The Investigation Of Thermal Stratification In Natural Displacement Ventilated Room Effected By Mixed Heated Sources

The investigation of natural displacement ventilation has aroused more and more attention of domestic and international scholars for the reasons of saving energy and to improving indoor air quality. The model experiment table of natural displacement ventilation was built to explore the influencing factor of indoor thermal stratification characteristic in the natural displacement ventilation room with mixed heated source of single point heated source and single vertical heated wall.Basic on experiment condition of model experiment table of natural displacement ventilation, the software of Fluent Airpak was adopted to simulate the changing regularity of indoor temperature and velocity of research object and explore the thermal stratification characteristics effected by varying parameters. According to model experiment table of natural displacement ventilation, the proportional similarity was derived. The model experiment table was used for simulating indoor natural displacement ventilation to explore the effective factors of thermal stratification characteristic. On the basic of the comparison and analysis for experimental data and numerical result, the reliability of the model experiment table of natural displacement ventilation room was proved. Furthermore, Buckinghamπtheorem and the methord of multiple linear regressions were adopted to derive experience formula of the height of thermal stratification of indoor natural displacement ventilation under the testing condition of experimental lable.Based on the numerical simulation and experimental investigation of natural displacement ventilation, the conclusions below had been obtained:1) According to demonstration and analysis, the model experiment table of natural displacement ventilation that was built in this investigation can be used for experiment investigation the thermal stratification characteristic of indoor natural displacement ventilation;2) There were entrainment and de-entrainment phenomenon happened next to the thermal stratification interface, the entrainment occurs below the interface between the thermal stratification and the environmental air, and the de-entrainment occurs at the mixing part with the indoor air above the thermal stratification interface;3) While the effective opening area was invariable in natural displacement ventilation room with mixed heated source, the strength of heated source has little influence on the height of thermal stratification;4) While the heated value of single point heated source and single vertical heated wall were constant, the height of thermal stratification increase with the increasing of effective opening area, in turn, reduce with the reducing of effective opening area.5) Buckinghamπtheorem and the methord of multiple linear regressions were adopted to derive experience formula of the height of thermal stratification of indoor natural displacement ventilation under the testing condition of experimental lable:...