Appendix A: Comprehensive Review of Methane Soot Experimental Data. Laminar. Laminar. 2 to 25. atm. atm. atm

Transcription

1 Appendix Appendix A: Comprehensive Review of Methane Soot Experimental Data Experiment Name Miller and Maahs (1977) K.A. Thomson et al. (2005) McCrain and Roberts (2005) Joo and Gülder (2009) in Air Joo and Gülder (2010) in Oxygen Garo et al. (1990) Shaddix and Smyth (1996) Smooke et al. (1999) Fuel Type of experiment (also C 2 H 4 in air) CH 4 in O 2 Coflow flame CH 4 in air Coflow Flame Steady and flickering conditions investigated Pressure Measurements made Attached Reference 1 to 50 Mass concentration of [1] carbon in exhaust Carbon particle density in exhaust NOx emissions Flame temperature 5 to 40 Distributions of soot [2],[3] Soot temperature 2 to Distribution of soot Local peak soot volume fraction Distributions of soot, temperature Distributions of soot, temperature 1 Measurements of soot, mean diameter, and number density along centreline Monodisperse assumption made 1 Soot profiles 1 Spatial measurements of Temperature, major species, and soot [4] [5] [6] [7] [8] [9] A-1

2 Lee et al. (2000) Schittkowski et al. (2002) Seeger et al. (2004) Qamar et al. (2009) Brookes and Moss (1999) Papagiannakis and Hountalas (2004) CH 4 in air and also in O 2 CH 4 in air (Also ethylene in air) Laminar Coflow flame Nonpremixed Coflow flame Nonpremixed Laminar CH 4 in air w/ bluff body Coflow flame Natural Delft Gas 1 in air burner Turbulent Coflow flame Piloted flame 2 Turbulent Piloted flame Natural Single Gas 3 and cylinder CI Diesel engine w/ DI Pilot diesel injection 1 Max size of primary particles vs height Distribution of soot 1 Soot, species, temperature distribution Primary particle radius distribution Primary particle number density distribution 1 Spatial distributions of soot, primary particle size, and major species 1 Distributions of soot PDFs of soot volume fraction Intermittency of soot 1 and to 4.86 (bmep) Distribution of mean soot, mixture fraction, and temperature Radiation intensity Engine out emissions of soot, NO, HC, and CO [10] [11] [12] [13] [14],[15] [16] 1 Simulated Dutch Natural Gas: X CH4 = , X C2H6 = , X C3H8 = , X C4H10 = , X C5H12 = , X C6H14 = , X N2 = , X CO2 = Premixed mixture of hydrogen, acetylene, and air at 3 Natural Gas by volume %: CH 4 = 0.98, C 2 H 6 = 0.006, C 3 H 8 = 0.002, C 4 H 10 = 0.002, C 5 H 12 = 0.001, N 2 = 0.008, CO 2 = A-2

3 Vincitore and Senkan (1997) Zhang et al. (1992) Decroix and Roberts (2000) Beltrame et al. (2001) Mungekar and Atreya (2006) Mueller and Wittig (1994) Diluted CH 4 (25% Ar) with 20% O 2 and 80% Ar as oxidizer CH 4 (varying dilution levels) with a varying oxidizer stream CH 4 (varying dilution levels with N 2 and O 2 ) CH 4 heavily diluted by Ar Counterflow Nonpremixed Laminar Counterflow Nonpremixed Laminar CH 4 in air Counterflow CH 4 in air Counterflow (enriched with O 2 ) Counterflow Partiallypremixed Laminar Shock tube 30 to Centreline measurements of soot s, particle diameters, and number density Centreline measurements of species Measurements have wrong exponents? 1 Detailed measurements of soot particle number density, soot volume fraction, temperature, and species Assumed monodispersed...proba bly Np? 1 2-D images of soot and measurements of peak soot 1 Peak soot volume fractions At least one case with distribution of soot as well 1 Centreline measurements of soot s, species Soot radiation release Time resolved measurements of soot particle size, number concentrations, and soot. (Data unavailable, only abstract was accessible) [17] [18] [19] [20] [21] [22] A-3

