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The effect of air flow rate on smoke stratification in longitudinal tunnel ventilation

Abstract

The construction of tunnels is associated with mining. For safety and suitable working conditions, it is necessary to ensure that there is suitable ventilation during construction. During operation, tunnels form the infrastructure of the area, which has a number of characteristics. Tunnel ventilation is designed with regards to many different factors. Longitudinal ventilation is especially used in one-way, extra-urban tunnels but in some cases also in urban or two-way tunnels. The article describes the purpose and types of tunnel ventilation, focusing on longitudinal ventilation and ventilation design strategy. Longitudinal tunnel ventilation is the cause of significant turbulence that affects the smoke stratification. The article compares different tunnel ventilation options in terms of selected strategies and the different values of applied airflow rates. A case study was conducted on the Klimkovice road tunnel in the Czech Republic using the fire model from the Fire Dynamics Simulator. The study compares the effect of airflow rate on smoke stratification. The study was conducted with air flow rate values of 0 to 5 m.s-1. The results of the study show that even with lower airflow rates, the smoke build-up is so significant that the safety of individuals in the tunnel cannot be ensured. The dynamicity of fire is also an important factor. Opting for a lower airflow rate strategy because of higher expected congestion or other factors is a questionable practice. Greater airflow rates, however, create better conditions for evacuating individuals, although it is also necessary to combine smoke stratification options with the selected ventilation strategy.

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The effect of air flow rate on smoke stratification in longitudinal tunnel ventilation

Author: Pokorný, Jiří
Publisher: Technická univerzita Košice, Fakulta baníctva, ekológie, riadenia a geotechnológií
Year: 2019
Source: https://dspace.vsb.cz/bitstreams/7ddc619c-190b-419b-a48e-77853f64f9a4/download
Ac a Mon anis ica Slo aca Volume 24 (2019), numbe 3, 173-187
173
The e ec o Ai Flow Ra e on Smoke S a i ica ion in Longi udinal
Tunnel Ven ila ion
Jiří Poko ný
1
, Lenka B uma o á
1
, Pe Kuče a
1
, Joze Ma inka
2
,
Adam Thomi zek
1
and Pa el Zaple al
3
The cons uc ion o unnels is associa ed wi h mining. Fo sa e y and sui able wo king condi ions, i is necessa y o ensu e ha he e
is sui able en ila ion du ing cons uc ion.
Du ing ope a ion, unnels o m he in as uc u e o he a ea, which has a numbe o cha ac e is ics. Tunnel en ila ion is designed wi h
ega ds o many di e en ac o s. Longi udinal en ila ion is especially used in one-way, ex a-u ban unnels bu in some cases also in u ban
o wo-way unnels.
The a icle desc ibes he pu pose and ypes o unnel en ila ion, ocusing on longi udinal en ila ion and en ila ion design s a egy.
Longi udinal unnel en ila ion is he cause o signi ican u bulence ha a ec s he smoke s a i ica ion. The a icle compa es di e en
unnel en ila ion op ions in e ms o selec ed s a egies and he di e en alues o applied ai low a es.
A case s udy was conduc ed on he Klimko ice oad unnel in he Czech Republic using he i e model om he Fi e Dynamics
Simula o . The s udy compa es he e ec o ai low a e on smoke s a i ica ion. The s udy was conduc ed wi h ai low a e alues o 0 o 5
m.s
-1
.
The esul s o he s udy show ha e en wi h lowe ai low a es, he smoke build-up is so signi ican ha he sa e y o indi iduals in he
unnel canno be ensu ed. The dynamici y o i e is also an impo an ac o . Op ing o a lowe ai low a e s a egy because o highe
expec ed conges ion o o he ac o s is a ques ionable p ac ice. G ea e ai low a es, howe e , c ea e be e condi ions o e acua ing
indi iduals, al hough i is also necessa y o combine smoke s a i ica ion op ions wi h he selec ed en ila ion s a egy.
Keywo ds: sa e y, unnel, i e, longi udinal en ila ion, smoke s a i ica ion
In oduc ion
Tunnel cons uc ion mus go hand in hand wi h sa e y. In he case o unnelling, he e is a necessi y o supply
esh ai o he exposed ace o unnel ubes. The design equi emen s o en ila ing unnels a en' as speci ic as
in, o example, gassy o non-gassy mines; howe e , he e is always he necessi y o supply esh ai o he
wo kplace.
