Study of Boilover Suppression by Air Bubble Blowing

吹气泡抑制沸腾的研究

• 批准号: 05650189
• 负责人: KITANO Michio
• 金额: $ 1.02万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05650189/
• 关键词: Fire Safety; Boilover; Air Bubble Blowing; Boiling; 防災; 微細空気泡吹込み

Burning up the oil spilled over the sea is considered to be one of the possible ways to remove the oil quickly. But a boilover phenomenon is an obstacle to putting this way to practical use. As a method to suppress boilover we proposed blowing air bubbles into the oil layr through the water layr under it, which might stir the layrs and decrease the heat transfer rate between the two layrs, and made experiments to confirm the effectiveness of this method. First, with the cup-type burner made of Pyrex glass, effects of some factors, such as fuel kind (n-heptane, ethylbenzene and n-dodecylbenzene), initial layr thickness of fuel or water, cup diameter, on the boilover characteristics were investigated. Next, based on the results the burner able to blow fine air bubbles into the two layrs from its bottom was made. With this apparatus the time history of temperature distribution inside the layrs during burning and the boilover occurrence time, t_<bo>, were measured. This time was used to ev … More aluate the effectiveness of the proposed method. The main results are as follows :1. Among the three kinds of fuels used here, boilover occurred only for dodecylbenzene whose boiling temperature (331ﾟC) is relatively higher than that of water.2. Concerning the boliover of dodecylbenzene :(1) The time t_<bo> becomes longer with an increase in the layr thickness of fuel or water, but it tends to be saturated for the latter.(2) With the burner cup diameter, t_<bo> becomes shorter because of the decrease in heat loss at the burner wall. It gets to be constant when the diameter is larger than 60 mm.(3) A proper amount of air bubble supply can suppress boilover effectively. In this case the fuel burned moderately and almost completely, unlike the case of the occurrence of strong boilover where much fuel was left unburned. However the reduction of smoke amount, which was expected from the fuel-air premixing effect, was not definitely confirmed. And when the amount of air supply becomes large the flame was extinguished before the fuel was completely consumed. Less

燃烧溢出到海面上的石油被认为是快速清除石油的可能方法之一。但沸腾现象是将这种方法投入实际应用的障碍。作为一种抑制沸腾的方法，我们提出了通过下面的水层将气泡吹入油层，从而搅动油层，降低两层之间的换热，并通过实验证实了该方法的有效性。首先，采用聚四氟乙烯玻璃制成的杯式燃烧器，研究了燃料种类(正庚烷、乙苯和正十二烷苯)、燃料或水的初始层厚度、杯径等因素对沸腾特性的影响。在此基础上，研制了能够从底部向两层内吹入细小气泡的燃烧器。用该装置测量了燃烧过程中炉层内部温度分布的时间历程和沸腾发生的时间t_lt；这个时间被用来EV…进一步评价了该方法的有效性。主要研究结果如下：1.在所用的三种燃料中，只有沸腾温度(331ﾟC)高于水的十二烷基苯发生沸腾。关于十二烷基苯的沸腾：(1)随着燃料或水厚度的增加，t_lt；bo&gt；时间变长，但对于后者则趋于饱和。(2)随着燃烧器杯直径的增大，t_&lt；bo&gt；由于燃烧器壁面热损失减少而变短。当直径大于60 mm时，气泡流量趋于恒定。(3)适量的气泡供给可以有效地抑制沸腾。在这种情况下，燃料适度燃烧，几乎完全燃烧，不像发生强烈沸腾的情况，即许多燃料没有燃烧。然而，燃料-空气预混效应预期的烟雾量的减少并未得到明确证实。当空气供应量变大时，火焰在燃料完全消耗之前被扑灭。较少

项目成果

北野三千雄,柴田潤: "空気泡の吹込みによる液体燃料の予混合燃焼" 日本機械学会論文集(B). 60. 3554-3550 (1994)

Michio Kitano，Jun Shibata：“通过吹气泡实现液体燃料的预混合燃烧”，日本机械工程师学会汇刊 (B) 60. 3554-3550 (1994)。

M.Kitano, J.Shibata: "Premixed Combustion of Liquid Fuel by Blowing Air Bubbles" Trans.Japan Soc.Mech.Engrs.Ser.B. 60-578 (1994)

M.Kitano，J.Shibata：“通过吹气泡实现液体燃料的预混合燃烧” Trans.Japan Soc.Mech.Engrs.Ser.B。