Ice Adhesion Force Research Articles

F131 TBAB水溶液の凝固時の固体表面への付着力に関する検討

TBAB slurry having good fluidity and high latent heat of fusion is one promising thermal storage material for air conditioning, but it is reported in solidification of TBAB solution a strong adhesion force to a solid surface such as a pipe's inner-wall through which TBAB slurry flows is generated. However, there are no researches for measurement of the strong adhesion force. In this paper, adhesion force of a frozen TBAB solution to glass or copper is measured. And comparing with ice adhesion force, the characteristics of adhesion force of the frozen TBAB solution are investigated based on separation behaviors of the frozen TBAB solution and ice from the glass or copper.

Investigation on controlling ice adhesion force to solid surface by using thin film made from silane-coupler

Ice adhesion to a cooling solid surface sometimes causes a major accident. While, recently, strong ice adhesion force is positively used to fix a workpiece on a table of machine tool during processing. Therefore, it is necessary to control ice adhesion force to the cooling solid surface. However, the control is indeed a nasty problem to handle. In this paper, as a control method of ice adhesion force to the cooling solid surface, a thin film made from a silane-coupler coated on the solid surface is investigated. The silane-coupler has an organic functional and alkoxyl groups, and the alkoxyl group is changed into a silanol group by hydrolysis. And it is expected that the silanol group can be linked with the slid surface through a hydrogen bonding, while ice adhesion force can be controlled by a characteristic of the organic functional group. And a possibility of control of ice adhesion force due to the thin film is investigated. And endurance and mechanical durability of surface modification by the thin film are also compared with those by conventional methods.

G133 SPMを利用したナノ/マイクロスケール場での氷の冷却面への付着力の測定 : 冷却固体面の影響の検討(OS-14: 固液相変化問題)

Ice adhesion to a cooling solid surface often occurs in many situations. And it causes many serious problems accompanied by economic losses. Thus, it is urgent to clarify a mechanism of ice adhesion to the cooling solid surface. And, in order to clarify the mechanism essentially, it is necessary to investigate it in nano-micro scale field. Thus, one of authors developed the measurement method of ice adhesion force in nano-micro scale fiel by SPM. In this paper, ice adhesion force was measured based on the method, varying surface temperatures of the cooling solid, the correlation between the ice adhesion force and surface temperature was clarified.

Effect of Different Aluminium Surface Treatments on Ice Adhesion Strength

Excessive ice accumulation on power network equipment can affect their integrity and cause damage with serious socioeconomic consequences. To mitigate that, de-icing techniques (mechanical or thermal) have been developed, but these techniques are often limited in their application and are generally expensive and time consuming. Recently, companies and research groups have focused on the development and application of icephobic coatings such as superhydrophobic materials intended to drastically reduce ice adhesion force on exposed equipments. The aim of this paper is the examine the influence of aluminium surface treatments on ice adhesion. Preparation of new and various aluminium surface treatments as well as the need to improve the knowledge of the mechanisms involved in ice adhesion are part of this research. Depending of the type of materials, surface roughness can either promote the formation of air pockets within pores or between coating surface asperities (low adhesion strength), or it can create ice mechanical anchoring if water partially or totally penetrates the porosity. Aluminium anodization using phosphoric acid was studied. Surface morphology was evaluated using scanning electron microscopy and measurements of ice adhesion strength were performed using a centrifuge technique. Based on these results, several surface treatments of aluminium have been considered including aluminium anodizing with partial Al2O3 etching followed by different sealing steps using hydrophobic polymer compounds such as polytetrafluoroethylene.

Investigation of method for measuring adhesion force of ice in nano/micro scale by using SPM

Ice adhesion to a cooling solid surface occurs in many situations, and it causes many serious problems that can lead to economic losses. Therefore, it is necessary to clarify the mechanism of ice adhesion to a cooling surface. In past studies, the adhesion force of ice was reported to be strongly governed by the surface energy of the cooling solid surface. In consideration of this surface energy, it is essential to investigate the ice adhesion force on a nano/micro scale. However, very little research has been conducted in nano/micro scale. Thus, in this paper, by using a scanning probe microscope (SPM), the methods for measuring the ice adhesion force and contact area between the cooling solid surface and formed ice are proposed, and the optimal measurement conditions of the SPM are determined. Then, the validity and effectiveness of the method are clarified.