The mos limi ing ac o s in en ila ing unnels a e he gases ca bon dioxide, monoxide, ni ogen oxides and
hyd ogen sulphide.
The ac ual en ila ion o he mined unnels depends on he p o ile and leng h o he exca a ion wo k. Fo
example, sho unnelling ac i i y can be en ila ed by na u al en ila ion o by di usion, p o ided he limi
concen a ions o he abo e gases a e no exceeded.
In o he cases, i is necessa y o use a i icial en ila ion (sepa a e), which is p o ided by ans usually loca ed
in on o he exca a ion po al and lu es, which b ing esh ai o he ace, o ice e sa used ai om he ace.
In such cases, i is blow o suc ion en ila ion, he mos commonly used ype o en ila ion being he blow ype,
especially wi h espec o he pu chase cos s o lu es, which may no ha e ein o cemen s, as in he case o he
suc ion ype o en ila ion. In excep ional cases, o example, when using unnelling pla o ms, o when
pe o ming small-p o ile unde g ound wo ks o ex usions whe e sepa a e en ila ion canno be es ablished, i
can be en ila ed by comp essed ai .
Gene ally, in unnelling, he e a e wo basic ac o s o conside when designing he ype o en ila ion,
namely blas ing and he associa ed exhaus en ila ion a e blas ing ope a ions, and he use o diesel engines,
which, apa om elec ic mo o s, a e he only kind ha can wo k and ope a e in unde g ound wo kspaces.
Du ing ope a ion, oad unnels a e a complex s uc u e, equipped wi h a numbe o cons uc ion elemen s and
acili ies ha enable i o ope a e, and in many cases con ibu e o ensu ing sa e y. I s ipula es he echnical and
main enance equi emen s o unnels longe han 500 m (Eu opean Pa liamen Di ec i e 2004/54/ES).
The sa e y equi emen s o building oad unnels a e gi en by na ional egula ions o each indi idual
coun y. Examples a e Road Tunnel Ven ila ion, Design, Dimensioning and Equipmen , ASTRA 13001 om
Swi ze land (ASTRA 13001, 2008), RABT 2006 Tunnel Equipmen and Ope a ion Guidelines om Ge many
(RABT, 2006), Tunnel Ven ila ion - Basic P inciples Aus ian Resea ch Associa ion o Roads, Rail and
T anspo om Aus ia (RVS 09.02.31 2008) Manual 021 No wegian Public Roads Adminis a ion S anda d
1
Jiří Poko ný, Lenka B uma o á, Pe Kuče a, Adam Thomi zek, VSB – Technical Uni e si y o Os a a, Facul y o Sa e y Enginee ing,
Lumí o a 630/13, 700 30 Os a a – Výško ice, Czech Republic, ji i.poko ny@ sb.cz, [email p o ec ed], [email p o ec ed],
[email p o ec ed]
2
Joze Ma inka, Slo ak Uni e si y o Technology in B a isla a, Facul y o Ma e ials Science and Technology in T na a, Jána Bo u
2781/25, 917 24 T na a, Slo ak Republic, [email p o ec ed]
3
Pa el Zaple al, VSB
-
Technical Uni e si y o Os a a, Facul y o Mining and Geology, 17. lis opadu 2172/15, 708 00 Os a a – Po uba,
Czech Republic, [email p o ec ed]
Jiří Poko ný, Lenka B uma o á, Pe Kuče a, Joze Ma inka, Adam Thomi zek and Pa el Zaple al: The e ec o Ai Flow Ra e on
Smoke S a i ica ion in Longi udinal Tunnel Ven ila ion
174
Road Tunnels 03.04 om No way (Manual 021, 2004)DMRB Volume 2 Sec ion 2 Pa 9 (BD 78/99) Design
(subs uc u es and special s uc u es). Special s uc u es. Design o oad unnels om G ea B i ain (DMRB,
1999) o NFPA 502 S anda d o Road Tunnels, B idges, and O he Limi ed Access Highways om he Uni ed
S a es (NFPA 502, 2017).
