Experimental and modeling study on ignition characteristics of 2, 5-Dihydrofuran.
The energy crisis and environmental pollution have restricted the development of the society. Searching for sustainable alternative fuels is one of the most promising development tendencies of internal combustion engine industry. The application of ethanol and biodiesel proves the potential of biomass fuels on energy sustainability and emission reduction. Furans and tetrahydrofurans are the second generation biomass fuels produced from agricultural waste [1, 2], such as straw, bagasse. Unlike ethanol as the first generation of biomass fuel, furans and tetrahydrofurans consumed no agricultural resources in the production process and expressed further advantages.
Furans and tetrahydrofurans have been widely researched on internal combustion engines. The feasibility of the application of 2-methylfuran (MF) and 2, 5-dimethylfuran (DMF) on internal combustion engine was studied [3, 4, 5] and conclude that the aldehydes emission and combustion characteristic are better than that of gasoline. Favorable power output and emission characteristics were achieved by addition of 2-methyltetrahydrofuran into gasoline . Matthias et al.  studied the spray and combustion of MF on a GDI engine, concluded that the full load thermal efficiency increased about 10% than that of 95# gasoline through improving compression ratio by 3.5. Combined with EGR, application of blended fuels of furans is a new way to improve the engine performance, emission and fuel economy.
The combustion characteristics of furans and tetrahydrogenfurans have also been comprehensively investigated. Detailed mechanism of furan combustion was developed by Tian et al.  and validated by three sets of low-pressure laminar premixed flame. Chemical kinetic of 2-methylfuran pyrolysis and oxidation was investigated by Somers et al.  and verified by ignition delay times and laminar flames. Xu et al.  optimized that mechanism at high temperature through shock tube experiment and carried out kinetic analysis work. Sirjean et al.  and Somers et al.  separately constructed and verified the kinetic of DMF oxidation. Researchers of Bielefeld University and Lorraine University [13,14, 15] also optimized and validated the kinetic of furans combustion. The detail kinetic of THF oxidation was developed and verified by laminar flames, ignition delay times and combustion velocity by Tran et al. Oxidation model of 2-methyltetrahydrofuran (MTHF) was developed and verified by Moshammer et al.  in 2013. These models can reveal the internal processes of the furans and tetrahydrofurans combustion.
Dihydrofurans (DHFs) are important intermediates in combustion action of furans and tetrahydrofurans and involved in detail mechanisms mentioned above. So, the investigation of DHFs oxidation is of significant for model optimization and understanding the combustion process of furans and tetrahydrofurans accurately. Lifshitz et al.  researched the thermal pyrolysis of 25DHF behind shock waves and discovered the main reactions in low temperature and concluded that 25DHF is less stable than furan and tetrahydrofuran (THF). Sudholt et al.  calculated the bond dissociation energies of carbon-hydrogen on the ring of 25DHF and investigated the derived cetane numbers of 25DHF in an Ignition Quality Tester. Ignition quality is not only a key factor in performance and emissions of internal combustion engines, but also a critical parameter in engine numerical simulation. Accurate ignition delay data measured in the shock tubes can be used in the development and verification of combustion models. In present study, the ignition delay times of 25DHF were measured behind reflected shock waves and the simulation of experiment based on Liu model was carried out. What's more, the comparisons to furan and MTHF were conducted to better perceive the combustion characteristics of 25DHF.
EXPERIMENTAL SETUP AND NUMERICAL APPROACH
The ignition delay data for the present study was collected behind the reflected shock waves. The present shock tube facility which has been described in details previously [20, 21] is consists of a 2000mm long driver section and a 7300mm long driven section, as shown in Figure 1. The driver section and the driven section are separated by a connecting flange (60mm long) with PET diaphragms on both sides.
