Neutron Imaging of an Unbalanced Flat-Plate Oscillating Heat Pipe

2014 ◽  
Author(s):  
John G. Monroe ◽  
Scott M. Thompson ◽  
Zachary S. Aspin ◽  
David Jacobson ◽  
Daniel Hussey
Keyword(s):  
Flat Plate ◽  
Heat Pipe ◽  
Neutron Imaging ◽  
Oscillating Heat Pipe

An Experimental Investigation of Three-Dimensional Flat-Plate Oscillating Heat Pipe

2009 ◽  
Author(s):  
Scott M. Thompson ◽  
Hongbin Ma ◽  
Robert A. Winholtz ◽  
Corey Wilson
Keyword(s):  
Experimental Investigation ◽  
Flat Plate ◽  
Heat Pipe ◽  
Three Dimensional ◽  
Neutron Imaging ◽  
Heat Fluxes ◽  
Working Fluid ◽  
Oscillating Heat Pipe ◽  
Oscillatory Pattern ◽  
Thermal Oscillations

An experimental investigation on the effects of condenser temperatures, heating modes and heat inputs on a miniature, three dimensional flat-plate oscillating heat pipe (3D FP-OHP) was conducted visually and thermally. The 3D FP-OHP was charged with acetone at a filling ratio of 0.80, had dimensions of 101.60 × 63.50 × 2.54 mm3, possessed 30 total turns, and had square channels on both sides of the device with a hydraulic diameter of 0.762 mm. Unlike traditional flat-plate designs, this new three-dimensional, compact design allows for multiple heating arrangements and higher heat fluxes. Transient and steady-state temperature measurements were collected at various heat inputs and the activation/start-up was clearly observed for both bottom and side heating modes during reception of its excitation power for this miniature 3D FP-OHP. The neutron imaging technology was simultaneously employed to observe the internal working fluid flow for all tests directly through the heat pipe’s copper wall. The activation was accompanied with a pronounced temperature field relaxation and the onset of chaotic thermal oscillations — all occurring with the same general oscillatory pattern at locations all around the 3D FP-OHP. Qualitative and quantitative analysis of these thermal oscillations, along with the presentation of the average temperature difference and thermal resistance, for all experimental conditions are provided. The novelty of the three-dimensional OHP design is its ability to still produce the oscillating motions of liquid plugs and vapor bubbles and, more importantly, its ability to remove higher heat fluxes.

Effect of Hydrophilic Nanostructured Cupric Oxide Surfaces on the Heat Transport Capability of a Flat-Plate Oscillating Heat Pipe

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
F. Z. Zhang ◽  
R. A. Winholtz ◽  
W. J. Black ◽  
M. R. Wilson ◽  
H. Taub ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Flat Plate ◽  
Heat Pipe ◽  
Heat Transport ◽  
Thermal Performance ◽  
Cupric Oxide ◽  
Neutron Imaging ◽  
Oscillating Heat Pipe ◽  
Heat Transport Capability ◽  
Insight Into

With a surface treatment of hydrophilic cupric oxide (CuO) nanostructures on the channels inside a flat-plate oscillating heat pipe (FP-OHP), the wetting effect on the thermal performance of an FP-OHP was experimentally investigated. Three FP-OHP configurations were tested: (1) evaporator treated, (2) condenser treated, and (3) untreated. Both evaporator- and condenser-treated FP-OHPs show significantly enhanced performance. The greatest improvement was seen in the condenser-treated FP-OHP, a 60% increase in thermal performance. Neutron imaging provided insight into the fluid dynamics inside the FP-OHPs. These findings show that hydrophilic nanostructures and their placement play a key role in an OHP's performance.

Experimental Investigation of Miniature Three-Dimensional Flat-Plate Oscillating Heat Pipe

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
S. M. Thompson ◽  
H. B. Ma ◽  
R. A. Winholtz ◽  
C. Wilson
Keyword(s):  
Experimental Investigation ◽  
Flat Plate ◽  
Heat Pipe ◽  
Three Dimensional ◽  
Neutron Imaging ◽  
Heat Fluxes ◽  
Working Fluid ◽  
Oscillating Heat Pipe ◽  
Oscillatory Pattern ◽  
Thermal Oscillations

An experimental investigation on the effects of condenser temperatures, heating modes, and heat inputs on a miniature three-dimensional (3D) flat-plate oscillating heat pipe (FP-OHP) was conducted visually and thermally. The 3D FP-OHP was charged with acetone at a filling ratio of 0.80, had dimensions of 101.60×63.50×2.54 mm3, possessed 30 total turns, and had square channels on both sides of the device with a hydraulic diameter of 0.762 mm. Unlike traditional flat-plate designs, this new three-dimensional compact design allows for multiple heating arrangements and higher heat fluxes. Transient and steady-state temperature measurements were collected at various heat inputs, and the activation/start-up of the OHP was clearly observed for both bottom and side heating modes during reception of its excitation power for this miniature 3D FP-OHP. The neutron imaging technology was simultaneously employed to observe the internal working fluid flow for all tests directly through the copper wall. The activation was accompanied with a pronounced temperature field relaxation and the onset of chaotic thermal oscillations occurring with the same general oscillatory pattern at locations all around the 3D FP-OHP. Qualitative and quantitative analysis of these thermal oscillations, along with the presentation of the average temperature difference and thermal resistance, for all experimental conditions are provided. The novelty of the three-dimensional OHP design is its ability to still produce the oscillating motions of liquid plugs and vapor bubbles and, more importantly, its ability to remove higher heat fluxes.

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