Microsoft Word - 1.docx CHEMICAL ENGINEERING TRANSACTIONS VOL. 77, 2019 A publication of The Italian Association of Chemical Engineering Online at www.cetjournal.it Guest Editors: Genserik Reniers, Bruno Fabiano Copyright © 2019, AIDIC Servizi S.r.l. ISBN 978-88-95608-74-7; ISSN 2283-9216 Experimental Determination of the Static Equivalent Pressures of Detonative Explosions of Cyclohexane/O2/N2- Mixtures in Long and Short Pipes (part 2 of 3) Hans-Peter Schildberg*, Julia Eble BASF SE, 67056 Ludwigshafen, Germany hans-peter.schildberg@basf.com The abstract of the second part of this paper is included in the abstract of part 1. The following final results can be derived from the experiments with C6H12/O2/N2: I: Because the focus of the work was not on investigating the bulging in the region of the stable detonation, the entire experimental series only produced two values for the ratio α between the static equivalent pressure of the stable detonation and the Chapman-Jouguet pressure pCJ (fields AC15 and AC16 of Table 1). Both values are larger than what had been found for α in a large number of experiments carried out in the past five years (Schildberg (2013 to 2018)). Because these two values are statistically not relevant and because there is no obvious reason why C6H12/O2/N2 mixtures should exhibit a value for α different from the other investigated explosive mixtures, no effort is invested to track down the reason for this deviation and it is assumed that α = 0.7 as found in the old tests still holds. Further below, α will be needed to calculate the ratio R between the static equivalent pressure at the location of the DDT and the static equivalent pressure of the stable detonation. II: The predetonation distances of the 3 stoichiometric mixtures tested both at Tinitial = 80 °C and Tinitial = 130 °C with almost the same initial pressure (to be compared: test 1 and test 5, 19 and 22, 20 and 25) were on the average 26 % longer at the higher initial temperature. This increase is presumably due to the fact that with rising initial temperature the speed of the initial shock front and henceforth also the speed of the unreacted gas behind the initial shock front (see Fig. 7 in Schildberg 2016) rise as well. Consequently, the deflagrative flame has to attain even higher speeds relative to the pipe wall such that the piston represented by the expanding reaction gases finally produces sufficient compression in the unreacted gas ahead of the flame front such that autoignition occurs in the precompressed zone. III: For 9 mixtures the ratio between pstat_reflected_stable and pstat_stable was measured. All ratios were between 2.06 and 2.9 and the average was 2.38, i.e. pstat_reflected_stable = 2.38 ⋅ pstat_stable This value confirms the value of 2.4 found in previous investigations (Schildberg 2013, 2015, 2016a, 2018). IV: Only for 3 of the 7 tests conducted in short pipes with stoichiometric mixtures (21 vol.-% ≤ O2- concentration in the O2/N2 mixture ≤ 30 vol.-%) a DDT occurred (tests 22, 32, 35). For scenario 5 the result obtained by averaging over the individual ratios of 4.28, 6.35 and 5.42 is: pstat_DDT_short = 5.35 ⋅ pstat_stable DOI: 10.3303/CET1977176 Paper Received: 2 December 2018; Revised: 5 April 2019; Accepted: 25 June 2019 Please cite this article as: Schildberg H.