Diaphragms of different thickness were selected according to the desired initial conditions. Before experiment, the tube is evacuated by vacuum system to the pressure below 1 Pa. High purity helium and nitrogen were mixed with precise quantities and ratios in the driver section to generate shock waves of desired velocities. 25DHF/[O.sub.2]/Ar mixtures were mixed in a 128 L stainless steel tank and kept stationary for at least 12 h to ensure sufficient homogeneousness. Purities of 25DHF, oxygen and argon were 97%, 99.999% and 99.999%, respectively. The mole ratios of the reactant mixtures are shown in Table 1. The O[H.sup.*] chemiluminescence is detected by a 307 [+ or -] 10 nm narrow band filter and a photomultiplier (Hamamatsu, CR131) at the endwall. The travel processes of the shock waves could be detected by four fast-response piezoelectric pressure transducers (PCB, 113B26) which located at the side wall of the driven section. Three time interval counters (Fluke PM6690) measured the times of the waves passing the pressure transducers. All signals were recorded by a Yokagowa DL750 digital recorder. By extrapolation, the incident shock velocity at the end wall could be calculated, which is essential for the calculation of the temperatures behind the shock waves . The ignition delay time is defined as the time interval between the arrival of incident shock wave at the end wall and the intersection of extrapolation of the maximum slope of the O[H.sup.*] radical curve to the zero baseline, as shown in Figure 2.
The ignition processes are simulated in an adiabatic and zero-dimensional homogeneous reactor based on the Senkin code [23, 24]. The calculated ignition delay time is defined as the time interval from the beginning of the reaction to the steepest rise of the temperature. The interaction between reflected shock wave and boundary layer could cause slight rise of pressure before the ignition. This phenomenon is simulated by setting 4%/ms in volume decrease, so the simulation of ignition could be more precise.
EXPERIMENTAL RESULTS AND DISCUSSIONS
Ignition Delay of 2, 5-Dihydrofuran
The experiments were carried out at the equivalence ratios of 0.5 and 1, pressures of 4atm and 10atm, with fixed fuel concentration of 0.5%. Correlation of ignition delay time with pressure, equivalence ratio and temperature was obtained by regression analysis.
[tau] = 2.305 x [10.sup.-2] [[phi].sup.1.49] [p.sup.-0.70] exp(30.057 / RT) (1)
Where [tau] is the ignition delay time in microsecond, and [phi] is the equivalence ratio and p represents the pressure in atm, and T is the temperature in kelvin, R=1.987 x [10.sup.-3] kcal/(mol x K). The correlation fitted the experiment well, as shown in Figure 3 ([R.sup.2]>98%). Note that the correlation is only suitable for the prediction at fuel concentration of 0.5%.
As can be seen from Figure 2, ignition delay times of 25DHF present obvious logarithmic relation with the reciprocal of temperature. The slopes of experiment data are almost the same at different pressures and equivalent ratios and the temperature from 1100 to 1650K, demonstrating the active energy is constant on a large range, as shown in Equation 1. The ignition delay times increase with the decrease of pressure and are lower at the equivalence ratio of 0.5 compared with that at stoichiometric condition. The elevation of the pressure could densify the mixture, so the possibility of molecular collision and the reactivity of reactions would increase and the ignition is accelerated in consequence. At high temperature, the ignition is mainly dominated by the reaction of H+ [O.sub.2] = O+ OH, which can strongly promote the ignition process. The increase of the oxygen concentration at fixed fuel concentration could boost the reactivity of this reaction and accelerate the ignition, thus the ignition delay time is lower at oxygen-rich mixture.
Chemical Kinetic Analysis of 2, 5-Dihydrofuran
2, 5-dimethyalfuran is an important intermediate in combustion of furans and tetrahydrofurans and involves in many chemical kinetic models. In present study, we chose Somers model , Liu model  and Tran model  for the simulation and comparison with experiment. Both Somers model and Liu model are integrated with kinetics of furan, 2-methylalfuran and 2, 5-dimethyalfuran. The furan kinetic of Somers model is from Tian et al.  and Sendt et al. , which contains the sub-mechanism of 25DHF. Validations have been done for the C0-C4 kinetic in Somers model, which could ensure precise simulations. The 25DHF sub-mechanism of Liu model is also from Tian et al.  and was updated based on laminar flame experiments. The C0-C4 chemistry in this mechanism is from [26, 27, 28]. Two reaction pathways related to dihydrofuryl radicals have been added. Tran model was developed by using EXGAS taking into account the specific combustion characteristic of cyclic ethers.
