mechanical smoke extraction for large fire loads in the gotthard base ...
mechanical smoke extraction for large fire loads in the gotthard base ...
mechanical smoke extraction for large fire loads in the gotthard base ...
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
MECHANICAL SMOKE EXTRACTION FOR<br />
LARGE FIRE LOADS IN THE GOTTHARD<br />
BASE TUNNEL<br />
6th International Conference<br />
TUNNEL SAFETY AND VENTILATION<br />
Graz, Austria: 23. – 25.04. 2012<br />
Christoph Brander, Pöyry Infra AG, Switzerland<br />
Mechanical <strong>smoke</strong> <strong>extraction</strong> <strong>for</strong> <strong>large</strong> <strong>fire</strong> <strong>loads</strong> <strong>in</strong> <strong>the</strong> Gotthard Base Tunnel<br />
23.-25.April 2012<br />
1
CONTENT<br />
The exhaust system at <strong>the</strong> Gotthard Base Tunnel<br />
Subject of <strong>in</strong>vestigation<br />
Simulation and model<strong>in</strong>g<br />
– Smoke exhaust plenum<br />
Results<br />
– Exhaust gas temperatures<br />
– Concrete and rock temperatures<br />
– Mass and volume flow, exhaust fan operat<strong>in</strong>g po<strong>in</strong>t<br />
Measures<br />
Mechanical <strong>smoke</strong> <strong>extraction</strong> <strong>for</strong> <strong>large</strong> <strong>fire</strong> <strong>loads</strong> <strong>in</strong> <strong>the</strong> Gotthard Base Tunnel<br />
23.-25.April 2012<br />
2
THE EXHAUST SYSTEM AT THE GOTTHARD BASE TUNNEL (1)<br />
Two s<strong>in</strong>gle-track tunnels,<br />
length 57 km<br />
2 multifunction stations<br />
4 emergency stations<br />
2 ventilation stations<br />
(Faido, Sedrun)<br />
8 fans, of which 4 <strong>smoke</strong><br />
exhaust fans with flow<br />
rate of 250 m 3 /s<br />
Installed <strong>mechanical</strong><br />
power up to 2500 kW<br />
Lengt of <strong>smoke</strong> exhaust<br />
plenums: 2150 – 4340 m<br />
Mechanical <strong>smoke</strong> <strong>extraction</strong> <strong>for</strong> <strong>large</strong> <strong>fire</strong> <strong>loads</strong> <strong>in</strong> <strong>the</strong> Gotthard Base Tunnel<br />
23.-25.April 2012<br />
3
THE EXHAUST SYSTEM AT THE GOTTHARD BASE TUNNEL<br />
Mechanical <strong>smoke</strong> <strong>extraction</strong> <strong>for</strong> <strong>large</strong> <strong>fire</strong> <strong>loads</strong> <strong>in</strong> <strong>the</strong> Gotthard Base Tunnel<br />
23.-25.April 2012<br />
4
SUBJECT OF INVESTIGATION<br />
Scenario of <strong>the</strong> study: Activ <strong>smoke</strong> exhaust system with a <strong>fire</strong> on a…<br />
– …passenger tra<strong>in</strong>. Fire load 20 MW with<strong>in</strong> 70 m<strong>in</strong>, up to 40 MW with<strong>in</strong> 360 m<strong>in</strong>.<br />
Total <strong>fire</strong> length: 480 m<strong>in</strong>.<br />
– …freight tra<strong>in</strong> or a tra<strong>in</strong> carry<strong>in</strong>g heavy good vehicles: Fire load 250 MW with<strong>in</strong> 30<br />
m<strong>in</strong>. Total <strong>fire</strong> length: 180 m<strong>in</strong>.<br />
Subject of <strong>in</strong>vestigation:<br />
– Air and concrete temperatures <strong>in</strong> <strong>the</strong> <strong>smoke</strong> exhaust plenums<br />
– Aerodynamic behaviour of <strong>the</strong> system (pressure loss, fan operation po<strong>in</strong>t,<br />
bouyancy…)<br />
Mechanical <strong>smoke</strong> <strong>extraction</strong> <strong>for</strong> <strong>large</strong> <strong>fire</strong> <strong>loads</strong> <strong>in</strong> <strong>the</strong> Gotthard Base Tunnel<br />
23.-25.April 2012<br />
5
NUMERICAL SIMULATION<br />
Boundary conditions<br />
– Complex exhaust plenum<br />
system<br />
– High air temperatures<br />
– Variation <strong>in</strong> air/<strong>smoke</strong> density<br />
– Altitude difference<br />
– Variation <strong>in</strong> pressure drop<br />
