Polymer and Composite Materials in Two-Phase Passive Thermal Management Systems: A Review

Abstract

The application of polymeric and composite materials in two-phase passive heat transfer devices is reviewed critically, with a focus on advantages and disadvantages of these materials in thermal management systems. Recent technology developments led to an increase of the power density in several applications including portable electronics, space and deployable systems, etc., which require high-performance and compact thermal management systems. In this context, passive two-phase systems are the most promising heat transfer devices to dissipate large heat fluxes without external power supply. Usually, heat transfer systems are built with metals due to their excellent thermal properties. However, there is an increasing interest in replacing metallic materials with polymers and composites that can offer cost-effectiveness, light weight and high mechanical flexibility. The present work reviews state-of the-art applications of polymers and composites in two-phase passive thermal management systems, with an analysis of their limitations and technical challenges.

Keywords: capillary loops; composite materials; heat pipes; heat transfer; polymer materials; pulsating heat pipes; thermosyphons; two-phase flow.

Figure 1

Structure of polypropylene molecular chain (a) and its three-dimensional graphical reconstruction (b).

Figure 2

Schematic of single thermosyphon pipe (a) and loop thermosyphon pipe (b) [56].

Figure 3

Flat loop thermosyphon built with a polyamide polymer composite [62].

Figure 4

Schematic of conventional heat pipe.

Figure 5

Schematic of human spine (a) and a bionic flexible heat pipe (b) [90].

Figure 6

Schematic of a loop heat pipe (a), and a capillary-pumped loop heat pipe (b) [91].

Figure 7

Schematic of a pulsating heat pipe.

Figure 8

Flexible polypropylene pulsating heat pipe (a) and detail of the selective transmission laser welding process (b).

Figure 9

Sketch of a polymer morphology consisting of crystalline and amorphous regions (a) and schematic of the gas permeation process through a polymer separating two regions where a gas species has different partial pressures, $P_{v,1}>P_{v,2}$ (b).

Figure 10

Contact angle of a water drop on (a) a polymer surface with medium surface energy ($\theta ={44}^{\circ })$ and (b) a polymer surface with low surface energy ($\theta ={110}^{\circ }$).