Reversal Ventilation as a Method of Fire Hazard Mitigation in the Mines
Abstract
:1. Introduction
1.1. Fire Hazard in Underground Mining
1.2. Reversal of Ventilation
- complete reversal—in this case the direction of airflow is changed in all underground workings,
- local reversal—the change only encompasses a part of the workings.
- The reversal may be achieved using several methods:
- change of the rotor rotation direction (only in the case of axial fans allowing for flow reversal) [1],
- the use of a reversal channel and reversion gates (in the case of both axial and radial fans) [1],
- placing special reversal fans set to suction, allowing for flow reversion in downcast shafts—in normal ventilation these fans are turned off,
- placing special reversal fans set to pumping, allowing for flow reversion in upcast shafts—in normal ventilation theses fans are turned off,
- supplying water to upcast shafts,
- use of stoppings, airlocks and air crossings to achieve local reversion in areas of exploitation.
1.3. Analysis of the Structure of a Mining Ventilation Network
- Group 1—simple networks—networks with a single downcast shaft and a single upcast shaft (Figure 1a),
- Group 2—complex networks—networks with a larger number of peripheral upcast shafts and a larger number of centrally positioned downcast shafts (Figure 1b). By introducing stoppings in single headings, these networks may be classified in the 1st group,
- Group 3—highly complex networks—downcast shafts located in various parts of mines and with a large number of peripheral and central upcast shafts (Figure 1c). These networks are predominant in Polish mining.
2. Materials and Methods
2.1. General Methodology
- method 1—change of a one main fan’s work from exhaust to forcing (chapter 3.1)—known method, without a branch connecting sub-networks of the main ventilation fans
- method 2—modification of following parameters: working points of main fans (constant exhaust mode) and resistance of local stoppings (chapter 3.2)—a brand new method, with a branch connecting sub-networks of the main ventilation fans.
2.2. Tools and Software
- airflow rate in particular excavations, m3/min or m3/s,
- pressure loss (dissipation), Pa,
- total fan head (Pa) and their airflow rate, m3/min,
- methane rate, m3/min,
- aerodynamic potentials in the nodes, Pa,
- smoke presence.
- Equations for nodes of the net (I Kirchoff’s law):
- Equations for cycles (II Kirchoff’s law):
- Vi—volume flow of i air stream,
- Wi—energy dissipation of i branch (pressure loss),
- Hi—head of i fan, natural draught or fire draught,
- m—number of branches in the net,
- n—number of nodes in the net,
- sji—an element of a matrix of node-branch incidence having a value: −1 when air flowing to i branch comes from j node, 1 when air from i branch flows to j node, 0 when there is no incidence between i branch and j node.
- cki—and element of cycle-branch matrix having a value: −1 when orientation of i branch is not the same as the orientation assumed for the entire k cycle, 1 when orientation of i branch is accordant to the orientation assumed for the entire k cycle, 0 when there is no incidence between i branch and k cycle.
2.3. Assumptions and Simplifications
3. Examples of Calculations of Reverse Air Distribution—Results and Discussion
3.1. Ventilation Network without a Branch Connecting Sub-Networks of the Main Ventilation Fans
3.1.1. Description, Aim and the Results
3.1.2. Discussion
Changes in Air Distribution
Escape Routes
- A—through branches 11–21, 21–22, 22–23 – 51 min + 75 min + 1 min = 127 min,
- B—through branches 12–21, 21–22, 22–23 – 48 min + 75 min + 1 min = 124 min,
- E—through branches 13–18 – 36 min.
Methane
- A—increase 166 Pa, change of potential assignment,
- B—increase 299 Pa, change of potential assignment,
- C—decrease 140 Pa, no change of potential assignment,
- D—decrease 95 Pa, no change of potential assignment,
- E—increase 528 Pa, no change of potential assignment.
Advantages and Disadvantages of Reversal Ventilation
- increase of methane hazard, particularly in section E (according to increase of aerodynamic potentials),
- change of air direction and amount in excavations. They can not fill the regulations,
- reversal of air direction in sections A and B, at some moment it leads to lack of air movement,
- minimal smoke amount in a function chamber.
