Settling Velocity For Modified Hazen's Equation Calculator

Modified Hazen's Equation:

\[ V_{sm} = 60.6 \times D_p \times (G - 1) \times \frac{(3 \times T) + 70}{100} \]

Settling Velocity (Vsm):

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1. What is the Modified Hazen's Equation?

The Modified Hazen's Equation is used to calculate the settling velocity of particles in a fluid. It provides an estimate of how quickly sediment particles will settle under the influence of gravity, taking into account particle diameter, specific gravity, and temperature effects.

2. How Does the Calculator Work?

The calculator uses the Modified Hazen's Equation:

\[ V_{sm} = 60.6 \times D_p \times (G - 1) \times \frac{(3 \times T) + 70}{100} \]

Where:

\( V_{sm} \) — Settling Velocity (m/s)
\( D_p \) — Diameter of Particle (m)
\( G \) — Specific Gravity of Sediment (-)
\( T \) — Temperature (°C)

Explanation: The equation accounts for the effects of particle size, density difference between particle and fluid, and temperature on the settling rate of particles in a fluid medium.

3. Importance of Settling Velocity Calculation

Details: Calculating settling velocity is crucial for designing sedimentation tanks, understanding sediment transport in rivers and oceans, wastewater treatment processes, and various environmental engineering applications where particle separation is required.

4. Using the Calculator

Tips: Enter particle diameter in meters, specific gravity (dimensionless), and temperature in degrees Celsius. All values must be valid (diameter > 0, specific gravity > 0).

5. Frequently Asked Questions (FAQ)

Q1: What is the range of applicability for this equation?
A: The Modified Hazen's Equation is generally applicable for small to medium-sized particles in water at typical environmental temperatures.

Q2: How does temperature affect settling velocity?
A: Temperature affects the viscosity of water - higher temperatures reduce viscosity, allowing particles to settle faster, while lower temperatures increase viscosity, slowing settlement.

Q3: What are typical values for specific gravity of sediment?
A: Most mineral sediments have specific gravity between 2.5-2.7, while organic particles may have values closer to 1.0-1.5.

Q4: When is this equation not appropriate?
A: This equation may not be accurate for very fine particles (where Brownian motion dominates), very large particles (where turbulence effects are significant), or non-spherical particles.

Q5: How does this compare to Stokes' Law?
A: The Modified Hazen's Equation is an empirical modification that accounts for temperature effects more explicitly and may provide better results for certain particle size ranges and environmental conditions.