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Experimental Study of Influence of Fan Combinations on the Performance of Ventilation and Ceiling Exhaust System of a Metro Running Tunnel
(1 School of Resource & Environment and Safety Engineering, Hunan University of Science and Technology, Xiangtan 411201;2 Tunnel Design Branch, China Railway Liuyuan Group Co., Ltd, Tianjin 300133)
Abstract Based on the metro running tunnel section from Wawuzhuang station to Guizhou Road station of Qingd?
ao metro line 1, a physical model of ventilation and exhaust system is built. In light of the fan combinations of option1 (Two forced fans + two exhaust fans), option 2 (Two forced fans + one exhaust fan on the left side of a smoke ceiling vent) and option 3 (Two forced fans + one exhaust fan on the right side of a smoke ceiling vent), an analysis is conducted and the input variable frequencies, power consumptions, air velocities and static pressures in the left and right carriageways are obtained under the three fan combination options. The experimental data show that the static pressure field in both carriageways are symmetrically distributed with the ceiling smoke vent as the symmetry axis,and characterized by an oscillating phenomenon, whether in option 1, option 2 or option 3. This oscillation exhibits an approximate constant of static pressures, and increase of consumed powers will hardly cause compensatory increase of air volumes, meanwhile it is also a key to evaluate the effects of fan combinations on relative shock loss
when air flow passes through ceiling smoke vent. In order to quantify the difference of the shock loss (i.e. resistance),a concept of the performance coefficient of the ventilation and exhaust system, and a calculation model of deviation percentage is proposed, with the result of the resistance in option 1 being the smallest under the three combination modes. Thus it is recommended that the option 1 should be a preferential fan combination for an extra-long and large tunnel.
Abstract：
Based on the metro running tunnel section from Wawuzhuang station to Guizhou Road station of Qingd?
ao metro line 1, a physical model of ventilation and exhaust system is built. In light of the fan combinations of option1 (Two forced fans + two exhaust fans), option 2 (Two forced fans + one exhaust fan on the left side of a smoke ceiling vent) and option 3 (Two forced fans + one exhaust fan on the right side of a smoke ceiling vent), an analysis is conducted and the input variable frequencies, power consumptions, air velocities and static pressures in the left and right carriageways are obtained under the three fan combination options. The experimental data show that the static pressure field in both carriageways are symmetrically distributed with the ceiling smoke vent as the symmetry axis,and characterized by an oscillating phenomenon, whether in option 1, option 2 or option 3. This oscillation exhibits an approximate constant of static pressures, and increase of consumed powers will hardly cause compensatory increase of air volumes, meanwhile it is also a key to evaluate the effects of fan combinations on relative shock loss
when air flow passes through ceiling smoke vent. In order to quantify the difference of the shock loss (i.e. resistance),a concept of the performance coefficient of the ventilation and exhaust system, and a calculation model of deviation percentage is proposed, with the result of the resistance in option 1 being the smallest under the three combination modes. Thus it is recommended that the option 1 should be a preferential fan combination for an extra-long and large tunnel.
CHEN Fangxing1 WANG Haiqiao1 CHEN Shiqiang1 TIAN Feng1,
2 ZHU Zhulong2
.Experimental Study of Influence of Fan Combinations on the Performance of Ventilation and Ceiling Exhaust System of a Metro Running Tunnel[J] MODERN TUNNELLING TECHNOLOGY, 2020,V57(5): 218-225
2020, Vol. 57 