Axial Flow Pump vs Centrifugal Pump: How to choose?

Pumps are the essential fluid conveying equipment in various sections including industrial applications, building construction, agricultural irrigation and civil infrastructure. While among the family of pumps, the axial flow pumps and centrifugal pumps are relatively common ones that have their own distinct features. They have completely different working principles, application fields and advantages and disadvantages, therefore, to ensure the optimized performance during the pump operation, it is important to take a lot of parameters and factors into consideration during the pump model selection. In this article, you may find out the differences between the axial flow pumps and centrifugal pumps regarding their designs, structures, working principles and working applications.

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The working principle of axial flow pumps

Firstly, the pumping fluid flows through the pump suction to arrive at the pump elbow, and then the fluid begins to engage with the blades of impeller itself which axes the fluid. The diameter of the impeller, the rotation direction of the impeller and the angle of the blades, etc., determine the pump flow rate, flow direction and pressure of the fluid. The kinetic energy of the fluid produced by the rotation of the blades will be transformed into pressure energy, so that the fluid pressure can be increased with the rotation speed of the blades. Under such a condition, it provides that so long as the fluid has reached the desired point of pressure then the fluid will be pumped out via the impeller discharge of an axial flow pump. 

In a word, an axial flow pump achieves the purpose of conveying of medium by accelerating it from the pump suction to the pump discharge through the rotation of its blades. Due to this working principle, the axial flow pumps are the most ideal pumping solution for needs of large flow rates and low outlet pressures.

Structure of axial flow pumps

An axial flow pump mainly consists of a pump casing(also known as pump elbow), an impeller, a main shaft and a mechanical seal. And the impeller is installed at the suction of the pump, the pump elbow the casing of the axial flow pump, inside which the above mentioned components are installed. With the function of all the components inside the pump elbow, the pump casing can guide the flow of the fluid and increase the pressure.

Features and advantages of axial flow pumps

Large flow rate and low discharge head: The Axial flow pumps are designed and manufactured to meet the requirements of high flow rates and low discharge head, which enable it to discharge large volume of fluid out of its pump casing in a efficient way.

Application of axial flow pumps

Working principle of centrifugal pumps

The fluid interacts with the pump impeller and pump casing after it enters the pump casing through the suction of the centrifugal pump. The impeller is composed of multiple blades and a back plate fixed on a rotating shaft. When the impeller start to rotate, due to the special shape of blades and rotational speed, the fluid begins to generate centrifugal force and gradually accelerates the fluid, increasing its kinetic energy. Kinetic energy is gradually converted into pressure energy. The pressure energy pushes the fluid to the outlet of the centrifugal pump and discharges it through the pipeline that connected to the pump outlet. Due to the centrifugal force, the center of impeller forms the negative pressure, which is the key factor that the centrifugal pump is able to continuously intake the fluid through its suction.

Structure of a centrifugal pump

Advantages and characteristics of centrifugal pumps

● Versatile Applications: Centrifugal pumps are able to handle diverse fluids, from clean water and wastewater to chemical solutions, offering exceptional adaptability across industries.

● High Efficiency: Centrifugal pumps can operate with superior energy efficiency, ensuring cost-effective fluid transfer while minimizing power consumption.

● Compact structure: The compact designed construction of centrifugal pumps simplifies manufacturing, upkeep, and repairs, lowering long-term operational expenses. With a compact design, the chemical centrifugal pumps fit seamlessly into confined installations without compromising performance.

● High-Capacity Performance: The centrifugal pumps are ideal for large-volume operations, which can rapidly move substantial liquid quantities to the required points.

● Moderate Discharge head: The centrifugal pumps are able to deliver the fluid to a higher head compared to axial flow pumps, centrifugal pumps are good at in mid-range head applications, reliably elevating liquids to required heights.

● Multistage structure availability: Multi-stage configurations enhance head range, addressing high-pressure requirements effectively.

● Operational Consistency: Centrifugal pumps maintain steady flow rates and pressure levels across varying operational demands.

● Low Noise Output: Compared to alternative pump types, centrifugal pumps are able to operate with reduced acoustic disruption.