3.2. Ventilation Network with a Branch Connecting Subnetworks of the Main Ventilation Fans
3.2.1. Description, Aim and the Results
3.2.2. Disscussion
Changes in Air Distribution
Escape Routes
- from A—127 min,
- from B—124 min,
- from E—36 min.
- from A—through the branch 11–21—51 min,
- from B—through the branch 12–21—48 min,
- from E—through the branch 13–18—36 min.
Methane
- A—branch 11–21—424 Pa,
- B—branch – 12–21—458 Pa,
- C—branch 15–17—349 Pa,
- D—branch 16–19—354 Pa,
- E—branch 13–18—256 Pa.
- A—14 m3 CH4/min,
- B—13 m3 CH4/min,
- C—11 m3 CH4/min,
- D—6.5 m3 CH4/min,
- E—15 m3 CH4/min.
Advantages and Disadvantages of the New Method
- shorter time of evacuation from the sections A and B. Time required from E remains the same,
- keeping constant air distribution beyond and in the sections, keeping constant difference of the potentials in the sections,
- lack of methane hazard increase (according to mentioned above points).
- However, the method requires additional measures (disadvantage). To conduct the ventilation procedure presented in Example 2, it is necessary to fulfil the following three conditions:
- the presence of a return air current connecting the subnetworks of the main ventilation fans in the mine ventilation network,
- the ability to adjust the operating points of the main ventilation fans,
- the possibility of smooth and remote change of resistance of regulating stoppings.
4. Conclusions
- (1)
- As so far, reversal ventilation in underground mines where methane hazard is present has been considered as dangerous. The authors proved that there is a method to perform safe reversal, keeping methane hazard at an acceptable level. It requires connection between the subnetworks of the main ventilation fans. The results of numerical computation of air distributions in mine ventilation networks presented in Examples 1 and 2 confirm the significance of the connection which is required for performing the kind of reverse ventilation that enables safe egress of workers due to fire in an intake group air current.
- (2)
- In highly complex networks which do not contain a branch connecting the main ventilation fan subnetworks (example 1), the reverse operation of a fan may cause considerable changes in the volumes of air flowing in the exploitation areas. This could lead to permissible air velocity parameters being breached and an increased methane hazard. The decision not to perform the reversal in such networks in mines with high methane hazards may thus be substantiated.
- (3)
- In highly complex networks containing branches connecting subnetworks of main ventilation fans (example 2), the reverse ventilation in part of the network may be conducted by adjustment of the main fans’ operating points and changing the resistance of regulating stoppings while maintaining the airflow in the exploitation areas.
- (4)
- The reverse ventilation described in example 2 reduces the time in which workers are present in the part of the escape route containing smoke and decreases the size of the smoke-affected zone while maintaining methane safety in the exploitation areas.
- (5)
- To perform the ventilation procedure presented in example 2, the following elements are necessary: the presence of a branch connecting the subnetworks of the main ventilation fans, the possibility of smooth and remote adjustment of the fan operating points and of the regulating stoppings.
- (6)
- It is advisable for the devices regulating the airflow and the main ventilation fans to be fully automated, that is, allowing for remote and smooth changes of their parameters. Applying such facilities could reduce the time required for reversal.
