FM - Fundamental Equation

FM – Fundamental Equation

This basic equation is referred to the Fundamental Flow Equation, also known as the General Flow equation.
Starting with Bernoulli’s equation, researchers have developed a formula for calculating the pressure drop in a gas pipeline, considering the pipe diameter, length, elevations along the pipe, gas flow rate and the gravity and compressibility of the gas as shown in this manual.

• 𝑄 − Flow Rate (ft³/day)
• 𝐷 − Internal Pipe Diameter (in)
• 𝐿 − Length of Pipeline(mi)
• 𝑃₁ − Upstream Pressure (psi)
• 𝑃₂ − Downstream Pressure (psi)
• 𝐺 − Gas Specific Gravity
• 𝑃_𝑏 − Pressure Base (psi)
• 𝑇_𝑏 −Temperature Base (°R)
• 𝑇_𝑓 − Gas Flowing Temperature (°R)
• 𝑍 − Compressibility Factor

• 𝐹 − Transmission Factor
• 𝑓 − Friction Factor
• 𝑘 − Pipe Roughness
• 𝐷 − Internal Diameter (in)

Input Parameters

1. To create a new case, click the “Add Case” button
2. Select the Unknown and desired Flow Equation.
3. Enter Case Name, Location, Date, and any necessary notes.
4. Fill out all required fields.
5. Make sure the values you are inputting are in the correct units.
6. Click the CALCULATE button.

• Temperature base(°F)
• Pressure base(psia)
• Gas Flowing Temperature(°F)
• Gas Specific Gravity
• Compressibility Factor
• Pipeline Efficiency Factor
• Upstream Pressure(psig)
• Flow Rate(MCFD)
• Internal Pipe Diameter(in)
• Length of Pipeline(mi)
• Upstream Elevation(ft)
• Downstream Elevation(ft)

Outputs/Reports

1. View the results.
2. If an input parameter needs to be edited be sure to hit the CALCULATE button after the change.
3. To SAVE, fill out all required case details then click the SAVE button.
4. To rename an existing file, click the SAVE As button. Provide all case info then click SAVE.
5. To generate a REPORT, click the REPORT button.
6. The user may export the Case/Report by clicking the Export to Excel/PowerPoint icon.
7. To delete a case, click the DELETE icon near the top of the widget.

• Flow Rate(ft/sec.)
• Transmission Factor
• Velocity(ft/sec.)
• Upstream Pressure(psi)
• Transmission Factor
• Velocity(ft/sec.)
• Downstream Pressure(psi)
• Transmission Factor
• Velocity(ft/sec.)
• Internal Pipe Diameter(in)
• Transmission Factor
• Velocity(ft/sec.)
• Erosional Velocity
• Sonic Velocity

Flow Rate

Upstream Pressure

Downstream Pressure

Internal Pipe Diameter