Numerical simulation and experimental research on indoor environment separated with down-feed air curtain

Abstract

Indoor environment separated with down-feed air curtain was numerically simulated and experimentally researched. Indoor airflow and temperature fields separated with air curtain were numerically simulated. Results show that both polluted airflow and thermal air current can be separated with a down-feed air curtain to prevent contaminants from spreading in the room space. In a test chamber, the smoke of burning Tibetan incense served as the source of contaminants, and the probe test shows that 1.0 μm is the prevailing diameter of the smoke particles. During the release of the smoke, the particle concentration of the indoor air was tested with a laser particle counter at the points of three different heights from the floor when the air curtain was running or not. Experimental results show that the higher the test point is located, the lower the particle concentration is, implying that the separating or isolating effect decreases as the air velocity of the curtain reduces along with the height descends. According to both simulation and experimental results, down-feed air curtain can separate indoor environment effectively when the supply air velocity of air curtain is not less than 3 m/s. In order to strengthen separation effect, it is suggested that the supply air velocity be speeded up to 5 m/s.

Keywords

air curtain / airflow field / temperature field / particle concentration / numerical simulation / test chamber

References

[1] Xu S., Fan Q. Replacement of hot air curtain with static pressure fan-coil and fresh air system[J]. Refrigeration and Air-Conditioning, 2005, 5(3): 90-92.

[2] Xie X., Luo K. Organizing analysis method of air curtain fitting for engineering device and testing[J]. Journal of Chang’an University (Arch and Envir Science Edition), 2004, 21(3): 29-31.

[3] Wang H., Zhang H. Test and application of air curtain in mine[J]. Journal of China Coal Society, 2006, 31(5): 615-617.

[4] Zhou R., He J., Xie J., et al. Numerical simulation and analysis of the air curtain for preventing smoke in subway station fire[J]. China Safety Science Journal, 2006, 16(3): 27-30.

[5] Song F., Zhang H., Wen Y., et al. Movable assembly air screen applied in clinical operation[J]. China Journal of Nosocomial, 2003, 13(12): 1147-1148.

[6] Zhao B., Li X., Yan Q. Simplified method for numerical simulation of indoor airflow[J]. Heating Ventilating and Air Conditioning, 2003, 33(3): 102-104.

[7] Fan H., Ren H., Li X. Numerical study on air flow around an opening with large eddy simulation[J]. Journal of Hydrodynamics, 2003, 15(6): 45-48.

[8] Li Z. H., Zhang A. M. Characteristics of diffuser air jets and airflow in the occupied regions of mechanically ventilated rooms: A literature review[J]. AShRAE Trans, 1993, 99(1): 1119-1226.

[9] Luo S., Heikkinen J., Bernard R. Modeling of the HESCO nozzle diffuser used in IEA Annex-20 experiment test room[J]. Building and Environment, 2004, 39(4): 367-384.

[10] Guo C., Zhang Y. Numerical simulation and experimental research on diffusion panel of HEPA supply outlet[J]. Journal of Tianjin University, 2006, 39(12): 1411 1416

[11] Chen Q., Suter P., Moser A. Influence of air supply parameters on indoor air diffusion[J]. Building and Environment, 1991, 26(4): 417-431.

[12] Zhao B., Li X., Yan Q. Influence of turbulence parameters at supply opening on indoor air distribution[J]. Building Energy and Environment, 2000, 19(1): 1-4.

[13] Tao W. Numerical Heat Transfer[M]. 2001, Xi’an: Xi’an Jiaotong University Press.

[14] Xu Z. Theory of Air Cleaning Technology[M]. 2003, Beijing: Science Press.

[15] Ministry of Construction of the Peoples Republic of China. GB 50019-2003. Code for Design of Heating, Ventilating and Air Conditioning[S]. China Planning Press, Beijing, 2003(in Chinese)