Parametric Sensitivity Analysis of Geometrical and Flow Parameters in Laminar Flow Through Helically Coiled Micro-Diameter Tubes

Abstract

This work investigates parametric sensitivity of geometric and flow parameters on the behavior of laminar flow in helically coiled micro-diameter tubes. Helical coils, owing to curvature-induced secondary flows (Dean vortices), have greater heat transmission characteristics than straight tubes and are therefore of extremely useful application in the case of small thermal systems. Systematic sensitivity analysis is carried out to study the effect of coil diameter, tube diameter, pitch with curvature ratio and flow parameters such as Reynolds number along with Pralongwithtl number on pressure drop, friction factor along with heat transfer efficiency. Results indicate that reduced coil and tube diameters significantly enhance convective heat transfer by elevating secondary flow in addition to the surface-area-to-volume ratio, but at the expense of rising frictional resistance. Similarly, modest increases in Reynolds number within the laminar regime reduce thermal performance without causing transition to turbulence. Generalized Nusselt number correlations are presented based on findings, supported by significant dimensionless properties to enable accurate prediction of thermal behavior in a variety of geometries as well as operation conditions. Thermodynamic analysis emphasizes the competition between increased heat transfer as well as entropy generation and implies the need for optimal design for effective use of energy