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
References
- Wacławik, J. Wentylacja Kopalń; AGH: Krakow, Poland, 2010; pp. 328–340. [Google Scholar]
- Saulov, D.; Klimenko, A.Y.; Torero, J.L. Underground fire prospective technologies. In Underground Coal Gasification and Combustion; Woodhead Publishing: Sawston, UK, 2018; pp. 583–599. [Google Scholar]
- Hansen, J. Full-scale fire experiments in an underground mine. In Proceedings of the 3rd International Symposium on Mine Safety Science and Engineering, Montreal, QC, Canada, 13–19 August 2016; pp. 13–19. [Google Scholar]
- Cheng, L.H.; Ueng, T.H.; Liu, C.W. Simulation of ventilation and fire in the underground facilities. Fire Saf. J. 2001, 36, 597–619. [Google Scholar] [CrossRef]
- Yuan, L.; Thomas, R.A.; Rowland, J.H.; Zhou, L. Early fire detection for underground diesel fuel storage areas. Process Saf. Environ. Prot. 2018, 119, 69–74. [Google Scholar] [CrossRef] [PubMed]
- Yuan, L.; Zhou, L.; Smith, A.C. Modeling carbon monoxide spread in underground mine fires. Appl. Therm. Eng. 2016, 100, 1319–1326. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Dudzińska, A.; Cygankiewicz, J. Analysis of adsorption tests of gases emitted in the coal self-heating process. Fuel Process. Technol. 2015, 137, 109–116. [Google Scholar] [CrossRef]
- Hansen, R. Modelling temperature distributions and flow conditions of fires in an underground mine drift. Geosyst. Eng. 2018, 1–16. [Google Scholar] [CrossRef]
- Chen, P.; Guo, S.; Wang, Y. Human evacuation affected by smoke movement in mine fires. Int. J. Coal Sci. Technol. 2016, 3, 28–34. [Google Scholar] [CrossRef] [Green Version]
- Wang, Y.; Li, X.; Wang, W.; Guo, Z. Experimental and in-situ estimation on hydrogen and methane emission from spontaneous gasification in coal fire. Int. J. Hydrog. Energy 2017, 42, 18728–18733. [Google Scholar] [CrossRef]
- Adjiski, V.; Mirakovski, D.; Despodov, Z.; Mijalkovski, S. Simulation and optimization of evacuation routes in case of fire in underground mines. J. Sustain. Min. 2015, 14, 133–143. [Google Scholar] [CrossRef] [Green Version]
- Adjiski, V.; Despodov, Z. Methodology for Optimal Fire Evacuations in Underground Mines Based on Simulated Scenarios. In Fire Safety and Protection; IntechOpen: London, UK, 2020; pp. 1–24. [Google Scholar]
- Nawrat, S.; Napieraj, S. The application of the simulation program for the analysis and design of the evacuation of mining crews from fire hazard areas. Bezpieczeństwo Pracy Ochrona Środowiska Górnictwie 2012, 8, 3–7. [Google Scholar]
- Adjiski, V.; Zubicek, V.; Despodov, Z. Monte Carlo simulation of uncertain parameters to evaluate the evacuation process in an underground mine fire emergency. S. Afr. Inst. Min. Metall. 2019, 119, 907–917. [Google Scholar] [CrossRef]
- Guangwei, Y.; Dandan, F. Escape route planning of underground coal mine based on improved ant algorithm. Math. Probl. Eng. 2013, 32–46. [Google Scholar] [CrossRef]
- Strzemiński, J. Main ventilation reversion in hard coal mines. Mechanizacja Automatyzacja Górnictwa 1998, 1, 31–37. [Google Scholar]
- Szlązak, N.; Szlązak, J. Ventilation of wall workings in coal mines in condition of methane and fire hazard. Górnictwo Geologia 2013, 8, 115–131. [Google Scholar]
- Rosiek, F.; Sikora, M.; Urbański, J. Main Ventilation Reversion in LGOM Mines. Min. Sci. 2007, 9, 89–105. [Google Scholar]
- Szlązak, N.; Zając, K. Ocena Możliwości Wykonania Rewersji Wentylacji Głównej w Kopalniach Węgla Kamiennego; Biblioteka Szkoły Eksploatacji Podziemnej: Kraków, Poland, 1998; pp. 1–90. [Google Scholar]
- Arif, W.; Kyuro, S.; Yuichi, S.; Yoshiaki, S.; Hiroyuki, T.; Kagemi, U.; Hiroyuki, M. Assessment of air dispersion characteristic in underground mine ventilation: Field measurement and numerical evaluation. Process Saf. Environ. Prot. 2015, 93, 173–181. [Google Scholar]
- Hasheminasab, F.; Bagherpour, R.; Aminossadati, S.M. Numerical simulation of methane distribution in development zones of underground coal mines equipped with auxiliary ventilation. Tunn. Undergr. Space Technol. 2019, 89, 68–77. [Google Scholar] [CrossRef]
- Thakur, P. Advanced Mine Ventilation: Respirable Coal Dust, Combustible Gas and Mine Fire Control; Woodhead Publishing: Cambridge, UK, 2018; pp. 61–77. [Google Scholar]
- Stewart, C.M.; Aminossadati, S.M.; Kizil, M.S. Improving the Performance of the Hardy Cross Algorithm for Large Ventilation Models. 2019. Available online: espace.library.uq.edu.au (accessed on 4 April 2020).
