Experimental Investigation of a Three-Layer Oscillating Heat Pipe

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
C. D. Smoot ◽  
H. B. Ma
Keyword(s):  
Thermal Conductivity ◽  
Experimental Investigation ◽  
Heat Pipe ◽  
Effective Thermal Conductivity ◽  
Heat Transport ◽  
Total Power ◽  
Oscillating Heat Pipe ◽  
Layer Effect ◽  
Layering Effect ◽  
Heat Transport Capability

An experimental investigation of a compact, triple-layer oscillating heat pipe (OHP) has been conducted to determine the channel layer effect on the heat transport capability in an OHP. The OHP has dimensions 13 mm thick, 229 mm long, and 76 mm wide embedded with two-independent closed loops forming three layers of channels. The unique design of the investigated OHP can be readily used to explore the channel layering effect on the heat transport capability in the OHP. The experimental results show that the addition of channel layers can increase the total power and at the same time, it can increase the effective thermal conductivity of the OHP. When the OHP switches from one layer of channels to two layers of channels, the highest effective thermal conductivity can be increased from 5760 W/mK to 26,560 W/mK. At the same time, the dryout limit can be increased. With three layers of channels, the OHP investigated herein can transport a power up to 8 kW with a heat flux level of 103 W/cm2 achieving an effective thermal conductivity of 33,170 W/mK.

An Experimental Investigation of Heat Transport Capability in a Nanofluid Oscillating Heat Pipe

2006 ◽  
Vol 128 (11) ◽  
pp. 1213-1216 ◽  
Author(s):  
H. B. Ma ◽  
C. Wilson ◽  
Q. Yu ◽  
K. Park ◽  
U. S. Choi ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Heat Pipe ◽  
Heat Transport ◽  
Working Fluid ◽  
New Approach ◽  
Oscillating Heat Pipe ◽  
Diamond Nanoparticles ◽  
Hplc Grade Water ◽  
Oscillating Motion ◽  
Heat Transport Capability

An experimental investigation of a nanofluid oscillating heat pipe (OHP) was conducted to determine the nanofluid effect on the heat transport capability in an OHP. The nanofluid consisted of HPLC grade water and 1.0vol% diamond nanoparticles of 5-50nm. These diamond nanoparticles settle down in the motionless base fluid. However, the oscillating motion of the OHP suspends the diamond nanoparticles in the working fluid. Experimental results show that the heat transport capability of the OHP significantly increased when it was charged with the nanofluid at a filling ratio of 50%. It was found that the heat transport capability of the OHP depends on the operating temperature. The investigated OHP could reach a thermal resistance of 0.03°C∕W at a heat input of 336W. The nanofluid OHP investigated here provides a new approach in designing a highly efficient next generation of heat pipe cooling devices.

High Thermal Conductivity of Diamond Nanofluids and its Effect on the Heat Transport Capability in an Oscillating Heat Pipe

2006 ◽  
Author(s):  
Corey Wilson ◽  
Hongbin Ma ◽  
K. Park
Keyword(s):  
Thermal Conductivity ◽  
Heat Pipe ◽  
Heat Transport ◽  
Pure Water ◽  
Experimental Results ◽  
Liquid Cooling ◽  
Oscillating Heat Pipe ◽  
Diamond Nanoparticles ◽  
Wire Method ◽  
Heat Transport Capability

In heat exchangers and liquid cooling devices the thermal conductivity of the liquid is an important factor in their design. Recently it has been shown that adding small amounts of nanoparticles to the liquid can significantly increase the thermal conductivity of the fluid [1]. This study investigates the thermal conductivity of diamond nanofluid. The nanofluid is HPLC grade water with 1% by volume diamond nanoparticles that are 5-50 nm in diameter. The thermal conductivity was measured by the transient hot-wire method. In order to verify the experimental measurement, the thermal conductivity of pure water (HPLC grade) was conducted and the measurement error is 3.6%. The experimental results show that the diamond nanoparticles can enhance the thermal conductivity of nanofluid. At an ambient temperature of 21 °C, the thermal conductivity for nanofluid was determined to be 1.00 W/m-K comparing with the thermal conductivity of 0.60 W/m-K for pure water (HPLC grade). Therefore, the nanofluid provides a significant increase in thermal conductivity. Utilizing this nanofluid, an oscillating heat pipe was developed and tested. Experimental results showed that when the oscillating heat pipe is charged with diamond nanofluids, the increase in heat transport capability can be significant and highly dependent on the operating temperatures.