As shown in Figure 4(a). the simulation results presented by the Liu model  are compared to current ignition data. It can be seen that
despite the simulations are higher than that of current experiment at middle-low temperature. the prediction is relatively good at various pressure and equivalence ratio. From Figure 4(b), simulation based on Somers model  is compared to experiment. The calculations of Somers model are low on medium-high temperature and the slopes are higher than that of the experiment on different pressure and equivalence ratio on large temperature range. Overall, there are deviations between experiment and calculation of Somers model, since no DHF combustion data could be dependent on as the development of the model. From Figure 4(c), Tran model  presents lower prediction at high temperatures and higher prediction at low temperatures than the measured value. However, the slope of the calculation result of Tran model is inaccurate. As for the effect of equivalence ratio on ignition delay, the prediction of Tran model is contrary to the actual situation. That may because Tran model is specific for the combustion of tetrahydrofuran.
Figure 5 shows the comparison on the deviations of the three models. By comparison, the prediction of Liu model is generally better, probably because the 25DHF sub-mechanism was updated based on series of fuel studies and two reaction pathways have been added . Reaction path analysis and sensitivity analysis were presented in the following based on Liu model to perceive the combustion characteristics of 25DHF in chemical kinetic perspective.
Reaction Pathway Analysis of 2, 5-Dihydrofuran
As in Figure 6. there are two main ways of the consumption of 25DE1F at 1600K. The major one is to generate [C.sub.4][H.sub.5]0-3([??]) by H elimination and H abstraction at C2 roughly through two reactions: [C.sub.4][H.sub.5]O-3+H=25DHF, 25DHF+H=[C.sub.4][H.sub.5]O-3+[H.sub.2]. The two reactions are active because the bond of carbon-hydrogen on the C2 of 25DHF is very weak , influenced by both the O atom and the double bond. The minor way of 25DHF consumption is to generate tetrahydrofuran-3-yl radical by H addition on C3 through furan25H+H= tetrahydrofuran-3-yl. By comparison, the other H elimination and H addition reactions to generate [C.sub.4][H.sub.5]O-2 and tetrahydrofuran-2-yl radical consume less 25DHF, and the initial decomposition reaction of 25DHF also expressed less influence. The main products of ring opening reactions are relatively simple. The main intermediate species after ring opening process are [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII], propylene etc., so the reactions involved these intermediates would vastly influence the whole ignition process, as shown in Figure 4. The branching ratio to generate [C.sub.4][H.sub.5]O -3 increased by 10.7% at 1600K, as a consequence, [C.sub.3][H.sub.5]Y, s[C.sub.3][H.sub.5] and propylene presented increased production rate.
Sensitivity Analysis of 2, 5-Dihydrofuran
The aim of sensitivity analysis is to find the reactions strongly affecting the ignition. The normalized sensitivity coefficient of the ith reaction (Si) is defined as:
[S.sub.i] = [tau](2[k.sub.i]) - [tau](0.5[k.sub.i])/1.5 [tau]([k.sub.i]) (2)
Where [tau] is the ignition delay time and [k.sub.i] is the reaction rate of the ith reaction in the model.