-P., Eble J., 2019, Experimental Determination of the Static Equivalent Pressures of Detonative Explosions of Cyclohexane/O2/N2-Mixtures in Long and Short Pipes (part 2 of 3), Chemical Engineering Transactions, 77, 1051-1056 DOI:10.3303/CET1977176 1051 Figure 3: Examples for residual plastic deformations found in the tests with 48.3x2.6 (tests 1,19 and 22) and 114.3x3.6 (test 32) pipes. Flame propagation was always from left to right, i.e. ignition was always at the left end of the pipes. The steel tape indicates the axial position, i.e. the distance to the ignition source (in units of cm). Figure 4: Examples for the increase of the pipe diameters produced by the detonation experiments, plotted over the distance from the ignition source. Further explanations to these special examples are given in the text. w e ld in g n e c k fla n g e w it h d is p la c e m e n t b o d y w e ld in g n e c k fla n g e w it h o u t d is p la c e m e n t b o d y w e ld in g n e c k fla n g e s 0 5 10 15 20 25 30 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 in c re a s e o f p ip e d ia m e te r [% ] distance from ignition source [mm] Test 19: 14.1 bar abs, 80 °C C6H12 : O2 : N2 = 2.7 : 24.3 : 72.9 [molar fractions] pipe: 48.3x2.6, length: 9390 mm, melt: 836880 w e ld in g n e c k fla n g e w it h d is p la c e m e n t b o d y w e ld in g n e c k fla n g e w it h o u t d is p la c e m e n t b o d y w e ld in g n e c k fla n g e s 0 5 10 15 20 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 in c re a s e o f p ip e d ia m e te r [% ] distance from ignition source [mm] Test 25: 12 bar abs, 130 °C C6H12 : O2 : N2 = 3.2 : 29.0 : 67.7 [molar fractions] pipe: 48.3x2.6, length: 9390 mm, melt: 836880 w e ld in g n e c k fla n g e w it h d is p la c e m e n t b o d y w e ld in g n e c k fla n g e w it h o u t d is p la c e m e n t b o d y w e ld in g n e c k fla n g e s 0 5 10 15 20 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 in c re a s e o f p ip e d ia m e te r [% ] distance from ignition source [mm] Test 32: 3.07 bar abs, 130 °C C6H12 : O2 : N2 = 3.2 : 29.0 : 67.7 [molar fractions] pipe: 114.3x3.6, length: 9570 mm, melt: 878536 w e ld in g n e c k fla n g e w it h d is p la c e m e n t b o d y w e ld in g n e c k fla n g e w it h o u t d is p la c e m e n t b o d y w e ld in g n e c k fla n g e s 0 5 10 15 20 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 in c re a s e o f p ip e d ia m e te r [% ] distance from ignition source [mm] Test 35: 3.17 bar abs, 130 °C C6H12 : O2 : N2 = 3.2 : 29.0 : 67.7 [molar fractions] pipe: 114.3x3.6, length: 9600 mm, melt: 878536 DDT at 4530 mm (s cenario 1) DDT at 3430 m m (s cenario 1) reflection of s table detonation (s cenario 4) reflection of uns table detonation (s cenario 7) DDT at 7910 mm (s cenario 5) DDT at 7540 m m (s cenario 5) reflection of uns table detonation (s cenario 7) reflection of uns table detonation (s cenario 7) Test 1: 20 bar abs, 70 °C, C 6 H 12 = 2.28 vol.-%, O 2 = 20.5 vol.-%, N 2 = 77.2 vol.-% location of DDT (scenario 1) at 3740 mm Test 19: 14.1 bar abs, 80 °C, C 6 H 12 = 2.7 vol.-%, O 2 = 24.3 vol.-%, N 2 = 72.9 vol.-% location of DDT (scenario 1) at 4530 mm 1052 Since R is about 3.7 for the investigated compositions (see further below), this result is in good accordance with the estimation formula for scenario 5 given in Schildberg (2016), i.e. this formula is confirmed: p stat_DDT_short = 1.5 ⋅ R ⋅ p stat_stable = 5.5 ⋅ p stat_stable. V: In the short pipe tests nos. 19, 32 and 35 the different ratios found for scenario 7 are 3.55, 10.84 and 8.44. The result obtained by averaging over the three individual ratios is: pstat_reflected_unstable = 7.6 ⋅ pstat_stable The estimation formula for scenario 7 given in Schildberg (2016) suggests: p stat_reflected_unstable = 1.5 ⋅ 2 ⋅ 2.4 ⋅ p stat_stable = 7.2 ⋅ pstat_stable. The averaged value is in good accordance with the value predicted by the estimation formula. The systematic scattering of the measured values (the values increase when the location of the DDT gets closer to the blind flange) is explained by Figures 5 and 6. Figure 5 gives the pressure distribution just before the DDT occurs. The estimation formula is based on the blue curve which is slightly simplified. The reality is better approximated by the red curve, which is not flat but drops with increasing distance from the flame front. Therefore scenario 7 will generate higher pressure values when the location of the DDT gets