ePubs

The open archive for STFC research publications

Full Record Details

Persistent URL http://purl.org/net/epubs/work/66856041
Record Status Checked
Record Id 66856041
Title Visualization of internal vapor redistribution in a wick-assisted rotating heat pipe using neutron radiography and synchronized thermal measurements
Contributors
Abstract Direct observation of internal two-phase flow in rotating heat pipe (RHP) remains limited because conventional thermal measurements cannot resolve vapor-liquid distribution inside metallic enclosures. This study combines time-resolved neutron radiography with thermal measurements to visualize internal phase distribution and relate vapor behavior to thermal resistance in a commercial wick-assisted copper RHP. The experiments were conducted under a constant 60 W heat load at rotational speeds of 0–150 RPM and inclination angles of 0°, 10°, and − 10°. Vapor fraction distributions were systematically extracted from neutron radiography to evaluate transient and quasi-steady hydrodynamic behavior at the condenser region. The results show that rotational speed and inclination angle were found to influence condensate redistribution, liquid retention, and wetting stability within the condenser cone. At 0°, the 50 RPM condition exhibited a delayed transition toward a wetter regime, whereas higher rotational speeds produced more stable post-transient behavior. At −10° inclination, 50 RPM minimized persistent liquid accumulation, while 100 RPM produced the most stable quasi-steady regime. In the non-rotating condition, gravity-induced liquid stratification resulted in relatively high thermal resistance (0.34–0.35°C/W). Rotation reduced thermal resistance non-monotonically, reaching a minimum value of 0.025 °C/W at 100 RPM before increasing again at 150 RPM. The results suggest that liquid residence time and wetting stability may play a more dominant role than centrifugal separation under the tested conditions. These findings provide proof of concept experimental insight into the relationship between internal phase distribution and thermal performance in rotating heat pipes under the investigated operating conditions.
Organisation ISIS , STFC , ISIS-IMAT
Keywords Thermal resistance , Rotating heat pipe , Vapor fraction , Rotor cooling , Neutron radiography
Funding Information
Related Research Object(s):
Licence Information:
Language English (EN)
Type Details URI(s) Local file(s) Year
Journal Article International Communications in Heat and Mass Transfer 178, no. 4 (2026): 111838. doi:10.1016/j.ich…transfer.2026.111838 2026