🚀 Pipe Flow Rate Calculator & Simulator
- Set Pipe Diameter (Inner Diameter): Enter the net inner diameter (mm) of the pipe using the slider or direct input field.
- Set Target Design Flow Rate: Input the required volumetric flow rate per hour or per minute, with options to select preferred units.
- Verify Recommended Flow Velocity Standards: Check the evaluation table to see if the calculated velocity meets the optimal physical velocity guidelines (0.5 to 6 m/s) for suction lines, delivery lines, or high-pressure hydraulic piping.
- Real-Time Flow Visualization & Feedback: Intuitively observe the movement speed and distribution profile of particles within the canvas, which flow smoothly in proportion to the velocity.
📚 Continuity Equation Formula & Design Guide for Pipe Inner Diameter, Flow Rate, and Velocity ▼
1. Fluid Continuity Equation and Flow Calculation Formula
The Continuity Equation is a fundamental physical law that establishes the relationship between the flow rate, velocity, and cross-sectional area of a fluid flowing through a piping system. In a steady, full-pipe flow of an incompressible fluid, the volumetric flow rate passing through the pipe per unit time is always constant and is determined by multiplying the cross-sectional area by the flow velocity.
Q = A × v = (π × D2 / 4) × v
Where Q is the volumetric flow rate (m3/s), A is the pipe’s internal cross-sectional area (m2), v is the average flow velocity (m/s), and D is the pipe inner diameter (m). In practical engineering calculations, mm is typically used for pipe size, and m³/h or LPM (L/min) for flow rate, so the following practical conversion formula is applied:
v = (4 × Q_m3/h) / (π × (D_mm / 1000)2 × 3600) ≈ 353.68 × Q_m3/h / D_mm2 [m/s]
2. Recommended Design Flow Velocity Guidelines by Piping Application (Water/Oil)
In piping design, setting the correct flow velocity directly affects the system’s durability and the energy efficiency of the pump. If the velocity is too high, frictional losses increase exponentially, potentially causing cavitation and pipe wear/erosion. Conversely, if the velocity is too low, excessively large pipe diameters are required to transport the same flow rate, increasing capital investment costs.
- Pump Suction Line (Water):
0.5 to 1.5 m/s(designed with the lowest velocity to prevent suction pressure loss and cavitation) - Pump Delivery Line (Water):
1.5 to 3.0 m/s(the economically optimal range balancing frictional resistance and pipe weight reduction) - Hydraulic Power Transmission Line (Oil):
2.0 to 6.0 m/s(high-pressure piping, which allows for a relatively higher design velocity limit)
3. Approach to Economic Pipe Diameter Selection
When finalizing piping design, the optimal economic pipe diameter is the point that minimizes the Life Cycle Cost (LCC), which summates the initial installation costs (prices of pipes and fittings) and operating energy costs (pump power required to overcome frictional pressure loss). This simulator features a built-in, real-time monitoring module that calculates various industrial velocity standards, fundamentally preventing errors in flow size design.