The present study basically examines thermal performance and relevant flow phenomena of a flat plate closed-loop pulsating heat pipe (FP-CLPHP) filled with binary mixtures. The heat pipe has eight turns, each of which consisting of asymmetrical channel pairs having cross sections as 2 mm × 2 mm and 1 mm × 2 mm (width × height). Binary mixtures are generated as mixtures of ethanol (E) and pentane (P) with different mixing ratios. Mainly, effects of volume mixing ratio (E/P = 1:1, 1:3 and 3:1), vertical (90°) and horizontal orientation (0°) and filling ratio (30% and 60%) on thermal characteristics are investigated under different heat inputs. For examination of flow dynamics, images are obtained by using a high-speed camera at 1000 fps. The results show that variation of volumetric percentage of each component significantly changes thermal performance. Increasing pentane in the mixture improves the thermal performance, such that heat pipe with mixing ratio of E/P = 1:3 can properly operate even at horizontal position. On the other hand, increasing volume of ethanol in mixture leads to collapse of the FP-CLPHP at both orientations (0° and 90°). Generally, the filling ratio of 30% shows better thermal performance. Complex bubble–liquid interactions and dynamics play critical roles on thermal characteristics. Two novel characteristic phenomena are identified for non-uniform PHPs: (1) flooding phenomenon and (2) asymmetrical rapid bubble growth phenomenon.

本研究主要研究填充有二元混合物的平板闭环脉动热管（FP-CLPHP）的热性能和相关的流动现象。热管有八匝，每个匝由截面为2 mm×2 mm和1 mm×2 mm（宽×高）的不对称通道对组成。二元混合物以具有不同混合比的乙醇（E）和戊烷（P）的混合物形式产生。主要是体积混合比（E / P = 1：1、1：3和3：1），垂直（90°）和水平方向（0°）以及填充率（30％和60％）对热特性的影响在不同的热量输入下进行研究。为了检查流动动力学，使用高速相机以1000 fps的速度获取图像。结果表明，每种组分的体积百分比的变化显着改变了热性能。混合物中戊烷含量的增加可改善热性能，从而使混合比为E / P = 1：3的热管即使在水平位置也可以正常工作。另一方面，混合物中乙醇体积的增加会导致FP-CLPHP在两个方向（0°和90°）处坍塌。通常，填充率为30％表现出更好的热性能。复杂的气泡-液体相互作用和动力学对热特性起着至关重要的作用。对于不均匀的PHP，发现了两个新颖的特征现象：（1）泛洪现象和（2）不对称快速气泡生长现象。3即使在水平位置也可以正确操作。另一方面，混合物中乙醇体积的增加会导致FP-CLPHP在两个方向（0°和90°）处坍塌。通常，填充率为30％表现出更好的热性能。复杂的气泡-液体相互作用和动力学对热特性起着至关重要的作用。对于不均匀的PHP，发现了两个新颖的特征现象：（1）泛洪现象和（2）不对称快速气泡生长现象。3即使在水平位置也可以正确操作。另一方面，混合物中乙醇体积的增加会导致FP-CLPHP在两个方向（0°和90°）处坍塌。通常，填充率为30％表现出更好的热性能。复杂的气泡-液体相互作用和动力学对热特性起着至关重要的作用。对于不均匀的PHP，发现了两个新颖的特征现象：（1）泛洪现象和（2）不对称快速气泡生长现象。