TY - JOUR
T1 - Heat transfer mechanisms of laminar flames of hydrogen + oxygen
AU - Cremers, M.F.G.
AU - Remie, M.J.
AU - Schreel, K.R.A.M.
AU - Goey, de, L.P.H.
PY - 2004
Y1 - 2004
N2 - Increasing the heat transfer from premixed laminar oxy-fuel flames to glass orquartz products is of major importance in the lighting industry. In this papera laminar flame of hydrogen + oxygen is used as an impinging jet in astagnation-flow-like configuration to investigate the heating of a glassproduct. The research was intended to analyze the crucial phenomena determiningthe heat transfer rate. The time scales of the processes taking place in theflame, the stagnation boundary layer, and the plate are quantified and fromthis it is shown that these zones can be decoupled. It will also be shown that,as a result, the heat flux entering the plate depends only on the stagnationflow and the plate's surface temperature. Two cases were studied. In one casethe stagnation boundary layer consisting of a burnt and chemically frozenmixture of hydrogen + oxygen or hydrogen + air is studied. In the other casethe flow is reactive in the stagnation boundary layer. An analyticalapproximation for the heat transfer coefficient is derived for the case withouta viscous sublayer. The effect of strain rate on the heat transfer coefficientsis incorporated in this model. This heat transfer coefficient is compared tonumerically calculated heat transfer coefficients for stagnation flows withboth reactive and nonreactive boundary layers. Furthermore, it is shown thatthe stagnation boundary layer is not in chemical equilibrium. First numericalresults indicate that surface chemistry can be expected to contributesignificantly to the heating process. Surface chemistry is studied numericallyby assuming a quartz plate coated with a platinum layer.
AB - Increasing the heat transfer from premixed laminar oxy-fuel flames to glass orquartz products is of major importance in the lighting industry. In this papera laminar flame of hydrogen + oxygen is used as an impinging jet in astagnation-flow-like configuration to investigate the heating of a glassproduct. The research was intended to analyze the crucial phenomena determiningthe heat transfer rate. The time scales of the processes taking place in theflame, the stagnation boundary layer, and the plate are quantified and fromthis it is shown that these zones can be decoupled. It will also be shown that,as a result, the heat flux entering the plate depends only on the stagnationflow and the plate's surface temperature. Two cases were studied. In one casethe stagnation boundary layer consisting of a burnt and chemically frozenmixture of hydrogen + oxygen or hydrogen + air is studied. In the other casethe flow is reactive in the stagnation boundary layer. An analyticalapproximation for the heat transfer coefficient is derived for the case withouta viscous sublayer. The effect of strain rate on the heat transfer coefficientsis incorporated in this model. This heat transfer coefficient is compared tonumerically calculated heat transfer coefficients for stagnation flows withboth reactive and nonreactive boundary layers. Furthermore, it is shown thatthe stagnation boundary layer is not in chemical equilibrium. First numericalresults indicate that surface chemistry can be expected to contributesignificantly to the heating process. Surface chemistry is studied numericallyby assuming a quartz plate coated with a platinum layer.
U2 - 10.1016/j.combustflame.2004.08.004
DO - 10.1016/j.combustflame.2004.08.004
M3 - Article
SN - 0010-2180
VL - 139
SP - 39
EP - 51
JO - Combustion and Flame
JF - Combustion and Flame
IS - 1-2
ER -