Curious about Jet drives.

Ahhh, V8 torque and soft suspension, those were the days!

-Tom

 

LOL Tom, probably why the old hands doesn't get sea sick so easily, them cars felt like boats on water

Still, nothing like a V8 eh. Pity about fuel being expensive and going scarce. I bet the next form of propulsion isn't going to sound like that, so better record some sounds while we have them.

 

Your right about the inertia. I read that in the Military section on Jet drives.
Without the stator the whole boat would tip.
There were other Hydro-dynamics the Stator took care of as well.
The output would be going out in a Scatterd mess, but the stator aligns the output to make it smooth, taking some of the resistance out of the ehausting water.

 

*Sigh*
Yes Thuddy, if only my wife thinks I'm right a couple of times eh

 

There aint enough Wisdom in the world to help you with that problem.

 

The stators need to run between the multi-stage impellors to 'straighten' the water flow so the next impellor can get a good 'bite', else the water inside the pump would end up rotating at next to the same speed as the impellor so the last one would do nothing

 

Yes, that's what I read. Also, though I didn't see it, I'm thinking the stator angles between Props were different than the last stator angle that wants to straighten out the flow.

On the number of Stages:
Wouldn't it be better to have a single stage rather than multiples?
There must be a reason for Multiples?

 

You can only achieve a certain pressure increase (=velocity increase) per stage, basically depending on impeller outlet peripheral speed. If you design the nozzle velocity (vj in my earlier text) above this limit; then you have to add another stage in series, just like we do in any other kind of rotodynamic pump.

And yes, a single stage, giving a high flow rate is generally better efficiency-wise, than a low flow - high velocity, multiple stage unit. It is all a question on finding the best balance between pump hydromechanical efficiency, the impulse efficiency and possible power density of the pump design elements.

 

Holy Cow, do I dont remember a lot!

Although I never got as far as Hydraulics. It's good to know we have PhD's when we need them.
Thank's y'all.

 

Probably not many PhD's - just a desire to know and understand everything about everything...

Thanks Hoyt !

 

I heard the weather is wet in Safrica. How much more water do you need for a jet drive?

 

SA is a water poor country.
I'll only admit to enough rainfall when there's more boats (with jet drives to stay on topic ) than cars here

Seems the whole world is suddenly getting more rain, there's floods in a lot of places.