Droplets evaporation in an insulated chamber with controlled concentrations of water vapor and temperatures

The experimental study results of the relative humidity (RH) distribution over an evaporating water droplet from the heated surface (323 Kelvin) inside an insulated chamber were presented. Registration of the evaporation process was carried out using an optical system. The concentration of water vapor was determined by hygrometers. It has been established that the water vapor inside is not evenly distributed due to the temperature gradient resulting from the supply of heat to the bottom and the loss through the side and top walls of the chamber. RH increased by 20-40% in comparison with the initial value at a distance of 2-20 mm from the sample surface during the evaporation of the droplets. At the same time water vapor in the insulated chamber condensed on its upper and side walls. After evaporation of the droplets, RH in the whole space of the chamber assumed the initial value

Modification of aluminum alloy surface properties by wave-long laser texturing

Change of the static contact angle (SCA) of 10 [mu]L distilled water droplet on laser textured aluminium alloy (AMG-6) substrates was studied. The texture was deposited by a laser system based on a fiber laser. An increase in the power of laser radiation is found to lead to a decrease in the SCA measured on the first day after texturing. Change of dispersion and polar surface energy components of textured substrates is determined. Under the influence of the environment, the surface properties of AMG-6 change with time. SCA increased and reached stable state on the twentieth day after texturing

Measurement of free surface energy of laser treated aluminum substrate

The change in the surface energy of the aluminum substrate after laser treatment has been determined experimentally. Surface energy is determined using the Advance KRUSS software. The laser treatment of the surface is found to increase its free surface energy. It changes the ratio of the polar and the dispersion components. Analysis of the crystalline planes of aluminum surface after laser treatment was provided by XRD X-ray diffractometry using a Shimadzu XRD 7000S diffractometer

Forced spreading over superhydrophobic and copper surfaces

Dynamic spreading over superhydrophobic and copper surfaces was studied experimentally under the condition of contact line movement with speed greater than 1 mm/sec. Three modes of spreading of distilled water drop over copper surfaces with sufficient typical roughness (0.591, 5.190 and 6.210 μM) were detected. The first one is drop formation when the contact line speed and dynamic contact angle increase sharply. The second mode is spreading of a drop, which is characterized by a monotonic decrease in the contact line speed and dynamic contact angle. The third one is a formation of an equilibrium contact angle at a constant wetted area (the contact line speed tends to zero, and spreading of a drop occurs as long as the driving force is greater than zero). Some features in spreading were detected on superhydrophobic surface with parameter roughness of 0.751μm compared to other substrates. During drop formation after sharp increase in the contact line speed and dynamic contact angle, there is a mode which is accompanied by a decrease in the contact line speed and monotonic increase in the advancing dynamic contact angle

Forced spreading over superhydrophobic and copper surfaces

Dynamic spreading over superhydrophobic and copper surfaces was studied experimentally under the condition of contact line movement with speed greater than 1 mm/sec. Three modes of spreading of distilled water drop over copper surfaces with sufficient typical roughness (0.591, 5.190 and 6.210 μM) were detected. The first one is drop formation when the contact line speed and dynamic contact angle increase sharply. The second mode is spreading of a drop, which is characterized by a monotonic decrease in the contact line speed and dynamic contact angle. The third one is a formation of an equilibrium contact angle at a constant wetted area (the contact line speed tends to zero, and spreading of a drop occurs as long as the driving force is greater than zero). Some features in spreading were detected on superhydrophobic surface with parameter roughness of 0.751μm compared to other substrates. During drop formation after sharp increase in the contact line speed and dynamic contact angle, there is a mode which is accompanied by a decrease in the contact line speed and monotonic increase in the advancing dynamic contact angle

Forced spreading over superhydrophobic and copper surfaces

Dynamic spreading over superhydrophobic and copper surfaces was studied experimentally under the condition of contact line movement with speed greater than 1 mm/sec. Three modes of spreading of distilled water drop over copper surfaces with sufficient typical roughness (0.591, 5.190 and 6.210 μM) were detected. The first one is drop formation when the contact line speed and dynamic contact angle increase sharply. The second mode is spreading of a drop, which is characterized by a monotonic decrease in the contact line speed and dynamic contact angle. The third one is a formation of an equilibrium contact angle at a constant wetted area (the contact line speed tends to zero, and spreading of a drop occurs as long as the driving force is greater than zero). Some features in spreading were detected on superhydrophobic surface with parameter roughness of 0.751μm compared to other substrates. During drop formation after sharp increase in the contact line speed and dynamic contact angle, there is a mode which is accompanied by a decrease in the contact line speed and monotonic increase in the advancing dynamic contact angle

Experimental determination of change in the liquid layer thickness on the heated surface by confocal sensor

Change of the distilled water layer thickness in time under the evaporation from stainless steel surface was studied experimentally. To register a change in the liquid layer thickness an experimental technique with the use of high-precision confocal method was developed. Change of the thickness of thin layers (less than 3 mm) in time is found to have a linear nature. At decreasing the thickness up to 0.5 mm, linear nature changes to the polynomial. It can be explained by the change in surface tension

Modification of aluminum alloy surface properties by wave-long laser texturing

Change of the static contact angle (SCA) of 10 μL distilled water droplet on laser textured aluminium alloy (AMG-6) substrates was studied. The texture was deposited by a laser system based on a fiber laser. An increase in the power of laser radiation is found to lead to a decrease in the SCA measured on the first day after texturing. Change of dispersion and polar surface energy components of textured substrates is determined. Under the influence of the environment, the surface properties of AMG-6 change with time. SCA increased and reached stable state on the twentieth day after texturing

Experimental determination of change in the liquid layer thickness on the heated surface by confocal sensor

Change of the distilled water layer thickness in time under the evaporation from stainless steel surface was studied experimentally. To register a change in the liquid layer thickness an experimental technique with the use of high-precision confocal method was developed. Change of the thickness of thin layers (less than 3 mm) in time is found to have a linear nature. At decreasing the thickness up to 0.5 mm, linear nature changes to the polynomial. It can be explained by the change in surface tension

Modification of aluminum alloy surface properties by wave-long laser texturing

Change of the static contact angle (SCA) of 10 μL distilled water droplet on laser textured aluminium alloy (AMG-6) substrates was studied. The texture was deposited by a laser system based on a fiber laser. An increase in the power of laser radiation is found to lead to a decrease in the SCA measured on the first day after texturing. Change of dispersion and polar surface energy components of textured substrates is determined. Under the influence of the environment, the surface properties of AMG-6 change with time. SCA increased and reached stable state on the twentieth day after texturing