Velocity Of Flow At Inlet Calculator

Formula Used:

\[ V_{fi} = \frac{Q}{\frac{\pi}{4} \times (D_o^2 - D_b^2)} \]

Flow Velocity at Inlet (V_fi):

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1. What is Flow Velocity at Inlet?

Flow Velocity at Inlet is the velocity of the flow at the entrance of the turbine. It is a crucial parameter in fluid dynamics and turbine design, representing the speed at which fluid enters the turbine system.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ V_{fi} = \frac{Q}{\frac{\pi}{4} \times (D_o^2 - D_b^2)} \]

Where:

\( V_{fi} \) — Flow Velocity at Inlet (m/s)
\( Q \) — Volume Flow Rate (m³/s)
\( D_o \) — Outer Diameter of Runner (m)
\( D_b \) — Diameter of Hub (m)
\( \pi \) — Archimedes' constant (approximately 3.14159)

Explanation: The formula calculates the inlet flow velocity by dividing the volume flow rate by the cross-sectional area available for flow between the outer runner diameter and hub diameter.

3. Importance of Flow Velocity Calculation

Details: Accurate calculation of flow velocity at inlet is essential for proper turbine design, efficiency optimization, and predicting performance characteristics. It helps in determining the kinetic energy available at the turbine inlet and influences the selection of appropriate turbine components.

4. Using the Calculator

Tips: Enter volume flow rate in m³/s, outer diameter and hub diameter in meters. All values must be positive, and the outer diameter must be greater than the hub diameter.

5. Frequently Asked Questions (FAQ)

Q1: Why is flow velocity at inlet important in turbine design?
A: Flow velocity affects turbine efficiency, cavitation potential, and overall performance. Proper velocity calculation ensures optimal energy extraction.

Q2: What are typical values for flow velocity at turbine inlets?
A: Typical values range from 2-15 m/s depending on turbine type and application, though specific designs may vary.

Q3: How does hub diameter affect flow velocity?
A: Larger hub diameter reduces the available flow area, increasing flow velocity for a given volume flow rate, and vice versa.

Q4: Can this formula be used for all turbine types?
A: This formula is generally applicable for axial flow turbines where flow enters through an annular section between hub and outer diameter.

Q5: What units should be used for accurate calculations?
A: Consistent SI units (meters for diameters, m³/s for flow rate) should be used to ensure accurate velocity results in m/s.