Rim Drive takes to the seas

[kach22i]

Remember that ducted fan (air) NASA has a webpage on? Well, something like it is taking to the seas.



Rolls-Royce introduces Rim Drive thruster technology
15 November 2005
http://www.rolls-royce.com/marine/overview.../newsitem12.htm

he first commercial application of a new type of Rolls-Royce tunnel thruster launches a technology which will have a major impact on marine propulsion in the future.

Rim Drive is a tightly integrated system combining electrical, mechanical and hydrodynamic elements. The electrical motor takes the form of a thin ring. Its stator is incorporated in the tunnel and its rotor carries propeller blades that point inwards.

The first application is on an offshore support vessel, in the form of a tunnel thruster type RT1600 rated at 800kW. In due course the power range of rim tunnel thrusters will be broadened, and the technology will be used in other types of propulsor. The electro-mechanical part of the technology will also be applicable to winches, steering systems and other Rolls-Royce products.

This technology has been developed in Norway over a period of several years by Rolls-Royce in Ulsteinvik and Smartmotor in Trondheim working in close collaboration. A prototype unit has been subjected to function trials and long periods of endurance testing in Norway, and to detailed hydrodynamic evaluation in the cavitation tank at the Rolls-Royce hydrodynamic research centre in Sweden.

Several features combine to provide advantages for the owner, as R&T Project Manager Gunnar Johnsen explains.

"Water flow through the unit is unobstructed since there is no gearbox in the tunnel, nor are struts needed to support a hub. Propeller blades are attached to the rim, eliminating uncontrolled flow between blades and tunnel. The permanent magnet motor design is very efficient. Together these factors give a high total efficiency and reduced noise and vibration. Because more thrust is produced for a given power input, fuel consumption is reduced, and this saving can be substantial in applications such as offshore support vessels operating in dynamic positioning (DP) mode where thrusters may run for hundreds or thousands of hours a year. Fuel saving is not only a matter of money; the impact of the vessel on the environment is also reduced.

"The Rim Thruster is designed to be mountable and dismountable under water, so that it can be removed for servicing if required without drydocking the vessel. We use water-lubricated bearings, eliminating propeller shaft seals and oil-filled gear housings.

"The motor is an integral part of the unit in the tunnel, so the ship designer no longer has to find space for a bulky electric motor in a thruster room. The only parts of the thruster inside the hull are the cables connecting it to the frequency control supply cabinet. The cabinet is similar to that used with any frequency controlled electrically driven thruster, and its location is flexible."

Olympic Shipping, based in Fosnavåg in Norway, has ordered the first RT1600 for their UT 712 CD anchor handler now under construction at Aker Yards Søviknes. This vessel will have twin CP propellers for main propulsion, and other thrusters to give the station keeping power needed to meet IMO DP2 dynamic positioning standard. The rim drive unit will be installed in the aft skeg acting as a stern side thruster.

Helge Gjerde, President-Offshore Propulsion in Rolls-Royce said, "We are delighted that Olympic Shipping is fitting the new thruster type to their latest vessel. As equipment manufacturers we are dependent on forward thinking shipowners to bring new products and systems to market. Olympic's UT 712L is also the first to fit the newly developed Rolls-Royce DP2 dynamic positioning system, and also the equipment for making work on deck safer."

Bjørn Kvalsund, operations director of Olympic Shipping, makes the point that, "Our background in fishing and offshore has shown us that good equipment is the key to success, and that investment in technology that increases efficiency pays off in the long term. We aim to provide our oil company customers with vessels suited to their present and future needs, not their past ones, and to offer fuel efficient vessels with low environmental impact. The safety and well-being of our crews is just as important, and equipment that produces less noise and vibration is a valuable contribution to this."

If developed into an airscrew/fan type application, I can see this technology making it's way on to larger hovercraft.

[kach22i]

The NASA version.


http://www.grc.nasa.gov/WWW/RT/2003/7000/7720emerson.html

[scottmandue]

You said:

Rim Drive thruster

Huh huh huh....

Sorry, someone had to say it.

[widebody911]

That looks suspiciously familiar...

eRAM electric supecharger dyno test day invitation next week

[kach22i]

Originally posted by widebody911
That looks suspiciously familiar...

eRAM electric supecharger dyno test day invitation next week

preliminary tests show over 3.5lbs of raw thrust, and that is significant out of a 3.5" diameter fan.

When they make a 3.5 feet diameter fan send me a PM.

[masraum]

That looks suspiciously familiar...



yep, sure does

[oldE]

The basic concept is also very similar to an Escher Wyss Straflo turbine. The inprovement seems to be in removing the shaft and bearing mass from the axis and incorporating them into the rim drive. Unlike the NASA unit, which relied upon magnetics for radial and axial stability, RR is using water-lubed bearings. Cool.
(OK. So I'm geeking out here.)

Les

[kach22i]

Originally posted by oldE
The basic concept is also very similar to an Escher Wyss Straflo turbine.

Looked it up, could not find what I wanted. This looked interesting though.

http://www.andritz.com/ANONIDZ2CA9204C47D4D49B/hydro-products-and-services-large-hydro-turbines-straflo-turbines

This concept is based upon a patent of the former Escher Wyss group and combines turbine runner and generator rotor. Andritz VA TECH HYDRO has more than 100 units installed with that concept, which is very short in length and therefore ideal for refurbishment projects. The important references are in Switzerland on the Rhine river, Laufenburg and Augst-Wyhlen. Also a Tidal installation in Canada is an important reference for Andritz VA TECH HYDRO.

EDIT:
While I have a few techno geeks looking at this thread, I'm looking for a ducted fan assembly (for air) which may be driven by a common automotive engine. Not having any luck finding one pre-made.

[oldE]

Kach22i,

Yeah, that's the beastie. E-W was bought by Sultzer a while back and they in turn were bought by VA. I recognize the image of a Straflo runner from their website.
The thing is a pretty interesting generator (anybody want to buy a "gererator"?). The stub axles bolt to the hub, water comes straight through the tunnel, turning the blades. The smooth part at the tips of the blades seals against the rim of the tunnel and the perimeter has (in the case of the Annapolis Royal unit) 144 electromagnets. The stator is mounted around the outside of the whole thing. At 50 RPM, with the magnets on 2 poles, it produces 60 cycle power at 4160 volts and up to 20Megs. Even though its made of stainless, it has a few electrolysis issues. (I get to give tours of the plant, could you tell?)

Les

[oldE]

Kach22i,

You have probably come across these guys before, but, just in case:

http://www.arrowprop.com/fan.html

(no affiliation)

Les

[kach22i]

Another one on the market or at least being marketed...............................update 12/20/2006

Fleetwater Marine
http://www.fleetwatermarine.com/carbon_fibre_thrusters.htm

Carbon fibre 'Ring' Thrusters

As with our carbon fibre propellers, conventional marine thruster units have changed little over the years. Most are essentially small shaft mounted propellers, but now we have designed a unique lightweight, low noise Ring thruster unit with individually replaceable carbon fibre blades.

Carbon fibre Ring thruster - Design

The Ring thruster comprises a circular housing containing an electric motor with carbon fibre propellers mounted on the interior of the ring. The design has many advantages over conventional propulsion units.

* The ring thruster in compact - saving space
* No additional gear box required - saving cost and weight
* No cavitation - reducing noise and improving efficiency
* No propeller fouling - Ropes and obstruction pass straight through the middle of the thruster
* Improved acceleration - particularly under high load
* Blades are mounted in a water cooled, ceramic seal - Avoiding blade degradation.
* No overheating - Entire housing and engine cooled by surrounding water