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Structural and Thermal Analysis of Heat Exchanger with Tubes of Elliptical Shape ByNawras H. Mostafa Qusay R. Al-Hagag
Abstract:
An approach to select the tube wall thickness distribution of streamlined tubes intended for use in heat exchangers is developed in this study. The main 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 shaped tube efficiency is also considered. The strain is calculated as a function of several dimensionless geometric ratios and the ratio of the internal pressure to elastic 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 charge air cooler made of polymeric material.
Introduction:Polymer heat exchangers have been used for decades in corrosive environments [1–4] and are now being considered in other applications where either weight is a concern or innovative geometries are desirable. The most common polymer heat exchanger is a tube bundle made of hundreds of circular tubes connected to headers. Elliptical and lenticular profiles are being considered due to their ability to reduce form drag over a wide range of flow rates [6–12]. There are three primary challenges to design the streamlined tubes: a. The tube wall thickness distribution (i.e. the geometry of the inner flow passage) must be selected so that the maximum stress in the tubes is less than the mechanical strength of the material. b. The deformation of the tubes must be within a range to avoid strain failure and to maintain a streamlined profile. c. The tube wall thickness distribution should be selected to reduce the wall thermal conductive resistance.
- وصف الــ Tags لهذا الموضوع
- elliptical tube, shaped tube efficiency, polymer, heat exchanger, deformation, strain, stress
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