Bladeless Turbine Engines: History and Potential

From two millennia ago, through Tesla and onward, the bladeless turbine remains a feasible option for transmitted power from a moving stream fluid to a solid rotating object such as a disc or a drum using the boundary layer that formed on its surface. Proposal given to hybridize the Tesla and Hero designs.

by Harry Valentine
for Pure Energy Systems News

RamGen's Rampressor-1 test rig. (source)

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Brief History

The history of bladeless turbine engines can be traced back to ancient Egypt and the steam engine built over 2000-years ago by Hero of Alexandria. Steam turbine engines subsequently faded into obscurity until they reappeared toward the end of the 19th century when Charles Parsons built a bladed turbine engine that powered a boat called Turbinia. Bladed turbines had previously been used in rivers to produce mechanical power and then electric power. 

Nikola Tesla and Anton Magnus were scientists who had worked independently of each other to develop their own unique design of the bladeless turbine engine. Both engines transmitted power from a moving stream fluid to a solid rotating object such as a disc or a drum using the boundary layer that formed on its surface. The axis of rotation for both engines was placed transverse to the direction in which the fluid flowed. Tesla's turbine comprised a stack of discs whereas the Magnus rotor was essentially a rotating drum that spun after being immersed in a fast moving stream.

Potential

There are many hobbyists, enthusiasts and researchers who have build variations of the engines that were proposed by Tesla, Magnus and even by Hero. RamGen of Seattle offers a power generator borrowing from the concept originated by Hero. It involves ramjets being placed at the ends of small levers that turn a shaft. The ramjets "fly" as speeds of up to Mach 3.5 and turn the shaft and electrical generation equipment at high rotational speeds (eg: 26,000-rpm).

A variation of the RamGen concept involves using steam as the working fluid. It is expelled under high pressure and at high temperature through rocket nozzles that are mounted at the ends of levers that turn a shaft. It is essentially a modern version of Hero's concept and can operate using saturated or wet steam. Hero's design can operate while using fast moving droplets of water that could severely damage turbine blades. Tesla's turbine can also operate on saturated steam except that thermal efficiency is lower than if superheated steam were used.

The ramjet and steamjet versions of Hero's engine would usually be housed inside a drum that would contain the exhaust gas and redirect it to a location from where it can be safely expelled from the engine. It is possible for the ramjets to "fly" at an absolute tangential velocity of Mach 1.2 while ejecting exhaust gases from the jetpipes at a velocity of Mach 2.5 or higher relative to the jetpipes. The absolute exhaust velocity would be Mach 2.5 - Mach 1.2 = Mach 1.3 relative to the stationary drum in which the jets "fly" in a circular path. The boundary layer effect of an exhaust stream moving at Mach 1.3 on the boundary layer of the stationary drum would exert a strong tangential reaction force.

Proposal to Hybridize the Tesla and Hero Designs

The system could be built to allow the drum to rotate in response to the force exerted on it by the fast moving stream of gas. Its net effect would be the potential to produce more power for the same energy consumption. The effects of centripetal acceleration on the swirling gas would cause it to exert a stronger boundary layer effect and higher shear force on the drum's inner surface. The rotating drum could provide extra power while also being able to serve as a guide for a Magnus rotor.

A section of the rotating drum could be built as an annulus after a section of concentric tube is attached inside it. The exhaust stream that leaves the steamjet nozzles could swirl into the annulus and would exert a shear force on both the inner and outer boundary layers. The inner surface of the rotating drum would serve as a moving guide that would direct a stream of gas on to outer surface of the inner tube that would then would behave as a Magnus rotor. 

The rotating drum could be build to include a series of concentric tubes that would form a series of annuli. The swirling gas could progressively move outward from a smaller diameter annulus to a larger diameter annulus one or it could move inward. Each outer surface of each concentric tube would in effect be a Magnus rotor while each inner surface would serve as a rotating guide. While the bladeless Hero rotor operates on a supersonic exhaust, the concentric stack of Magnus rotors could operate on a stream of gas that enters it a near sonic speed.

The exhaust velocity from the supersonic nozzles of the modified Hero rotors would determine as to whether the swirling gas should progressively move into annuli of progressively larger diameter or to annuli of progressively smaller diameter. The research of Viktor Schauberger in regard to vortex theory could be applied to optimize the overall performance of a stack of concentric Magnus rotors. A potentially cost competitive and robust engine may be the result if ramjets are used on the Hero rotor. Droplets of water from an exhaust of saturated steam could erode the inner surfaces of the tubular guides of the concentric Magnus rotors.

An alternative engine layout would combine the supersonic Hero rotor with a Tesla turbine that could extract energy from the fast swirling exhaust. Tesla turbines generally deliver their peak efficiency when the gas entering between the discs is near sonic speed. Maximum power output generally occurs when the gas enters the spaces between the discs at Mach 1.5. The Hero rotor's fast swirling exhaust would travel along the inner surface of drum and through a short annular section before swirling into the small spaces between the discs of the Tesla turbine. The option to compound a Tesla turbine with a Hero rotor may result if a very rugged, robust and cost competitive engine.

Previously published at:  http://pesn.com/2007/09/11/9500497_Bladeless_Turbines/