What is Wenzel equation?
What is Wenzel equation?
Wenzel’s statement can be described by: cosΘm = rcosΘY. where Θm is the measured contact angle, ΘY is Young’s contact angle and r is the roughness ratio. Roughness ratio is defined as the ratio between the actual and projected solid surface area (r=1 for a smooth surface and > 1 for a rough surface).
What is Young’s equation?
Young’s equation is a formula developed by the English physicist Thomas Young, which is used to define the relationship between the contact angle, the surface tension, the interfacial tension between a liquid and a solid surface, and the surface free energy of the solid.
How to derive young’s equation?
3.2. Derivation of Young’s equation
- G(h, h’, r)= a∫0[2πrγ⋅√1+(dhdr)2 +U(r,h)+[2πr(γSL− γSO)]]dr E25.
- V0=a∫02πr⋅[h(r)]dr E26.
- ˜G(h,h′,r)=2πγr√1+h′2 +U(r,h)+2πr(γSL− γSO)+ 2πβrh E28.
Is talc have low wettability?
is, talc is hydrophobic, chemically inert, organophilic, platy, and has low electrical and high thermal conductivity [16]. properties with the wettability parameter [17]. will clearly influence any fine particle processing operation.
What is apparent contact?
The apparent contact angle is the angle between the apparent solid surface and the tangent to the liquid-fluid interface (Fig. 1a). For two-dimensional or axisymmetric systems, there exists a unique correspondence between this definition and experimentally measured contact angles. (a) The apparent contact angle.
What is Young’s contact angle?
The contact angle is the angle, conventionally measured through the liquid, where a liquid–vapor interface meets a solid surface. It quantifies the wettability of a solid surface by a liquid via the Young equation. It changes with surface tension and hence with the temperature and purity of the liquid.
What is the spreading coefficient?
The spreading coefficient or parameter is a measure of the tendency of a liquid phase to spread (complete wetting) on a second, liquid or solid phase.
What is dynamic contact angle?
The term dynamic contact angle measurements refers to techniques that measure the contact angle during movement. This is usually accomplished by adding liquid to a static droplet on a surface and thus pushing the front of the liquid across the unwetted surface.
Why is the contact angle of water Zero?
The angle of contact does not depend on the manner of contact. When a liquid has concave meniscus, the angle of contact is acute. When it has a convex meniscus, the angle of contact is obtuse. For pure water and perfectly clean glass, the angle of contact is 0°.
What is the contact angle of a material?
The contact angle is the angle, conventionally measured through the liquid, where a liquid–vapor interface meets a solid surface. It quantifies the wettability of a solid surface by a liquid via the Young equation.
Which is the correct formula for the acceleration?
Formula of Acceleration 1 Final Velocity is v 2 Initial velocity is u 3 Acceleration is a 4 Time taken is t 5 Distance traveled is s More
How is the Wenzel equation based on the roughness scale?
It is important to notice that the Wenzel equation is based on the assumption that the liquid penetrates into the roughness grooves (as in Figure 1). It has been stated that if the droplet is larger than the roughness scale by two to three orders of magnitude, the Wenzel equation applies 4.
How to calculate the acceleration of a meter per second?
It is denoted by symbol a and is articulated as- meter per second squared or m/s 2 is the S.I unit for Acceleration, If t (time taken), v (final velocity) and u (initial velocity) are provided. Then the acceleration is given by formula
Do you have to subtract initial velocity from final velocity to calculate acceleration?
You need to subtract the initial velocity from the final velocity. If you reverse them, you will get the direction of your acceleration wrong. If you don’t have a starting time, you can use “0”. If the final velocity is less than the initial velocity, the acceleration will be negative, meaning that the object slowed down.