4 Kellerer et al. (1996) Kellerer et al. (2000) Agafonov et al. (2008) CH 4 heavily diluted by Ar CH 4 heavily diluted by Ar CH 4 /Ar and CH 4 /Ar/O 2 mixtures Fuel rich Shock tube Fuel rich Shock tube 15 to to 60 Shock tube 5 and 55 Xin and Gore CH 4 in air Turbulent (2005) Fuel into quiescent air Xu et al. (1998) CH 4 in O 2 Premixed flame Xu and Faeth (2000) D Anna et al. (2008) Desgroux et al. (2008) CH 4 in O 2 Premixed Flat flame CH 4 in O 2 Pre-mixed flat flame (McKenna Burner) CH 4 in N 2 Premixed and O 2 flame Measurements of soot particle diameter and number density correlated to temperature and pressure. (However, data for methane is not readily available in paper) Measurements of soot, particle diameters, and number densities correlated to temperature and pressure. (However, data for methane is not readily available in paper) Measurements of soot yield correlated to temperature. 1 Spatial distributions of soot (2-D) 1 Soot and mean particle diameter along axis of flame Temperature and major species along axis of flame 1 Soot s and species as function of height above burner 1 Measurements of organic carbon, soot, and PAH as function of height above burner 0.20 to 0.28 Spatially resolved measurements of soot [23] [24] [25],[26] [27] [28] [29] [30] [31] A-4

5 References for Comprehensive Review of Methane Soot Experimental Data [1] Miller I.M. and Maahs H.G., High-Pressure flame system for pollution studies with results for methane-air diffusion flames, NASA Technical Note, NASA TN D-8407, 1977 [2] Thomson K.A., Gülder O.L., Weckman E.J., Fraser R.A., Smallwood G.J., Snelling D.R., Soot concentration and temperature measurements in co-annular, nonpremixed CH 4 /air flames at pressure up to 4 MPa, Combustion and Flame, vol. 140, pp , 2005 [3] Liu F., Thomson K.A., Guo H., Smallwood G.J., Numerical and experimental study of an axisymmetric coflow laminar methane-air diffusion flame at pressures between 5 and 40 ospheres, Combustion and Flame, vol. 146, pp , 2006 [4] McCrain L.L., Roberts W.L., Measurements of the soot volume field in laminar diffusion flames at elevated pressures, Combustion and Flame, vol. 140, pp , 2005 [5] Joo H.I. and Gülder O.L., Soot formation and temperature field structure in co-flow laminar methane-air diffusion flames at pressures from 10 to 60, Proceedings of the Combustion Institute, vol. 32, pp , 2009 [6] Joo H.I. and Gülder O.L., Soot formation and temperature structures in small methane-oxygen diffusion flames at subcritical and supercritical pressures, Combustion and Flame, vol. 167, pp , 2010 [7] A. Garo, G. Prado and J. Lahaye, Chemical aspects of soot particles oxidation in a laminar diffusion flame, Combustion and Flame, vol. 79, pp , 1990 [8] Shaddix C.R., Smyth K.C., Laser-Induced Incandescence Measurements of Soot Production in Steady and Flickering Methane, Propane, and Ethylene Diffusion Flames, Combustion and Flame, vol. 107, pp , 1996 [9] Smooke M.D., Mcenally C.S., Pfefferle L.D., Computational and Experimental Study of Soot Formation in a Coflow, Laminar Diffusion Flame, Combustion and Flame, vol. 117, pp , 1999 [10] Lee K., Megaridis C.M., Zelepouga S., Saveliev A.V., Kennedy L.A., Charon O., Ammouri F., Soot Formation Effects of Oxygen Concentration in the Oxidizer Stream of Laminar Coannular Nonpremixed Methane/Air Flames, Combustion and Flame, vol. 121, pp , 2000 [11] Schittkowski, T., Mewes, B., Brüggemann, D., "Laser-induced incandescence and Raman measurements in sooting methane and ethylene flames", Physical Chemistry Chemical Physics, Volume 4, Issue 11, pp , 2002 [12] Seeger T., Egermann J., Dankers S., Beyrau F., Leipertz A., Comprehensive Characterization of a Sooting Laminar Methane-Diffusion Flame Using Different Laser Techniques, Chemical Engineering and Technology, vol. 27, Issue 11, pp , 2004 [13] Qamar N.H., Alwahabi Z.T., Chan Q.N., Nathan G.J., Roekaerts D., King K.D., Soot in a piloted turbulent jet non-premixed flame of natural gas, Combustion and Flame, vol. 156, pp , 2009 [14] Brookes S.J. and Moss J.B., Predictions of Soot and Thermal Radiation Properties in Confined Turbulent Jet Diffusion Flames, Combustion and Flame, vol. 116, pp , 1999 [15] Brookes S.J. and Moss J.B., Measurements of soot production and thermal radiation from confined turbulent jet diffusion flames of methane, Combustion and Flame, vol. 116, pp , 1999 A-5