In he Czech Republic and Slo akia, hese equi emen s a e go e ned by go e nmen dec ees (Go e nmen
dec ee no. 269/2009; Go e nmen dec ee no. 344/2006), echnical s anda ds ČSN 737507, 2013; STN 737507,
2008) and me hodical ins uc ions issued by minis ies (Ma aso á e al., 2010).
Unde he Eu opean Pa liamen Di ec i e (EU) no. 305/2011 (which s ipula es he ha monized condi ions o
in oducing cons uc ion p oduc s on he ma ke and epeals EU di ec i e 89/106/EHS), one o he condi ions
oad unnels mus also comply wi h a e i e sa e y equi emen s (Regula ion (EU) No 305, 2011). The
equi emen s include secu ing he load-bea ing p ope y o he s uc u e, limi ing he sp ead o i e inside and
ou side he s uc u e, ensu ing he e acua ion and he sa e y o indi iduals and secu ing he sa e y o escue
uni s. Sa e y s anda ds o unnels a e also gi en by he Wo ld Road Associa ion (Wo ld Road Associa ion
PIARC, 2019).
Ope a ing oad unnels is his o ically associa ed wi h a ious eme gency si ua ions. One o he mos
dange ous si ua ions is i e, signi ican examples being he inciden in 1982 a he unnel in Salang, A ghanis an,
whe e 176 people died, he i e in he Mon blanc unnel in F ance in 1999, which killed 39 people, and he
Go ha d unnel in Swi ze land in 2001, whe e mo e han 100 people los hei li es. O he no able examples
include he i e in he unnel on he highway be ween Flo ence and Bologna in 1993, which killed ou people,
he i e in he P ände unnel nea B egenz in Aus ia in 1995, also killing ou people, and he i e in he unnel
nea Pale mo in 1996, which killed i e people. The causes o hese i es we e ei he oad acciden s o ca i es.
(Wo ld Road Associa ion PIARC, 2019)
F om 2013 o 2018, he Czech Republic expe ienced i e oad unnel i es (Poko ny e al., 2018). Compa ed
o he a e age o al numbe o i es in he Czech Republic, which is a ound 20,000, his igu e is negligible (Fi e
Rescue Se ice, Czech Republic, 2019). Despi e his and no signi ican loss o li e o damage o p ope y and he
en i onmen , his o ical e en s demons a e ha he consequences o i es in unnels can be de as a ing.
(K očo á, 2015)
In o de o mi iga e eme gency si ua ions, unnels mus be p epa ed s uc u ally, echnically and
o ganisa ionally (Yang, 2016) by he enginee ing a chi ec , cons uc ion company, unnel ope a o and escue
uni s (especially he i e escue se ices and police). One o he mos impo an equi emen s o secu ing he
sa e y o unde g ound s uc u es is en ila ion. The equi emen s o unnel en ila ion a e simila o he
equi emen s o gene al abo eg ound s uc u es (Poko ny and Gondek, 2016).
I is possible o classi y oad unnel en ila ion in o s anda d ope a ing en ila ion, eme gency en ila ion
( i es), and en i onmen ally iendly en ila ion. In pa icula , s anda d ope a ional equi emen s can be
unde s ood as hose ensu ing a sui able en i onmen o pe sons who may be p esen . Eme gency ope a ion
means c ea ing condi ions ha ensu e he sa e e acua ion o pe sons and e ec i e in e en ion o escue uni s.
En i onmen al en ila ion should ensu e a minimal impac o he unnel ope a ion on he en i onmen . (ASTRA
13001, 2008; Minis y o T anspo , Depa men o Roads, 2013; Tomaško á and Va go á, 2018).
The aim o his s udy was o de e mine he e ec o longi udinal unnel en ila ion on he sa e y o
indi iduals and he e ec i eness o i e se ices unde a gi en s a egy and he e o e also he di e en ai low
a e alues. The a icle in es iga es whe he some s a i ica ion o smoke emained using low ai low a es.
Ma e ial and Me hods
Tunnel i e en ila ion
Tunnel i e en ila ion is a suppo ing measu e o he e acua ion and escue o indi iduals and also suppo s
escue uni s.
Fo he design o i e en ila ion in unnels, he essen ials a e he ollowing (ASTRA 13001, 2008; NFPA
502, 2017):
 a ic in ensi y and mode,
 unnel leng h,
 ope a ing mode (one-way o wo-way).
