Generation Law And Action Characteristics Of Stress On Icing Adhesion Interface

Icing is a common natural phenomenon,which widely exists in aviation,power transmission,marine engineering,low-temperature refrigeration and other engineering fields.Icing can cause many problems,and even cause loss of life and property.The existing research on the icing problem is mainly to explain the physical and chemical phenomena and characteristics of the icing process and to solve the harm of icing adhesion.However,there are few studies on the formation law and stress characteristics of the icing interface during the icing process.In this paper,the strain characteristics of the icing adhesion interface are taken as the starting point,and the formation process of icing is revealed through the strain generation law and action characteristics of the adhesion interface during icing,which provides theoretical support for the field of anti-acing/deicing.The main conclusions of this paper are as follows:Based on the expansion characteristics of materials and the phase change expansion characteristics of water,the hypothesis that water will produce stress at the interface during the freezing process on the surface of materials is put forward.The self-built experimental device was used to observe the freezing law of water.Through theoretical deduction,compared with the volume change in the phase change expansion stage of water,the volume change caused by the contraction of materials in cold is relatively small,and the phase change expansion and adhesion of water are the reasons for the stress at the interface.Based on the formation principle of ice interface stress,an indirect method for measuring interface strain is proposed.By sticking a circular strain gauge on the lower surface of a relatively thin metal material,the strain characteristics of the upper surface can be transferred to the lower surface.By comparing the experimental group,the interfacial strains of samples with water on the surface and samples without water on the surface were collected at the same time,and the variation law of interfacial strain of icing adhesion was obtained by comparison.According to the proposed principle and method of interface strain acquisition,the corresponding test system is built.The research carried out the strain acquisition test in the icing process,collected the strain change between the interface with water sample and the interface without water sample,exchanged the dripping sample and repeated the test.The influence of environmental temperature and water volume on the strain difference of the icing adhesion interface was studied,and the formation and strain distribution of the icing adhesion interface were also observed.The test shows that there is a stable interfacial strain difference between the water sample and the anhydrous sample,which proves that the phase change expansion of water produces stress at the interface.The decrease of ambient temperature and the increase of water volume can lead to an increase of interfacial strain difference.After the icing process is over,the interfacial strain difference remains stable,which is due to the formation of the icing adhesion interface,and the interfacial strain at the edge of the icing adhesion interface is relatively large,while the strain near the center of the circle is relatively small.Combined with the law of water freezing and the change law of interface strain,the stress characteristics and adhesion formation mechanism of the icing adhesion interface are explained.The change law of interfacial stress is that it increases rapidly at first,and then decreases gradually to be stable,which is consistent with the change law that the icing interface moves up and expands in the phase change stage of water droplets and acts on the tangential direction.Both the increase of water volume and the decrease of ambient temperature can lead to an increase of interfacial strain difference,which is consistent with the changing law of influencing factors of interfacial ice adhesion strength.At the end of the icing process,the interface strain difference remains at a constant value,indicating the formation of the icing adhesion interface.Combined with the change law of phase change water temperature and the change law of interface strain,the formation process of the icing adhesion interface is further verified.Based on the formation process of the icing adhesion interface,the strain distribution law of interface is analyzed,and the stress concentration phenomenon at the edge of water film is proved by the change process of interface mechanics.By studying the stress characteristics and adhesion formation mechanism of the icing adhesion interface,a method of anti-acing/deicing is proposed.By interfering with the formation of the icing adhesion interface and changing the characteristics of the contact interface between ice and solid,the stable adhesion interface formed between the ice coating on the substrate surface and the substrate is destroyed.It is found that the discontinuous surface characteristics can effectively reduce the interfacial adhesion strength,and further optimize the discontinuous surface characteristic parameters.When the diameter of circular coated silicone rubber is 3.5mm,the distance between circle centers is 6.5 mm,the vacancy ratio is 8.5% and the coating thickness is 0.25 mm,the reduction rate of ice adhesion strength on the surface of aluminum alloy samples can reach 52.38%.In this paper,the generation law and action characteristics of stress on the icing adhesion interface are studied.It is innovative in the following aspects: explaining the icing phenomenon from the generation and change law of interface stress in the process of icing formation,and explaining the scientific problem of how icing is formed with the mechanical characteristics of the interface.An interface strain acquisition method is proposed and a strain testing system is developed.The formation mechanism of adhesion interface stress,the influence mechanism of factors on icing adhesion interface stress,and the formation and stress distribution law of the icing adhesion interface are revealed.According to the law of icing,the formation law of icing adhesion interface and the law of stress distribution,an anti/deicing method is proposed to provide technical support for the field of anti-icing/deicing.