Parameter analysis of jet tunnel ventilation for long distance construction tunnels at high altitude

Wang, Hui; Jiang, Zhongan; Zhang, Guoliang; Zeng, Fabin

doi:10.1016/j.jweia.2022.105128

Cited by 19 publications

(7 citation statements)

References 29 publications

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“…The tunnel construction mainly includes drilling, blasting, slag removal, secondary lining, and other processes; the on-site construction schematic diagram is shown in Figure 1. Forced ventilation should consider the exhaust of blasting gases from the working face, the maximum number of workers in the tunnel, the minimum allowable air flow velocity, the degree of dilution and discharge of exhaust gas from the internal combustion engine, etc, and then comprehensively determine the maximum value of the required air flow volume; the required air flow volume of the unilateral tunnel is shown in Table 1 [8].…”

Section: Engineering Background 21 Project Overviewmentioning

confidence: 99%

“…Sci. 2024, 14, x FOR PEER REVIEW 3 of 17 of exhaust gas from the internal combustion engine, etc, and then comprehensively determine the maximum value of the required air flow volume; the required air flow volume of the unilateral tunnel is shown in Table 1 [8].…”

Section: Engineering Background 21 Project Overviewmentioning

confidence: 99%

“…This situation may cause dyspnea for construction workers and lead to death by suffocation in severe cases [4][5][6]. In the selection of ventilation methods for long highway tunnels, full diameter air flow ducts are mostly used to match high-power forced ventilations in foreign countries [7], while in China, inclined shafts, parallel pilot tunnels, and shafts are usually built and a combination of forced and roadway ventilation methods are adopted [8,9]. Through numerical simulation and on-site monitoring, scholars discussed the above ventilation measures and ventilation effects, and summarized the air flow and pollutant migration laws in the tunnel under the forced ventilation method [4,10,11].…”

Section: Introductionmentioning

confidence: 99%

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Analysis of the Stability of the Double-Hole Complementary Ventilation and Ventilation Network of the Tunnel Constructed by Drilling and Blasting Method

Deng,

Chen,

Rao

2024

Applied Sciences

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Currently, double-hole complementary ventilation is a mature ventilation method for operating tunnels, but how to carry out it in the construction tunnel poses a new challenge. Due to the desynchronization in the construction period of the double-hole tunnel, there is an instantaneous difference in the air flow demand between the two working faces. The study analyzes the impact of geometric parameters, specifically Lt (the distance from the traffic cross passage to the working face of the advance side tunnel), Lp (the distance between the pedestrian cross passage and the working face of the advance side tunnel), Ht (height of the upper step), and Lw (safe step distance of the double-hole working face) on ventilation network stability. The results show that with the increase of Lt and Lp, the Rm resistance of each branch changes non-uniformly, and the stability of the ventilation network is significantly different. Then, when Lt, Lp = 80 and 180 m, the air flow directions of the double-hole tunnel are the same. Finally, when Lt and Lp = 130 m, the air flow directions are inconsistent, which indicates that in the range of 80 m < Lt or Lp < 180 m, the cross-section size of the cross passage affects the stability of the ventilation network. However, when 2.5 m < Ht < 3 m, or 30 m < Lw < 50 m, the stability of the ventilation network is not affected, and the flow field of the double-holes does not interfere with each other. The conclusions obtained confirm that the double-hole complementary ventilation method is available in construction tunnels, and has potential for implementation.

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Section: Engineering Background 21 Project Overviewmentioning

confidence: 99%

Section: Engineering Background 21 Project Overviewmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Analysis of the Stability of the Double-Hole Complementary Ventilation and Ventilation Network of the Tunnel Constructed by Drilling and Blasting Method

