Axial flow pump is a famous type of dynamic pump. So, this article mainly describes to axial flow pump working principle, and it’s some other aspects. In the axial flow pump, the fluid flows in a parallel direction to the axis of rotation. This type of dynamic pump has an axial impeller in a pipe. The centrifugal pumps have an inflow of the fluid perpendicular to the impeller, while the axial pumps have a parallel suction flow of fluid to the axis of the impeller. This dynamic pump mostly contains three or four blades that mountain on an impeller. The orientation of the blades should allow the water being pumped to discharge axially (i.e., in the same direction of the impeller axis) nor perpendicular. The parallel alignment of the impeller blades creates a very low pressure when pumping water.
These dynamic pumps can generate high flow rates, up to hundreds of thousands of gallons per minute. It is sometimes called a propeller pump because the axial impeller is similar to a ship’s propeller. In some configurations, the flow rate and head can be adjusted by changing the pitch of the impeller blades.
The performance specifications of the axial pumps are a little bit different than other types of pumps. The head produced at normal operating points is minimal, but the curve between versus capacity and the head is considerably vertical than other centrifugal pumps. The shut-off pressure can be three times the pump’s delivery head at the point with the greatest efficiency. Besides, the required power rises when the flow rate declines, and the maximum power consumption is with the power switched off (zero flow). This contrasts with the same tendency for the radial-pump, which requires higher flow rates and higher power.
Working Principle of Axial Flow Pump
In the axial flow pump, the impeller blades guide the fluid axially. The pressure of these pumps is generated by passing the fluid over the impeller vanes. In these dynamic pumps, the impeller vanes have an airfoil section through which fluid runs and creates pressure.
The liquid pushes in the direction of the axis of rotation of the impeller. That is, the fluid particles do not transform their radial position as they flow through the pump. This permits the liquid to flow axially into the impeller and to exit the fluid approximately axially. The propellers of these dynamic pumps drive through an electric motor.
The required power increases with a decreasing flow rate, and the maximum power is drawn at a zero-flow rate. While in the case of the centrifugal radial-pump, this feature is the opposite, in which power requirements increase with increasing the flow rate. The power requirements and pump heads also increase as the slope increases to adjust the pump to system conditions for the most efficient operation.
Compared to conventional centrifugal or radial pumps, axial pumps can pump up to three times more liquids with a delivery head of fewer than 4 meters. By changing the propeller pitch, you can easily set these dynamic pumps to run with maximum efficiency at high or low pressure and low/high pressure.
The axial flow pump generally has a low head than radial pumps but can generate higher currents. Axial flow pumps can only produce heads of 10 to 20 feet. This is lower as compared to other types of centrifugal pumps.
Applications of Axial Pump
1) These dynamic pumps largely use in different industries all over the world.
2) These pumps use for handling sewage by fisheries, agriculture, municipal and commercial.
3) Axial flow pump uses in digesters and powerplants for circulating fluids.
4) This type of dynamic pump uses for low heads and high flow rate applications.
5) They use in the chemical industries for the circulating of fluids in the evaporator.
6) In sailboats, these used for transferring pumps that use for sailing ballast.
Advantages
- The main advantage of axial pumps is that they have a relatively low head and a relatively high flow rate.
- These dynamic pumps are ideal for l high flow rate and low head.
- With axial pumps, the effects of fluid turning are less severe.
- Axial pumps can easily be set up for low flow and high head for high-efficiency operation.
- Of the many conventional pumps, these pumps are the smallest.
- The small size makes it easy to use and handle.
Disadvantages
- These pumps have a high cost.
- These pumps can’t control liquids having high viscosity.
- They are not best for applications where require a high head.
Difference between Centrifugal Pump and Axial Flow Pump:
| Sr. | Centrifugal Pump | Axial Flow Pump |
| 1. | In a Double Suction Pump, the flow of the liquid is radial to the shaft of the impeller. | In these, the flow of liquid is parallel to the impeller shaft. |
| 2. | They are best for high-head applications. | They are best for low-head applications. |
| 3. | They have a large size as compared to axial pumps. | They have small in size. |
| 4. | They are not too easy to control. | They are easy to control. |
In this article, we study the axial flow pump and its working principle. Axial pumps are widely using in different industries. Thesepumps get preference over the centrifugal radial pumps due to their small size; they are easing to use. Radial flow pumps don’t provide good efficiency as axial flow pumps provide. But these pumps have a high cost, and they aren’t best for high viscous liquids.
For More Reading, visit the below-given article.
2) Positive displacement pump and its types.
3) Dynamic pumps and their different types.