Sensitivities of the most influential reactions at the pressure of 10atm, temperature of 1250K and 1600K, stoichiometric mixture and fuel concentration of 0.5% are shown in Figure 7. Reaction pathway analysis showed that the main intermediate products are C3H5Y and sC3H5 etc. which are consumed by many sensitive reactions in decomposition process, such as [C.sub.3][H.sub.5]Y +H (+M) < = > [C.sub.3][H.sub.6]Y (+M) and s[C.sub.3][H.sub.5]+[O.sub.2]=C[H.sub.3]CHO+CHO. These reactions are more sensitive at low temperature, indicating that these intermediates have larger influence on the low-temperature ignition. Besides, consumption reactions of small species such as C[H.sub.3] and [C.sub.2][H.sub.2]T, could strongly promote ignition. The prediction deviation of ignition delay time increases at low temperature, while sensitivity of most reactions is higher at that temperature range compared with that at low temperature as shown in Figure 7. This phenomenon indicated that the relatively large prediction deviation of 25DHF at low temperature maybe due to the slight inaccuracy in the rate of dominated reactions or the absence of some reaction pathways at lower temperature.
COMPARISON TO FURAN AND MTHF
A number of studies have been done on furan and 2-methyltetrahydrofuran (MTHF) which are potential biomass fuels. Furan could be used as gasoline octane enhancing additive for its favorable antiknock property. MTHF-gasoline blend is beneficial to power output and emission characteristics . The overall understanding of the combustion characteristic of 25DHF could be achieved by comparing 25DHF with furan and MTHF whose molecule structure are similar to 25DHF.
The ignition delay times of furan were measured by Wei et al.  and the correlation with pressure, temperature and fuel-air radio was conducted at the temperature of 1320-1880 K, pressure of 1.210.4atm, and equivalence ratios of 0.5-2.0 with the fixed oxygen concentration of 2.25%. Wang et al.  studied the ignition characteristic of MTHF and the correlation was also obtained at the pressure of 1.2 to 10atm, temperature of 1000 to 1900K, equivalence ratio of 0.5-2.0, and fuel mole ratio from 0.25% to 1.0%. The formulas obtained by Wei et al.  and Wang et al.  are as follows:
[[tau].sub.Furan] = 9.96 x [10.sup.-4] [[phi].sup.0.663] [p.sup.-0.684] exp(41.9/RT) (3)
[[tau].sub.MTHF] = 4.79 x [10.sup.-5] [p.sup.-0.59] [X.sup.-0.65] [[phi].sup.1.24] exp(37.2/RT) (4)
Where [tau] is the ignition delay time in microsecond, and [phi] is the equivalence ratio and p represents the pressure in atm, and T is the temperature in kelvin, R= 1.987 x [10.sup.-3] kcal/(molK). X is the mole ratio of the fuels.
From Figure 8(a), the ignition delay time of furan is the longest among three fuels and the steepest slope on a large range indicating the relatively higher activity energy. While at low temperature, the ignition delay of 25DHF is the shortest with a gentle slope, showing smaller activation energy. It can be explained based on molecular structure. Compared with furan which contains two double bonds, 25DHF contains only one double bond, expresses less stable structure and lower initial activation energy, and that lead to relatively higher reactivity of 25DHF than that of furan. Lifshitz  researched 25DHF pyrolysis and concluded that the 25DHF is less stable than furan, the same as in this study. The ignition delay of 25DHF approached furan at high temperature, probably due to the similar combustion property of the two fuels at high temperature. At 4atm and 10atm, the ignition delay times of 25DHF and MTHF cross at 1400K and 1460K, separately.
To acquire kinetic understanding of the ignition process of the three fuels, sensitivity analysis was done. Furan model optimized by Xu et al.  was applied for the sensitivity analysis work. The MTHF kinetic model developed and verified in 2013 by Moshammer et al.  was used in the current sensitivity analysis work of MTHF. Liu model was adopted to analyze ignition process of 25DHF.
