| In recent years,the comfort and health has become the focus of people’s attention.According to incomplete statistics,modern people spend about 80% of times a day indoors,which shows that the quality of people’s daily life has a great relationship with the indoor environment.The adjustment of indoor environment is mainly achieved by air conditioning.Therefore,the study of indoor comfort has become an important research direction of air conditioning major.With the rapid development of computer technology,the research method of comfort is gradually changed from traditional experiment to computer simulation.Airpak,as the most classical software of computational fluid dynamics(CFD)for air conditioning field,is widely used in the research of comfort.Firstly,the current research situations of indoor comfort are introduced.Then we confirm the content of the article,which is to compare indoor comfort under different conditions,including different air supply parameters and air supply modes.Finally,the optimal air supply condition and the rule of comfort change are obtained.In this study,computer simulation and experiment are combined.Because computer simulation has the advantages of saving time and workload,Airpak software simulation is regarded as the main research method.In order to improve the credibility of the conclusion,the measurement is used to verify the simulation.After obtaining the reliable model,the simulation analysis of multiple working conditions are carried out.The specific research contents are as follows:1.The artificial environment room is regarded as research object.Under the experimental condition,the height 1.1m is selected as the test height.Then the temperature and velocity of the measuring points are recorded to evaluate indoor air distribution.2.Airpak is used to simulate the working condition of the experiment,and the simulated values of the same point are obtained.Then they are compared with the experimental values to verify the simulation reliability.3.Firstly,we use a proven model to simulate the air distribution of the room under different air supply temperatures(20℃,22℃,24℃)and different air supply velocities(2m/s,3m/s,4m/s,5m/s).Next,the height of Y=1.1m is selected as the research section,then the temperature,velocity,air age,PMV and PPD of the section are analyzed.Finally,the average values of each index are plotted to create curves,indicating the trends of change.4.In practical engineering,the influence of air supply parameter and air supply mode on indoor environment comfort is equally important.The common air supply modes include upper supply and bottom return,upper supply and upper return,bottom supply and upper return.Based on this view,the comfort of three air supply modes is simulated,and the same cross section is selected to analyze the indexes under different modes of air supply.Through the above research,the following conclusions are drawn:1.Under the experimental condition,the air distribution in the room is uniform.The ADPI value of the test area is 90%.The area meets the requirements of comfort.2.Through the comparison between simulated values and experimental values,we find that the average temperature deviation is 0.9℃,and the velocity deviation is 0.06m/s.The conclusion shows that the model is reliable.3.In the study of the different air supply temperatures and air supply velocities,the average temperature of each section is analyzed.It is found that the average temperature decreases with the increase of the velocity of the air supply.When the air supply temperature is 20℃,22℃,24℃,the average temperature drop of the section is 2.3℃,1.9℃and 1.5℃.The air velocity and air age of each section are summarized,they are negatively correlated.When the air supply velocity increases from 2m/s to 5m/s,the air age of the section decreases from 230 s to 92 s.PMV and PPD are the most important two indexes of comfort.As the velocity increases gradually,the changing trends of PMV are the same under different air supply temperature,showing a decreasing trend.But the trends of PPD are different: when the air supply temperature is higher 24℃,the air supply velocity increases from 2m/s to 5m/s,PPD decreases from 25% to 12%;When the temperature is lower 20℃,the PPD index rises directly from 12% to 40%.Interestingly,when the temperature is 22℃,PPD increases after an initial decrease.At the 3m/s,PPD gets the minimum value of 8%,and the environmental satisfaction is the highest.4.The different modes of air supply were compared at 20℃and 4m/s.It is found that the section temperature of upper supply and bottom return is the highest,the velocity is the smallest,and the air age is the biggest.But because of the temperature,the body feeling is relatively comfortable,the dissatisfaction is the lowest,PPD is 29%.On the contrary,the temperature of bottom supply and upper return is the lowest,the velocity is the largest and the feeling of the human body is the coldest,the value of PPD is 34%.All indicators of upper supply and upper return are centered in three air supply modes.Through this study,it is hoped to provide some theoretical reference for the design of comfort air condition.We confirm that the Airpak software has a good feasibility in the field of indoor comfort research. |