Understanding the effect of superhydrophobic coatings on energy reduction in anti-icing systems

Abstract In the development of anti/de-icing systems for aeronautics, wind turbines or telecommunication antennas to date, less attention is paid to coating strategies. The majority of studies dealing with coatings have focused mainly on reducing ice adhesion forces, to easily remove ice, once it has formed. In this study we focused on an alternative strategy that consists of promoting the shedding of liquid water as a way to reduce the total amount of water present on the surface that can freeze. Shedding of liquid from the surface can be enhanced by modification of surface wettability, by means of the application of superhydrophobic coatings, i.e. water repellent coatings, characterized by low water adhesion forces. To study the effect of superhydrophobic coatings on surfaces exposed to icing conditions, tests were performed in an open loop icing wind tunnel (IWT) on a standard NACA0021 airfoil in two different icing conditions. Three samples were used during the tests, each one is characterized by different wettability properties. To simulate the presence on anti/de-icing system, the wing was also equipped with an electrical heater, mounted at the inner side of the wing leading edge. Results from IWT tests demonstrated that surface wettability is an important controlling factor not only for reducing ice accretion on the wing, but also for reducing by up to 80% the energy required to avoid ice accretion on the wing. The findings from IWT tests as described, together with results from a previous work on drop shedding, reinforced the hypothesis that shedding of drops is the key controlling mechanism for an efficient icing mitigation strategy.

Measurement method and results of ice adhesion force on the curved surface of a wind turbine blade

Experimental adhesion force measurements were conducted on accumulated ice on the leading edge of a scaled wind turbine blade in both glaze and rime icing regimes. An apparatus was first designed for specifically measuring the adhesion force of ice on a curved surface at climatic temperature where a vertical force was applied to the mounted structure in the test apparatus. Adhesion force measurements were measured and adhesion pressure calculated for plain and ice-mitigated test specimens. Results are presented for the increase in force of ice adhesion over a curved surface area in proportion to degree centigrade decrease in temperature.

Fundamental study of adhesion of ice to cooling solid surface (Discussion on influence of copper oxide layer on ice adhesion force)

In many situations, ice often adheres to a cooling solid surface, frequently causing serious accidents. It is critical to clarify the mechanism of ice adhesion to the cooling surface in order to prevent ice adhesion. In a past study, the shearing stresses of two kinds of test plates with a copper surface having the higher thermal conductivity were measured. The shearing stress corresponds to ice adhesion force. Both shearing stresses were significantly different; however, the cause remains unclear. Therefore, the present study focuses on an oxide layer as the main factor causing the difference of both shearing stresses; the influence of the oxide layer formed on shearing stress was discussed. And in the removal and reformation processes of the oxide layer, the time variation of the shearing stress was clarified. Moreover, the relationship between the state of the copper surface and the shearing stress was also clarified by surface analysis.

B142 表面改質の氷の剥離挙動への影響(固液相変化を伴う伝熱現象III)

Ice adhesion to a cooling solid surface often occurs in many situations. And it causes many serious problems accompanying economic losses. Therefore, it is necessary to clarify the mechanism of ice adhesion to the cooling surface. In the past studies, ice adhesion force was affected by behavior of removal of ice from the surface of the cooling plate. Moreover, the force is also affected by surface modification such as plasma and ultraviolet rays irradiation to the plate surface and removal of the oxide layer from the plate surface. Thus, in this paper, considering shear stress corresponding to adhesion force, the relationship between behavior of removal of ice from the copper plate surface and surface modification is investigated with variation in the surface temperatures.

Fundamental study on adhesion of ice to solid surface: Discussion on coupling of nano-scale field with macro-scale field

In a previous study, it was reported that the removal process (behavior) of ice from a cooling solid surface depended on the characteristic of the solid surface, and that the ice adhesion force to the cooling surface was mainly governed by the surface energy of the surface. In the present study, using the method of surface analysis, the ice removal process and the ice adhesion force clarified in a macro-scale field were also discussed in a nano-scale field to couple these scale fields. Simultaneously, another surface analysis of the solid surface was carried out to identify the distributions of hydrophilic and hydrophobic groups on a solid surface. Attempts to couple the nano-scale field with the macro-scale field revealed that the results for both scale fields were in approximate qualitative agreement.

Suppression of ice adhesion force to cooling wall due to voltage application

For ice storage, one of the authors has previously reported on the ice slurry formed by cooling water–silicone oil mixture with stirring. When the mixture is stirred in a vessel, the oil is charged due to static electricity. If the vessel can attract the charged oil, suppression of ice adhesion force to a cooling wall may be possible. In this study, therefore, a certain voltage was applied to the vessel filled with the mixture with cooling and stirring simultaneously, and water was frozen in the vessel. Then, the ice adhesion force to the cooling vessel wall was measured under a constant apparent adhesion area between the ice and cooling vessel wall. From the measurement results, optimal conditions of the oil viscosity, rotation speed and applied voltage to suppress the ice adhesion force effectively were clarified. Moreover, the factors governing suppression of the ice adhesion force were clarified.