Based on he abo e c i e ia, unnels can be di ided in o he ollowing ca ego ies o en ila ion pu poses
(ASTRA 13001, 2008; Minis y o T anspo , Depa men o Roads, 2013):
 unnels wi h unidi ec ional a ic and low p obabili y o conges ion (ca . T1, usually highway unnels),
 unnels wi h unidi ec ional a ic and a high p obabili y o conges ion (ca . T2, usually highway
unnels),
 unnels wi h wo-way a ic (ca . T3).
The ollowing concep s (s a egies) a e applied in designing i e en ila ion (Minis y o T anspo , Road
Depa men , 2013):
Ac a Mon anis ica Slo aca Volume 24 (2019), numbe 3, 173-187
175
 na u al (longi udinal) en ila ion (sui able o sho unnels o T1 unnels),
 longi udinal en ila ion, ixed ins alla ion (sui able o unnels o T1 unnels),
 longi udinal en ila ion wi h ai low egula ion a de ined alues (sui able o T2 and T3 unnels),
 ans e se en ila ion (sui able o T2 and T3 unnels).
The gi en classi ica ion was pu in place in he Czech Republic. In p inciple, howe e , i is also used o
many o eign coun ies whe e he classi ica ion may be modi ied.
Fo longi udinal en ila ion in unnels, he equi ed ai low a e is essen ial. Ai low eloci y equi emen s
a y somewha in he design guidelines and a e lis ed in Table 1 o cla i y.
Table 1. Ai low eloci y se poin s o longi udinal en ila ion
Coun y Cha ac e (ca ego y) unnel Requi ed low a e
o longi udinal
en ila ion (m.s
-1
) No e
F ance
(Annexe n° 2,
2000)
one-way ex a-u ban unnels 3
one-way u ban unnels
3 ecommended o unnels up
o 500 m long
1 - 2
(Phase 1)
3
(Phase 2)
Phase 1 - he e acua ion o
pe sons
2nd phase - suppo o
escue uni s
bidi ec ional 3
Czech Republic
(Minis y o
T anspo ,
Depa men o
Roads, 2013)
unidi ec ional unnels wi h a
lowe incidence o conges ion
(T1)
c i ical ai eloci y up
o 10 he c i ical speed is
gene ally abou 3 m.s
-1
unidi ec ional unnels wi h a
highe incidence o conges ion
(T2) 1.2
bidi ec ional unnels (T3) 1.2
Ge many
(RABT, 2006)
unidi ec ional unnels wi h a
lowe incidence o conges ion 2.3 – 3.6 depends on unnel slope,
unnel ube shape
( ec angula , hipped) and
i e in ensi y
unidi ec ional unnels wi h a
highe incidence o conges ion 1.5
bidi ec ional unnels (T3) 1.5
Ne he lands
(Huijben e al.
(2006)
No dependen on unnel
cha ac e is ics 2.5
No way
(Manual 021,
2004)
unnels longe han 500 m and
inclined ≥ 2 ° min. 2 i e en ila ion is speci ied
by calcula ion
o he unnels
wi h inclina ion < 2 ° 2 i e in ensi y 5 MW
3.5 i e in ensi y 20 MW
Aus ia
(RVS 09.02.31
(2008)
No dependen on unnel
cha ac e is ics 2 o ai olume low in he
unnel 120 m
3
.s
-1
Swi ze land
(ASTRA 13001,
2008)
unidi ec ional unnels wi h a
lowe incidence o conges ion
(RV 1) 3
unidi ec ional unnels wi h a
highe incidence o conges ion
(RV 2) 1.5 - 3 depending on he unnel
g adien and di ec ion o
en ila ion
bidi ec ional (GV) 1.5
Slo akia
(TP 049, 2018)
one-way a ic wi h a low
p obabili y o conges ion
(common highway unnels) (A)
1.5 - 2
(1 – 1.5 o excep ional
bidi ec ional a ic)
phase 1 - he e acua ion o
pe sons
in he case o smoke
ex ac ion wi h longi udinal
en ila ion 1.5 - 2 m.s
-1
om
bo h sides o he ex ac ion
poin
one-way a ic wi h a high
p obabili y o conges ion
(common highway unnels) (B) 1 – 1.5
wo-way a ic unnels (C) 1 – 1.5
all a ian s c i ical ai eloci y up 2nd phase - suppo o
Jiří Poko ný, Lenka B uma o á, Pe Kuče a, Joze Ma inka, Adam Thomi zek and Pa el Zaple al: The e ec o Ai Flow Ra e on
Smoke S a i ica ion in Longi udinal Tunnel Ven ila ion
176
o 10 escue uni s
ini ia ion upon he demand
o escue uni s
Uni ed S a es o
Ame ica
(NFPA 502, 2017)
No dependen on unnel
cha ac e is ics
c i ical ai eloci y up
o 10
2.54 – 2.95 la ge-scale es s
G ea B i ain
(DMRB 1999) No dependen on unnel
cha ac e is ics
1.3 i e ou pu 3 MW
3 i e ou pu 25 MW
7 i e ou pu 25 MW
Table 1 shows ha in unidi ec ional unnels wi h a lowe incidence o conges ion, c i ical speeds a e
gene ally equi ed. In unidi ec ional unnels wi h a highe incidence o conges ion, i is usually equi ed o
educe he ai low a e below he c i ical speed ( he low a e educ ion is in he ange o 1.2 – 1.5 m.s
-1
).
