City University of Hong Kong Department Name

 

Studies on airflow and smoke dispersion

 

 Numerical simulation by Computational Fluid Dynamics (CFD) technique is highly useful to examine the effect of HVAC installations on the airflow environment, and hence the thermal conditions, indoor air quality, and fire/pollutant distributions in any confined space. Both transient and steady-state analysis can be executed. Good accuracy of the simulation results relies on the proper use of computational tool, numerical grid, and boundary conditions. Extensive validation through comparison with experimental data and analytical tests are also essential. For displacement ventilation systems, the use of renormalized-group (RNG) k-e model has been found better than the standard or the low-Reynolds-number models, whereas for fire propagation and smoke dispersion in a confined space, the adoption of the large-eddy-simulation (LES) approach becomes a necessity.

  

Elevation view of smoke and flame propagation in underground car park with two different ventilation rates

      Displacement ventilation may provide better indoor air quality and energy performance in buildings with a comfortable environment compared with mixing ventilation. The research of displacement ventilation has been mainly conducted in Scandinavian countries, which is gaining its popularity in North America. Hong Kong has higher temperatures in summer than those in Scandinavian cities.  Besides, the offices in the Hong Kong may have more equipment that produces more heat. Therefore, the cooling load is higher in Hong Kong than that in Scandinavian countries. In many Hong Kong offices, there is a large core space that is completely isolated from the external climate. Cooling is always needed in the core spaces. There is a great potential to use displacement ventilation in such spaces. Therefore, direct application of the Scandinavian results for Hong Kong design is not feasible. Research into displacement ventilation for Hong Kong situation is therefore justified.

 

 

Related publications:

 

Book chapter:

Fong Alan, Zhang Lin, Chow Tin-tai. Fire services engineering and performance-based design. In: Development Trends in Building Services Engineering, Chapter 5, City University of Hong Kong Press, ISBN: 978-962-937-162-3, Hong Kong, China, 2009, pp.143-172.

Journal articles

Lin Z, Chow TT, Wong TC. Radon concentration of a ventilated indoor space in Hong Kong. Journal of Mechanical Engineering, 46(7), 2000, 466-474.

You F, Lin Z, Zhou JJ, Chow TT, Zou YH, Li PD. An experimental and simulation study on plenum cable fire. Journal of Safety and Environment, 2(6), 2002, 29-33. (in Chinese with English Abstract)

You F, Zhou JJ, Zhou YH, Li PD, Lin JZ, Chow TT. Preliminary real-scale experimental studies on cable fires in plenum. Journal of Fire Sciences, 21(6), 2003, 465-484.

Lin Z, Chow TT, You F, Zhou JJ, Zou YH. A partial differential model for the pyrolysis of materials with movable residual layer. Mechanics of Advanced Materials and Structures, 12, 2005, 1-7.

Lin Zhang, Chow TT, Tsang CF, Chan LS, Fong KF. Effect of air supply temperature on the performance of displacement ventilation (Part I) – thermal comfort, Indoor and Built Environment, 14(2), 2005, 103-115.

Lin Zhang, Chow TT, Tsang CF, Fong KF, Chan LS. Effect of air supply temperature on the performance of displacement ventilation (Part II) – indoor air quality, Indoor and Built Environment, 14(2), 2005, 117-131.

Lin Z, Chow TT, Fong KF, Wang QW, Li Y. Comparison of performances of displacement and mixing ventilations (Part I) ¾ thermal comfort. International Journal of Refrigeration – Revue Internationale Du Froid, 28(2), 2005, 276-287.

Lin Z, Chow TT, Fong KF, Tsang CF, Wang QW. Comparison of performances of displacement and mixing ventilations (Part II) ¾ indoor air quality. International Journal of Refrigeration – Revue Internationale Du Froid, 28(2), 2005, 288-305.

Lin Zhang, Chow TT, Tsang CF, Fong KF, Chan LS. CFD study on effect of the air supply location on the performance of the displacement ventilation system, Building and Environment, 40(8), 2005, 1051-1067.

Lin Z, Chow TT, Wang Qiuwang, Fong KF, Chan LS. Validation of CFD model for research into displacement ventilation. Architectural Science Review, 48(4), 2005, 305-316.

Lin Z, Chow TT, Tsang CF. Effect of headroom on performance of the displacement ventilation system. Indoor and Built Environment, 15(4), 2006, 333-346.

Lin Z, Chow TT, Tsang CF. Effect of door opening on the performance of displacement ventilation in a typical office building. Building and Environment, 42(3), 2007, 1335-1347.

You Fei, Lin John Z, Zhou Jianjun, Chow TT. Direct numerical simulation on the pyrolysis of materials with volatile residue layer. Applied Mathematical Modelling, 31(4), 2007, 770-779.