6 [16] Papagiannakis R.G. and Hountalas D.T., Combustion and exhaust emission characteristics of a dual fuel compression ignition engine operated with pilot Diesel fuel and natural gas, Energy Conversion and Management, vol. 45, pp , 2004 [17] Vincitore A.M. and Senkan S.M., Experimental Studies of the Micro-Structures of Opposed Flow Diffusion Flames: Methane, Combustion Science and Technology, vol. 130, pp , 1997 [18] Zhang C., Atreya A., Lee K., Sooting structure of methane counterflow diffusion flames with preheated reactants and dilution by products of combustion, 24 th International Symposium on Combustion (The Combustion Institute), pp , 1992 [19] Decroix M.E. and Roberts W.L., Transient Flow Field Effects on Soot Volume Fraction in Diffusion Flames, Combustion Science and Technology, vol. 160, pp , 2000 [20] Beltrame, A., Porshnev, P., Merchan-Merchan, W., Saveliev, A., Fridman, A., Kennedy, L. A., Charon, O., Soot and NO formation in methane-oxygen enriched diffusion flames., Combustion and Flame, vol. 124(1-2),pp , 2001 [21] Mungekar H.P. and Atreya A., Flame Radiation and Soot Emission From Partially Premixed Methane Counterflow Flames, Journal of Heat Transfer, vol. 128, Issue 4, pp , 2006 [22] Mueller A., Wittig S., Experimental study on the influence of pressure on soot formation in a shock tube, Springer Series in Chemical Physics, Issue 59, pp , 1994 [23] Kellerer H., Müller A., Bauer H.J., Wittig S. Soot Formation in a Shock Tube under Elevated Pressure Conditions, Combustion Science and Technology, vol , pp , 1996 [24] Kellerer H., Koch R., Wittig S., Measurements of the Growth and Coagulation of Soot Particles in a High-Pressure Shock Tube, Combustion and Flame, vol. 120, pp , 2000 [25] Agafonov G.L., Borisov A.A., Smirnov V.N., Troshin K.Y., Vlasov P.A., Warnatz J., Soot formation during pyrolysis of methane and rich methane/oxygen mixtures behind shock waves, Combustion Science and Technology, vo. 180, pp , 2008 [26] Agafonov G.L., Smirnov V.N., Vlasov P.A., Shock tube and modeling study of soot formation during the pyrolysis and oxidation of a number of aliphatic and aromatic hydrocarbons, Proceedings of the Combustion Institute, vol. 33, pp , 2011 [27] Xin Y. and Gore J.P., Two-dimensional soot distributions in buoyant turbulent fires, Proceedings of the Combustion Institute, vol. 30, Issue 1, pp , 2005 [28] Xu F., Lin K.C., Faeth G.M., Soot formation in laminar premixed methane/oxygen flames at ospheric pressure, Combustion and Flame, vol. 115, pp , 1998 [29] Xu, F. and G. M. Faeth, "Structure of the Soot Growth Region of Laminar Premixed methane/oxygen Flames." Combustion and Flame, vol. 121 (4), pp , 2000 [30] D Anna A., Sirignano M., Commodo M., Pagliara R., Minutolo P., An experimental and modelling study of particulate formation in premixed flames burning methane, Combustion Science and Technology, vol. 180, pp , 2008 [31] Desgroux P., Mercier X., Lefort B., Lemaire R., Therssen E., Pauwels J.F., Soot measurement in low-pressure methane flames by combining laser-induced incandescence and cavity ring-down spectroscopy: Effect of pressure on soot formation, Combustion and Flame, vol. 155, pp , 2008 A-6

7 Appendix B: Approach to Updating Model Parameters Here, the steps to updating the model parameters in the simplified model referred to in Section Error! Reference source not found. are outlined and commented on. 1. A sensitivity analysis on all the parameters in the simplified model was performed (See Section Error! Reference source not found.). The effect of each parameter, such as, on the peak calculated sooting behaviour in the wing of the flame is recorded. The effect on centreline sooting behaviour was also noted, but of less interest due to large uncertainties with soot model performance in this region. For example, a factor of two increase in will correspond to a factor of ~1.6 increase in peak soot, 1.9 increase in peak soot inception rate, 1.1 increase in peak soot diameter, etc.. 2. The results of the sensitivity analysis were used to identify the parameters that affect the soot characteristics of interest in the simplified model; namely: soot, soot number density, and soot diameter. The qualitative results are summarized in the table below: Soot Characteristic Soot Soot number density Soot diameter Note - Increases with increasing - Increases greatly with increasing - Not sensitive to - Increases with increasing - Not sensitive to - Not sensitive to - Not sensitive to - Decreases with increasing - Increases slightly with increasing - Increases with increasing - Increases slightly with increasing - Increases slightly with increasing Quantitatively, these results were compiled into an excel spreadsheet where each parameter was assumed to have an independent, multiplicative effect on each soot characteristic. The following example illustrates this statement: A-7

