1、1+g:s5.1fNATIONALADVISORYCOMMIITEEFOR AERONAUTICSTECHNICAL NOTE 3829EFFECT OF PRESSURE ON THE SPONTANEOUS IGNITIONTEMPERATURE OF LIQUID FUELSBy Cleveland ONeal, Jr.Lewis Flight Propulsion LaboratoryCleveland, OhioWashingtonOctober 1956AFWXProvided by IHSNot for ResaleNo reproduction or networking pe
2、rmitted without license from IHS-,-,-TECH LIBRARY KAFB, NM -NATIONAL ADVISCRY CCMMITT13EFOR AERONAUTICS Iilllllllllullllrlllllll!l=DoLL75iTECHNICAL NE 3829IGNITIONEFFECT OF PRESSURE ON THE SPONTANEOUSTEMPERATURE OF LIWID FUEISBy Cleveland ONeal,Jr.SUMMARYSpontaneous ignition temperatures from 1 to 9
3、 atmospheres weremeasured in air for -heptane (straight-chainparaffin), isooctane(branched-chainpsreffin), benzene (aromatic),and 3P-4 and JP-5 fuels.A 125-cc Erlenmeyer flask W6S employed as the ignition ch-er, andfuel was injected in a solid stream (no spray) into the flask enclosedin a bonib. Fue
4、l chsrges were varied to obtain the lowest temperatureat which ignition occurs. Time lags before ignition were measured ateach pressure for all fuels. AU fuels that were tested showed a decrease in the spontaneousignition temperature as the pressure was raised; the rate of decrease. was greatest in
5、the range of 1 to 3 atmospheres. The total decrease ofthe spontaneous ignition temperature over the pressure range consideredwas 276 C for benzene, 236 C for isooctane, 6CP C for n-heptane and.JP-4 fuel, and 41 C for W-5 fuel.The difference in the spontaneous ignition temperature of two fuelsat 1 at
6、mospherebecomes less at a higher pressure. For example, JT-4and W-5 fueM differ by 250 C at 1 atmosphere and by 13C at 9atmospheres.Two set fuels that were specified as JP-4 showed a constant differ-ence of about 20 C in the spontaneous ignition temperature over theexperimentalpressure range”. By pe
7、rcolation of the fuel samples throughsilica gel, the spontaneous ignition temperature of the fuel with thehigher value was reduced by aroximately 10 to 12 C.From a Mmited nuoiberof ignition lag experiments with isooctane, 467 to 2310 C; n-heptane, 2500 to 191 C; JP-4 fuel,272 to 210 C; JP-5 fuel, 24
8、7 to 206d.2. In general, the spontaneous ignition temperature decreased sharplyas the pressure was raised from 1 to 3 of 4 atmospheres. At higher pres-sures, very little change took place. j3. Two different samples of Jl?-4fuel showed a constant difference inthe spontaneous ignition temperature of a
9、pproximately20 C over the gentire pressure range. By percolating the fuels through silica gel thedifferencewas reduced to 10 C.4. The difference in the spontaneous ignition temperature of twofuels at a low pressure cannot be used fdr estimating the respectivespontaneous ignition temperatures at high
10、er pressures, because differencessre greatly reduced when pressure is raiqed.5. For -heptane, a plot of time lag before ignition against thereciprocal of temperature yields a line with some curvature. The straightportion of the ignition lag - temperature curves for each of the threefuel charges at t
11、hree pressures gave an average activation energy of21,000 caloriesper mole. ,Lewis Flight Propulsion Laboratory . .National Advisory Committee for AeronauticsCleveland, Ohio, Jiily10, 19561.2.3.4.Setchkin, Nicholas P.:Liquids. Jour. Res.pp. 49-66.REFERENCESSelf-IgnitionTeeratures of CombustibleNat.