- Tabibian, S.M.; Najafabadi, M.K.; Shahizare, B. Review of common fire ventilation methods and Computational Fluid Dynamics simulation of exhaust ventilation during a fire event in Velodrome as case study. SN Appl. Sci. 2019, 1, 685. [Google Scholar] [CrossRef] [Green Version]
- Sabanov, S.; Tussupbekov, Y.; Aldoamzharov, B.; Karzhau, A.S.; Mukhamedyarova, Z. Risk Estimation Approach Considering Implementation of Automated Ventilation Systems into Kazakhstan Metal Mines. In Proceedings of the 28th International Symposium on Mine Planning and Equipment Selection—MPES, Perth, Australia, 2–4 December 2019; Topal, E., Ed.; Springer: Berlin/Heidelberg, Germany, 2019. [Google Scholar]
- Dziurzyński, W.; Krach, A.; Pałka, T. Method of ventilation reversal in regions containing ascending and descending currents in the conditions of fire and methane explosion hazards. Górnictwo Geologia 2013, 8, 19–34. [Google Scholar]
- Pach, G. Safe and energy-efficient ventilation in mines–application of the golden ratio method in designing forced air distribution for ventilation networks. Conference Mining—Prospects and threats, Coal—Cheap, clean energy and workplaces. In IOP Conference Series: Earth and Environmental Science; PublisherIOP Publishing: Bristol, UK, 2018; Volume 198. [Google Scholar]
- State Mining Authority. 2019. Available online: http://www.wug.gov.pl/bhp/stan_bhp_w_gornictwie (accessed on 8 November 2019).
- Conti, R.S. Responders to Underground Mine Fires. In Proceedings of the 32nd Annual Conference of the Institute on Mining Health, Safety and Research, Salt Lake City, UT, USA, 5–7 August 2001; pp. 111–121. [Google Scholar]
- Singh, R.V.K. Spontaneous Heating and Fire in Coal Mines. Procedia Eng. 2013, 62, 78–90. [Google Scholar] [CrossRef] [Green Version]
- Ray, S.K.; Sahay, N.; Singh, R.P.; Singh, A.K.; Bhowmick, B.C. Reversal of underground mine ventilation. J. Mines Met. Fuels 2002, 50, 339–344. [Google Scholar]
- Minister of Energy. Regulation of the Minister of Energy on specific requirements for running underground mining facilities. Dziennik Ustaw, 23 November 2016. [Google Scholar]
- Trenczek, S. Assessment of methane and spontaneous fire hazards level in the areas ventilated by refreshment of returned air in light of the applicable regulations. Przegląd Górniczy 2017, 73, 21–28. [Google Scholar]
- Pach, G. Substitute characteristics of ventilators in the forced airflow problems. Systemy Wspomagania Inżynierii Produkcji 2017, 6, 232–246. [Google Scholar]
