Thermal performance characteristics in plain horizontal tubes influenced by combined wire coil and twisted tape inserts

Abstract

 In this paper, heat transfer, friction factor behaviors in a tube equipped with the combined devices between two different types of twisted tape y=2.7 and y=3.0 and a wire coil pitch ratio are experimentally investigated. This paper presents heat transfer enhancement in single-phase transitional flow by wire-coil insert with geometrical parameters rib height-to-diameter ratio e/D=0.071, and rib pitch-to-height ratio p/e =7.5. The experiments were conducted at different measured fluid temperatures in a turbulent flow regime with Reynolds numbers ranging from 1000 to 10000 using water as the test fluid. Compared to each enhancement device, the heat transfer rate is further augmented by the compound devices. Over the range investigated, the highest Nu* of around 5.6 at Reynolds number 2000.