all six conditions relatively exactly. But in computing the position of the vortexcenters, both models’ results deviated from the PIV results; however, the simulationresults from the standard model were better than the results from the CHEN model.The deviation between the two models with the PIV results also exists in the airflowvelocity field. This deviation was smaller near the flow field’s central positions, andlarger near the wall. Again, the results from the standard model were closer to thePIV results than the results from the CHEN model. In summary, the standardmodel gave more accurate results than the CHEN model when the flow in the smallventilation room was simulated.