Borgmeyer B, Wilson C, Winholtz R A, Ma H B, Jacobson D, Hussey D
Department of Mechanical and Aerospace Engineering, University of Missouri-Columbia, Columbia, MO 65201.
National Institute of Standards and Technologies, 100 Bureau Drive, Gaithersburg, MD 20899.
J Heat Transfer. 2010 Jun;132(6). doi: 10.1115/1.4000750.
An experimental investigation into the parameters affecting heat transport in two three-dimensional oscillating heat pipes (OHPs) was implemented. A three-dimensional OHP is one in which the center axis of the circular channels containing the internal working fluid do not lie in the same plane. This novel design allows for more turns in a more compact size. The OHPs in the current investigation is made of copper tubings (3.175 mm outside diameter, 1.65 mm inside diameter) wrapped in a three-dimensional fashion around two copper spreaders that act as the evaporator and condenser. The two OHPs have 10 and 20 turns in both the evaporator and condenser. The 20-turn OHP was filled to 50% of the total volume with a high performance liquid chromatography grade water. Transient and steady state temperature data were recorded at different locations for various parameters. Parameters such as heat input, operating temperature, and filling ratio were varied to determine its effect on the overall heat transport. Neutron radiography was simultaneously implemented to create images of the internal working fluid flow at a rate of 30 frames per second. Results show the average temperature drop from the evaporator to condenser decreases at higher heat inputs due to an increase in temperature throughout the condenser region due to greater oscillations. These large oscillations were visually observed using neutron radiography. As the operating temperature is increased, the thermal resistance is reduced. A decrease in filling ratio tends to create more steady fluid motion; however, the heat transfer performance is reduced.
对影响两根三维振荡热管（OHP）中热传输的参数进行了实验研究。三维振荡热管是指包含内部工作流体的圆形通道的中心轴不在同一平面内的热管。这种新颖的设计允许在更紧凑的尺寸内实现更多的转弯。当前研究中的振荡热管由铜管（外径3.175毫米，内径1.65毫米）制成，以三维方式缠绕在两个用作蒸发器和冷凝器的铜质散热器周围。两根振荡热管在蒸发器和冷凝器中均有10圈和20圈。20圈的振荡热管中填充了高性能液相色谱级水，填充量为总体积的50%。针对各种参数，在不同位置记录了瞬态和稳态温度数据。改变热输入、工作温度和填充率等参数，以确定其对整体热传输的影响。同时进行了中子射线照相，以每秒30帧的速率生成内部工作流体流动的图像。结果表明，在较高热输入下，从蒸发器到冷凝器的平均温度降会降低，这是由于冷凝器区域内温度因更大的振荡而升高。通过中子射线照相可以直观地观察到这些大的振荡。随着工作温度的升高，热阻会降低。填充率的降低往往会使流体运动更加稳定；然而，传热性能会降低。
