This paper presents an aproach for tile predictionof heat transfer augmentation in decaying swirling flow in apipe by ma- an analogy between tile increase in friction factordue to swirl and increase in heat transfer due to swirl. Theproposed method can be used to predict heat transfer fordecaying swirling flow in smooth and rough pipes which canbe applied to different swirl generators based on the knowninlet swirl conditions. An ex-mental study is performedregarding the swirling flow of air in smooth and rough pipes.The ex-mental study covered only the fluid dynamics ofswirling flow. No heat transfer ex-ments were done. It isdetermined ex-flintily that in swirling flows degree of swirldecays continuously along the smooth and rough pipes and thetotal loss factor is the sum of friction friction for non-swirlingflow and the swirl loss factor Swirl loss factor is found to be afunction of the degree of swirl and pipe relative roughness.Using the relations obtained experimentally for the variation ofswirl strength and loss factor along the pipe, an equation isproposed to be used for the prediction of heat transfer inturbulent decaying swirling flows.
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