Con e sely, highe ai low a es will cause a mo e in ense in lux o smoke o he unnel (smoke s a i ica ion
will be quickly in e up ed, and he smoke will be channelled in one di ec ion).
The i e en ila ion design is s ongly linked o isk analysis. Risk analysis de e mines he choice o ype and
s a egy o he en ila ion sys em. The gene al echniques o isk analysis a e applied o e alua e isk in oad
unnels ( o example, ČSN EN 31010, 2011; ČSN ISO 31000, 2018).
Fi e design
An impo an ac o in designing unnel en ila ion is he i e scena io mos likely o de elop i e (Hauku
Ingason e al., 2015; ISO 16733-1, 2015; KUČERA e al., 2009). The hea ou pu o he i e scena io in ela ion
o he numbe o hea y uck ehicles pe uni o ime ( ypically a day) and he leng h o he unnel is 5, 30 and
50 MW. Di e en hea ou pu s can be de e mined in he isk analysis. (Minis y o T anspo , Roads
Depa men , 2013). A hea ou pu alue o 30 MW is ypically conside ed in a i e en ila ion design.
Fi e en ila ion design and s a egy in unnels
Jus as in o he buildings and s uc u es, he mo emen o smoke c ea ed du ing a unnel i e is a ec ed by
se e al ac o s ha ange om low o high impo ance. The main ac o s a ec ing he mo emen o smoke in
unnel s uc u es a e as ollows (Poko ny and Gondek, 2016):
 he unnel’s geome y,
 chimney e ec ,
 e ec o s a iona y ehicles,
 wind,
 buoyancy e ec c ea ed by he i e,
 inc eased gas olume,
 en ila ion equipmen .
When i e en ila ion is designed o unnel s uc u es, hese a e impo an ac o s ha mus be conside ed.
Sui able s a egies a e applied o en ila e oad unnels. The s a egy o longi udinal unnel en ila ion
depends on he cha ac e is ics o he unnel in e ms o a ic di ec ion (one-way o wo-way) and he p obabili y
o conges ion occu ing (low o high). Fi e en ila ion should ul il i s gi en unc ion in he selec ed s a egy.