Chow TT, Lin Zhang, Tsang CF. Applying large eddy simulation in the study of fire and smoke spread at underground car park. International Journal on Architectural Science, Vol.7, No.2, 2008, 35-46.

Lin Zhang, Chow TT, Tsang CF, Fong KF, Chan LS, Shum WS. Effect of ventilation system on smoke and fire spread in a public transport interchange. Fire Technology, 44(4), 2008, 463-479.

Lin Z, Chow TT, Tsang CF, Fong KF, Chan LS, Shum WS and Tsai L. Effect of internal partitions on the performance of under floor air supply ventilation in a typical office environment. Building and Environment, 44, 2009, 534-545.

Lin Z, Wang J, Yao T, Chow TT, Fong SKF. Numerical comparison of dispersion of human exhaled droplets under different ventilation methods. World Review of Science, Technology and Sustainable Development, 10(1/2/3), 2013, 142-161.

Conference papers:

Lin Z, Chow TT, Fong KF, Chen Q. Review on application of displacement ventilation to Hong Kong buildings. Proceedings of 5th International Conference on Tall Buildings, Hong Kong, China, Dec 1998, Vol.1, pp.246-51.

Lin Z, Chow TT, Fong KF, Wang QW, Chen Q. Validation of CFD simulation of concentration of gaseous impurities in a typical Hong Kong office. Proceedings of the 20th Congress of IIR, Sydney, Australia, Sep 1999, Vol.5, pp.3211-3219.

Lin Z, Chow TT, Fong KF, Wang QW, Chen Q. Review on removal of indoor VOC emissions by ventilation. Proceedings of the International Conference on Urban Pollution Control Technology, Hong Kong, China, Oct 1999, pp.465-470.

Lin Z, Chow TT, Fong KF, Wang QW, Chen Q. Validation of CFD model for research into application of displacement ventilation to Hong Kong buildings. Proceedings of ISHVAC 99, the 3rd International Symposium on Heating, Ventilation and Air-conditioning, Shenzhen, China, Nov 1999, Vol.2, pp.602-613.

Lin Z, Chow TT, Fong KF, Liu JP. CFD simulation of concentration of gaseous impurities in a typical Hong Kong industrial workshop. Proceedings of ROOMVENT 2000, Reading, UK, Jul 2000, pp.167-172.

Lin Z, Chow TT, Fong KF. Review on application of displacement ventilation to Hong Kong buildings. Proceedings of Nanjing C Hong Kong HVAC Seminar 2000, Nanjing, China, May 2000, pp. 1:17-24. (in Chinese)

Lin Z, Chow TT, Fong KF, Liu JP. CFD simulation of concentration of gaseous impurities in a typical Hong Kong classroom, Proceedings of Healthy Buildings 2000, the 6th International Conference, Espoo, Finland, Aug 2000, Vol.2, pp.383-388.

Lin Z, Chow TT, Fong KF, Liu JP. CFD simulation of concentration of gaseous impurities in a typical Hong Kong shop. Proceedings of ACHRB 2000, IIR International Symposium, Shanghai, China, Oct 2000, pp.195-199.

Lin Z, Chow TT, Liu JP, Fong KF. CFD simulation of transient cooling in a typical Hong Kong office. Proceedings of Dublin 2000, Dublin, Ireland, Sep 2000. (CD ROM)

Lin Z, Chow TT, Fong KF, Liu JP. CFD investigation into gaseous impurities in a shop with displacement Ventilation. Proceedings of IAQVEC 2001, the 4th International Conference on IAQ, Ventilation & Energy Conservation in Buildings, Changsha, China, Oct 2001, Vol. 2, pp.731-738.

Yu CK, Lin Z, Chow TT. CO2 concentration in a typical Hong Kong classroom. Proceedings of IAQVEC 2001, the 4th International Conference on IAQ, Ventilation & Energy Conservation in Buildings, Changsha, China, Sept 2001, Vol. 2, pp.771-778.

Lin Z, Chow TT, Fong KF. CFD investigation into gaseous impurities in a workshop with displacement ventilation. Proceedings of ROOMVENT 2002, the 8th International Conference on Air Distribution in Rooms, Copenhagen, Denmark, Sep 2002, pp.701-704.

Lin Z, Chow TT, and Li Y. Deflection ventilation a conceptual introduction. Energy Efficient Healthy Building (Proceedings of Healthy Building 2003), Singapore, 7-11 December 2003, vol. 2, pp 363-369.

Lin Z, Chow TT, Fong KF, Tsang CF. CFD investigation of concentration of gaseous impurities in a classroom with displacement ventilation. Proceedings of VI International HVAC+R Technology Symposium, Istanbul, Turkey, May 2004, pp.343-348.

 

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