- Krach, A. Determining diagonal branches in mine ventilation networks. Arch. Min. Sci. 2014, 59, 1097–1105. [Google Scholar] [CrossRef] [Green Version]
- Dziurzyński, W.; Krawczyk, J. Calculation possibilities of selected simulation programmes applied in the world mining industry describing the flow of air, fire gases and methane in the mine workings network. Przegląd Górniczy 2012, 68, 1–11. [Google Scholar]
- Trutwin, W. Zmiany ciśnienia bezwzględnego w rejonie ściany jako wskaźnik zagrożenia metanowego. In Prace Instytutu Mechaniki Górotworu; Instytut Mechaniki Górotworu PAN: Kraków, Poland, 2012; pp. 239–244. [Google Scholar]
- Lolon, S.; Brune, J.; Bogin, G.; Grubb, J.; Saki, S.; Juganda, A. Computational fluid dynamics simulation on the longwall gob breathing. Int. J. Min. Sci. Technol. 2017, 27, 185–189. [Google Scholar] [CrossRef]
- Lunarzewski, L.W. Gas emission prediction and recovery in underground coal mines. Int. J. Coal Geol. 1998, 35, 117–145. [Google Scholar] [CrossRef]
- Konsek, S.; Mazurek, C.; Jędrzejek, K.; Słowik, A. Regulacja przewietrzania w grupowym prądzie powietrza odprowadzanym do szybu wydechowego jako element optymalizacji i stabilizacji sieci wentylacyjnej kopalni na przykładzie KWK Jankowice. In Górnictwo, Perspektywy, Zagrożenia. Klimatyzacja, Zagrożenia Aerologiczne; P.A. Nova: Gliwice, Poland, 2014; pp. 62–70. [Google Scholar]
Start node | 1 | 2 | 3 | 3 | 4 | 4 | 5 | 6 | 6 | 7 | 7 | 8 | 9 | 9 | 10 |
End node | 3 | 4 | 5 | 6 | 5 | 9 | 8 | 7 | 11 | 8 | 10 | 14 | 15 | 16 | 12 |
Time of movement (min) | 10 | 12 | 4 | 33 | 6 | 15 | 15 | 18 | 12 | 41 | 6 | 25 | 10 | 10 | 10 |
Start node | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 18 | 19 | 20 | 21 | 22 | 24 |
End node | 13 | 21 | 21 | 18 | 17 | 17 | 19 | 18 | 19 | 20 | 20 | 24 | 22 | 23 | 25 |
Time of movement (min) | 17 | 51 | 48 | 36 | 8 | 45 | 50 | 10 | 5 | 11 | 8 | 62 | 75 | 1 | 1 |
Start Node | End Node | Airflow and Methane Rate in Case of Normal Ventilation (m3/min) | Difference of Aerodynamic Potentials—No Reversal (Pa) | Airflow and Methane Ratein Case of Reverse Ventilation (m3/min) | Difference of Aerodynamic Potentials—Reversal(Pa) | Differences in Airflow Rate (m3/min) | Remarks |
---|---|---|---|---|---|---|---|
22 | 23 | 2755,04 (27,0) | +2713 | −3299,55 (0) | −2642 | −6054,59 | Reverse fan operation |
24 | 25 | 3810,50 (32,5) | +2453 | 4228,40 (48,6) | 2162 | 417,9 | Normal fan operation |
1 | 3 | 3433,75 (0) | −328 | −1259,19 (10,8) | +44 | −4692,94 | Reversion of air current |
2 | 4 | 3131,79 (0) | −327 | 2188,05 (0) | −159 | −943,74 | |
