Simulation Flow &temperature And Prediction Of Thermal Comfort Of A Room Controlled By The Penetrative FADS

Fabric air dispersion system(FADS), made of flame retardant polyester material, is a new flexible air supply terminal. It sets air transport and dispersion in one. Simultaneously FADS makes the air dispersion uniform and the air supply large without blow feeling. In addition,FADS also has many other advantages, such as light weight, easy-clean, and anti-condensation.Hence FADS is widely applied in ventilation engineering. In this paper, the numerical simulation flow field and temperature field of a room, which is controlled by the FADS in penetration mode,are carried out. And the thermal comfort of the room is evaluated. First of all, the physical model of the room with cloth duct is established by using the Fluent numerical simulation software. The cloth duct is cylindrical with a diameter of 0.3 m and a length of 5 m. Secondly, the mathematical control equations of gas flow are established according to the characteristics of gas flow. The flow velocity and temperature boundary conditions needed to simulate are measured under cooling and heating conditions respectively. Thirdly, the numerical simulation of flow field and temperature field are carried out. And the reliability of the numerical simulation is verified by comparing the numerical simulation results with actual measurement results. Finally,based on the standard of indoor ventilation and comfort, the thermal comfort of the room under cooling conditions is evaluated. The conclusions are as follows:(1) The gas flow control equations are established based on conservation of mass,momentum and energy conservation law. Meanwhile, according to the turbulent characteristics of gas flow in lab controlled by the FADS, the standard ??- model equation of the two equation is used to simulate the flow field and temperature field in the room controlled by the FADS in penetration mode. And the simulation is feasible by the experimental verification.(2) In the room controlled by the FADS in penetration mode, the axial velocity of air supply jet decreases and the jet section gradually expands with the increase of the range. Simultaneously in the area of the air jet and the attached jet, the flow rate of air is high. And in other regions theflow velocity of air is slow and well-distributed.(3) In the room controlled by the FADS in penetration mode, the temperature field has obvious temperature stratification phenomenon. In addition to the jet area and the ground, the difference of temperature is small, and the temperature dispersion is uniform. In the jet region,with the increase of the range, the air temperature gradually decreases at heating condition, and gradually increases in cooling condition.(4) Based the Fanger model, Fountain model and Gong model and 36 temperature and 36 flow velocity in the room simulated at cooling condition, the PD1 and PD2 values of blow feeling dissatisfied rate and the PS values of thermal comfort at 36 points are respectively obtained. And then the thermal comfort in the room controlled by the FADS in penetration mode could be forecasted and judged. The PD1 value, PS value and PD2 value of the head, shoulders and legs are small and relatively close. The PD1 value of the ankle D is about 8.6%, and the PD2 value is about 0.04%. Compared to other parts of the body, the PD1 value and PD2 value of the ankle D are higher, leading to the highest hair sense unsatisfactory rates.(5) In the room controlled by the FADS in penetration mode, the turbulence intensity is low and uniform. After the FADS starts to run at 21 ? and reaches equilibrium, in horizontal direction, 80% of the air turbulence intensity is less than 23.2%. In vertical direction, 70% of the air turbulence intensity is less than 31.71%.