Deng,

Chen,

Rao

2024

Applied Sciences

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“…Chang et al [23] analyzed the air flow characteristics and DPM concentration distribution in the heading face and validated the simulation results using field measurement data, concluding that longer duct lengths in the existing ventilation system have better DPM dilution performance. Wang et al [24] conducted numerical simulation and analysis of the key parameters of jet tunnel ventilation technology and concluded that when the fans are installed at effective spacing, the wind speed and turbulence intensity are stable while the central control line k value of the overall impact coefficient is the highest and the ventilation effect is the best. The complex ventilation conditions allow for more ways to solve the problem of low oxygen utilization in diffuse oxygen supply, and one of the possible solutions is the recirculation ventilation technique.…”

Section: Introductionmentioning

confidence: 99%

Optimization of controlled circulating ventilation and oxygen supply scheme for high-altitude mine heading face based on CFD

Zhang¹,

Wang²,

Zhang³

et al. 2023

3rd International Conference on Applied Mathematics, Modelling, and Intelligent Computing (CAMMIC 2023)

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With the depletion of mineral resources in the plains, Chinese mining industry has shifted to higher altitudes where low pressure and low oxygen has become a bottleneck limiting further development of mining technology. The traditional diffusion type of oxygen supply has low oxygen utilization. Controlled circulation ventilation offers a good alternative for oxygen supply to workers in high altitude mines. In this study, a CFD approach was used to conduct a single factor analysis of circulating duct height, distance between circulating duct outlet and heading face, oxygen supply duct height, forcing duct air velocity and circulating duct air velocity to investigate their effects on the oxygen mass fraction located at the heading face. In addition, an orthogonal experiment was designed to analyze the effect of the above five factors on the distribution of oxygen mass fraction in the heading face. The results showed that the effect of forcing duct air velocity on the oxygen mass fraction in the heading face was the greatest. The average oxygen mass fraction in the heading face is highest when the height of circulating duct was 0.9 m, the distance between circulating duct outlet and heading face was 2 m, the height of oxygen supply duct was 1.0 m, the air velocity of forcing duct was 3 m/s and the air velocity of circulating duct was 2.5 m/s.

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“…Recent research shows great value in the use of CFD models in assessing tunnel ventilation objectives under diverse scenarios [3][4][5][6][7]. A variety of CFD software packages is available to resolve the whole range of emerging issues, whereas Ansys Fluent is the most used fluid flow simulation module [8].…”

Section: Introductionmentioning

confidence: 99%

Comparative Analysis of Numerical Methods Regarding the Backflow Investigation in Tunnels of Zentrum am Berg

Patsekha

Wei

Galler

2022

Berg Huettenmaenn Monatsh

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The efficiency of tunnel ventilation systems is commonly evaluated through numerical modelling. In this survey, two CFD models were developed by means of Fire Dynamic Simulator and Ansys Fluent software. The simulation results were used to assess the model performance in studying the backflow distribution in a real tunnel. A full-scale experiment to evaluate the ventilation conditions in the western railway tunnel was carried out in Zentrum am Berg. The velocity values were obtained for 90 examined points located at 10 cross-sections along a 100-meter tunnel part. The results showed good agreement in velocity variation trends from field measurements and those predicted by numerical models. At cross-sections more distant from the fan outlets, the FDS and Fluent models overestimated the flow velocities to a different extent. The simulated backflow development corresponds well to the observed three specified regions (initial, transitional, and developed) with distinctive flow structures. The FDS calculations confirmed the registered spontaneous changes in flow direction at points with a prevailed flow direction in the vicinity of the jet fans. Despite some discrepancies in results, the comparative analysis of two numerical models showed their applicability in the backflow investigation.

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Parameter analysis of jet tunnel ventilation for long distance construction tunnels at high altitude

Cited by 19 publications

References 29 publications

Analysis of the Stability of the Double-Hole Complementary Ventilation and Ventilation Network of the Tunnel Constructed by Drilling and Blasting Method

Analysis of the Stability of the Double-Hole Complementary Ventilation and Ventilation Network of the Tunnel Constructed by Drilling and Blasting Method

Optimization of controlled circulating ventilation and oxygen supply scheme for high-altitude mine heading face based on CFD

Comparative Analysis of Numerical Methods Regarding the Backflow Investigation in Tunnels of Zentrum am Berg

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