The aim o longi udinal en ila ion in unnels ope a ing wi h one-way a ic and a low p obabili y o
conges ion (T1) is o channel (expel) he smoke in he di ec ion o ehicle a ic and p e en i sp eading
owa ds s a iona y ehicles. The c i ical ai low a e is ypically be ween 2.5 o 3 m.s
-1
. (ČSN 737507, 2013)
The aim o longi udinal en ila ion in unnels wi h one-way a ic and a high p obabili y o conges ion (T2)
o in wo-way a ic unnels (T3) is o channel he smoke and limi i s sp ead, o else dec ease i s low a e and
c ea e he condi ions o smoke s a i ica ion o a ce ain pe iod o ime. Gene ally, he ai low a e used is 1.2
m.s
-1
. (ČSN 737507, 2013)
The c i ical gas low a e is de ined as he a e ha ensu es he smoke is channelled in he di ec ion o ehicle
a ic and limi s i s sp ead owa ds s a iona y ehicles. The c i ical gas low a e and a e age smoke empe a u e
can be de e mined by Kennedy’s model and calcula ed wi h he ollowing equa ions (NFPA 502, 2017):


=

∙

∙
∙∙
∙

∙∙




(1)


=+

∙

∙∙

 (2)
whe e
V
c
c i ical low a e [m.s
-1
]
Ac a Mon anis ica Slo aca Volume 24 (2019), numbe 3, 173-187
177
K
1
F oude numbe , F
-1/3
(0.606) [-]
K
g
slope/g adien ac o [-]
g accele a ion due o g a i y [m.s
-2
]
H heigh o he unnel a he loca ion o he i e [m]
Q con ec i e a io o eleased hea lux [kW]
ρ
a e age densi y o in oduced ai [kg.m
-3
]
c
p
speci ic hea capaci y o smoke [kJ.(kg.K)
-1
]
An a ea pe pendicula o he ai low [m
2
]
T
a e age smoke empe a u e [K]
T a e age in oduced ai empe a u e [K]
Case s udy
Aim o he s udy
The equen ly selec ed s a egies, and he e o e also di e en ai low a es o longi udinal i e en ila ion in
oad unnels, we e e alua ed in he case s udy.
The Klimko ice unnel loca ed in he Mo a ia-Silesian egion nea he ci y o Os a a in he Czech Republic
was selec ed o he case s udy. The Klimko ice unnel is pa o he D47 highway along he Bílo ec – Os a a,
Rudná sec ion. The unnel is designed o one-way a ic wi h wo unnel ubes. The leng h o he unnel is
app oxima ely 1000 m. The wid h o he oad is 9.5 m, and he wid h o he wo-way sidewalks is 1 and 1.2 m,
he heigh o he unnel is 4.8 m. The unnel ubes ha e a longi udinal g adien o 0.6 %. The unnel ubes a e
connec ed wi h i e jumpe s. Longi udinal en ila ion is ins alled in he unnel and consis s o eigh pai s o
en ila o s. The en ila o s comply wi h he s anda d equi emen s o he Czech Republic o emain ope a ional
in empe a u es o 400 °C o 90 minu es. The en ila o s always become ope a ional a e i e seconds. The
unnel commenced ope a ion in 2008.
Fi e model
The ma hema ical i e model used o he case s udy is he Fi e Dynamics Simula o (FDS). The FDS model
is a CFD model de eloped by NIST (Na ional Ins i u e o S anda ds and Technology, Ma yland, USA) and
allows nume ous pa ame e s associa ed wi h i e de elopmen o be se , including he ‘enclosu e olume’ ac o .
The model applies Na ie –S okes equa ions, which a e use ul o e alua ing he lux o smoke mo emen and
also ake hea in o accoun . This i e model uses he Smoke iew so wa e o isualise he nume ical calcula ions.
(Fi e Dynamics Simula o , 2019)
A compu ing g id wi h cell dimensions o 0.5 x 0.5 x 0.5 m was used o calcula ion. The ini ial empe a u e
was se o 15 °C, ela i e ai humidi y a 70 %. The en i onmen al condi ions we e de e mined p ima ily by he
echnical p ope ies o he conc e e linings and he ai low a e in o he compu ing zone.
The inpu assump ions o he s udy
Fo he pu poses o he s udy, he unnel was e alua ed as an isola ed sys em wi hou conside ing ex e nal
e ec s on he po al (such as wind). The poin o o igin o he i e was se a a dis ance o 256 m om he mo e
ele a ed po al in he di ec ion o a ic (app oxima ely one- hi d o he unnel leng h). The main channel o
longi udinal en ila ion was he e o e expec ed o be agains he g adien o he unnel. The hea ou pu o he
i e was simula ed a wo design le els: 5 MW (pe sonal ehicle i e) and 30 MW (small uck o eigh ehicle
i e). The ai low a e o he unnel was se o when en ila ion was no in ope a ion, hese being 0.5 m.s
-1
,
1 m.s
-1
, 1.5 m.s
-1
, 2 m.s
-1
, 2.5 m.s
-1
, 3 m.s
-1
, 3.5 m.s
-1
and 5 m.s
-1
.
The geome y o he unnel and he loca ion o he i e o igin a e shown in Fig. 1.