closer to the blind flange (x/L = 1), because this will increase the pressure of the unreacted gas ahead of the blind flange at the instant when the detonation front arrives (illustrated in Figure 6). VI: The variation of the ratio R between the static equivalent pressure at the location of the DDT in the long pipe configuration (scenario 1) and the static equivalent pressure of the stable detonation (scenario 3) as function of C6H12 content is shown in Figure 7. The variation of R along the stoichiometric line is qualitatively identical with what had been found for H2/O2/N2, CH4/O2/N2 and C2H4/O2/N2. However, the absolute value of R at C6H12 concentrations close to the concentration of C6H12 in stoichiometric C6H12/air mixtures is about 3.7, and this is less than the corresponding values of R for the other mixtures (ca. 5 for H2/O2/N2, ca. 5.5 for CH4/O2/N2, ca. 5.6 for C2H4/O2/N2). Once R is known, the short pipe scenarios 5 and 8 can be predicted based on the estimation formulae provided in Schildberg (2016a). Figure 5: Difference between idealized and true pressure profile of the initial shock wave. a) DDT occurs in short pipe at large distance from pipe end b) DDT occurs in short pipe close to pipe end Figure 6: Explanation why – on basis of Figure 5 - the pstat-values of scenario 7 increase when the location of the DDT gets closer to the blind flange of the pipe (x/L = 1). All plots show the pressure distribution in the second half of a pipe close to the instant of DDT occurrence. 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1 1 10 100 axial position x/L in pipe p re s s u re /p in iti a l 2 5 50 20 peak of compressed unreacted gas directly ahead of flame front, shortly before DDT occurs pressure/distance profile extending downstream of the high pressure peak up to the initial shockfront propagating into the quiescent mixture is flat in a first order approximation (solid blue line). Actually, it decays slightly with x/L (red dashed-dotted line) quiescent gas mixture, initial pressure is still the same as at the instant of ignition hot reaction products unreacted gas mixture 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1 1 10 100 axial position x/L in pipe p re s s u re /p in iti a l 2 5 50 20 reflected initial shockwave propagates backwards, speed is of the order of 500 m/s DDT has just occurred, shockfront coupled with flame front propagates with about 2000 m/s to x/L = 1 (reflected initial shockwave is still far away from the location where the DDT occurred, i.e. DDT is scenario 1) When the shockfront arrives at x/L=1, the pressure in the unreacted mixture is still about 2⋅pinitial, i.e. scenario 7 delivers half the pressure as in right picture 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1 1 10 100 axial position x/L in pipe p re s s u re /p in iti a l 2 5 50 20 DDT has just occurred, shockfront coupled with flame front propagates with about 2000 m/s to x/L = 1 (reflected initial shockwave has reached the DDT location before the DDT occurred, i.e. DDT is scenario 5) reflected initial shockwave propagates backwards, speed is of the order of 500 m/s When the shockfront arrives at x/L=1, the pressure in the unreacted mixture is about 4⋅pinitial, i.e. scenario 7 delivers twice the pressure as in left picture 1053 Figure 7: Variation of R in dependence on the C6H12-content in stoichiometric C6H12/O2/N2 mixtures at Tinitial = 80 °C and 130 °C. Only the dark-red triangle represents a value for an over-stoichiometric mixture. The orange dashed line is a guide to the eye for the data of the stoichiometric mixtures. 