Volume of Fluid Displaced for a Single-acting Pump Formula |
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| \( V_{fd} \;=\; \dfrac{ \pi \cdot p_d^2 \cdot SL \cdot n_c }{ 4 }\) | ||
| Symbol | English | Metric |
| \( V_{fd} \) = Volume of Fluid Displaced | \(bbl\) | - |
| \( \pi \) = Pi | \(3.141 592 653 ...\) | - |
| \( p_d \) = Piston Diameter | \(in\) | - |
| \( SL \) = Stroke Length | \(in\) | - |
| \( n_c \) = Number of Cylinders | \(dimensionless\) | - |
Volume of fluid displaced for pumps is the amount of liquid or gas that a pump moves or transfers during a single cycle or stroke of its operation. In positive displacement pumps, such as piston, diaphragm, or gear pumps, this volume is determined by the pump's internal geometry, specifically the size of the chamber or cavity that traps and moves the fluid. Each cycle displaces a fixed volume of fluid, regardless of the pressure or flow resistance, which is why these pumps are often used for precise metering or high-pressure applications. The volume of fluid displaced is needed in pump design and selection, as it directly affects the pump’s flow rate, efficiency, and suitability for specific applications, such as water supply, oil transfer, or chemical dosing. Nowing this ensures proper pump sizing to meet desired flow requirements while minimizing energy losses.
Volume of Fluid Displaced for a Duplex Pump Formula |
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| \( V_{fd} \;=\; \dfrac{ n_c \cdot SL \cdot [\; ( 2 \cdot p_d^2 ) - r_d^2 \;] \cdot \eta_v }{ 42 \cdot 294 }\) | ||
| Symbol | English | Metric |
| \( V_{fd} \) = Volume of Fluid Displaced | \(bbl\;/\;stroke\) | - |
| \( n_c \) = Number of Cylinders | \(dimensionless\) | - |
| \( SL \) = Stroke Length | \(in\) | - |
| \( p_d \) = Piston Diameter | \(in\) | - |
| \( r_d \) = Rod Diameter | \(in\) | - |
| \( \eta_v \) (Greek symbol eta) = Volumetric Efficiency | \(dimensionless\) | - |
Volume of Fluid Displaced for a Triplex Pump Formula |
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| \( V_{fd} \;=\; \dfrac{ SL \cdot p_d^2 \cdot \eta_v }{ 42 \cdot 98.03 }\) | ||
| Symbol | English | Metric |
| \( V_{fd} \) = Volume of Fluid Displaced | \(bbl\;/\;stroke\) | - |
| \( SL \) = Stroke Length | \(in\) | - |
| \( p_d \) = Piston Diameter | \(in\) | - |
| \( \eta_v \) (Greek symbol eta) = Volumetric Efficiency | \(dimensionless\) | - |