Study On Airflow Distribution Of Inducing Airflow By Metal Board In Large Space Building

There are many kinds of airflow distribution schemes for air conditioning system in large space buildings,among which stratified air conditioning is considered to be the most reasonable and energy efficiency.But there still exists some problems to be solved in the actual engineering,such as the actual effect of airflow distribution is not ideal,the energy consumption is still larger,etc.Therefore,it is great significance for stratified air conditioning to improve air distribution effect and energy utilization by the innovative design of the air supply terminal.In this paper,according to the features of air flow in the stratified air conditioning of the large space buildings,and combined with the principle of attached jet,a combined type of air supply was proposed,named as inducing airflow by metal board.comparing the side wall circular nozzle air supply with inducing air supply by metal board,the temperature and velocity non-uniformity coefficient,effective blowing temperature,Air Diffusion Performance Index(ADPI)and energy utilization coefficient were analyzed under the different air supply schemes.This paper selected the waiting hall of the railway station as the application object,and through the design and calculation of the stratified air conditioning,the supplied air temperature and velocity,the installation height of the air supply port were obtained.To simplify reasonably physical model of the waiting hall and stablish the simulation model,the Reliable k-? model,DO radiation model and Simple algorithm were used.Under the condition of constant air volume and air temperature,the temperature and velocity distribution of the circular nozzle air supply and metal board diversion side air supply were simulated by Fluent in summer.The temperature and velocity distribution of the metal board diversion under air supply is simulated by changing the air volume.In addition.Under the condition of constant air volume and air temperature,the velocity and temperature distribution of three schemes are simulated and analyzed in winter.The specific research content is as follows:(1)In summer,when using the circular nozzle air supply,the supplied air temperature and velocity were 18?,6.78m/s.The average air velocity and temperature were 0.34m/s,27.8? in the air conditioning zone.when metal board diversion side air supply was used,the supplied air velocity was 4 m/s.The average velocity and temperature were 0.28 m/s,26.8 ? in air conditioning zone.The velocity and temperature non-uniformity coefficient of the two plans were nearly same,but the APDI value of the metal board diversion side air supply was higher.When using the metal board diversion under air supply,the total air volume decreased by 25%,the supplied air temperature and velocity were 18?,1.5m/s.The average air velocity and temperature were 0.23m/s,26.2? in the air-conditioning zone.The energy utilization coefficient was the largest,the cooling capacity was fully utilized,but the APDI value was the smallest.(2)For hot air heating in winter,when using the circular nozzle air supply,the supplied air temperature and velocity were 30 ?,6.88 m/s.The average temperature and air velocity were 21.7 ?,0.25 m/s in the airconditioning zone,the maximum temperature of non-air conditioning zone was 22.7 ?,the temperature difference between upper and lower was about 1 ?;when metal board diversion side air supply was used,the supplied air velocity was 4 m/s.The average temperature and air velocity were 21.6 ?,0.15 m/s in the air-conditioning zone,the maximum temperature of non-air conditioning was 22.7 ?,the temperature difference between upper and lower was about 1.1 ?,the APDI value is higher;When using the metal board diversion under air supply,the supplied air velocity was 3 m/s.The average temperature and air velocity were 22?,0.26m/s in air-conditioning zone,and the maximum temperature of the non-air conditioning area was 22.4?,The temperature difference between the upper and lower was about 0.4?,which effectively alleviates the problem of “upper heat and lower cold”.The Energy Utilization Coefficient was larger,but the APDI value was the smallest.(3)The area and the temperature difference of the metal board were smaller,which caused that the Radiant Cooling / Heating capacity was not obvious.If the radiation effect is not considered,the metal plate can be designed more beautiful and practical.