Characteristics of an Additively Manufactured Titanium Oscillating Heat Pipe

Isothermalization of spacecraft structures is often necessary for JPL's science missions. Oscillating heat pipes (OHPs) are compact devices that utilize latent heat to passively isothermalize a surface with tremendous effect. These OHP channels can be embedded within a structure of any geometry with additive manufacturing to significantly increase the effective conductivity of the material. OHPs have previously been made with aluminum to maximize heat transfer capability but OHPs can also greatly enhance materials such as titanium with poor thermal conduction. In spacecraft design, titanium is a desirable material due to its structural strength, but is often not used in key thermal infrastructure due to its low conductivity unless thermal isolation is required. Therefore, isothermalizing materials that have previously been disqualified from design applications due to poor thermal performance opens up new possibilities for efficient design. As a result, a novel additively manufactured titanium OHP has been developed to characterize the performance of OHP technology within low-conducting materials. The prototype OHP is embedded in a flat plate sample as a monolithic piece, thus removing any internal interface resistances, with 42 turns and a working fluid of R-134a as is consistent with other material OHP tests. Furthermore, the prototype shows a two-orders of magnitude increase in thermal conductivity compared to normal titanium. This study demonstrates the design, manufacturing, and thermal performance characteristics of the prototype titanium OHP and its potential for thermal design moving forward.