Numerical Simulation Research On Residential Central Fresh Air System

With the continuous improvement of people’s living standard,more and more architectural decoration has been used and the indoor air quality is getting worse and worse.A good indoor air quality can not only provide a healthy environment,but also improve work efficiency.Therefore,people take more and more attention on the indoor environment,especially the fresh air problem.In this paper,starting from the problems of modern air to expound the necessity of indoor air organization analysis and the application prospect of central fresh air system.Using FLUENT software is simulated on the south of a high-grade residential apartment with central air system.According to the air flow organization variables to compile the UDF and UDS two development routines and the central fresh air system mechanical position,natural air inlet position and the wind speed are optimized according to the calculation results.On the basis of the bedroom and other rooms for optimization of mechanical and natural air inlet position of the air inlet,setting up a one-way flow and two-way flow of central air system basin model,comparative analysis the flow field results of one-way flow and two-way flow of central fresh air system.The results show that the location of the two-way flow of central fresh air system mechanical air inlet more moving door and Window,the lower the air age,air is fresh,the best position in the coordinates X(4.22 m,4.02 m)Y(2.00 m,1.80 m),air age is 273s;the location of the one-way flow of central fresh air system mechanical air inlet more moving door,the lower the air age,air is fresh,the best position in the coordinates X(-4.80m,-4.50m)Z(1.35m,1.65m),air age is 415s;Mechanical air inlet and natural air inlet speed has great influence on the age of air.Among them,To ensure indoor air age is not more than 500 s,mechanical air inlet of the critical wind speed 0.4 m/s and natural air inlet of the critical wind speed 0.6 m/s;PMV value are smaller at the air inlet,cold feeling,many activities of the human body for the area,such as computer desk and bed near,PMV and PPD can meet the requirements.One-way flow of central air system by natural inlet air flow,perpendicular to the air inlet,which will cause cross-ventilation effect,have some impact on the occupants;the two-way flow at the top of the central air system with independent air the air inlet,which can supply air from top to bottom,can avoid drafts,turbulence intensity much higher effectively,can achieve the overall effect of air agitation better.Finally,A and B different door model the fresh air system is analyzed.Natural air inlet wind speed can reach more than 0.6 m/s meet into the wind conditions to A and B.The flow of the sitting room and bedroom performance is better.Kitchen and toilet exhaust outlet velocity is larger,easier to discharge sewage gas.Comparing the simulation results shows that:the wind speed distribution of A door model is wider.However,B family prone to linear cross ventilation effect,people will feel uncomfortable,the streamline distribution of A door model is more reasonable than B.