Fundamental studies on hydrogen-oxygen burner concept at different equivalence ratios

Abstract

In order to the omnipresent hydrogen strategy we have done fundamental investigation of a stateof-the-art burner concept for hydrogen and oxygen combustion. The overall target is a sustainable and eco-friendly generation of superheated steam for industrial purposes. The burner concept we pursued is a non-premixed coaxial arrangement of an inner oxygen nozzle and an outer hydrogen nozzle. Basically two types of nozzles were designed for different equivalence ratio (ER) with a consistent nozzle exit velocity and power. Based on preceding results from numerical simulation, test conditions were defined for the fuel-rich nozzle with an ER of 4.2 and the stochiometric nozzle. For both nozzles an exit velocity of 100 m/s with nominal power of 10 kW at atmospheric conditions was achieved. With a specified cooling system for the optical accessible combustion chamber and burner front plate, it is possible to moderate the thermal stress in an appropriate level. For the detection of flame characteristics as flame length and shape, OH*- chemiluminescence was applied. The measurement technology used consists of an OH*-camera in connection with an image intensifier by LaVision The comparison with results from numerical simulation has shown an agreement on fundamentals for both investigated nozzles types. The variation in flame length for the rich and stochiometric test case has been calculated exactly within a tolerance of about 1 mm. The flame length in the stochiometric nozzle is about twice of the length of the fuel-rich nozzle. Both flames were attached to the orifice without any thermoacoustic behavior. The experiments have shown the influence of a variation in ER on flame characteristics as flame length and the ability of operating a generator for clean superheated steam safely.