<p>A gas-lance apparatus and method for injecting a rate-enhancing gas between a flame and a thermal load to augment combustion of fuel undergoing combustion in the flame. A fan-shaped main jet is introduced between the flame for producing a low pressure field of the rate-enhancing gas between the flame and the thermal load. The low pressure field deforms the flame into the shape of the main jet and draws the flame toward the thermal load. The main jet decays along its length due to entrainment of combustion-environment gas in the main jet. In order to delay such decay, a fan-shaped booster jet of rate-enhancing gas is introduced between the main jet and the thermal load. The booster jet has a higher velocity than the main jet and is positioned adjacent to the main jet. <IMAGE></p>
