Synergistic Influence And Application Of Attached Ventilation And Deflector On Indoor Air Distribution

As a new type of ventilation,the airflow from the air supply outlet is attached to the vertical wall based on the Kanda effect,and changes the direction of movement after hitting the ground to form an air lake similar to displacement ventilation,which is better for sending fresh air to the personnel activity area.Compared with the traditional ventilation method,the air supply outlet arrangement,energy consumption,and the creation of good indoor air quality have certain advantages.However,the general indoor environment is complex,and the main body of airflow moving downward against the wall may be obstructed by obstacles in the room,thus affecting the formation of the air lake.The scientific combination of the attached ventilation and the deflector plate arranged at the appropriate position on the vertical wall,allowing the jet body to change direction by hitting the deflector plate in advance,can avoid the influence of indoor obstacles on the airflow organization.The position and form of the deflector has a large impact on the indoor airflow organization.The deflector can effectively divide the area in the room through the airflow organization,so by changing the parameters of the deflector it is possible to create the airflow organization required by the environment.The energy consumption can be further reduced by setting the deflector to target the partitioned area and to meet the environmental requirements of the control area.(1)Comparing the characteristics of airflow organization in rooms of different sizes with the same air supply parameters for mixed ventilation,attached ventilation and attached ventilation with deflectors and analyzing the temperature field and velocity field in the room in combination with the comfort index.The results show that with the increase of room size,the advantage of effective blowing sensory temperature index in the room with vertical wall attached ventilation gradually decreases from 5% to 10% to-0.4% to 5%;compared with the mixed ventilation,the average air age in the room with attached ventilation decreases from 114% to 91.5%,and the advantage of air age index gradually becomes apparent.However,regardless of whether deflectors are added or not,for the design of attached ventilation in large-sized spaces,it is important to consider the effects of inertia and thermal buoyancy on the diffusion of the "air lake" and to control the appropriate ratio.(2)To investigate the effect of different parameters of deflector on the organization of airflow of attached ventilation,the influence of the angle between the deflector and the wall,the installation height and length on the indoor air quality was studied.The results showed that the average air temperature in the room was lowest when the angle between the deflector and the wall was 100°,and the small angle of the deflector led to an increase in the temperature inhomogeneity coefficient in the working area.The increase of the length of the deflector did not represent the enhancement of the ability to take away the residual heat in the working area,and the length of the deflector in practical application should be fully verified with the application reality.After the arrangement of the deflector plate exceeded a certain height,the effect on the room temperature field was limited and depended mainly on the attenuation of the momentum of the jet’s main body before it reached the deflector plate.(3)A general ward model(length 5m width 4m height 2.8m)was established to simulate the temperature field,velocity field and pollutant dispersion in a general ward with different ventilation methods when patients and related equipment were used as heat and pollution sources.The results showed that the inclusion of deflectors enabled the airflow to avoid the influence of indoor obstacles,changed the airflow direction before the airflow hit the floor,formed air lakes near the personnel,and created a more excellent airflow organization.In terms of pollutant dispersion,compared with the attached ventilation and mixed ventilation,the attached ventilation with deflectors could better avoid dispersion and better discharge pollutants from the room.The average concentration of pollutants in the ward with deflector-adhered ventilation was only 0.3 times higher than the average concentration of pollutants in the room with mixed ventilation and adherent ventilation,reducing the risk of cross-contamination in the general ward.Figure[53] table [13] reference [63]...