4. Pressure-time diagrams of cyclohexane/O2/N2-detonations recorded for the run-up stage An typical example for pressure/time recordings taken for a test is provided by Figure 8. The individual frames show the signals recorded by 15 pressure sensors distributed along the pipe. The positions are printed in the top left corner of each frame and give the distance from the ignition source. The initial shock wave is too small to be visible in the plots, but the development of the zone of precompressed gas directly ahead of the flame front, the detonation peaks, the retonation peaks and the reflected peaks of detonation and retonation can be seen. The topmost frame displays the current of the arc discharge used as ignition source. The instant when the current attains its maximum value is taken as zero point on the time scale. Note that the distance between P4 and P5 is only half of the distance we had between all other neighboring sensors. Examples for the development of the precompressed zone of unreacted mixture ahead of the flame front in the course of run-up to detonation are shown in Figures 9 to 11. In Figure 9 the pressure peak associated with the precompressed zone of unreacted gas ahead of the flame front is clearly present for the first time at sensor P3. At sensor P4, which was the last pressure measurement upstream of the DDT loction, the peak has attained 470 bar, i.e. at P4 the unreacted gas ahead of the flame front got precompressed by a factor 33.5 = 470bar/14bar. In Figure 10 the precompression factor at sensor P5 will be larger than 83.3 = 1000 bar/12bar (signal of P5 was cut off at 1000 bar). In Figure 11, which displays the pressures in a short pipe, the precompression factor at P9 is 157 = 500bar/3.17bar. In Table 2 all precompression factors found in the experiments are compiled. The values scatter a lot, because the distances between the last pressure sensor upstream of the DDT location and the DDT location vary between 0 and the maximum distance between adjacent pressure sensors, which is 630 mm. Therefore, the maximum precompression factors attained in the precompressed zone of unreacted mixture directly before the DDT occurred will all be larger than the values given in Table 2. When comparing the precompression factors found for stoichiometric cyclohexane/O2/N2- mixtures in long pipes with those found for stoichiometric H2/O2/N2, CH4/O2/N2 and C2H4/O2/N2 at oxygen concentrations between 1 and 1.5 times the O2-concentration of the stoichiometric combustible/air mixture, the factors of Cyclohexane seem to be only about 50 % to 75 % of the values found for the other mixtures, which are in the range of 70 to 130. A comparison of precompression factors found for stoichiometric mixtures in short pipes is not meaningful due to the relatively small number of tests conducted with C6H12. 1054 Figure 8: Pressure/time recordings taken for Test 28 by 15 pressure sensors along the pipe. Note that the distance between P4 and P5 is only half of the usual value. The topmost frame displays the ignition current. -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 100 200 300 cu rr en t [ A ] File: V28, Cyclohexane-O2-N2,30 O2,4.6 C6H12, 12 bar abs,130 C, 48.3x2.6 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 50 100 150 200 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 50 100 150 200 P re ss ur e [b ar a bs ] -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 50 100 150 200 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 250 500 750 1000 P re ss ur e [b ar a bs ] -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 250 500 750 1000 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 100 200 300 400 500 re to n a tio nprecom pressed unreacted m ixture ahead of flam e front reflecte d re to na tio n Pr es su re [b ar a bs ] -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 100 200 300 400 500 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 100 200 300 400 500 P re ss ur e [b ar a bs ] -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 100 200 300 400 500 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 100 200 300 400 500 Pr es su re [b ar a bs ] -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 100 200 300 400 500 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 100 200 300 400 500 P re ss ur e [b ar a bs ] -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 100 200 300 400 500 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 100 200 300 400 500 Pr es su re [b ar a bs ] -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 100 200 300 400 500 Time [ms] re fle ct e d s h o ck f ro n t o f st a b le d e to n a tio n sta b le d e to n a tio n p ro p a g a te s w ith v = 2 0 9 5 m /s (N o te : u n sta b le d e to n a tio n b e tw e e n 2 9 8 0 m m a n d 4 3 0 0 m m , sta b le d e to a n a t io n fro m 4 3 0 0 u p to e n d o f p ip e ) Note: Reflection of stable detonation occurs at 9390 mm at the surface of the displacement body mounted inside the welding neck flange. ignition current P01_630 mm P02_1260 mm P03_1890 mm P04_2520 mm P05_2840 mm (DDT between P5 and P6 at 2980 mm) P06_3470 mm P07_4100 mm P08_4730 mm P09_5370 mm P10_6000 mm P11_6620 mm P12_7260 mm P13_7890 mm P14_8520 mm P15_9150 mm 1055 a) Initial shock wave is propagating with 445 m/s. Furthermore, b) Signal of sensors 4 to 8 in a scale to show the precom- the peak associated with the precompressed zone is visible pressed zone and the peaks of the unstable detonation. Figure 9: Pressure-time recordings characterising the run-up to detonation in a long pipe (Test 20). Figure 10: Pressure-time recordings characterising the run-up to detonation in a long pipe (Test 28). Figure 11: Pressure-time recordings characterising the run-up to detonation in a short pipe (Test 35). File: ....V20 15 15.1 15.2 15.3 15.4 15.5 15.6 15.7 15.8 15.9 16 16.1 16.2 16.3 16.4 16.5 16.6 16.7 16.8 16.9 17 0 100 200 300 400 500 P re ss ur e [b ar a bs ] P04_2840 mm (DDT between P4 and P5 at 3060 mm) 15 15.1 15.2 15.3 15.4 15.5 15.6 15.7 15.8 15.9 16 16.1 16.2 16.3 16.4 16.5 16.6 16.7 16.8 16.9 17 0 200 400 600 800 P05_3480 mm 15 15.1 15.2 15.3 15.4 15.5 15.6 15.7 15.8 15.9 16 16.1 16.2 16.3 16.4 16.5 16.6 16.7 16.8 16.9 17 0 200 400 600 800 P re ss ur e [b ar a bs ] P06_3800 mm 15 15.1 15.2 15.3 15.4 15.5 15.6 15.7 15.8 15.9 16 16.1 16.2 16.3 16.4 16.5 16.6 16.7 16.8 16.9 17 0 200 400 600 800 P07_4120 mm 15 15.1 15.2 15.3 15.4 15.5 15.6 15.7 15.8 15.9 16 16.1 16.2 16.3 16.4 16.5 16.6 16.7 16.8 16.9 17 0 200 400 600 800 P re ss ur e [b ar a bs ] P08_4440 mm Time [ms] unstaböle detonation propagates at average speed of v = 2285 m /s average speed of peak between P3 and P4: 578 m/s = 630mm/1.09ms File: V20, Cyclohexane-O2-N2, 30 O2, 3.35 C6H12, 14 bar abs, 80 C, 48.3x2.6 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 10 20 30 40 50 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 10 20 30 40 50 P re ss ur e [b ar a bs ] 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 10 20 30 40 50 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 10 20 30 40 50 Pr es su re [b ar a bs ] 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 10 20 30 40 50 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 10 20 30 40 50 Pr es su re [b ar a bs ] 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 10 20 30 40 50 Time [ms] P02_1580 mm P03_2210 mm P04_2840 mm (DDT between P4 and P5 at 3060 mm) P05_3480 mm P06_3800 mm P07_4120 mm P08_4440 mm initial shock front propaga tes into un reacted m ixture w hich is at rest and still at the initial pressure w ith v = 445 m /s v = 295 m/s v = 578 m/s File: V28, Cyclohexane-O2-N2,30 O2,4.6 C6H12, 12 bar abs,130 C, 48.3x2.6 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10 10.5 11 11.5 12 12.5 13 13.5 14 0 10 20 30 40 50 P01_630 mm 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10 10.5 11 11.5 12 12.5 13 13.5 14 0 10 20 30 40 50 P re ss ur e [b ar a bs ] P02_1260 mm 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10 10.5 11 11.5 12 12.5 13 13.5 14 0 10 20 30 40 50 P03_1890 mm 