Head-on Quenching of Transient Laminar Flame: Heat Flux and Quenching Distance Measurements

Abstract

Ecole Nationale Supé rieure de Mé canique et d'Aé rotechnique, Futuroscope Chasseneuil Cedex, FranceThis work presents results of quenching distance and heat flux measurements during the head-on quenching of transient laminar stoichiometric methane=air flame in the pressure range 0.05-1.7 MPa. The results of direct visualization have been used to measure the quenching distance and to prove the relationship relating the quenching distance and heat flux to the wall over the global combustion reaction rate. It is shown that quenching distance decreases from 0.43 to 0.016 mm with pressure rise from 0.05 to 1.7 MPa. The maximum wall heat flux increases nonlinearly from 0.35 to 2.3 MW=m 2 with pressure rise from 0.05 to 1.7 MPa. The dimensionless value of the heat flux depends only slightly on the pressure and decreases from 0.3 to 0.2 with rise of pressure in this pressure range. Flame-wall interaction time is about constant and equal to 0.15-0.155 ms in all ranges of pressure variation.

Interactions of hydrogen flames with walls: Influence of wall temperature, pressure, equivalence ratio, and diluents

“…The temperature gradient at the wall, and consequently the heat flux, is higher there because of the smaller quenching distance. Recall from Section 1 that Sotton et al [5], using stoichiometric methane/air flames impinging on the walls of a constant volume combustion chamber, found that wall heat flux increased non-linearly over a pressure rise from 0.05 to 1.7 MPa. Furthermore, quenching distances were seen to decrease over the same pressure rise.…”

“…Additionally, the peak heat release rates would be decreased. Sotton et al [5] states that there are no experimental methods that allow direct measurement of quenching distances at high pressures, i.e. at engine conditions.…”

“…Such parameters include wall temperature (T w ), equivalence ratio ( ), chamber pressure, and surface reactivity [1][2][3][4][5][6][7][8][9][10][11][12][13]. Popp [4] found using direct numerical simulation (DNS) that the peak heat release rate of propane/air flames occurs directly at the surface for isothermal wall temperatures above 400 K. Sotton et al [5] determined that the wall heat flux increases non-linearly with increasing chamber pressure for methane flames. Hasse et al [1], using iso-octane flames, and Owston [3], using n-heptane flames, have numerically observed the increase of wall heat flux for increasing surface temperature (300 K < T w < 600 K) seen also by Popp et al [6,7] using propane flames.…”

Unsteady heat transfer during the turbulent combustion of a lean premixed methane–air flame: Effect of pressure and gas dynamics

“…In a previous study [5], this method was found to provide heat losses in agreement with numerical simulation: for polished steel, with stoichiometric methane-air mixture at 0.1 MPa, the theoretical value of heat flux, 0.5 MW/m 2 , was determined with 10% uncertainty. The precision of heat flux measurement increases with increasing heat flux, due to increasing signal to noise ratio.…”

“…Comparing the results obtained in both aerodynamic conditions is then expected to show the influence of charge motion on heat losses. Results in the turbulent case are also compared to results obtained in a previous study [5] in the laminar regime, for the same conditions.…”