Laminar Flame Speed Measurements and Modeling of Pure Alkanes and Alkane Blends at Elevated Pressures

Abstract

Alkanes such as methane, ethane, and propane make up a large portion of most natural gas fuels. Natural gas is the primary fuel used in industrial gas turbines for power generation. Because of this, a fundamental understanding of the physical characteristics such as the laminar flame speed is necessary. Most importantly, this information is needed at elevated pressures to have the most relevance to the gas turbine industry for engine design. This study includes experiments performed at elevated pressures, up to 10 atm initial pressure, and investigates the fuels in a pure form as well as in binary blends. Flame speed modeling was done using an improved version of the kinetics model that the authors have been developing over the past few years. Modeling was performed for a wide range of conditions, including elevated pressures. Experimental conditions include pure methane, pure ethane, 80/20 mixtures of methane/ethane, and 60/40 mixtures of methane/ethane at initial pressures of 1 atm, 5 atm, and 10 atm. Also included in this study are pure propane and 80/20 methane/propane mixtures at 1 atm and 5 atm. The laminar flame speed and Markstein length measurements were obtained from a high-pressure flame speed facility using a constant-volume vessel. The facility includes optical access, a high-speed camera, a schlieren optical setup, a mixing manifold, and an isolated control room. The experiments were performed at room temperature, and the resulting images were analyzed using linear regression. The experimental and modeling results are presented and compared with previously published data. The data herein agree well with the published data. In addition, a hybrid correlation was created to perform a rigorous uncertainty analysis. This correlation gives the total uncertainty of the experiment with respect to the true value rather than reporting the standard deviation of a repeated experiment. Included in the data set are high-pressure results at conditions where in many cases for the single-component fuels few data existed and for the binary blends no data existed prior to this study. Overall, the agreement between the model and data is excellent.

Effects of oil and water contamination on natural gas engine combustion processes

“…Experimental data taken from Huang et al [14], Petersen et al [25], Sayed et al [26], and Burke et al [27]. Figure 6 shows predictions of laminar flame speeds of a natural gas-air mixture with φ=1, pressure of 1.01 atm and temperature of 300 K. Again, predictions from the two mechanisms compare reasonably well with each other and most experimental data, particularly that of Egolfopoulos et al [28] and Bradley et al [29]. Given the results of the validation studies, the LLNL n-heptane detailed mechanism was utilized as the reaction mechanism for the autoignition, ignition delay, and laminar flame speed calculations.…”

Laminar Flame Characteristics of C1–C5 Primary Alcohol-Isooctane Blends at Elevated Temperature

“…Present total bias uncertainty was estimated to be 1.3-2 cm¨s´1 with the detailed analysis given in [44,45]. The standard deviation (σ S 0 u ) arising from data processing was 0.3-2 cm¨s´1.…”

“…The spark ignition and the chamber confinement are recognized to affect the accuracy of laminar flame speed measurements, therefore a flame radius of 8-22 mm was utilized to do the data processing. The total experimental uncertainty was evaluated according to the theory of Moffat et al [41] which has been widely adopted in previous studies [42][43][44]. It can be described as: …”

Oxidation of Ethylene—Air Mixtures at Elevated Pressures, Part 2: Chemical Kinetics

“…While further improvement is still needed, the current version is much improved over the original one as a result of the experiments and modeling presented in Kopp et al [1] and the present paper, respectively. ... [2] ... [9] ... [4] ... [13] ... [11] ... [12] ... [16] ... [8] ... [17] ... [7] ... [14] ... [10] ... [15] ... [19] ... [5] ... [20] ... [6] ... [21] ... [1] ... [22] ... [18] ... [23] Ċ ... [34] ... [31] ... [35] ... [32] ... [36] ... [33] ... [30] ... [37] ... [26] ... [38] ... [27] ... [39] ... [28] ... [40] ... [24] ... [41] ... [25] ... [42] …”