E alua ion me hod o he s udy
The s udy e alua ed he e ec o ai low a e on e aining smoke s a i ica ion in he unnel. En i onmen
isibili y was selec ed as a limi ing c i e ion. Visibili y was e alua ed a 20 e enly spaced measu emen poin s
along he axis o he unnel (one poin e e y 50 m o he unnel’s leng h) a a heigh o 2.5 m abo e he oad’s
su ace ( he con en ional limi alue o e alua ing he sa e y o indi iduals in espec o smoke om a i e)
(ČSN P CEN/TR 12101-5, 2008). The momen o in e up ion o smoke s a i ica ion was de ined as he momen
when isibili y dec eased o 15 m. This is he con en ional limi alue when panic and a signi ican inc ease in
he di icul y o e acua ion is an icipa ed (Folwa czny and Poko ný, 2006; Hu ley, 2015). Gene ally, he ime o
he sa e e acua ion o indi iduals ia an unp o ec ed eme gency exi is expec ed a 2.5 min (HOSSER, 2013).
The a e o mo emen o indi iduals owa ds an unp o ec ed eme gency exi is ypically gi en as 30 m.min
-1
(ČSN 73 0804, 2010). On he basis o hese assump ions, he dis ance o mo ing indi iduals o a sa e dis ance
was app oxima ely 75 m.

Jiří Poko ný, Lenka B uma o á, Pe Kuče a, Joze Ma inka, Adam Thomi zek and Pa el Zaple al: The e ec o Ai Flow Ra e on
Smoke S a i ica ion in Longi udinal Tunnel Ven ila ion
178
Tunnel geome y
Loca ion o i e in he unnel
Fig. 1. The geome y o he unnel and he loca ion o he i e o igin
Simula ion esul s
The ollowing igu es show he esul s o he i e simula ion model. Fig. 2 shows he empe a u e p o ile a
180 s du ing i e he mal powe 30 MW and he mo emen o smoke nea he i e o igin poin wi hou
en ila ion a 600 s and du ing he i e he mal powe a 5 MW.
Tempe a u e p o ile a i e he mal powe o 30
MW Smoke mo emen wi hou en ila ion and i e powe
o 5 MW
Fig. 2. Rep esen a ion o empe a u e p o ile and smoke mo emen in he enclosed space
The mo emen o smoke nea he i e o igin a 5 MW and 30 MW a 600 s and a ious smoke eloci ies a e
shown in Fig. 3.
The mal powe o i e
5 MW 30 MW
Smoke mo emen a a low a e o 0.5 m.s
-
1
and ou pu o 5 MW Smoke mo emen a a low a e o 0.5 m.s
-
1
and ou pu o 30 MW
Smoke mo emen a a low a e o 1.0 m.s
-
1
and ou pu o 5 MW Smoke mo emen a a low a e o 1.0 m.s
-
1
and ou pu o 30 MW
Smoke mo emen a a low a e o 3.5 m.s
-
1
and ou pu o 5 MW Smoke mo emen a a low a e o 3.5 m.s
-
1
and ou pu o 30 MW
Fig. 3. Demons a ion o smoke mo emen nea he i e o igin a a he mal ou pu o 5 MW and 30 MW
Visibili y was e alua ed a e 100 seconds, 200 seconds, 300 seconds, 400 seconds, 500 seconds, and 600
seconds a e he i e's de elopmen . The dec ease in isibili y o a i e hea ou pu o 5 MW in ela ion o he
simula ed ime and unnel posi ion is
line).
Fig
Fig
.
Ac a Mon anis ica Slo aca V
Visibili y was e alua ed a e 100 seconds, 200 seconds, 300 seconds, 400 seconds, 500 seconds, and 600
seconds a e he i e's de elopmen . The dec ease in isibili y o a i e hea ou pu o 5 MW in ela ion o he
simula ed ime and unnel posi ion is
shown in Figu es 4 o 12
Fig. 4.
Visibili y wi hou en ila ion in ela ion o simula ed ime and posi ion in he unnel
Fig
. 5. Visibili y o he low a e o 0.5 m.s
-1
in ela ion o simula ed ime and posi ion in he unnel
.
