How to calculate a centrifugal pump for a jet boat.

In summary, the individual is seeking advice on the dimensions of the impeller for their self-built jet boat project. They have approximately 90 horsepower and are using two v-belts and pulleys to transmit the power. They are aiming for maximum thrust and are looking for a formula to calculate the impeller diameter and RPM. The conversation suggests that this is a complex task and it may be best to seek assistance from a jet boat forum or purchase a premade impeller.
  • #1
beef supreme
2
0
I am building a jet boat as a project this year. I am going construct the impeller my self but don't know what dimensions I need to make it to get the most out of the engines without over loading them. Here's what I have to work with:

The power source is going to be approximately 90 hp at 3600 rpm with about 130 ft-lb of torque. That power is going to be transmitted by two B section v-belts and pulleys. What I'm trying to accomplish is to get as close to 90 hp out of a water jet as possible. I can do about 50 square inches at the input and output of the impeller and a nozzle of about 12.5 square inches at the rear of the boat. My question is what diameter do I want to make the impeller assuming the circumference times the height of the opening at the edge is equal to the intake (50 inches^2) and what rpm?

Any insight on the matter would be greatly appreciated. Thanks
 
Physics news on Phys.org
  • #2
I think you need to go find a jet boat forum. I suspect optimising the prop to match the boat is as much a black art as a science.
 
  • #3
I really need someone who has a good general knowledge of fluid dynamics and such who can perhaps give me a formula to figure how to achieve the maximum gross thrust with the 90ish horsepower input.
People on boat forums, in my experiences, generally haven't known much about the physics surrounding these things.
 
  • #4
Honestly, I think you'd be best off buying a premade impeller designed for about your level of power input. This is far from a trivial calculation, and as CWatters said, is probably as much a black art as it is a science (unless you have access to an advanced CFD program and a supercomputer, as well as a fair amount of time to figure out how to run it).
 

1. How do I determine the required flow rate for a centrifugal pump for a jet boat?

To calculate the required flow rate for a centrifugal pump, you will need to know the boat's maximum speed and weight, as well as the desired acceleration and thrust. You can then use a formula that takes into account these factors to determine the required flow rate.

2. What factors should I consider when selecting a centrifugal pump for a jet boat?

Some important factors to consider when selecting a centrifugal pump for a jet boat include the boat's weight, maximum speed, desired acceleration, and the pump's flow rate and pressure capabilities. You should also consider the pump's efficiency and durability, as well as any specific design features that may be necessary for your boat's setup.

3. How do I calculate the head and pressure requirements for a centrifugal pump for a jet boat?

The head and pressure requirements for a centrifugal pump can be calculated using the boat's weight, speed, and desired acceleration, as well as the pump's flow rate and efficiency. A formula that takes into account these factors can be used to determine the head and pressure requirements.

4. What type of impeller should I choose for a centrifugal pump for a jet boat?

The impeller type you choose for your centrifugal pump will depend on your boat's specific needs. A closed impeller is typically more efficient and provides higher pressure, while an open impeller is better for handling solids and provides higher flow rates. It is important to carefully consider your boat's requirements and choose the appropriate impeller type.

5. How can I ensure the proper maintenance and performance of a centrifugal pump for a jet boat?

To ensure the proper maintenance and performance of your centrifugal pump, it is important to regularly check for any wear or damage, and to clean and lubricate the pump as needed. Additionally, following the manufacturer's recommended maintenance schedule and properly storing the pump during off-seasons can help to extend its lifespan and maintain its performance.

Similar threads

How pressure increases in centrifugal compressor?
    • Mechanical Engineering
Replies
3
Views
2K
What is the formula for calculating water jet reaction force?
    • Mechanics
Replies
3
Views
15K
Underground pump vault airflow considerations
    • Mechanical Engineering
Replies
15
Views
788
Centrifugal pump restricted output
    • General Engineering
2
Replies
35
Views
4K
Automotive Poor Man's Hydrostatic drive: power steering pump as motor?
    • Mechanical Engineering
Replies
19
Views
819
Pump has a suction lift of more than 10.3 m
    • Mechanical Engineering
Replies
6
Views
5K
(Extremely basic) centrifugal pump design
    • Mechanical Engineering
Replies
5
Views
2K
Can a Direct Link Between Car Engine and Jet Pump Power an Amphibious Vehicle?
    • General Engineering
Replies
32
Views
3K
Calculating equivalent horsepower for a jet engine
    • Mechanical Engineering
Replies
7
Views
5K
Electrical Choosing a DC motor for a DIY Centrifugal Blower
    • DIY Projects
Replies
4
Views
4K

Hot Threads

Recent Insights

Back
Top