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以多个不同管径的TiO2纳米管阵列表面以及不同Ti表面作为换热壁面,以去离子超纯水作为工质,进行重复池沸腾实验。在实验前后进行了样品润湿性能测试实验,测量了超纯水在样品表面上的静态接触角;在实验中,使用高速摄像机观测气泡动力学过程。实验结果表明,管径不是对池沸腾换热性能产生重要影响的唯一主要因素,管径尺度的凹坑难以形成有效的汽化核心,不利于强化换热。实验中没有观察到大量微小气泡,证实没有大量有效的汽化核心。由于TiO2纳米管阵列表面的润湿性能较好,其能明显提高池沸腾的临界热通量(CHF),最大增幅度可达116%。但部分样品在经历CHF后会出现脱落现象,脱落后,CHF明显降低。
A series of experiments were carried out on the surface of TiO2 nanotube array with different diameters and different Ti surfaces as heat transfer wall, and deionized ultrapure water as working fluid. The wettability test of the sample was carried out before and after the experiment. The static contact angle of the ultrapure water on the surface of the sample was measured. In the experiment, the dynamic process of the bubble was observed using a high-speed camera. The experimental results show that the pipe diameter is not the only major factor that has an important influence on the pool boiling heat transfer performance. It is difficult for the pits of the pipe diameter scale to form an effective vaporization core, which is not conducive to heat transfer enhancement. No large amount of microbubbles were observed in the experiment, confirming that there was not a large number of effective vaporization cores. Due to the better wettability of TiO2 nanotube arrays, the critical heat flux (CHF) of pool boiling can be significantly increased, with a maximum increase of 116%. However, part of the samples exfoliated after experiencing CHF. After exfoliation, CHF decreased significantly.