The physical properties affecting flow properties primarily relate to the characteristics of the particles themselves, impacting how easily a substance can flow.
Here's a breakdown of the key physical properties:
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Surface Texture:
- Smooth Surface: Promotes good flowability. Reduced friction between particles allows them to slide past each other easily.
- Rough Surface: Hinders flowability. Increased friction due to surface irregularities causes particles to interlock and resist movement.
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Particle Shape:
- Spherical/Rounded Particles: Generally exhibit better flow properties due to minimal interlocking and reduced friction.
- Flat and Elongated Particles: Lead to poor flowability and high porosity. Their shape increases the potential for interlocking and creates larger void spaces, impeding flow.
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Particle Size Distribution:
- Uniform Particle Size: Can lead to either good or poor flow depending on other factors. Smaller, uniform particles can sometimes exhibit poor flow due to increased cohesive forces.
- Wide Particle Size Distribution: Often improves flow. Smaller particles can fill the voids between larger particles, reducing interlocking and improving packing density, but very fine particles may stick together and reduce flow.
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Density:
- High Density: Generally contributes to good flow properties. Denser particles are less likely to be affected by electrostatic forces and have higher momentum, aiding flow.
- Low Density: Can hinder flow, especially if combined with irregular shapes or rough surfaces.
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Porosity:
- Low Porosity: Correlates with good flow properties. Denser packing reduces interparticle friction and promotes smoother flow.
- High Porosity: Indicates larger void spaces between particles, potentially leading to interlocking and reduced flow.
In summary, a substance with smooth, rounded, dense particles of varying sizes, and low porosity will generally exhibit superior flow properties. Conversely, rough, elongated, low-density particles of uniform size, and high porosity will likely result in poor flowability.