Experimental Investigation of Ultrasonic Frequency Effect on an Oscillating Heat Pipe

2016 ◽  
Author(s):  
Nannan Zhao ◽  
Benwei Fu ◽  
Hongbin Ma ◽  
Fengmin Su
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Transport ◽  
Frequency Effect ◽  
Ultrasonic Frequency ◽  
Sound Effect ◽  
Oscillating Heat Pipe ◽  
Ultrasonic Sound ◽  
Heat Transfer Capacity ◽  
Heat Transport Capability

The heat transport capability in an oscillating heat pipe (OHP) significantly depends on the oscillating frequency. An external frequency directly affects the natural frequency in the system. In this investigation, the ultrasound sound effect on the heat transport capability in an OHP was conducted with focus on the ultrasonic frequency effect on the oscillating motion and heat transfer capacity in an OHP. The ultrasonic sound was applied to the evaporating section of the OHP by using the electrically-controlled piezoelectric ceramics. The heat pipe was tested with or without the ultrasonic sound with different frequencies. In addition, the effects of operating temperature, heat load from 25 W to 150 W were investigated. The experimental results demonstrate that the heat transfer capacity enhancement of the OHP depends on the frequency of the ultrasound field, and there exists an optimum combination of the frequencies which will lead to the largest enhancement of the heat transfer capacity of the OHP.

Effect of nanofluid on the heat transport capability in an oscillating heat pipe

2006 ◽  
Vol 88 (14) ◽  
pp. 143116 ◽  
Author(s):  
H. B. Ma ◽  
C. Wilson ◽  
B. Borgmeyer ◽  
K. Park ◽  
Q. Yu ◽  
...  
Keyword(s):  
Heat Pipe ◽  
Heat Transport ◽  
Oscillating Heat Pipe ◽  
Heat Transport Capability

Experimental Investigation of Micro Heat Pipes Fabricated in Silicon Wafers

1993 ◽  
Vol 115 (3) ◽  
pp. 751-756 ◽  
Author(s):  
G. P. Peterson ◽  
A. B. Duncan ◽  
M. H. Weichold
Keyword(s):  
Thermal Conductivity ◽  
Experimental Investigation ◽  
Heat Pipe ◽  
Effective Thermal Conductivity ◽  
Heat Pipes ◽  
Silicon Wafers ◽  
Temperature Gradients ◽  
Cover Plate ◽  
Micro Heat Pipe ◽  
Micro Heat Pipes

An experimental investigation was conducted to determine the thermal behavior of arrays of micro heat pipes fabricated in silicon wafers. Two types of micro heat pipe arrays were evaluated, one that utilized machined rectangular channels 45 μm wide and 80 μm deep and the other that used an anisotropic etching process to produce triangular channels 120 μm wide and 80 μm deep. Once fabricated, a clear pyrex cover plate was bonded to the top surface of each wafer using an ultraviolet bonding technique to form the micro heat pipe array. These micro heat pipe arrays were then evacuated and charged with a predetermined amount of methanol. Using an infrared thermal imaging unit, the temperature gradients and maximum localized temperatures were measured and an effective thermal conductivity was computed. The experimental results were compared with those obtained for a plain silicon wafer and indicated that incorporating an array of micro heat pipes as an integral part of semiconductor devices could significantly increase the effective thermal conductivity; decrease the temperature gradients occurring across the wafer; decrease the maximum wafer temperatures; and reduce the number and intensity of localized hot spots. At an input power of 4 W, reductions in the maximum chip temperature of 14.1°C and 24.9°C and increases in the effective thermal conductivity of 31 and 81 percent were measured for the machined rectangular and etched triangular heat pipe arrays, respectively. In addition to reducing the maximum wafer temperature and increasing the effective thermal conductivity, the incorporation of the micro heat pipe arrays was found to improve the transient thermal response of the silicon test wafers significantly.

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