3 | 6 | 2436,41 (0) | −659 | −1345,60 (11,5) | +201 | −3782,01 | Reversion of air current |
3 | 5 | 997,34 (0) | −41 | 86,41 (0,7) | −207 | −910,93 | |
4 | 5 | 777,93 (0) | −42 | 233,04 (0) | −4 | −544,89 | |
4 | 9 | 2353,86 (0) | −616 | 1955,01 (0) | −425 | −398,85 | |
5 | 8 | 1775,27 (0) | −315 | 319,45 (0,7) | −10 | −1455,82 | |
6 | 7 | 1022,15 (0) | −64 | 287,07 (2,5) | −5 | −735,08 | |
6 | 11 | 1414,26 (0) | −277 | −1632,66 (14,0) | +370 | −3046,92 | Reversion of air current |
8 | 7 | 1373,48 (0) | −367 | 86,30 (0,7) | −414 | −1287,18 | |
7 | 10 | 2395,63 (0) | −40 | 200,77 (1,8) | −1 | −2194,86 | |
8 | 14 | 401,78 (0) | −610 | 405,75 (1,4) | −622 | 3,97 | |
9 | 15 | 1055,82 (0) | 0 | 833,94 (0) | 0 | −221,88 | |
9 | 16 | 1298,04 (0) | −175 | 1121,07 (0) | −131 | −176,97 | |
10 | 12 | 1340,78 (0) | −125 | −1666,88 (13,0) | +193 | −3007,66 | Reversion of air current |
10 | 13 | 1054,85 (0) | −124 | 1867,65 (14,8) | −388 | 812,8 | |
11 | 21 | 1414,26 (14,0) | −500 | −1632,66 (14,0) | +666 | −3046,92 | Reversion of air current |
12 | 21 | 1340,78 (13,0) | −549 | −1666,88 (13,0) | +848 | −3007,66 | Reversion of air current |
13 | 18 | 1054,85 (15,0) | −247 | 1867,65 (29,8) | −775 | 812,8 | |
14 | 17 | 401,78 (0) | −20 | 405,75 (1,4) | −21 | 3,97 | |
15 | 17 | 1055,82 (11,0) | −372 | 833,94 (11,0) | −232 | −221,88 | |
16 | 19 | 1298,04 (6,5) | −374 | 1121,07 (6,5) | −279 | −176,97 | |
17 | 18 | 1457,60 (11,0) | −147 | 1239,69 (12,4) | −106 | −217,91 | |
18 | 19 | 562,98 (5,0) | −30 | 858,54 (8,4) | −71 | 295,56 | |
18 | 20 | 1949,47 (21,0) | −184 | 2248,80 (33,7) | −245 | 299,33 | |
19 | 20 | 1861,02 (11,5) | −154 | 1979,60 (14,9) | −174 | 118,58 | |
20 | 24 | 3810,50 (32,5) | −807 | 4228,40 (48,7) | −993 | 417,9 | |
21 | 22 | 2755,04 (27,0) | −949 | −3299,55 (0) | +1360 | −6054,59 | Reversion of air current |
Branch Number | Branch Nodes | Resistance (kg/m7) | Airflow Rate | Dissipation (Pa) | Depression (Pa) | |
---|---|---|---|---|---|---|
(m3/min) | (m3/s) | |||||
1 | 22 23 | 0.000 | 2368.49 | 39.4748 | 0.000 | 2715.705 |
2 | 24 25 | 0.000 | 3909.00 | 65.1501 | 0.000 | 2397.300 |
3 | 1 3 | 0.100 | 3273.38 | 54.5564 | 297.640 | 0.000 |
4 | 2 4 | 0.120 | 3004.11 | 50.0685 | 300.823 | 0.000 |
5 | 3 6 | 0.400 | 2303.69 | 38.3948 | 589.663 | 0.000 |
6 | 3 5 | 0.150 | 969.70 | 16.1616 | 39.180 | 0.000 |
7 | 4 5 | 0.250 | 719.96 | 11.9994 | 35.996 | 0.000 |
8 | 4 9 | 0.400 | 2284.15 | 38.0692 | 579.705 | 0.000 |
9 | 5 8 | 0.360 | 1689.66 | 28.1609 | 285.494 | 0.000 |
10 | 6 7 | 0.220 | 1001.23 | 16.6872 | 61.262 | 0.000 |