● Extended-Distance Capability: Centrifugal pumps with higher head are perfect for long distance fluid transfer, such as municipal water distribution networks.

Industrial Applications of Centrifugal Pumps

Comparison of fluid dynamics modes between axial flow pumps & centrifugal pumps

Axial Flow Pump Design:

- Propels liquid parallel to the drive shaft via rotating impeller blades

- Generates linear current optimal for high-volume, low-pressure scenarios

- Mimics natural riverine flow patterns

Centrifugal Pump Design:

- Utilizes radial motion to drive fluid to the pump outlet via centrifugal force

- Creates vortex-like circulation suited for moderate flow and pressure demands

- Delivers uniform dispersion from central intake

Comparison of pump efficiency between axial flow pumps and centrifugal pumps

- Axial pumps peak in low-head, high-flow applications with minimal friction loss

- Centrifugal pump units achieve optimal energy conversion at medium pressure and flow ranges

Comparison of head ranges between axial flow pumps and centrifugal pumps

Axial flow pumps demonstrate optimal performance in low-to-moderate pressure scenarios. When operating under elevated pressure conditions, their flow capacity diminishes steadily due to heightened hydraulic resistance and frictional forces. This results in a characteristic efficiency curve that maintains a gradual decline, aligning these pumps with applications demanding substantial liquid volume transfer at limited pressure requirements.

Centrifugal pumps exhibit a distinct pressure-flow relationship characterized by an initial performance surge followed by stabilization. Under low-pressure conditions, these pumps achieve maximum volumetric output, with flow rates inversely correlating to pressure elevation. Within their optimal operational thresholds, however, they maintain predictable flow-pressure proportionality, rendering them ideal for moderate hydraulic demands balancing both parameters.

Comprehensive comparison of advantages and disadvantages

Axial Flow Pump Profile

Optimal Use Cases: High-volume fluid transfer under minimal pressure conditions

If you are looking for more details, kindly visit Horizontal-Shaft Axial Flow Pump.

Performance Advantages

- Superior volumetric throughput for rapid bulk fluid movement

- Energy-optimized operation in low-pressure environments

- Streamlined hydrodynamic design minimizes turbulence losses

Operational Limitations

- Pressure ceiling restricts high-pressure system compatibility

- Progressive efficiency decline beyond specified pressure thresholds

Centrifugal Pump Profile

Ideal Applications: Balanced pressure-flow systems with moderate operational demands

Functional Benefits

- Adaptive performance across variable viscosity mediums

- Stable pressure maintenance through radial acceleration mechanics

- Robust construction for extended duty cycle operations

Design Considerations

- Throughput limitations in ultra-low pressure configurations

- Precision component alignment requirements increase service complexity

Pump Selection Criteria Overview

• 1. Operational Parameters: Quantify required flow rates, head specifications, and fluid properties of the required pumps.

• 2. Mechanical Understanding: Recognize operational principles of different pump features.

• 3. Performance Matching: Align pump type with application demands (axial flow pumps for high volume purpose, centrifugal pumps for high pressure purpose).

• 4. Medium Compatibility: Assess fluid viscosity, corrosion potential, temperature and particle content.

• 5. Energy Considerations: Evaluate efficiency curves across operational ranges to select higher efficiency pumps.

• 6. Space Constraints: Verify physical dimensions against installation area.

• 7. Maintenance Factors: Prioritize service accessibility and component durability

• 8. Cost Analysis: Balance initial investment against life-cycle expenses.

• 9. Supplier Evaluation: Partner with certified manufacturers offering technical support.

Summary & Final Recommendations

In the design process of various fluid conveying projects, selection between axial flow pumps and centrifugal pumps requires careful and comprehensive analysis of operational demands, as each of them have quite different advantages as well as advantages against various applications. For proven pumping solutions supported by decades of engineering expertise, please contact us for customized guidance.

In this chapter, we will examine the pumps that move water throughout a water distribution system.

Contact us to discuss your requirements of Circulating Pump Manufacturer. Our experienced sales team can help you identify the options that best suit your needs.