Methane Laminar Flame Speed Measurement at High Gas Temperature Using Rapid Compression Machine-Flame (RCM-Flame)

Abstract

An outwardly expanding spherical flame speed has been studied using a constant volume chamber, a spherical bomb, and a shock tube. However, the literature reports very few laminar flame speed measurements at high gas temperatures relevant to the combustion system conditions. Therefore, this research primarily focuses on measuring the laminar flame speeds at high gas temperatures using a new experimental technique called rapid compression machine flame (RCM-Flame). The laminar flame speeds were measured using a stoichiometric mixture of methane, oxygen, and argon at an average compressed gas pressure of 3.04 bar and a range of gas temperatures from 740 to 765 K. The effects of the RCM chamber size, ignition energy, and temperature inhomogeneity on the flame propagation process were investigated by performing both one-dimensional (1D) and three-dimensional (3D) numerical modeling. The AramcoMech 3.0-detailed kinetic model was reduced under the studied conditions by considering ignition delay times and flame speeds to perform 3D numerical modeling. The linear extrapolation method of expanding a spherical flame showed that laminar flame speeds obtained through the experiments agree well with simulated data generated using 1D and 3D numerical modeling.

Measurement and Simulation of Autoignition-Assisted Flame Speed of N-Heptane Mixture at Elevated Gas Temperature

“…The RCM-Flame apparatus, located at the Combustion Physics Laboratory (CPL, ) of Wayne State University, was used to measure autoignition-assisted flame speeds. A schematic of the RCM-Flame apparatus is shown in Figure , and its details can be found in previous works. − However, to make this work discrete, some details are provided herein.…”

“…An in-house image processing code was developed and used to extract the flame radius from the recorded images using a high-speed camera. 9 The sub-level pixels around the flame edges were also smoothed, significantly affecting image quality. The code initially improved the image quality and reduced the pixellevel noise by applying a Gaussian filter.…”

Laminar Burning Velocities at Engine-Relevant Conditions of Methane, Hydrogen, and Ammonia: A Rapid Compression Machine Study

“…Optimal spark timing for the initialization of the flame has been determined with hot wire measurements. Compared to previous systems, 16 the spatial resolution of the optical setup has been increased by a factor of 3. Detailed uncertainty quantification has been performed.…”

“…Both types of facilities are heavily used for the determination of ignition delay times 6 method necessitates a significant investment of effort, given the costly operation of shock tubes and the inherent challenges posed by laser ignition and the typical short measuring times of a few milliseconds that must be overcome. 10 In 2022, Goyal and Samimi-Abianeh 16 published the first LBVs measured in an RCM at 3 bar and ≈750 K, for a stoichiometric CH 4 /air flame that was ignited via spark electrodes. One year later, the same authors published a second study regarding LBVs of a stoichiometric n-heptane/air flame at ≈620 K and 7 bar measured in an RCM.…”