Hydrogen Vortex Flow Impact on the Catalytic Wall

An experimental study of a hydrogen-containing jet's impact on a palladium-based catalyst in an air atmosphere was carried out. High-intensity temperature fluctuations on the catalyst surface are obtained in the case when large-scale vortex structures are contained in the jet. These superstructures have a longitudinal size of 20-30 initial jet diameters and a transverse size of about 3-4 diameters. To form such structures, it is necessary to use long, round tubes in the Reynolds number range of 2000-3000 as a source of the impinging jet when a laminar-turbulent transition occurs in the channel according to the intermittency scenario. This effect was obtained at a low hydrogen content in the mixture (X-H2 = 3 horizontal ellipsis 15%) and a low initial temperature of the catalyst (180 degrees C). It is shown that the smallest temperature fluctuations are obtained for the laminar flow in the tube (<1.5%), and they are more significant (<4%) for the turbulent regime at low Reynolds numbers (Re < 6000). The greatest temperature fluctuations were obtained during the laminar-turbulent transition in the tube (up to 11%). Two important modes have been established: the first with maximum temperature fluctuations in the local region of the stagnation point, and the second with the greatest integral increase in temperature fluctuations over the entire area of the catalyst.