8 Ex. Every parameter is multiplied by two ( and are held constant). Then the final effect on peak soot is estimated to be: Peak soot in wing is expected to increase by a factor of approximately 2.24 The purpose of this was to create a tool to quickly evaluate a set of parameters and provide a first approximation as to what the effect on the subsequent calculation of soot characteristics would be. It is important to note that this was not used to provide meaningful quantitative data, but to establish trends caused by changing model parameters. 3. Using the Smooke et al. [63] dataset as an example, converged simulations are obtained for both the simplified and detailed model (see Section Error! Reference source not found.). The simplified model was found to have a soot that was too low compared to experimental results. As seen in the table in Step 2, nearly every parameter could be the cause of a soot volume fraction that is too low. Additional comparisons to the detailed model for soot diameter and soot number density are also made in order to provide additional insight into which parameters may be problematic. For example, if soot is too low, but soot number density is too high, then increasing the inception rate may no longer be desirable as it will increase soot volume fraction, but also increase soot number density. 4. The soot inception, surface growth, and oxidation rates are compared along a pathline of maximum soot (see Section Error! Reference source not found.). An integrated rate is also calculated by performing a simple trapezoidal sum under the area of each curve (see Error! Reference source not found.) with axial height (z) as the independent variable. In the case of the Smooke et al. [63] data set, the following table summarizes the findings: A-8

9 Peak Rate [mol/cc/sec] (Simplified/Detailed) Integrated Rate [mol/cm 2 /sec] (Simplified/Detailed) Inception 1.6E E E E-06 Simplified 2.5x higher Simplified 6.5x higher Surface Growth 3.4E E E E-04 Detailed 7.0x higher Detailed 3.5x higher O 2 Oxidation 2.6E E E E-05 Detailed 5.8x higher Detailed 2.3x higher OH Oxidation 1.1E E E E-04 Detailed 3.5x higher Detailed 4.6x higher As one can observe, the simplified model predicted a higher inception rate than the detailed model while the detailed model predicted a higher surface growth and oxidation rates both with respect to the local peak rate on the pathline of maximum soot and the integrated rate. For reference, the following table summarizes the same analysis for the improved simplified model: Peak Rate [mol/cc/sec] (Improved Simplified/Detailed) Integrated Rate [mol/cm 2 /sec] (Improved Simplified/Detailed) Inception 1.4E-5 6.5E E E-06 Simplified 2.2x higher Simplified 5.9x higher Surface Growth 7.4E-5 2.4E E-4 1.7E-04 Detailed 3.2x higher Detailed 1.5x higher O 2 Oxidation 5.2E E E-5 8.5E-05 Detailed 2.9x higher Detailed 1.5x higher OH Oxidation 1.9E E E E-04 Detailed 3.5x higher Detailed 2.5x higher 5. Using the results from Step 3 and 4 as a guideline, several new sets of model parameters were formulated and briefly evaluated using the excel tool developed in Step 2 as a first approximation. It should be noted that since the simplified model was found to be most sensitive to the surface growth rate (in Step 1 and 2), a difference of 10% in the surface growth rate will have a far larger A-9

10 effect on the calculation of soot /soot diameter than a 10% difference in inception or oxidation rates. Thus, there was a higher priority in adjusting the surface growth compared to the inception, oxidation, and agglomeration rates. In addition, adjusting the inception, surface, and oxidation rates was based primarily on the integrated rates calculated by the models. If a new set of parameters showed promise (i.e. could potentially improve soot, soot diameter, and soot number density calculations), they were incorporated into the simplified model and a converged solution would be obtained. Steps 3-4 were then repeated. Once a satisfactory set of parameters were arrived at, this process (Steps 3-5) were repeated for the other data sets investigated. It should be noted that while the final version of the improved model still has a peak inception rate that is still higher than the detailed model, the integrated surface growth rates of the two models are much more closely matched. The author concedes that future iterations of this model using this approach could further improve the parameters used (i.e. by reducing the inception rate and further increasing the growth rate), but it should be noted that it is particularly time consuming and computationally expensive procedure. In particular, since the parameters in this model are not, in reality, independent (for example, inception rate decreases as surface growth increases in the simplified model) and also vary differently as the operating condition changes, many iterations are needed to arrive at a desired result. As a further example, if the inception rate is reduced to be on par with the detailed model for the Smooke et al. [63] flame, soot s and diameters are underpredicted by orders of magnitude at the higher pressure flames investigated. As such, this method is best used for providing a direction as to what parameters and in what way they should be adjusted, but not necessarily the magnitude of adjustment, of which is still an iterative process. It is hoped that future improvements to the detailed sectional model will reduce any uncertainties in the inception, surface growth, and oxidation rates that it calculates, making this method a more straightforward process. A-10