11 | 6 11 | 0.500 | 1302.45 | 21.7076 | 235.609 | 0.000 |
12 | 7 8 | 0.700 | −1295.32 | −21.5887 | −326.251 | 0.000 |
13 | 7 10 | 0.025 | 2296.55 | 38.2759 | 36.626 | 0.000 |
14 | 8 14 | 13.600 | 394.33 | 6.5722 | 587.443 | 0.000 |
15 | 9 15 | 0.000 | 1022.74 | 17.0457 | 0.000 | 0.000 |
16 | 9 16 | 0.375 | 1261.41 | 21.0235 | 165.746 | 0.000 |
17 | 10 12 | 0.250 | 1224.00 | 20.4000 | 104.040 | 0.000 |
18 | 10 13 | 0.400 | 1072.55 | 17.8758 | 127.818 | 0.000 |
19 | 11 21 | 0.900 | 1302.45 | 21.7076 | 424.097 | 0.000 |
20 | 12 21 | 1.100 | 1224.00 | 20.4000 | 457.778 | 0.000 |
21 | 13 18 | 0.800 | 1072.55 | 17.8758 | 255.637 | 0.000 |
22 | 14 17 | 0.450 | 394.33 | 6.5722 | 19.437 | 0.000 |
23 | 15 17 | 1.200 | 1022.74 | 17.0457 | 348.665 | 0.000 |
24 | 16 19 | 0.800 | 1261.41 | 21.0235 | 353.591 | 0.000 |
25 | 17 18 | 0.250 | 1417.07 | 23.6179 | 139.451 | 0.000 |
26 | 18 19 | 0.350 | 566.68 | 9.4447 | 31.221 | 0.000 |
27 | 18 20 | 0.175 | 1922.95 | 32.0491 | 179.750 | 0.000 |
28 | 19 20 | 0.160 | 1828.09 | 30.4682 | 148.530 | 0.000 |
29 | 20 24 | 0.200 | 3909.00 | 65.1501 | 848.906 | 0.000 |
30 | 20 21 | 0.200 | −157.97 | −2.6328 | −1.386 | 0.000 |
31 | 21 22 | 0.750 | 2368.49 | 39.4748 | 1168.697 | 0.000 |
32 | 23 999 | 0.000 | 2368.49 | 39.4748 | 0.000 | 0.000 |
33 | 25 999 | 0.000 | 3909.00 | 65.1501 | 0.000 | 0.000 |
34 | 900 1 | 0.000 | 3273.38 | 54.5564 | 0.000 | 0.000 |
35 | 900 2 | 0.000 | 3004.11 | 50.0685 | 0.000 | 0.000 |
36 | 999 900 | 0.000 | 6277.49 | 104.6249 | 0.000 | 0.000 |
Branch Number | Branch Nodes | Resistance (kg/m7) | Airflow Rate | Dissipation (Pa) | Depression (Pa) | |
---|---|---|---|---|---|---|
(m3/min) | (m3/s) | |||||
1 | 22 23 | 0.000 | 2800.00 | 46.6667 | 0.000 | 3185.883 |
2 | 24 25 | 0.000 | 3477.48 | 57.9580 | 0.000 | 2220.218 |
3 | 1 3 | 0.100 | 3273.37 | 54.5562 | 297.638 | 0.000 |
4 | 2 4 | 0.120 | 3004.11 | 50.0684 | 300.822 | 0.000 |
5 | 3 6 | 0.400 | 2303.68 | 38.3946 | 589.659 | 0.000 |
6 | 3 5 | 0.150 | 969.69 | 16.1616 | 39.179 | 0.000 |
7 | 4 5 | 0.250 | 719.96 | 11.9993 | 35.996 | 0.000 |
8 | 4 9 | 0.400 | 2284.15 | 38.0692 | 579.705 | 0.000 |
9 | 5 8 | 0.360 | 1689.65 | 28.1608 | 285.492 | 0.000 |
10 | 6 7 | 0.220 | 1001.23 | 16.6872 | 61.262 | 0.000 |
11 | 6 11 | 0.511 | 1302.45 | 21.7075 | 241.158 | 0.000 |
12 | 7 8 | 0.700 | −1295.32 | −21.5887 | −326.250 | 0.000 |
13 | 7 10 | 0.025 | 2296.55 | 38.2758 | 36.626 | 0.000 |
14 | 8 14 | 13.600 | 394.33 | 6.5722 | 587.446 | 0.000 |
15 | 9 15 | 0.000 | 1022.74 | 17.0457 | 0.000 | 0.000 |
16 | 9 16 | 0.375 | 1261.41 | 21.0235 | 165.746 | 0.000 |
