Mechanical analysis of streamlined tubes with non-uniform wall thickness for heat exchangers

Abstract

An approach to select the tube wall thickness distribution of streamlined tubes intended for use in heat exchangers is developed. The goal is to retain a streamlined outer profile (resist deformation) and to prevent strain failure due to the applied internal pressure. The effect of the tube wall thickness distribution on heat transfer is also considered. The strain is calculated as a function of several dimensionless geometric ratios and the ratio of the internal pressure to material modulus. Using the finite element method, a set of dimensionless design curves is created for elliptical tube geometries. From these curves, a range of possible materials and tube geometries can be selected that meet a specific strain limit. To illustrate the approach, structure-satisfied elliptical designs are selected and their thermal performance is evaluated for an automotive radiator and an automotive charge air cooler made of polymeric materials. The same method can be extended to tubes of other shapes and materials.