AN INVESTIGATION OF THE ENHANCEMENT OF HEAT TRANSFER AS QUICK COOLING OF THE HEATED PLATE

加热板快速冷却强化传热的研究

• 批准号: 06650271
• 负责人: MATSUMOTO Kenichi
• 金额: $ 1.09万
• 依托单位: KURUME NATIONAL COLLEGE OF TECHNOLOGY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06650271/
• 关键词: heat transfer enhancement; boilin heat transfer; cooling; quenching; vapor explosion; 急速冷却; 沸騰伝熱促進・制御; 沸騰特性曲線

In case of cooling of hot plate by the coolant, the hot plate is covered with the vapor layr when it was heated to high temperature. Consequently, the reduction of heat transfer from the hot plate is produced by means of the thermal resistance of vapor layr. The object of our investigation is to find the meth- ods of the enhancement of heat transfer by making of disturbance to the vapor layr and to increase the cooling effects of the hot plate.(1) On the ralation of the chemical properties and the stability of the liquid-vapor interfaceThe vibration of liquid-vapor interface is affected by the interfacial tension of liquid. The kinetic instability theory of liquid-vapor interface gives some suggestions an influence of the interfacial tension. An experimental investigation of the effects of interfacial tension carried out by addition of a surface active agent into the coolant (water). It has been definitely shown by experiments that the addition of a surface active agent has a favorable influence upon the existence of vapor layr. In case of addition of a surface active agent, the film boiling are maintaining at low heat flux region and the vapor layr has been existed for any length of time. Although we expected initialy that an lower interfacial tension accelerates the touch of the liquid to the hot plate surface.(2) On the effect of the hot plate surface roughnessWe have investigated the effect of sourface roughness of hot plate and found that large roughness or contaminations on sourface made easy to contact of coolant and surface. The metal wire nets covered on the plate, especially, disturbed the existence of the vapor film layr.

在由冷却剂冷却热板的情况下，当热板被加热到高温时，热板被蒸气层覆盖。因此，通过蒸汽层的热阻产生来自热板的热传递的减少。我们研究的目的是寻找通过对蒸汽层进行扰动来强化传热并提高热板冷却效果的方法。(1)气液界面的化学性质与界面稳定性的关系气液界面的振动受界面张力的影响。汽液界面动力学不稳定性理论对界面张力的影响给出了一些建议。通过向冷却剂（水）中添加表面活性剂对界面张力影响的实验研究。实验明确表明，表面活性剂的加入对汽层的存在有有利的影响。在添加表面活性剂的情况下，膜沸腾维持在低热流密度区，汽层存在的时间可以任意长。虽然我们最初预期较低的界面张力会加速液体与热板表面的接触。(2)热板表面粗糙度的影响我们研究了热板表面粗糙度的影响，发现表面粗糙度大或污染物容易使冷却剂与表面接触。特别是覆盖在板上的金属丝网，干扰了汽膜层的存在。