As shown in Figure 9(a) and Figure 9(b), both furan and 25DHF ignition are greatly prohibited by hydrogenation reaction of furan+H=[C.sub.4][H.sub.5]O-3, which is the largest furan consumption reaction in laminar flames  and ignition behind shock waves . The reason of noteworthy effect of this reaction on 25DHF kinetic is that furan is a relatively stable intermediate in 25DHF ignition. However, the competitive reaction, MF22H=Furan+C[H.sub.3], is one of the most important reactions to promote furan ignition. From Figure 9(c), MTHF-2(+M)=[C.sub.3][H.sub.6]+C[H.sub.3]CHO(+M) is the key reaction which can prohibit MTHF ignition and the competitive reaction MTHF2(+M)=[C.sub.4][H.sub.8]-1+C[H.sub.2]O(+M) is one of the reactions to promote ignition. Unlike furan and MTHF, initial reactions and dehydrogenation reactions of 25DHF perform weak sensitivity to ignition delay, but reactions involved intermediates such as [C.sub.3][H.sub.5]Y and s[C.sub.3][H.sub.5], show greater influence. That may be the causes of the differences in the slope of 25DHF ignition delay times compared with other two fuels, even though the similar molecular structures of the three species. Reactions involved these intermediates should be paid attention to in the optimization of Liu model in the future.
The ignition delay times of 25DHF were measured behind reflected shock waves at the pressures of 4, 10atm, temperatures of 1110-1650K, for the lean ([phi] = 0.5) and stoichiometric ([phi] = 1.0) mixtures with fixed fuel concentration of 0.5%. Reaction pathway and sensitivity analysis were performed by using Liu mech. By comparing the ignition delay and kinetic of 25DHF, furan and 2-methyltetrahydrofuran (MTHF), the combustion characteristics of 25DHF have been realized from a broad perspective. The main conclusions could be summarized as follows:
1. The ignition delay times of 25DHF present obvious logarithmic downward trend as temperature increases and were lower at fuel-air radio of 0.5 than that of stoichiometric mixtures. Correlation of ignition delay time as a function of pressure, equivalence ratio and temperature could be obtained by multivariate linear regression.
2. Compared with Somers model and Tran model, Liu model presented better simulation. Chemical kinetic shows that the reactions involved main intermediate products such as [C.sub.3][H.sub.5]Y and s[C.sub.3][H.sub.5] largely influence the ignition of 25DHF. However, the calculated ignition delay times are higher than current experiment data at low temperature, which is probably due to the lack of some reaction pathways.
3. The ignition delay times of 25DHF are shorter than that of furan and the slopes are smaller than that of furan and MTHF, demonstrating lower activation energy than that of furan and MTHF.
Xiangshan Fan, Xibin Wang, Kangkang Yang, Yaoting Li, Chuanzhou Wu, and Ziqing Li
Xi'an Jiaotong University
[1.] Chheda, Juben N., Rom N-Leshkov, Yuriy. and Dumesic, James A. "Production of 5-hydroxymethylfurfural and furfural by dehydration of biomass-derived mono- and poly-saccharides". Green Chemistry 9(4). 342. 2007. doi:10.1039/b611568c.
[2.] Lange, Jean-Paul., van der Heide, Evert., van Buijtenen, Jeroen. et al. "Furfural-A Promising Platform for Lignocellulosic Biofuels". ChemSusChem 5(1). 150-166. 2012. doi:10.1002/cssc.201100648.
[3.] Ma, Xiao., Xu, Hongming., Jiang, Changzhao, et al. "Ultra-high speed imaging and OH-LIF study of DMF and MF combustion in a DISI optical engine". Applied Energy 122(247-260. 2014. doi:10.1016/j. apenergy. 2014.01.071.
[4.] Daniel, Ritchie., Xu, Hongming., Wang, Chongming. et al. "Combustion performance of 2,5-dimethylfuran blends using dual-injection compared to direct-injection in a SI engine". Applied Energy 98(59-68. 2012. doi:10.1016/i.apenergy. 2012.02.073.
[5.] Wang, Chongming., Xu, Hongming., Daniel, Ritchie. et al. "Combustion characteristics and emissions of 2-methylfuran compared to 2,5-dimethylfuran, gasoline and ethanol in a DISI engine". Fuel 103(200-211. 2013. doi:10.1016/i.fuel.2012.05.043.
