Fire re Suppre ression ssion Simulation lation Stu Study Kshitij (KD) D) Deshm hmukh, Ph.D.
Background und Automa Au matic tic Fire re Extingu inguish ishing g Systems ms (AFES FES) Pro rotec ect against st fuel el fi fires res ins nsid ide e milita litary y and nd commer mercial cial ve vehicles hicles (air, land, nd, and nd sea) – Occupant areas – Cargo areas – Engine compartments – Landing gear bays
Why y model l Fire Suppressio ession n Sys ystems ms? Design igning ing the e system m is difficul icult – Nozzle type, placement, suppressant concentration – Especially in a cluttered volume Simul mulation tion is a cost-sa savin ving g tool to evalua aluate e and nd optimi imize ze the design sign before re test st & build uild STAR AR-CC CCM+ + is uni niquel uely y suit ited d for this s simul mulation: tion: – Complicated geometries – Complex multiphase physics – Fuel combustion – Suppression chemistry – Generation and transport of toxic gases – Other crew survivability criteria
Fire Suppress ession ion Simulatio lation n Stu Study Effective fire suppression agents are mostly HFC HFC materials have high Global Warming Potential (GWP) & Ozone depletion potential (ODP) - thousands of times that of carbon dioxide Fire Suppression Simulation study – To test out concept agents without expensive testing and experiments – To optimize agent bottle location to maximize suppression efficacy – To minimize delivery dosage of agent concentration for suppression to keep adverse effects below lowest acceptable level – To simulate actual vehicle and tactical scenarios using exploratory test box simulation setup and experimental test data 5 supp ppression ression agen ents ts simul mulated d over ver 4 year ars Only y FM20 200+ 0+SBC BC disc scuss ussed ed here re FM200 200 = C 3 HF HF 7 (liq iqui uid) d) & SBC = NaHCO CO 3 (soli lid) d)
Geometr try: : Explorat rator ory y test box Mesh 158K Cells, Walls @ 130 F Ref. Fire Extinguishing Agents for Protection of Occupied Spaces in Military Ground Vehicles, Steven E. Hodges, Steven J. McCormick, Fire Technology, Volume 49, Issue 2 , pp 379-394
Phys ysic ics s Models ls Tra rans nsient ient • St Start at fir fire det etect ction on • Model el fir fireball ll buil ild up Ana nalys lysis is • Model el for small ll tim ime past dis ischar harge ge Turb rbulence lence • K-epsil silon on • Reali lizable ble wall ll funct ctions ons Mo Mode del • Segregat gated ed solver lver Lag agra rangian ngian • Two wo-way y coupli pling ng • Evaporati ation n for li liquid id dro roplets plets Physics ysics • Devola lati tili liza zati tion & combu bustion stion of solids lids Liq iquid id Fuel el • Liq iquid d spray y usin ing g dro rople plet t dis istr tributi ution on • Aut Auto o fla flash sh Inj njec ectio tion • Cont ntinuous nuous in inje ject ction on
Phys ysic ics s Models ls Suppre Su pressant ssant • Mim imic ic rele lease se from rom pressur suriz ized ed bot ottle tle • Bot oth h li liquid id and vapor phase Di Disc scharge arge • Di Dischar harge e tap apers s wit ith fal alli ling ng pressure sure Combu mbustion stion • Hybrid id EBU w/ fin finite e rate e kin inetics etics • 14 14 species s & 12 reacti tions ons reduce ced set et Mode Mo del • Soot as trans nspor ported ed scalar lar Su Suppre pression ssion • Catalyt lytic c & non on-cata catalyti ytic c effe fect cts • Succes ess s crit iteria eria = thermal rmal + chemical mical Mecha Me hanisms nisms • Ac Acid id gases s monit nitored ored Rad adiation iation • Partic ticipati ating g media ia DOM S4 • User-code coded d absor orpti ption on coeffic icie ient Mo Model del • WSGG model for CO2, H2O & Soot
Fire Suppress ession ion animation ation # 1 1
Fire Suppress ession ion animation ation # 2 2
Crew ew Surviv ivability bility Criter eria ia Consi side dere red d in in Parame Pa rameter er Require ireme ment nt CFD? D? Fire suppression Extinguish all flames w/o reflash < 2 nd degree burns over 10 sec Skin burns Overpressure < 11.6 psi Agent concentration Below adverse effect level Acid gases < 746 ppm over 5 minutes (HF + HBr + 2 COF 2 ) Oxygen level > 16% Discharge noise Below hearing protection limit × Discharge forces Not to exceed 8g ×
Explor orat atory y test box results lts comparis ison on Crit iter eria Above ve Design n conc. c. Belo low w design gn conc. c. Experiment CFD Experiment CFD Overall PASS SS PASS SS FAIL IL FAIL IL Extinguish all flames YES YES YES NO HF acid (PPM) < 20 47 3975 N/A COF2 acid (PPM) <20 97 1550 N/A O2 levels 17.4% 18.0% 16.5% N/A Set etup tailor ored ed to capture success essful ful suppression ession rather than suppression ession failu lure re
Applic lication ation to Nozz zzle le design ign I II Nozzle zzle conf nfig iguratio ations I II Discharge harge pattern erns: s: Fire re Ball l (red) ed), SBC (yello ellow), ), FM200 200 (Blue) Blue)
Summar ary Challenge: – Fire suppression system design is challenging due to demanding requirements, cluttered environments, and complex physics. – Development efforts include many design / test / fail / repeat cycles. Solution: – CFD-based simulation of the fire suppression event predicts whether the design will meet suppression success criteria. – STAR-CCM+ is unique in having this capability in a general-purpose CFD tool. Impact: – Reduction in time and cost by evaluating and optimizing on virtual designs prior to test. – Minimal development effort due to commercial, off-the-shelf CFD tool. – Improved occupant survivability in case of a fire. Fire Suppre pressi sion n Modeling ng using ng Comput utational ational Fluid d Dynamic amics, s, Vamshi M. Korivi, Bradley A. Williams, Steven J. McCormick, Kshitij Deshmukh, 2014 NDIA Ground Vehicle Systems Engineering & Technology (GVSETS) Symposium, Novi, MI, 14 th August 2014, http:/ p://ww /ww2. 2.esd.or esd.org/ g/gvse gvsets/
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