Temperature distribution along the surface of evaporating droplets
Kai Zhang1, Liran Ma2, Xuefeng Xu1
1School of Technology, Beijing Forestry University, Beijing 100083, China.
Summary
Drying droplets can have non-monotonic surface temperature distributions, contrary to previous assumptions. This finding impacts understanding droplet flow and controlling deposition processes.
Area of Science:
- Fluid dynamics
- Heat transfer
- Surface science
Background:
- Droplet evaporation is crucial in various applications.
- Surface temperature significantly influences droplet flow fields.
- Previous research often assumed monotonic temperature variations.
Purpose of the Study:
- To investigate non-monotonic surface temperature distributions in drying droplets.
- To analyze the interplay between evaporative cooling and heat conduction.
- To understand the impact of temperature gradients on droplet flow structure.
Main Methods:
- Theoretical analysis of heat transfer and fluid dynamics.
- Modeling of evaporative cooling and substrate heat conduction.
- Development of a phase diagram for surface temperature distribution.
Main Results:
- Identified three distinct patterns of surface temperature distribution: monotonic increase, monotonic decrease, and non-monotonic.
- Demonstrated that non-monotonic distributions arise from combined evaporative cooling and heat conduction.
- Established a phase diagram to predict temperature distribution patterns.
Conclusions:
- Surface temperature distribution in drying droplets is not always monotonic.
- Understanding these distributions is key to explaining the Marangoni effect.
- This research offers insights for controlling evaporation-driven deposition and material assembly.
Related Concept Videos
01:18Vaporization
33.3K
The physical form of a substance changes by changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize (convert into vapor). The process is called vaporization—a surface phenomenon. For vaporization to occur, kinetic energy must be greater than the intermolecular forces that keep molecules bonded. The amount of energy needed to vaporize a quantity of liquid at a given pressure and a constant temperature is called the heat of vaporization. When...
33.3K
01:27Distribution of Molecular Speeds
4.0K
The motion of molecules in a gas is random in magnitude and direction for individual molecules, but a gas of many molecules has a predictable distribution of molecular speeds. This predictable distribution of molecular speeds is known as the Maxwell-Boltzmann distribution. The distribution of molecular speeds in liquids is comparable to that of gases but not identical and can help to understand the phenomenon of the boiling and vapor pressure of a liquid. Consider that a molecule requires a...
4.0K
02:39Phase Transitions: Vaporization and Condensation
16.9K
The physical form of a substance changes on changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize (convert into vapor). The process is called vaporization—a surface phenomenon. Vaporization occurs when the thermal motion of the molecules overcome the intermolecular forces, and the molecules (at the surface) escape into the gaseous state. When a liquid vaporizes in a closed container, gas molecules cannot escape. As these gas phase...
16.9K
01:01Distillation: Vapor–Liquid Equilibria
4.1K
Distillation is a separation technique that takes advantage of the boiling point properties of disparate elements in a mixture. To perform distillation, we begin by heating a miscible mixture of two liquids with a significant difference in boiling points (at least 20°C). As the solution heats up and reaches the bubble point of the more volatile component, some molecules of the more volatile component transition into the gas phase and travel upward into the condenser, which is a glass tube...
4.1K
01:22Surface Tension of Fluid
1.9K
Surface tension is a fundamental property of fluids, occurring at the boundary between a liquid and a gas or between two immiscible liquids. This phenomenon arises from the cohesive forces between molecules at the fluid's surface, creating an effect similar to a stretched elastic membrane. Inside each fluid, molecules are equally attracted in all directions by neighboring molecules, but surface molecules experience a net inward force, resulting in surface tension.
Surface tension varies...
Surface tension varies...
1.9K
02:44Heating and Cooling Curves
23.2K
When a substance—isolated from its environment—is subjected to heat changes, corresponding changes in temperature and phase of the substance is observed; this is graphically represented by heating and cooling curves.
For instance, the addition of heat raises the temperature of a solid; the amount of heat absorbed depends on the heat capacity of the solid (q = mcsolidΔT). According to thermochemistry, the relation between the amount of heat absorbed or released by a substance,...
For instance, the addition of heat raises the temperature of a solid; the amount of heat absorbed depends on the heat capacity of the solid (q = mcsolidΔT). According to thermochemistry, the relation between the amount of heat absorbed or released by a substance,...
23.2K