Pressure losses and heat transfer in non-circular channels with hydraulically smooth walls

Abstract

The article deals with the determination of the effect of channel geometry on friction pressure losses and heat transfer in the developed turbulent flow in non-circular channels with hydraulically smooth walls. Universal dimensionless relationship for friction coefficient is formulated which takes into account the geometry effect expressed in terms of the geometry factor K T . The empirical relationship for the geometry factor K T and channel shape is evaluated by two ways: by the integral geometry criterion L∗ and by the laminar geometry factor K L . Using an analogy between momentum and heat transfer the universal dimensionless relationship for the Nusselt number at isothermal flow is deduced from the universal criterion relationship for ξ. An extensive experimental material was treated to evaluate and test these two universal relationships. In most cases compared an excellent agreement between experimental results and the universal criterion relationship was found.