17 | 10 12 | 0.263 | 1224.00 | 20.4000 | 109.588 | 0.000 |
18 | 10 13 | 0.400 | 1072.55 | 17.8758 | 127.818 | 0.000 |
19 | 11 21 | 0.900 | 1302.45 | 21.7075 | 424.093 | 0.000 |
20 | 12 21 | 1.100 | 1224.00 | 20.4000 | 457.776 | 0.000 |
21 | 13 18 | 0.800 | 1072.55 | 17.8758 | 255.639 | 0.000 |
22 | 14 17 | 0.450 | 394.33 | 6.5722 | 19.437 | 0.000 |
23 | 15 17 | 1.200 | 1022.74 | 17.0457 | 348.665 | 0.000 |
24 | 16 19 | 0.800 | 1261.41 | 21.0235 | 353.591 | 0.000 |
25 | 17 18 | 0.250 | 1417.07 | 23.6178 | 139.450 | 0.000 |
26 | 18 19 | 0.350 | 566.68 | 9.4446 | 31.220 | 0.000 |
27 | 18 20 | 0.175 | 1922.94 | 32.0490 | 179.750 | 0.000 |
28 | 19 20 | 0.160 | 1828.09 | 30.4681 | 148.529 | 0.000 |
29 | 20 24 | 0.200 | 3477.48 | 57.9580 | 671.826 | 0.000 |
30 | 20 21 | 0.200 | 273.55 | 4.5592 | 4.157 | 0.000 |
31 | 21 22 | 0.750 | 2800.00 | 46.6667 | 1633.334 | 0.000 |
32 | 23 999 | 0.000 | 2800.00 | 46.6667 | 0.000 | 0.000 |
33 | 25 999 | 0.000 | 3477.48 | 57.9580 | 0.000 | 0.000 |
34 | 900 1 | 0.000 | 3273.37 | 54.5562 | 0.000 | 0.000 |
35 | 900 2 | 0.000 | 3004.11 | 50.0684 | 0.000 | 0.000 |
36 | 999 900 | 0.000 | 6277.48 | 104.6247 | 0.000 | 0.000 |
Node | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Potential—normal ventilation (Pa) | 0 | 0 | −298 | −301 | −337 | −887 | −949 | −622 | −881 | −985 | −1123 | −1089 | −1113 |
Potential—reversal ventilation (Pa) | 0 | 0 | −298 | −301 | −337 | −887 | −949 | −622 | −881 | −985 | −1128 | −1095 | −1113 |
Node | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | |
Potential—normal ventilation (Pa) | −1210 | −881 | −1046 | −1229 | −1369 | −1400 | −1548 | −1547 | −2716 | 0 | −2397 | 0 | |
Potential—reversal ventilation (Pa) | −1210 | −881 | −1046 | −1229 | −1369 | −1400 | −1548 | −1553 | −3186 | 0 | −2220 | 0 |
© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Share and Cite
Pach, G.; Różański, Z.; Wrona, P.; Niewiadomski, A.; Zapletal, P.; Zubíček, V. Reversal Ventilation as a Method of Fire Hazard Mitigation in the Mines. Energies 2020, 13, 1755. https://doi.org/10.3390/en13071755
Pach G, Różański Z, Wrona P, Niewiadomski A, Zapletal P, Zubíček V. Reversal Ventilation as a Method of Fire Hazard Mitigation in the Mines. Energies. 2020; 13(7):1755. https://doi.org/10.3390/en13071755
Chicago/Turabian StylePach, Grzegorz, Zenon Różański, Paweł Wrona, Adam Niewiadomski, Pavel Zapletal, and Václav Zubíček. 2020. "Reversal Ventilation as a Method of Fire Hazard Mitigation in the Mines" Energies 13, no. 7: 1755. https://doi.org/10.3390/en13071755