6. Visibili y o he low a e o 1.0 m.s
-1
in ela ion o simula ed ime and posi ion in he unnel
sou ce o i e
Ac a Mon anis ica Slo aca V
olume 24
(201
Visibili y was e alua ed a e 100 seconds, 200 seconds, 300 seconds, 400 seconds, 500 seconds, and 600
seconds a e he i e's de elopmen . The dec ease in isibili y o a i e hea ou pu o 5 MW in ela ion o he
shown in Figu es 4 o 12
( he sou ce o
i e is indica ed by
Visibili y wi hou en ila ion in ela ion o simula ed ime and posi ion in he unnel
in ela ion o simula ed ime and posi ion in he unnel
in ela ion o simula ed ime and posi ion in he unnel
(201
9), numbe 3, 173-187
179
Visibili y was e alua ed a e 100 seconds, 200 seconds, 300 seconds, 400 seconds, 500 seconds, and 600
seconds a e he i e's de elopmen . The dec ease in isibili y o a i e hea ou pu o 5 MW in ela ion o he
i e is indica ed by
he ed dashed
in ela ion o simula ed ime and posi ion in he unnel
in ela ion o simula ed ime and posi ion in he unnel
Jiří Poko ný,
Lenka B uma o á, Pe Ku
Smoke S a i ica ion in Longi udinal Tunnel Ven ila ion
180
Fig
.
Fig
.
Fig
.
Fig.
Lenka B uma o á, Pe Kuče a, Joze Ma inka, Adam Thomi zek
Smoke S a i ica ion in Longi udinal Tunnel Ven ila ion
.
7. Visibili y o he low a e o 1.5 m.s
-1
in ela ion o simula ed
.
8. Visibili y o he low a e o 2.0 m.s
-1
in ela ion o simula ed ime and posi ion in he unnel
.
9. Visibili y o he low a e o 2.5 m.s
-1
in ela ion o simula ed ime and posi ion in he unnel
10. Visibili y o he low a e o 3.0 m.s
-1
in ela ion o simula ed ime and posi ion in he unnel
e a, Joze Ma inka, Adam Thomi zek
and Pa el Zaple al:
The e ec o Ai Flow Ra e on
in ela ion o simula ed
ime and posi ion in he unnel
in ela ion o simula ed ime and posi ion in he unnel
in ela ion o simula ed ime and posi ion in he unnel
in ela ion o simula ed ime and posi ion in he unnel
The e ec o Ai Flow Ra e on
ime and posi ion in he unnel
in ela ion o simula ed ime and posi ion in he unnel
in ela ion o simula ed ime and posi ion in he unnel
in ela ion o simula ed ime and posi ion in he unnel
Fig.
Fig
The dec ease in isibili y p esen du ing a i e hea ou pu o 30 MW in ela ion o simula ed ime and
posi ion
inside he unnel is shown on Figu e 13
Fig
Fig.
Ac a Mon anis ica Slo aca V
11. Visibili y o he low a e o 3.5 m.s
-1
in ela ion o simula ed ime and posi ion in he unnel
Fig
. 12. Visibili y o he low a e o 5.0 m.s
-1
in ela ion o simula ed ime and posi ion in he unnel
The dec ease in isibili y p esen du ing a i e hea ou pu o 30 MW in ela ion o simula ed ime and
inside he unnel is shown on Figu e 13
o 21
( he sou ce o i e is indica ed by he ed dashed line).
Fig
. 13.
Visibili y wi hou en ila ion in ela ion o simula ed ime and posi ion in he unnel
14. Visibili y o he low a e o 0.5 m.s
-1
in ela ion o
sou ce o i e
Ac a Mon anis ica Slo aca V
olume 24
(201
in ela ion o simula ed ime and posi ion in he unnel
in ela ion o simula ed ime and posi ion in he unnel
The dec ease in isibili y p esen du ing a i e hea ou pu o 30 MW in ela ion o simula ed ime and
( he sou ce o i e is indica ed by he ed dashed line).
Visibili y wi hou en ila ion in ela ion o simula ed ime and posi ion in he unnel
in ela ion o
simula ed ime and posi ion in he unnel
(201
9), numbe 3, 173-187
181
in ela ion o simula ed ime and posi ion in he unnel
in ela ion o simula ed ime and posi ion in he unnel
The dec ease in isibili y p esen du ing a i e hea ou pu o 30 MW in ela ion o simula ed ime and
( he sou ce o i e is indica ed by he ed dashed line).
simula ed ime and posi ion in he unnel