An experimental study on the heating process with a tubular flame

In this paper, we have proposed a new heating technique, which uses an inner hot gas region of a tubular flame and passes a gas to be heated through it. To elucidate the validity of this technique, two types of tubular flame burners, a non-swirling, counterflow type burner and a swirl type burner, have been made and the effects of swirl intensity on the heating processes have been investigated. Results show that the temperature of the heated gas stream does not increase so much in the counterflow type burner, whereas the temperature increases so rapidly in the swirl type burner. In the latter case, the rate of the temperature increase is increased as the swirl intensity of the burner is increased. Thus, a swirling tubular flame can be a useful tool for heating a gas stream with compactness and high performance.