Impeller and propeller are used to help a boat or any other waterways vehicles to move forward or backward or to help with the cooling of the machines.
Sometimes due to constant movement and the equipment parts being subjected to friction, they might get heated up. This can lead to explosions and is an occupational hazard.
Key Takeaways
- An impeller is a rotating component used to increase the pressure and flow of a fluid.
- A propeller is a type of fan used to propel a vehicle through a fluid such as air or water.
- Impellers are used in pumps and compressors, whereas propellers are used in aircraft and marine vessels.
Impeller vs Propeller
An impeller is a rotor with vanes used in a centrifugal pump to increase the pressure and flow rate of a fluid. Impellers are commonly used in pumps for various applications. A propeller is a type of fan with rotating blades used to generate thrust and propel an object through a fluid.
Impeller pumps in the water from the surrounding ocean, sea, or whichever water body the boat is moving in to cool the machines present within the boat which might be overheated due to constant use and the action of friction that might make it susceptible to burning away of rubber or plastic parts or even an explosion.
A propeller is a fan that helps in the motion of the boat in a forward or backward direction depending on the model and year of manufacture of the propeller.
The fan moves in a certain way and forces the water to move between its blades, therefore, creating a pressure movement in the boat. It is the main reason a boat moves if not rowed.
Comparison Table
| Parameters of Comparison | Impeller | Propeller |
|---|---|---|
| Suction Type | Intrinsic | Extrinsic |
| In Contact with Water | No | Yes |
| Material | Rubber | Stainless steel |
| Aim | Pressure | Propulsion |
| Presence Of Axis | No | Yes |
What is Impeller?
An impeller is a system of pumps that depends on the sucking action of a rotor thereby forcing a jet of water into the boat machinery.
By machinery, it does not mean that the pump consists of nuts, bolts, and many various iron or aluminum parts, instead, the entire pump and the suction system are mainly made up of rubber-like material.
This is to help increase the momentum that is aided by the rubber to the water and also to reduce maintenance costs as iron might rust due to constant contact with water.
But that doesn’t mean there aren’t any steel or iron parts inside the pump. An axis made of stainless steel is present within the impeller and this helps in spreading the water around the entire system.
There are three different types of impellers and are called the high solidity impeller, medium solidity impeller, and low solidity impeller. Impellers are classified based on the type of fluids that it disperses or on the viscosity of the liquids that it needs to suck in.
To move the fluids or in this case, the water, the impeller adopts the rotatory motion of fluids. The energy required by the impeller to suck the water in and to disperse it around the entire system is taken from the surrounding water itself.
This helps in conserving energy and also reduces polluting the water by using other means such as oil or gasoline.
Proper maintenance of the impeller is required to ensure that there is no wear and tear in the rubber tubes and linings. Lubrication is also needed.
Even though impellers cool the engine down, it is kept far away from the engine. Impellers are kept inside a small box-like structure and the water is dispersed by other means to the engine and other parts.
What is Propeller?
Propeller is a fan that has three to four blades made of iron or similar water-resistant materials and forces water away from it. Propeller is placed out in the open and within the water body surrounded by water but in the underside of the boat.
The main principle behind a propeller is that it converts the rotational motion with the water is pushed away to linear motion which is the forward propulsion of the boat.
The blades are placed with even space around an axis which rotates and provides an extrinsic sucking force, that is it pushes the water away. This extrinsic force pushes the water forward following Newton’s third law.
The propeller is placed at such an angle after taking into account the size and mass of the boat that it is supposed to help move.
A propeller makes sure that the water body and the tides within it are not disturbed while the boat moves as the movement of water-assisted by the propeller is from front to back.
The propeller does not force the water to skip off to the sides of the boats and thereby does not disturb the water body. At times, with the size of the boat, exceptions can be made to the standard number of blades present in a propeller.
The greater the size, the more the blades and this would help reduce the force put on the engine to move the boat. Propellers use rotational motion and the energy needed to help in the extrinsic suction is also harnessed from the water.
It has to be maintained once in a while and searched for rust or wear and tear for proper functioning.
Main Differences Between Impeller and Propeller
- An impeller is placed with a box inside the boat without beginning near water whereas a propeller is placed out in the water completely submerged.
- The parts of a propeller are made of stainless steel or other similar materials whereas the parts of an impeller are made of rubber.
- An impeller work on a forward motion of the parts whereas propellers are powered by rotational motion which brings about the major difference between the two.
- A propeller use blades to carry out their function whereas impellers work with tubes and vanes.
- Impeller uses the principle behind pressure whereas propeller uses the principle of propulsion or motion.
- https://asmedigitalcollection.asme.org/gasturbinespower/article-abstract/103/4/688/405065
- https://www.sciencedirect.com/science/article/pii/000712269190179N
Last Updated : 17 July, 2023
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Piyush Yadav has spent the past 25 years working as a physicist in the local community. He is a physicist passionate about making science more accessible to our readers. He holds a BSc in Natural Sciences and Post Graduate Diploma in Environmental Science. You can read more about him on his bio page.
