Study On Pool Boiling Heat Transfer Performance Of Self-rewetting Solution Based On Nano-porous Surface

As highly integrated,electronic components of the heat dissipation become an important problem to be solved.Phase change heat transfer can be more big heat transfer,therefore become the important way to solve the problem of heat dissipation.At present,the means of improving the efficiency of phase change heat transfer are mainly concentrated in heat exchange surface morphology and thermal properties of nature two aspects.This paper uses anodic oxidation method,and titanium plate for base,with organic and inorganic acid neutral electrolyte electrolyte was prepared titanium dioxide nanotube array,its structure was characterized and as a heat transfer surface.From different solubility heptanol solution as the wetting solution,the surface tension and thermal physical property test,etc.Structures,pool boiling experiment platform,the examination of nano porous surface and the wetting solution combined with boiling heat transfer performance of heat transfer enhancement and analysis mechanisms.Preparation of nano porous surface characterization indicated that different ingredients of TiO₂ nanoarray pipe diameter size is different,organic neutral electrolyte was prepared under 40 v 180 nm nano tube diameter,inorganic acid solution was prepared under 25 v 80nm nano tube diameter.Can be found by comparing the organic,neutral electrolyte preparation of pipe diameter size and wall thickness of nanotube arrays compared with inorganic acid electrolyte has obvious increasing trend,and stability also had the very big improvement.To test found that the wetting solution compared to the conventional Newtonian fluid,the surface tension of the wetting solution with the thermometer shows different correlation.Comparison and deionized water from wetting solution under the condition of two kinds of heat transfer working medium,heat transfer performance of the nano porous surface differences.In concentration was 0.1 wt%of the wetting solution under the condition of pool boiling heat transfer coefficient and the critical heat flux density respectively reached 22.46 kW/m²·?and 536.64 kW/m²,compared to under the condition of distilled water increased by 121.2%and 121.2%respectively.By high-speed camera records to the boiling process,bubbles merge phenomenon in the process of boiling,gasification core density,air bubble detachment frequency and diameter etc.Has the very big difference.In the wetting solution under the condition of frequency and gasification of bubbles from the core density compared with distilled water significantly larger,at the same time,the out diameter of bubble is smaller.In the process of boiling,the wetting solution effectively prevented the merger between adjacent bubbles,at the same time with the increase of heat flux appeared obvious micro air bubble boiling state.Combined with bubbles force,on the heat transfer mechanism of the nano porous surface wetting solution is analyzed.Analysis under the influence of surface tension with temperature changes,made under the condition of alcohol aqueous solution easily between bubbles and the heat transfer surface in the formation of more obvious surface tension gradient and density difference,thus forming the Marangoni effect of local,make cold since wetting solution flow to the heat transfer surface automatically,improves the thermal efficiency change,have played an important role in improving dry up limit.Pool boiling system was established under the condition of the nanometer porous surface and heptanol solution bubble from the diameter and the critical heat flux prediction model,for the cooling technology in the field of electronic design provide important theoretical guidance.