– No regulation of <strong>the</strong> fans<br />
(constant caracteristic)<br />
Numerical simulation:<br />
– Aerodynamic model 1D <strong>in</strong> flow<br />
direction<br />
– Comb<strong>in</strong>ed <strong>the</strong>rmodynamic<br />
models <strong>for</strong> concrete and rock<br />
Mechanical <strong>smoke</strong> <strong>extraction</strong> <strong>for</strong> <strong>large</strong> <strong>fire</strong> <strong>loads</strong> <strong>in</strong> <strong>the</strong> Gotthard Base Tunnel<br />
23.-25.April 2012<br />
6
RESULTS – EXHAUST GAS TEMPERATURE (1)<br />
Significant cool<strong>in</strong>g of <strong>the</strong><br />
exhaust gas<br />
Large length of <strong>the</strong><br />
exhaust system<br />
Maximum exhaust gas<br />
temperature rises with<br />
time due to lower mass<br />
flow<br />
(1) Partition wall, multifunctional station<br />
(2) Access tunnel<br />
(3) Exhaust fan<br />
Mechanical <strong>smoke</strong> <strong>extraction</strong> <strong>for</strong> <strong>large</strong> <strong>fire</strong> <strong>loads</strong> <strong>in</strong> <strong>the</strong> Gotthard Base Tunnel<br />
23.-25.April 2012<br />
7
RESULTS – EXHAUST GAS TEMPERATURE (2)<br />
Fire dim<strong>in</strong>ishes after<br />
180 m<strong>in</strong><br />
Increas<strong>in</strong>g<br />
temperatures<br />
Large amounts of heat<br />
stored <strong>in</strong> <strong>the</strong> concrete<br />
surround<strong>in</strong>g<br />
Mechanical <strong>smoke</strong> <strong>extraction</strong> <strong>for</strong> <strong>large</strong> <strong>fire</strong> <strong>loads</strong> <strong>in</strong> <strong>the</strong> Gotthard Base Tunnel<br />
23.-25.April 2012<br />
8
RESULTS – CONCRETE AND ROCK TEMPERATURE<br />
Critical variable <strong>for</strong> assess<strong>in</strong>g <strong>the</strong> impact of <strong>the</strong> <strong>fire</strong> on <strong>the</strong> concrete<br />
Small fraction of heat arrives at a depth of 30 cm<br />
Radial shell model and l<strong>in</strong>ear layer model lead to almost identical results,<br />
dist<strong>in</strong>ction is important <strong>for</strong> longer observation periods and smaller<br />
dimensions<br />
Mechanical <strong>smoke</strong> <strong>extraction</strong> <strong>for</strong> <strong>large</strong> <strong>fire</strong> <strong>loads</strong> <strong>in</strong> <strong>the</strong> Gotthard Base Tunnel<br />
23.-25.April 2012<br />
9
RESULTS – EXHAUST GAS DENSITY / VOLUME FLOW<br />
Exhaust gas density > 1kg/m 3 at fan station<br />
Decreas<strong>in</strong>g mass flow with <strong>in</strong>creas<strong>in</strong>g temperatures<br />
exhaust gas density<br />
volume flow<br />
Mechanical <strong>smoke</strong> <strong>extraction</strong> <strong>for</strong> <strong>large</strong> <strong>fire</strong> <strong>loads</strong> <strong>in</strong> <strong>the</strong> Gotthard Base Tunnel<br />
23.-25.April 2012<br />
10
RESULTS – VOLUME FLOW, FAN OPERATION POINT<br />
Increas<strong>in</strong>g system pressure loss,<br />
Aerodynamic and eng<strong>in</strong>e power capacity needed<br />
Maximum bouyancy:1670 Pa (Faido) and 5000 Pa (Sedrun)<br />
3 % system pressure change with 40 MW <strong>fire</strong> load<br />
Mechanical <strong>smoke</strong> <strong>extraction</strong> <strong>for</strong> <strong>large</strong> <strong>fire</strong> <strong>loads</strong> <strong>in</strong> <strong>the</strong> Gotthard Base Tunnel<br />
23.-25.April 2012<br />
11
THANK YOU FOR YOUR ATTENTION!<br />
CONTACT:<br />
Name: Christoph Brander<br />
Mail: christoph.brander@poyry.com<br />
Phone: 0041 76 356 2217<br />
Mechanical <strong>smoke</strong> <strong>extraction</strong> <strong>for</strong> <strong>large</strong> <strong>fire</strong> <strong>loads</strong> <strong>in</strong> <strong>the</strong> Gotthard Base Tunnel<br />
23.-25.April 2012<br />
12
Change language