Determination of the Flame Speed of Methane Muzammil Arshad Mechanical and Aerospace Engineering Department Florida Institute of Technology December 10, 2009

OBJECTIVES To calculate the Laminar flame speed of Methane using Correlations and Chemkin. Verification of calculations experimentally by using a flat flame burner. These are test calculations for my thesis. The calculations and subsequent experiments were done to check the results which should be similar to the flame speeds achieved by Botha & Spalding. Methane flame speeds at different pressures, Temperatures and Molar Concentrations of Oxygen are done before. Project Goal: To calculate the methane flame speed by calculating the Mass flow rate of Methane, nitrogen and oxygen and subsequent experimentation on a test setup. Objectives 1. Calculation of flow rate of methane, nitrogen and oxygen and finding out the subsequent pressures. 2. Finding out the Flame speed using Correlations and Chemkin 3. Running experiments @ various eq. ratios to find out the Laminar flame speeds 4. Comparing the results with Botha & Spalding (also discussed in Glassman) Approach 1. Literature Review 2. Development of a Generic Hydrocarbon Mathematical Model using Excel and Chemkin 3. Development of a Physical setup for experiments 3. Running Experiments 4. Analysis & comparison of results to the previous research 1/1/2019

Literature Review Flat Flame Burner: McKenna Burner Usage: Experiments on Flame stabilization, heat transfer & flame speeds/structures Flames generally stabilizes close or even attached to surface of flame holder => Conduction + Radiation to flame holder (heat) Burner Head Cooling methods: Water cooling Heating of flame holder well above temp: of unburned gas (Q net loss of flame to burner = 0 (Ideally),=>Adiabatic =>SL = Vu), Q measured by thermocouples attached to burner head Stabilization of flame far from the surface of burner (depends on burner exit speed) Vb < SL, Tf < Tad Botha & Spalding determined heat loss of flames by using water cooled burner and measured it by temperature rise of water Q is inversely proportional to Vu (also in Figure 19, Glassman) When Vu = SL and Vu exceeds SL => flame does not remain plane but distorts. The value of Vu corresponding to Q = 0, is found by extrapolation. 1/1/2019

Physical Model 1/1/2019

Mathematical Model in Excel Shroud Gas   Area of shroud 9.33131E-05 m2 Flow rate 6.39941E-05 m3/s Density 1.145044176 kg/m3 Mass flow rate 7.32761E-05 kg/sec Area of shroud (m2) Flow rate (m3/s) Density (kg/m3) Mass flow rate (kg/s) Flow rate (CFM) Flow Rate (SCFM) 0.135603515 Volume flow rate (m3/s) Volume flow rate (cfm) Volume flow rate (scfm) Fuel 0.000167016 0.000256968 0.544515855 Nitrogen 0.001362018 0.001197472 2.537443883 Oxygen 0.000668065 0.000513937 1.08903171 Shroud gas (Nitrogen) Total @ Burner 0.002197099 0.002032371 4.306594963 1/1/2019

Mathematical Approach Mass and Mole fractions of Methane, Nitrogen and Oxygen Flame Speed Calculations using Correlations Total Mass flow rate at burner outlet Mass flow rates of Methane, Nitrogen and Oxygen Orifice selection Running time of gas cylinders 1/1/2019

Experimental Results & Conclusions Four sets of experiments performed till now: Set No. 1: The results were found in close agreement with previous research i.e. 40 cm/sec. (Plotted Unburned velocity Vu and Heat loss Q) Main Problem: The trend line for the linear fit was found to be 0.2 which is not linear at all. Reason: Change in temperature too big. Set No. 2: The second round of experiments were performed by reducing the delta T to a minimum of 2 K. The results produced a linear relationship between Vu and Q but the flame speed came out to be 22 cm/sec. Also, the slope of the line became positive which should have been negative according to Botha & Spalding. Set No. 3 and 4: Experiments performed with different approach through which we learned more about the process. New idea has emerged which will be applied in new set of experiments. Note: Chemkin is being used to find the Flame Speed (SL) that is used in the calculations to get accurate mass flow rates and subsequent pressures 4. Literature Review in Progress to find out more details about the procedure. 1/1/2019