[6.] Rudolph, T. W. and Thomas, J. J. "NOx, NMHC and CO emissions from biomass derived gasoline extenders". Biomass 16(1). 33-49. 1988. doi:10.1016/0144-4565(88)90014-5.
[7.] Thewes, Matthias., Muether, Martin., Pischinger, Stefan. et al. "Analysis of the Impact of 2-Methylfuran on Mixture Formation and Combustion in a Direct-Injection Spark-Ignition Engine". Energy & Fuels 25(12). 5549-5561. 2011. doi:10.1021/ef201021a.
[8.] Tian, Zhenyu., Yuan, Tao., Fournet, Rene. et al. "An experimental and kinetic investigation of premixed furan/oxygen/argon flames". Combustion and Flame 158(4). 756-773. 2011. doi:10.1016/i. combustflame.2010.12.022.
[9.] Somers, Kieran P., Simmie, John M., Metcalfe, Wayne K. et al. "The pyrolysis of 2-methylfuran: a quantum chemical, statistical rate theory and kinetic modelling study". Physical Chemistry Chemical Physics 16(11). 5349. 2014. doi:10.1039/c3cp54915a.
[10.] Xu, Nan., Tang, Chenglong., Meng, Xin. et al. "Experimental and Kinetic Study on the Ignition Delay Times of 2,5-Dimethylfuran and the Comparison to 2-Methylfuran and Furan". Energy & Fuels 29(8). 5372-5381. 2015. doi: 10.1021/acs.energyfuels.5b00906.
[11.] Sirjean, Baptiste., Fournet, Rene., Glaude, Pierre-Alexandre. et al. "Shock Tube and Chemical Kinetic Modeling Study of the Oxidation of 2,5-Dimethylfuran". The Journal of Physical Chemistry A 117(7). 1371-1392.2013. doi: 10.1021/ip308901q.
[12.] Somers, Kieran P., Simmie, John M., Gillespie, Fiona. et al. "A comprehensive experimental and detailed chemical kinetic modelling study of 2,5-dimethylfuran pyrolysis and oxidation". Combustion and Flame 160(11). 2291-2318. 2013. doi:10.1016/i. combustflame.2013.06.007.
[13.] Liu, Dong., Togbe, Casimir., Tran, Luc-Sy. et al. "Combustion chemistry and flame structure of furan group biofuels using molecular-beam mass spectrometry and gas chromatography--Part I: Furan". Combustion and Flame 161(3). 748-765. 2014. doi:10.1016/i.combustflame.2013.05.028.
[14.] Tran, Luc-Sy., Togbe, Casimir., Liu, Dong. et al. "Combustion chemistry and flame structure of furan group biofuels using molecular-beam mass spectrometry and gas chromatography--Part II: 2-Methylfuran". Combustion and Flame 161(3). 766-779. 2014. doi:10.1016/i. combustflame.2013.05.027.
[15.] Togbe, Casimir., Tran, Luc-Sy., Liu, Dong. et al. "Combustion chemistry and flame structure of furan group biofuels using molecular-beam mass spectrometry and gas chromatography--Part III: 2,5-Dimethylfuran". Combustion and Flame 161(3). 780-797. 2014. doi:10.1016/i. combustflame.2013.05.026.
[16.] Tran, Luc-Sy., Verdicchio, Marco., Monge, Fabiola. et al. "An experimental and modeling study of the combustion of tetrahydrofuran". Combustion and Flame. 2015. doi:10.1016/j.combustflame.2014.12.010.
[17.] Moshammer, Kai., Vranckx, Stijn., Chakravarty, Harish K. et al. "An experimental and kinetic modeling study of 2-methyltetrahydrofuran flames". Combustion and Flame 160(12). 2729-2743. 2013. doi:10.1016/j.combustflame.2013.07.006.
[18.] Lifshitz, Assa., Bidani, Menashe.and Bidani, Shimon. "Thermal reactions of cyclic ethers at high temperatures. 4. Pyrolysis of 2, 5-Dihydrofuran behind reflected shocks". The Journal of Physical Chemistry 90(22). 6011-6014. 1986. doi:10.1021/j100280a110.
