Experimental study on the heat transfer performance of an oscillating heat pipe with self-rewetting nanofluid

Author(s):  
Xinjun Su ◽  
Ming Zhang ◽  
Wei Han ◽  
Xianmin Guo
2012 ◽  
Vol 197 ◽  
pp. 216-220
Author(s):  
Zhong Chao Zhao ◽  
Rui Ye ◽  
Gen Ming Zhou

To solve the cooling problem in modern electronic device, a kind of heat pipe radiator was designed and manufactured in this paper. The heat transfer performance of heat pipe radiator and its relationship with air velocity were investigated by experimental method. The experimental results show that the heat pipe radiator can meet the temperature requirement of electronic device with the power range from 40W to 160W. To keep the operational temperature of electronic device with power of 160W under 75°C,the air velocity should be keep at 1.7m/s. The heat dissipation performance of heat pipe radiator was enhanced with the air velocity increased from 0.2m/s to 1.7m/s.for the electronic equipment with power of 160W.


Author(s):  
Nannan Zhao ◽  
Benwei Fu ◽  
Dianli Zhao ◽  
Hongbin Ma

The ultrasonic effect on the oscillating motion and heat transfer in an oscillating heat pipe (OHP) containing acetone was investigated experimentally. The ultrasonic sound was applied to the evaporating section of the OHP by using electrically-controlled piezoelectric ceramics. The ultrasonic sound is used to generate and maintain the oscillating motion, and, thereby, heat transfer is enhanced. The heat pipe was tested with or without the ultrasonic sound. In addition, the effects of heat load, filling ratio, orientation, operating temperature, and input power from 15 W to 200 W were investigated. The experimental results demonstrate that ultrasonic sound can affect the oscillating motions and enhance the heat transfer performance of the acetone OHP. In particular, the application of the ultrasonic sound on an acetone OHP can significantly reduce the thermal resistance of the acetone OHP and enhance the heat transfer performance in a low power input region. The investigation will provide an insight into the oscillating mechanism of the acetone OHP influenced by ultrasonic sound and provide a new way to enhance the heat transfer performance of the OHP.


Author(s):  
Lilin Chu ◽  
Yulong Ji ◽  
Chunrong Yu ◽  
Yantao Li ◽  
Hongbin Ma ◽  
...  

Abstract In order to understand the heat transfer performance, startup and fluid flow condition of oscillating heat pipe (OHP) with hydraulic diameter far exceeding the maximum hydraulic diameter (MHD), an experimental investigation on heat transfer performance and visualization was conducted. From the experimental performance, it is found that the OHP can still work well with ethanol as the working fluid when the tube diameter has exceeded the MHD of 91.6%. In addition, the detailed flow patterns of the OHP were recorded by a highspeed camera for vertical and horizontal orientation to understand its physical mechanism. In the vertical orientation, initially working fluid generates small bubbles, and then the small bubbles coalesce and grow to vapor plugs, the vapor plugs finally pushes the liquid slugs to oscillate in the tube. In the horizontal orientation, the working fluid surface fluctuates due to the vapors flow from the evaporator to the condenser and bubbles burst in the evaporator. When the peak of liquid wave reaches the upper surface of tube, a liquid slug has been formed, and then the steam flow pushes the liquid slugs to oscillate in the tube.


2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Tingting Hao ◽  
Hongbin Ma ◽  
Xuehu Ma

A new oscillating heat pipe (OHP) charged with hybrid fluids can improve thermal performance. The key difference in this OHP is that it uses room temperature liquid metal (Galinstan consisting of gallium, indium, and tin) and water as the working fluid. The OHP was fabricated on a copper plate with six turns and a 3 × 3 mm2 cross section. The OHP with hybrid fluids as the working fluid was investigated through visual observation and thermal measurement. Liquid metal was successfully driven to flow through the OHP by the pressure difference between the evaporator and the condenser without external force. Experimental results show that while added liquid metal can increase the heat transport capability, liquid metal oscillation amplitude decreases as the filling ratio of liquid metal increases. Visualization of experimental results show that liquid metal oscillation position and velocity increase as the heat input increases. Oscillating motion of liquid metal in the OHP significantly increases the heat transfer performance at high heat input. The lowest thermal resistance of 0.076 °C/W was achieved in the hybrid fluids-filled OHP with a heat input of 420 W. We experimentally demonstrated a 13% higher heat transfer performance using liquid metal as the working fluid compared to an OHP charged with pure water.


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