Due to their widespread use and effectiveness, two types of pumps stand out in the fluid handling industry: centrifugal and axial flow pumps. These pumps are crucial to a variety of industries, including chemical processing, power generation, irrigation, and water treatment. Engineers, facility managers, and anyone else involved in fluid management systems must be aware of the differences between these two types of pumps.

Working Principle

Axial Flow Pump 

The fundamental workings of axial flow pumps, also known as propeller pumps, are straightforward. The fluid flows parallel to the pump axis, as the name suggests. An axial flow pump has an impeller that looks like a propeller and pushes the fluid along the axis of rotation without changing the direction in which it flows. When it comes to moving a lot of fluid against relatively low heads, this design is especially effective.

Its impeller blades are shaped so that there is a pressure difference between their front and back surfaces. The fluid is moved forward by the kinetic energy it receives from the impeller's rotation. After passing through the impeller blades and exiting the pump at the outlet, the fluid maintains its axial direction throughout the process. they are extremely effective for low-head, high-flow applications due to the low amount of turbulence and energy loss caused by their linear flow path.

Centrifugal Pump

Centrifugal pumps, on the other hand, move fluid by applying centrifugal force to the system. The fluid is pushed outward by the rotating impeller after entering the pump from the center, close to the axis of rotation. The fluid receives both velocity and pressure from this radial movement.

Fluid is drawn into the pump by a low-pressure area at the center of the impeller's rotation. The fluid then gains kinetic energy as it moves between the impeller blades and is thrown outward by the centrifugal force. The fluid enters the pump casing, or volute, when it reaches the outer edge of the impeller. Here, its velocity is converted into pressure energy. Compared to axial flow pumps, this design enables centrifugal pumps to handle a wider range of flow rates and produce higher pressures.

Structural Design

Axial flow and centrifugal pumps' distinct working principles are reflected in their structural designs, which significantly influence their performance characteristics and application suitability.

Axial Flow Pump:

An Axial Flow Pump has a structural design that is relatively straightforward and streamlined. The impeller, which resembles a marine propeller, is the most important component. When compared to a centrifugal pump, this impeller typically has between three and six blades. In order to effectively move the fluid along the axis of rotation, the blades have a particular pitch and contour.

The cylindrical casing houses the impeller, which is attached to a shaft. The shape of the casing ensures that the fluid flows in the same axial direction from the inlet to the outlet. Before or after the impeller, some axial flow pumps have guide vanes that help direct the flow and increase efficiency.

Centrifugal Pump:

Due to the distinct operating principle of a centrifugal pump, its structural design is more complex. The impeller, casing, shaft, and frequently a diffuser or volute are the primary components.

The centrifugal pump's heart is the impeller, which comes in closed, semi-open, and open configurations. It typically has between six and twelve blades, which is more than an axial flow pump impeller. These curved blades are made to efficiently transform the impeller's rotational energy into the fluid's kinetic and pressure energy.

The impeller is surrounded by the pump casing, which is made to collect the fluid that comes out of the impeller and direct it to the outlet. A volute, a spiral-shaped channel that gradually increases in size as it wraps around the impeller, is included in many designs. The fluid's velocity is converted into pressure energy by this design.

Performance Curve

A pump's performance curve is a graphical representation of its operation, typically illustrating the relationship between head (pressure) and flow rate. It is essential to comprehend these curves in order to select the appropriate pump for a given application and ensure its effective operation.

Flow Axial Pump:

An Axial Flow Pump has a distinctive performance curve that reflects its design for high flow rates at relatively low heads. In most cases, the curve reveals:

1. Low Head and High Flow Rate: The flow rate with the lowest head typically marks the beginning of the curve. When there is little resistance in the system, this point is the pump's maximum capacity.

2. Strong Curve: The flow rate decreases relatively quickly as the head increases. A steep curve is the result, indicating that axial flow pumps are sensitive to system head changes.

3. Limited Range of Operation: Due to the axial flow pump's focus on high-flow, low-head applications, the curve frequently covers a smaller range of heads than that of centrifugal pumps.

4. The highest efficiency level (BEP): these pumps are designed to move large volumes of fluid, so their BEP is typically located at the higher end of their flow range.

5. Power curve that is relatively flat: these pumps have a flatter power consumption curve over their operating range, indicating that the amount of power required does not change significantly with flow rate.

Axial flow pumps are ideal for flood control, irrigation, and cooling water circulation in power plants where large volumes of water must be moved against relatively low heads due to their performance profile.

Centrifugal Pump:

A centrifugal pump generally has a more adaptable performance curve because it can handle a wider range of heads and flow rates:

1. At Zero Head, Maximum Flow: Typically, the curve begins with the maximum flow rate at zero head, which is the theoretical maximum output assuming no system resistance.

2. Scalar Curve: In comparison to axial flow pumps, the flow rate decreases more gradually as the head increases. Because of this, the curve becomes flatter, which indicates that centrifugal pumps are able to maintain relatively high flow rates even as the system head grows.

3. Large Operating Area: The curve frequently demonstrates the versatility of centrifugal pumps by covering a wider range of heads and flow rates.

4. The highest efficiency level (BEP): The BEP, which provides a balance between head and flow rate, is typically found near the middle of the performance curve for centrifugal pumps.

5. Energy Curve: Up until a certain point, the power consumption curve for centrifugal pumps frequently displays rising power requirements with increasing flow rates.

6. Stop the Head: The shut-off head is the point at which the curve reaches its maximum head at zero flow. The maximum pressure that can be produced by a centrifugal pump is represented by this one-of-a-kind property.

Centrifugal pumps can be used in a wide range of applications thanks to their performance profile, including HVAC systems, industrial processes, and firefighting equipment.

There are a number of reasons why understanding these performance curves is essential:

1. Picking a Pump: By matching the requirements of the system to the capabilities of the pump, it aids in selecting the appropriate pump for a particular application.

2. System Structure: These curves are used by engineers to design piping systems and ensure that the pump and system are compatible.

3. Energy conservation: Operating a pump close to its Best Efficiency Point cuts down on energy use and costs.

4. Troubleshooting: By contrasting actual performance with expected performance, performance curves can be used to diagnose issues.

5. Pump Control: Using effective control strategies, such as variable speed drives, to optimize pump operation under various conditions requires an understanding of the curve.

Axial Flow Pump for Sale

Tianjin Kairun stands out as a reputable manufacturer that offers customization options to meet the specific requirements of our customers when it comes to selecting an Axial Flow Pump for your requirements. We are a reliable choice in the pump industry because of our commitment to quality and customer satisfaction.

Tianjin Kairun welcomes your inquiries if you are in the market for an axial flow pump and looking for a manufacturer that can provide a solution that is tailored to your particular requirements. Our team of experts is ready to help you pick the right pump for your job or make it your own. You can get in touch with us at catherine@kairunpump.com if you want more information or to talk about your pump needs.

References:

1. Karassik, I. J., Messina, J. P., Cooper, P., & Heald, C. C. (2008). Pump Handbook (4th ed.). McGraw-Hill Education.

2. Gülich, J. F. (2014). Centrifugal Pumps (3rd ed.). Springer.

3. Tuzson, J. (2000). Centrifugal Pump Design. John Wiley & Sons.

4. Lobanoff, V. S., & Ross, R. R. (2013). Centrifugal Pumps: Design and Application (2nd ed.). Elsevier.

5. Nelik, L. (1999). Centrifugal and Rotary Pumps: Fundamentals with Applications. CRC Press.