README file for modified Bunsen flame technique dataset ======================================================= This file provides a description of the data presented for the laminar flame speed measurements using the modified Bunsen flame technique. The data presented in the file is both the raw data and the processed results. Details regarding the experimental setup, uncertainty in measurements, analysis approach and discussion of the results are documented in the PhD dissertation (Laminar Flame Speed and Stretch Sensitivity of Hydrocarbon Fuels at High Preheat, Pressure and Vitiation), which can be found at http://hdl.handle.net/1853/52216. The data is provided as an excel file and a tab separate text file. Excel file structure -------------------- The excel file contains two sheets viz. Dataset and Modified Bunsen flame technique. The Dataset sheet provides an overview of the measurements performed and the ideal conditions which the results are compared to. It also links to appropriate rows where the corresponding data is presented in the second sheet. The Modified Bunsen flame technique lists all the measurements conditions in a continuous order. The dataset at a given condition are separated from others by horizontal border. This sheet has the following columns: Column Column label Description C–H Fuel mixture Composition of fuel mixture in terms of actual flowrate (metered) and mole fraction of individual species C–E Flowrate (slpm) Flowrate of individual fuel species (methane (CH4), ethane (C2H6) and propane (C3H8)) in standard liter per minute (slpm) F–H Mole fraction (%) Fuel composition in terms of mole fraction of fuel species in the fuel mixture I–U Oxidizer mixture Composition of oxidizer mixture in terms of actual flowrate (metered) and mole fraction of individual species. I–O Flowrate (slpm) Flowrate of individual oxidizer component (air, oxygen (O2), nitrogen (N2), carbon dioxide (CO2), steam (H2O), helium (He)) in standard liter per minute (slpm). There are two columns for air viz. “Air (total)”and “Air”. The distinction is described later in the report. P–U Mole fraction (%) Oxidizer composition in terms of mole fraction of individual components in the oxidizer mixture. To avoid confusion, air is not split as O2 and N2. V Total flowrate (slpm) This is the total fuel and air flowrate exiting the burner. This flowrate accounts of any bypass of the fuel and air mixture and hence is less than the sum of fuel and air flowrate by the amount that was bypassed. W Equivalence ratio Equivalence ratio of the final mixture exiting the burner. X Temperature (K) Temperature, in Kelvin, of the mixture near the exit of the burner. Y Pressure (atm) Pressure, in atmosphere, in the test section. For atmospheric test this pressure is equal to the room pressure. Z Flame speed (cm/s) Calculated flame speed of the mixture, in centimeter per second. AA Normalized flame height (h/D) Estimated height of the Bunsen flame normalized by the diameter of the burner. AB Flame area fluctuation Standard error in the mean flame area measurement. This is calculated for 95% confidence interval and is equal to 1.96 σ/√n, where σ is the standard deviation of the mean flame area measured and n is the number of instances over which the area is averaged. AC Burner type This refers to whether the measurements were performed on an unpiloted straight tube or a piloted contoured burner. AD Burner diameter (mm) Inner diameter of the burner at the exit plane. AE Pilot flame on Indication if the pilot flame was present or not during the data acquisition. AF–AG Room conditions Room temperature and pressure conditions during the experiment. AH Remarks Comments on the conditions during the run. A Default sort order Sort order of the data in the table. It is included so as to easily reset the table back to original order. Not relevant to the data. Note that the data not recorded or available during the experiment is listed as NR. Tab separated file structure ---------------------------- The data entries in the tab separated file follow the same format as the excel file. In addition, the file also lists the number of data points for each dataset. These lines are listed in the file header and are marked by “!” at the beginning of the line. Lines which list multiple numbers of data points refer to same dataset with a change in experiment condition viz. burner diameter or equivalence ratio. Difference between the “Air” and “Air (total)” column ----------------------------------------------------- The Oxidizer mixture column list two values for air flowrate. The “Air (total)” value refers to the value directly metered this is same as the “Air” column except in the case where steam dilution is present. During the experiment to avoid changing the fuel–air mixture composition while varying the flowrate entering the burner, a bypass line was added before the burner. When in use, the flow through the bypass line was metered to determine the flow entering the burner. This was not done once the steam was added because the meter was not rated for high temperature. Instead the fuel–air mixture was mixed before steam was added to it. To adjust the flowrate one would vent part of the fuel–air mixture and then add the steam to the mixture. As a result when steam dilution is present, the equivalence ratio calculations are based on the “Air (total)” flowrate, whereas the oxidizer composition calculations are based on “Air” flowrate value. Note on slpm ------------ The reference standard condition used for calculating the flowrate in slpm is 298.15 K and 1 atm. Last revised: 2014 Jul 23