Choke Area Using Bernoulli's Equation Calculator

Bernoulli's Equation:

\[ A_c = \frac{W_c}{\rho_m \cdot t_{pt} \cdot C \cdot \sqrt{2 \cdot g \cdot H}} \]

Casting Mass (Wc):

Density of Metal (ρm):

kg/m³

Pouring Time (tpt):

Efficiency Factor (C):

Effective Metal Head (H):

Area of Choke Section of Sprue (Ac):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Bernoulli's Equation for Choke Area?

The Bernoulli's Equation for calculating choke area in sprue design is derived from fluid dynamics principles. It determines the cross-sectional area at the choke section of a sprue where the metal flow is controlled to ensure proper mold filling in casting processes.

2. How Does the Calculator Work?

The calculator uses the Bernoulli's Equation:

\[ A_c = \frac{W_c}{\rho_m \cdot t_{pt} \cdot C \cdot \sqrt{2 \cdot g \cdot H}} \]

Where:

\( A_c \) — Area of Choke Section of Sprue (m²)
\( W_c \) — Casting Mass (kg)
\( \rho_m \) — Density of Metal (kg/m³)
\( t_{pt} \) — Pouring Time (s)
\( C \) — Efficiency Factor of Gating System
\( g \) — Gravitational acceleration (9.80665 m/s²)
\( H \) — Effective Metal Head of Mould (m)

Explanation: The equation calculates the minimum cross-sectional area required at the sprue choke to allow the specified mass of metal to flow through in the given pouring time under the influence of gravity.

3. Importance of Choke Area Calculation

Details: Accurate choke area calculation is crucial for proper mold design, ensuring complete mold filling, preventing casting defects, and optimizing metal flow characteristics during the casting process.

4. Using the Calculator

Tips: Enter casting mass in kg, density in kg/m³, pouring time in seconds, efficiency factor (0-1), and effective metal head in meters. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the significance of the choke section in sprue design?
A: The choke section controls the flow rate of molten metal, ensuring proper mold filling and preventing turbulence that can cause casting defects.

Q2: How is the efficiency factor determined?
A: The efficiency factor accounts for energy losses in the gating system and typically ranges from 0.6 to 0.8 for well-designed systems.

Q3: What is effective metal head and how is it measured?
A: Effective metal head is the vertical distance from the pouring basin to the choke section, representing the driving pressure for metal flow.

Q4: Can this equation be used for all casting metals?
A: Yes, but the density value must be appropriate for the specific metal being cast (e.g., aluminum, iron, bronze).

Q5: What are typical values for pouring time?
A: Pouring time varies with casting size and complexity, typically ranging from a few seconds for small castings to several minutes for large ones.