ABSTRACT
Objective To establish a complete heat transfer boundary condition model in a cockpit including the inner wall heat transfer boundary condition and the air supply heat transfer boundary condition of the air distribution system. Methods The temperature field in the cockpit was carried out unmerical caculation with above model and the traditional method which was assumed uniform heat flux through walls and flow flux out of each air supply hole individually.An experiment was carried out to prove the caculation accuracy of both methods. Results The comparison between calculation and experiment results shows that the temperature field calculation accuracy of this model was much higher than traditional method’s.This model could indicate the unevenness and the asymmetry of the heat transfer through walls and the air temperature out of air supply holes of air distribution system. Conclusion This model is reasonable and has a good engineering application value.
ABSTRACT
In dynamic state,the airflow and particle distribution of class Ⅲ biosafety laboratory is simulated by means of the CFD.The identical results of the simulation and the practical survey show good reliability of this experiment.The result indicates that the good unidirectional air distribution is formed in main lab and air distribution is the main factors to determine the character of particle distribution.
ABSTRACT
Objective To know the characteristics of size distribution of the inhalable particles in the indoor air in the condition the under-floor air distribution systems were used and to study the effect of human activities and smoking. Methods The frequency of inhalable particulate matter was determined in Jun.-Jul.,2007. The surface area and mass concentration were calculated based on the assumption that the particulate was sphere and its density was 1g/cm3. The relationship between frequency, surface area, mass concentration and particle size were shown in logarithmic plot. Results It was found that the logarithm of cumulative frequency and the logarithm of diameter was a linear relation, the logarithm of cumulative total surface area and diameter was a linear relation and the logarithm of cumulative total mass and diameter was a linear relation. Particle of no less than 1 micron increased due to human activities, total mass concentration were two times the concentration of no human activities. The particle of no larger than 1 micron may increase due to smoking. Conclusion The diameter of the particle matter has relationship with the cumulative frequency, the cumulative total surface and the cumulative total mass.