12、Bur. Standards, VO153,no. 1, July 1954,Zdbetakis,M. G., Furno, A. L., and Jones, G. W.: Minimum SpontaneousIgnition Temperatures of Conibustibl in Air. Ind. and Eng. Chem.,vol. 46, no. 10, Oct. 1954, pp. 2173-2178.Tausz, J., and Schulte, F.: Determination of Ignition Points of LiquidFuefi .?+ 96.0 1
13、.6040 3.72 206 403 .62 47.4 .7960 5.07 2cQ 392 .74 51.6 .8680 6.45 185 383 i1.07 82.2 1.37100 7.80 l.sl 376 1.36 103.2 1.72120 9.15 I_81 376 1.24 66.0 1.1oOoctal87267L590518487469458448-6.05.48.424.038.680.484.076.60.10.09.14.443.661.341.401.28014204060801001171.001.952.363.725.076.457.808.954673553
14、102702532432372310.08.1785.62.621.071.071.07Benzene o204060801001161.002.363.725.076.457.808.9062654450038536034636011571011932725680655680.0.(58.37.37 .37.37.37.57.8.418.031.243.234.825.820.40.14.30.52.72.58.43.34(P-4 : -0 1.00 272 522 O.m 6.0 0.1020 2.36 235 455 r .3-7 46.2 .7740 3.72 224 435 .50
15、73.8 1.2360 5.07 219 426 .62 78.0 1.3080 6.45 217 423 .74 74.4 1.24100 7.80 210 410 1.07 106.2 1.77116 8.90 210 410 1.07 101.4 1.69JP-5477419410403403396403020406080100U61.002.363.725.076.457.808.902472152102062062022069.673.875.050.452.842.010.8O.ls1.231.25.84.88.70.18.62.62.62.62.62,Provided by IH
16、SNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA TN 3829 I-3,.TABLE 11. - ANALYSIS DATA FOR JP-4 FUEL BEFOREAND AFT PERCOLATION THROUGH SILICA GELProperty I Fuel At=Initial boiling 144point, OFFinal boilingpoint, %Reid vapor pressure,lb/sq in.Hydrogen-carbon r
17、atioHeat of ccmibustion,cal. (est.)Aniline point, FMolecular weightStoichiometricfuel-air ratioAromatics, volumepercentSpontaneous ignitiontemperature, C, at1 atm9 atmI 4742.60.168.8,675139.3134.0677SL.4252188After18,775159.85.0260194Fuel B IBefore1524822.30.17118,725141.11310.0675io.3272210After18,
18、825162.31.3273200a71a15Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA TN 38297YK6LEIII. - TIME IAGS BEFORE IGNITIONFOR -HEPTANE W13!HTHREE FU6L CHARGES AT THREE PRESSTIRESrempera- Pressure, atmkure Oc 2.36 5.07. 7.80Fuel cherge; cd”0.17 0.37 0.
19、68 0.17 0.37 0.68 0.17 0.37 0.68Ignition la.gj sec270 - - 3.0 - - - - - -260 3.0 3.6 4.8 - 2 ?4 2.7 - - -250 4.2 5.7 7.2 2.7 3.3 4.5 1.2 2.1 3.0240 6.6 8.4 10.5 3.9 4,2 7.2 2.4 3.0 4.2230 U*1 15.3 17.4 6.0 6.9 10.2 4.2 4.5 5.7225 - - 23.4 6.6 - - - - -220 19.8 24.3 - 10.2 10.5 17.1 7.2 7.5 9.3217 -
20、- - 13.5 - - 9.3 - -210 - - - - 23.1 35.1 - 13.2 18.3206 - - - - - - - 19.8 -.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-m We valveFTemue gw3A. mob8aTatimsweeprigurm1. - 9p3ntane0us Igmitiontqatura appzatusfa highpr,a.Provided by IHSNot for Resa
21、leNo reproduction or networking permitted without license from IHS-,-,-16 NACA TN 3829.1221141071100,LOv644-i2s572-500428-356t660620500-FuelO Benzene540 u IsooctaneQ -HeptaneTailedsymbolsdenote1 checkolnts500- m 1,1!;460-I,420. I 380- I n34.0 v d d1b 300 I260 - , dL220 & A &180 v2 3 4 5 6 7 8 9 10Ii
22、iiiiii iiiPressure,atm(a) Pure”hydrocarbons.Figure2. - Effectof pressure”onspontaneousIgnLtiontelnperatureofliquldfuelsin air.,.“Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-17300Tailed symbolsdenote “checkpoints7v260vFuel220 N v A1 -.- v B f180 (
23、b) ZP-4 fuel.260220 h &AMOo 2 4 6 8 10Pressure,atm(c) JT-5 fuel.Figure 2. - Continued.ignitiontanperatureEffect of pressureon spcdaneousof liquidfuels in air.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-1812211481076100 O“500426I356660620 cJ560Fue
24、lV JP-4 (“A”)540 reptaneo Benzene500?460420380- i E - 0340& 300 K 260 * L- -220 -w . w - .- AA _ o-1800 1 “2 3 4 ,5 : 6 7 6 9 10Figure2. -Of llquldConcluded.EffectfuelsIn air.Fressure,atm(d)All,fuels.of preeagre.onspontaneousQtion temperature.Provided by IHSNot for ResaleNo reproduction or networkin
25、g permitted without license from IHS-,-,-NACA TN 38294C.2ClCa)i!4.11.3 1.9Pressure,atm0 2.365.07: 7.80Reciprocal of temperature, l/Tj %(a) Fuel charge, 0.17 cubic centimeter.Figure 3. - Time lags before ignition as a functionofreciprocal of tempe=ture for -heptaue in airat various pressures.Provided
26、 by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-20 NACA TN 38291.8Pressure,atm2.365.077.601.9 2.0 : 2.1 -Reciprocal of temperature,-l/T, OK(b) Fuel charge, 0.37 cubic cwtimeter.Figure3. - Continued.Timelagsbeforeignitionas a functionofreciprocal of tmrperatu
27、refor-heptane in air at variouspressures.2X1O-3.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-21NACA TN 38294(2(I1I 1.9Pressure, .aimo 2.365.07: 7.802.0 2.1Reciprocal of temperature, l/T, %(c) Fuel charge, 0.68 cubic centimeter. 2.2xlo-3Hgure 3. - Concluded. Time lags before ignitimas a function of reciprocalof temperaturefor=-heptane in air at variouspressures.NACA -Langley Field, Va.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
