Prandtl layer turbine

Details Prandtl layer turbine Prandtl layer turbine

1999-01-08

2001-12-11

Ryznic, John E. (Department: 3745)

Rotary kinetic fluid motors or pumps

Smooth runner surface for working fluid frictional contact

C415S090000, C416S175000

Reexamination Certificate

active

06328527

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to an apparatus used to transmit motive force between a fluid and a plurality of spaced apart rotatable members. The apparatus may be used to transmit the motive force from a fluid to the spaced apart members or, alternately, from the spaced apart members to the fluid.
BACKGROUND OF THE INVENTION
Prandtl layer turbines were first described by Nikola Tesla in U.S. Pat. No. 1,061,206 (Tesla). For this reason, these turbines are sometimes referred to as “Tesla Turbines”.
FIGS. 1 and 2
show the design for a prandtl layer turbine as disclosed in Tesla. As disclosed by Tesla, a prandtl layer turbine
10
comprises a plurality of discs
12
which are rotatably mounted in a housing
14
. Housing
14
comprises ends
16
and ring
18
which extends longitudinally between ends
16
. Discs
12
are spaced apart so as to transmit motive force between a fluid in housing
14
and rotating discs
12
.
The discs
12
, which are flat rigid members of a suitable diameter, are non-rotatably mounted on a shaft
20
by being keyed to shaft
20
and are spaced apart by means of washers
28
. The discs have openings
22
adjacent to shaft
20
and spokes
24
which may be substantially straight. Longitudinally extending ring
18
has a diameter which is slightly larger than that of discs
12
. Extending between opening
22
and the outer diameter of disc
12
is the motive force transfer region
26
.
The transfer of motive force between rotating discs
12
and a fluid is described in Tesla at column 2, lines 30-49. According to this disclosure, fluid, by reason of its properties of adherence and viscosity, upon entering through inlets
30
, and coming into contact with rotating discs
12
, is taken hold of by the rotating discs and subjected to two forces, one acting tangentially in the direction of rotation and the other acting radially outwardly. The combined effect of these tangential and centrifugal forces is to propel the fluid with continuously increasing velocity in a spiral path until it reaches a suitable peripheral outlet from which it is ejected.
Conversely, Tesla also disclosed introducing pressurized fluid via pipes
34
to inlets
32
. The introduction of the pressurized fluid would cause discs
12
to rotate with the fluid travelling in a spiral path, with continuously diminishing velocity, until it reached central opening
22
which is in communication with inlet
30
. Motive force is transmitted by the pressurized fluid to discs
12
to cause discs
12
to rotate and, accordingly, shaft
20
to rotate thus providing a source of motive force.
Accordingly, the design described in Tesla may be used as a pump or as a motor. Such devices take advantage of the properties of a fluid when in contact with the rotating surface of the discs. If the discs are driven by the fluid, then as the fluid passes through the housing between the spaced apart discs, the movement of the fluid causes the discs to rotate thereby generating power which may be transmitted external to the housing via a shaft to provide motive force for various applications. Accordingly, such devices function as a motor. Conversely, if the fluid in the housing is essentially static, the rotation of the discs will cause the fluid in the housing to commence rotating in the same direction as the discs and to thus draw the fluid through the housing, thereby causing the apparatus to function as a pump or a fan. In this disclosure, all such devices, whether used as a motor or as a pump or fan, are referred to as “prandtl layer turbines” or “Tesla turbines”.
Various designs for prandtl layer turbines have been developed. These include those disclosed in U.S. Pat. No. 4,402,647 (Effenberger), U.S. Pat. No. 4,218,177 (Robel), U.S. Pat. No. 4,655,679 (Giacomel), U.S. Pat. No. 5,470,197 (Cafarelli) and U.S. Reissue Pat. No.
28
,
742
(Rafferty et al). Most of these disclosed improvements in the design of a Tesla turbine. However, despite these improvements, Tesla turbines have not been commonly used in commercial environment.
SUMMARY OF THE INVENTION
In accordance with the instant invention, there is provided an apparatus comprising:
(a) a longitudinally extending housing having a fluid inlet port and a fluid outlet port;
(b) a plurality of spaced apart members rotatably mounted in the housing to transmit motive force between fluid introduced through the fluid inlet port and the spaced apart members, the spaced apart members having an upstream end and a downstream end; and,
(c) at least one fan member positioned in series with the spaced apart members.
At least one fan member may be positioned adjacent the upstream end and/or the downstream end of the spaced apart members and/or between two of the spaced apart member. Each spaced apart member may comprise a disc which has a surface for passage of fluid from an inner opening in the spaced apart member to an outer edge of the spaced apart member and the fan member has at least one blade which rotates in a space and the diameter of the space is substantially the same as the diameter of the inner opening of the spaced apart member immediately downstream and/or downstream of the fan member.
In another embodiment, the fan member is rotatably mounted with the spaced apart members.
In another embodiment, at least one fan member may be positioned upstream of and/or downstream of the spaced apart members.
In accordance with the instant invention, there is also provided a turbine comprising:
(a) a housing having a fluid inlet port and a fluid outlet port;
(b) a shaft rotatably mounted in the housing;
(c) a plurality of spaced apart discs mounted on the shaft and rotatable therewith, each disc having a radial inner end defining an inner opening, a radial outer end and a pair of opposed surfaces extending therebetween, each surface having a radial inner portion and a radial outer portion; and,
(d) at least one fan member mounted on the shaft.
At least one fan member may be positioned adjacent the upstream end and/or the downstream end of the spaced apart members and/or between two of the spaced apart member.
In one embodiment, the fan member has at least one blade which rotates in a space and the diameter of the space is substantially the same as the diameter of the inner opening of the disc immediately downstream and/or downstream of the fan member.
In accordance with the instant invention, there is also provided an apparatus comprising:
(a) longitudinally extending housing having a means for permitting a fluid to enter the housing and means for permitting a fluid to exit from the housing;
(b) a plurality of spaced apart means for transmitting motive force between fluid introduced through the means for permitting a fluid to enter the housing and the spaced apart means, the spaced apart means having an upstream end and a downstream end, each spaced apart means having a pair of opposed surfaces whereby the fluid passing over the surface forms a boundary layer which delaminates as it passes over the surface; and,
(c) the apparatus having one or more of the characteristics selected from the group consisting of:
i. means for introducing the fluid under pressure to the upstream end; and,
ii. means for assisting in the withdrawal of fluid from the downstream end.
The means for introducing the fluid under pressure to the upstream end may be positioned in the housing. The means for assisting in the withdrawal of fluid from the downstream end may be positioned in the housing.
In accordance with the instant invention, there is also provided a method for transmitting motive force between a fluid and a plurality of spaced apart members comprising:
(a) introducing the fluid into a housing having a plurality of spaced apart members rotatably mounted in the housing;
(b) passing the fluid through the spaced apart members having an upstream end and a downstream end to form a boundary layer which passes over the spaced apart members; and,
(c) passing the fluid through a fan to alter the fluid flow characteristics of the boundary layer as it passes through the housing.
Th

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