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10 10.5 11 11.5 12 12.5 13 13.5 14 0 10 20 30 40 50 P re ss ur e [b ar a bs ] P04_2520 mm 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10 10.5 11 11.5 12 12.5 13 13.5 14 0 10 20 30 40 50 P05_2840 mm (DDT between P5 and P6 at 2980 mm) 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10 10.5 11 11.5 12 12.5 13 13.5 14 0 10 20 30 40 50 P re ss ur e [b ar a bs ] P06_3470 mm 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10 10.5 11 11.5 12 12.5 13 13.5 14 0 10 20 30 40 50 P07_4100 mm Time [ms] v = 375 m/s v = 386 m/s initial shock front propagates into unreacted mixture which is at rest and still at the initial pressure with v = 450 m /s File: V28, Cyclohexane-O2-N2,30 O2,4.6 C6H12, 12 bar abs,130 C, 48.3x2.6 10.5 10.6 10.7 10.8 10.9 11 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 11.9 12 12.1 12.2 12.3 12.4 12.5 12.6 12.7 12.8 12.9 13 0 50 100 150 P03_1890 mm 10.5 10.6 10.7 10.8 10.9 11 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 11.9 12 12.1 12.2 12.3 12.4 12.5 12.6 12.7 12.8 12.9 13 0 250 500 750 1000 P re ss ur e [b ar a bs ] P04_2520 mm 10.5 10.6 10.7 10.8 10.9 11 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 11.9 12 12.1 12.2 12.3 12.4 12.5 12.6 12.7 12.8 12.9 13 0 250 500 750 1000 P05_2840 mm (DDT between P5 and P6 at 2980 mm) 10.5 10.6 10.7 10.8 10.9 11 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 11.9 12 12.1 12.2 12.3 12.4 12.5 12.6 12.7 12.8 12.9 13 0 250 500 750 1000 P re ss ur e [b ar a bs ] P06_3470 mm 10.5 10.6 10.7 10.8 10.9 11 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 11.9 12 12.1 12.2 12.3 12.4 12.5 12.6 12.7 12.8 12.9 13 0 100 200 300 400 500 P07_4100 mm Time [ms] v = 732 m/s v = 1103 m/s v = 2333 m/s File: V35, Cyclohexane-O2-N2, 30 O2, 3.6 C6H12, 3.17 bar abs,130 C, 114.3x3.6 30 30.5 31 31.5 32 32.5 33 33.5 34 34.5 35 35.5 36 36.5 37 37.5 38 38.5 39 39.5 40 0 5 10 15 P03_4210 mm 30 30.5 31 31.5 32 32.5 33 33.5 34 34.5 35 35.5 36 36.5 37 37.5 38 38.5 39 39.5 40 0 5 10 15 P re ss ur e [b ar a bs ] P04_4860 mm 30 30.5 31 31.5 32 32.5 33 33.5 34 34.5 35 35.5 36 36.5 37 37.5 38 38.5 39 39.5 40 0 5 10 15 P05_5500 mm 30 30.5 31 31.5 32 32.5 33 33.5 34 34.5 35 35.5 36 36.5 37 37.5 38 38.5 39 39.5 40 0 5 10 15 20 P re ss ur e [b ar a bs ] P06_6150 mm 30 30.5 31 31.5 32 32.5 33 33.5 34 34.5 35 35.5 36 36.5 37 37.5 38 38.5 39 39.5 40 0 50 100 150 P07_6790 mm 30 30.5 31 31.5 32 32.5 33 33.5 34 34.5 35 35.5 36 36.5 37 37.5 38 38.5 39 39.5 40 0 50 100 150 200 Pr es su re [b ar a bs ] P08_7110 mm 30 30.5 31 31.5 32 32.5 33 33.5 34 34.5 35 35.5 36 36.5 37 37.5 38 38.5 39 39.5 40 0 100 200 300 400 500 P09_7430 mm (DDT between P9 and P10 at 7540 mm) 30 30.5 31 31.5 32 32.5 33 33.5 34 34.5 35 35.5 36 36.5 37 37.5 38 38.5 39 39.5 40 0 100 200 300 400 500 Pr es su re [b ar a bs ] P10_7760 mm 30 30.5 31 31.5 32 32.5 33 33.5 34 34.5 35 35.5 36 36.5 37 37.5 38 38.5 39 39.5 40 0 100 200 300 400 500 P11_8080 mm Time [ms] File: V35, Cyclohexane-O2-N2, 30 O2, 3.6 C6H12, 3.17 bar abs,130 C, 114.3x3.6 37.5 37.6 37.7 37.8 37.9 38 38.1 38.2 38.3 38.4 38.5 38.6 38.7 38.8 38.9 39 0 50 100 150 37.5 37.6 37.7 37.8 37.9 38 38.1 38.2 38.3 38.4 38.5 38.6 38.7 38.8 38.9 39 0 50 100 150 200 P re ss ur e [b ar a bs ] 37.5 37.6 37.7 37.8 37.9 38 38.1 38.2 38.3 38.4 38.5 38.6 38.7 38.8 38.9 39 0 100 200 300 400 500 P re ss ur e [b ar a bs ] 37.5 37.6 37.7 37.8 37.9 38 38.1 38.2 38.3 38.4 38.5 38.6 38.7 38.8 38.9 39 0 100 200 300 400 500 37.5 37.6 37.7 37.8 37.9 38 38.1 38.2 38.3 38.4 38.5 38.6 38.7 38.8 38.9 39 0 100 200 300 400 500 P re ss ur e [b ar a bs ] P07_6790 mm P08_7110 mm P09_7430 mm (DDT between P9 and P10 at 7540 mm) P10_7760 mm P11_8080 mm 500 Time [ms] v = 901 m/s v = 1488 m/s unstable detonation propagates at a speed of v = 2303 m /s (basis: (tim e from P10 to P15 at 9370m m ) v = 901 m/s v = 467 m/s v = 397 m/s v = 532 m/s v = 609 m/s 1056