Abstract: The invention relates to a method for determining the instantaneous rate of the mass flow of a flow of a fluid pulsating periodically at a frequency f, said method comprising the following steps: a) a pressure gradient in the flow over a certain period (P) is determined, b) the harmonic amplitude of the pressure gradient is calculated by means of Fourier transformation, c) the frequency f and the time t are converted into dimensionless numbers F, t and d) the rate of the mass flow is determined using a table from which at least one corresponding value describing the mass flow rate and/or a phase difference can be deduced for each dimensionless number F of the frequency f.

Abstract: A device is used for supplying fuel to a burner in a fuel cell system with a reformer. The fuel comprises a materials flow of a reformate gas, which materials flow is depleted of hydrogen, and a materials flow of a compound which comprises carbon and hydrogen. According to the invention, the device comprises at least one nozzle means in which the two materials flows can be mixed together. At least one of the materials flows is controllable as far as its through-flow is concerned.

Abstract: The invention relates to a method for determining the instantaneous rate of the mass flow of a flow of a fluid pulsating periodically at a frequency f, said method comprising the following steps: a) a pressure gradient in the flow over a certain period (P) is determined, b) the harmonic amplitude of the pressure gradient is calculated by means of Fourier transformation, c) the frequency f and the time t are converted into dimensionless numbers F, t and d) the rate of the mass flow is determined using a table from which at least one corresponding value describing the mass flow rate and/or a phase difference can be deduced for each dimensionless number F of the frequency f.

Abstract: A porous burner has a mixing space for premixing reducing agent and oxidizing agent, and an adjoining combustion space filled with a porous material. A flame barrier is arranged between the mixing space and the combustion space. The flame barrier is made from a porous material with a material porosity of less than 60%. This material has a density of at least 1300 kg/m3. The preferred use of a porous burner configured in this way lies in the combustion of hydrogen or hydrogen-rich gas.

Abstract: A device is used for supplying fuel to a burner in a fuel cell system with a reformer. The fuel comprises a materials flow of a reformate gas, which materials flow is depleted of hydrogen, and a materials flow of a compound which comprises carbon and hydrogen. According to the invention, the device comprises at least one nozzle means in which the two materials flows can be mixed together. At least one of the materials flows is controllable as far as its through-flow is concerned.

Abstract: A packing as a porous body for burners, in particular for heating systems, is provided with a housing having an inlet for a gas/air mixture as a combustable gas mixture, a combustion chamber, an ignition device in the combustion chamber and an exhaust gas outlet. The combustion chamber is at least partly filled with a three-dimensional ordered packing of heat resistant ceramic material, foil material, or sheet metal material having continuous hollow cavities for the formation of a defined flame zone.

Abstract: A burner with a housing enclosing a combustion chamber and with an inlet for a gas/air fuel mixture and an outlet for combustion gas is disclosed. The combustion chamber is filled with a porous material whose porosity varies along the combustion chamber in such a way that the pore size increases in the direction of flow of the gas/air mixture so that a critical Peclet number for the pore size and accordingly for flame development results at a boundary surface or in a determined zone of the porous material, above which number a flame can develop and below which number the flame development is suppressed.