Manufacturability Analysis of Thermally-Enhanced Polymer Composite Heat Exchangers

Abstract

Thermally-enhanced polymer composite heat exchangers are an attractive alternative for applications such as the use of seawater as a cooling medium and other corrosive environments that traditionally use expensive exotic metallic alloys, but a number of manufacturing challenges exist. The goal of this thesis is to develop an understanding of the manufacturing feasibility, in particular mold filling and fiber orientation, of utilizing thermally-enhanced polymer composites and injection molding to manufacture polymer heat exchangers. To best predict mold filling feasibility, this thesis proposes developing an explicit construction of the boundary, represented as a surface based on the parameter space, which separates the feasible and infeasible design space. The feasibility boundary for injection molding in terms of the design parameters is quite complex due to the highly nonlinear process physics, which, consequently, makes molding simulation computationally intensive and time consuming. This thesis presents a new approach for the explicit construction of a moldability-based feasibility boundary based on intelligent Design of Experiments and adaptive control techniques to minimize the number or computation experiments needed to build an accurate model of the feasibility boundary. Additionally, to improve the flexibility of the mold filling prediction framework to changes in overall heat exchanger design, a model simplification approach is presented to predict mold filling for general finned-plate designs by determining an equivalent flat plate representation and utilizing a developed flat plate mold filling metamodel to estimate mold filling. Finally, a fiber orientation measurement methodology is presented for experimentally determining fiber orientation behavior for sample heat exchanger geometries that develops both a local and global understanding of the fiber orientation behavior and compares thesis findings to simulation predictions. The work presented in this thesis significantly advances the understanding of manufacturability considerations for utilizing thermally-enhanced polymer composites in heat exchanger applications and is useful in design exploration, optimization, and decision-making approaches.