[19.] Sudholt, Alena., Cai, Liming., Heyne, Joshua. et al. "Ignition characteristics of a bio-derived class of saturated and unsaturated furans for engine applications". Proceedings of the Combustion Institute 35(3). 2957-2965. 2015. doi:10.1016/j.proci.2014.06.147.
[20.] Jiang, Xue., Zhang, Yingjia., Man, Xingjia. et al. "Experimental and Modeling Study on Ignition Delay Times of Dimethyl Ether/n-Butane Blends at a Pressure of 2.0 MPa." Energy & Fuels 28 (3):2189-2198.2014. doi:10.1021/ef402277h.
[21.] Tang, Chenglong., Wei, Liangjie., Man, Xingjia. et al. "High temperature ignition delay times of C5 primary alcohols". Combustion and Flame 160(3). 520-529. 2013. doi:10.1016/j.combustflame.2012.11.018.
[22.] Morley, Chris. A chemical equilibrium program for windows. http:// www.c.morley.dsl.pipex.com/.
[23.] Lutz, A. E., Kee, R. J., Miller, J. A. "Senkin: A fortran program for predicting homogeneous gas phase chemical kinetics with sensitivity analysis". Sandia National Labs., Livermore, 1988.
[24.] Kee, R. J., Rupley, F. M., Miller, J. A. "Chemkin-II: A fortran chemical kinetics package for the analysis of gas-phase chemical kinetics". Sandia Report. 1989.
[25.] Sendt, Karina., Bacskay, George B. Mackie, John C. "Pyrolysis of Furan: Ab Initio Quantum Chemical and Kinetic Modeling Studies". The Journal of Physical Chemistry A 104(9). 1861-1875. 2000. doi:10.1021/ jp993537b.
[26.] Gueniche, H. A., Glaude, P. A., Fournet, R. et al. "Rich premixed laminar methane flames doped by light unsaturated hydrocarbons". Combustion and Flame 151(1-2). 245-261. 2007. doi:10.1016/j. combustflame.2007.05.007.
[27.] Husson, B., Bounaceur, R., Tanaka, K. et al. "Experimental and modeling study of the oxidation of n-butylbenzene". Combustion and Flame 159(4). 1399-1416. 2012. doi:10.1016/j. combustflame.2011.12.006.
[28.] Sarathy, S. Mani., Vranckx, Stijn., Yasunaga, Kenji. et al. "A comprehensive chemical kinetic combustion model for the four butanol isomers". Combustion and Flame 159(6). 2028-2055. 2012. doi:10.1016/j.combustflame.2011.12.017.
[29.] Wei, Liangjie., Tang, Chenglong., Man, Xingjia. et al. "High-Temperature Ignition Delay Times and Kinetic Study of Furan". Energy & Fuels 26(4). 2075-2081. 2012. doi:10.1021/ef300336y.
[30.] Wang, J., Wang, X., Fan, X., and Yang, K., "Shock Tube Experimental and Modeling Study of MTHF Ignition Characteristics at High Temperatures," SAE Technical Paper 2015-01-1807, 2015, doi:10.4271/2015-01-1807.
Table 1. Composition of fuel mixtures (in mole fraction) [phi](%) 2,5-DHF(%) [O.sub.2](%) Ar(%) P(atm) 0.5 0.5 5 94.5 4 1 0.5 2.5 97 4/10
|Printer friendly Cite/link Email Feedback|
|Author:||Fan, Xiangshan; Wang, Xibin; Yang, Kangkang; Li, Yaoting; Wu, Chuanzhou; Li, Ziqing|
|Publication:||SAE International Journal of Fuels and Lubricants|
|Date:||Apr 1, 2016|
|Previous Article:||Combined effect of oxygen enrichment and emulsification techniques on performance, emission and combustion of a WCO based CI engine.|
|Next Article:||MMT effects on gasoline vehicles: a literature review.|