U.S. patent number 3,899,875 [Application Number 05/433,672] was granted by the patent office on 1975-08-19 for gas regeneration tesla-type turbine.
Invention is credited to Eli Oklejas, Jr., Robert A. Oklejas.
United States Patent |
3,899,875 |
Oklejas , et al. |
August 19, 1975 |
Gas regeneration tesla-type turbine
Abstract
A gas turbine is disclosed. The turbine comprises a casing and a
rotor mounted on bearings within the casing. The rotor is of a
Tesla-type configuration. Means are provided on the rotor to
conduct cooling air to alternate spaces between sets of disc-like
blades of the rotor and to conduct a working fluid to opposite
alternate spaces between the blades. The air cools the blades and
is correspondingly heated. A collecting chamber receives the heated
air and conducts it ultimately to a combustion chamber.
Inventors: |
Oklejas; Robert A. (Monroe,
MI), Oklejas, Jr.; Eli (Monroe, MI) |
Family
ID: |
23721098 |
Appl.
No.: |
05/433,672 |
Filed: |
January 16, 1974 |
Current U.S.
Class: |
60/39.511;
60/805 |
Current CPC
Class: |
F02C
3/00 (20130101); F01D 1/36 (20130101) |
Current International
Class: |
F01D
1/00 (20060101); F02C 3/00 (20060101); F01D
1/36 (20060101); F02c 007/10 (); F02c 007/12 () |
Field of
Search: |
;415/58,90,178,116
;60/39.51R,39.45,39.35,39.34,39.75 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Freeh; William L.
Assistant Examiner: Ross; Thomas I.
Attorney, Agent or Firm: Freiburger; Thomas M. Barker, Jr.;
Vincent L.
Claims
We claim:
1. A gas turbine, comprising:
a housing;
a hollow, cylindrical rotatable shaft within said housing and
having a plurality of spaced-apart exhaust ports therein;
a plurality of flat, circular turbine blades within said housing
and concentrically disposed in spaced relation upon said shaft,
defining a plurality of interblade spaces circumjacent said shaft,
every second space defining a turbine space disposed about at least
one of said exhaust ports, remaining spaces defining air spaces
alternating with said turbine spaces, each blade having openings
therethrough;
ducts in said turbine spaces sealingly connecting said openings in
said blades from one blade to the next, thereby establishing
communication among said air spaces;
at least one combustion gas nozzle disposed at the periphery of
each turbine space substantially tangentially thereto;
sealing means on said housing in circumferential relationship to
said blades for peripherally closing each turbine space from nozzle
to nozzle and for isolating the flow of working fluid from each
nozzle into the turbine space;
a combustion chamber connected to said nozzles; and
a collection chamber defined by said housing about the periphery of
said air spaces leading ultimately to an air inlet of said
combustion chamber.
2. The gas turbine of claim 1 which further includes an air
compressor disposed to deliver compressed air to said air
spaces.
3. The gas turbine of claim 1 which further includes an external
gas regenerator having an air inlet receiving air from said air
spaces and an air outlet positioned to deliver air to said
combustion chamber, and having a combustion gas inlet receiving
exhaust gas from said hollow shaft and an outlet disposing of the
exhaust gas after its heat exchange with air from said regenerator
air inlet.
4. The gas turbine of claim 3 which further includes an air
compressor disposed to deliver compressed air to said air
spaces.
5. The gas turbine of claim 1 wherein said turbine spaces are
narrower than said air spaces.
6. The gas turbine of claim 1 wherein said ducts and blade openings
communicating therewith are located contiguous with said shaft and
non-coincident with said shaft exhaust ports in said turbine
spaces.
7. A gas turbine, comprising:
a housing;
a hollow cylindrical rotatable shaft having a plurality of spaced
apart exhaust ports therein;
a plurality of flat, circular turbine blades concentrically
disposed in spaced relation upon said shaft, and defining a
plurality of interblade spaces circumjacent said shaft, every
second space defining a turbine space disposed about at least one
of said exhaust ports, remaining spaces defining air spaces
alternating with said turbine spaces, each blade having openings
therethrough;
ducts in said turbine spaces sealingly connecting said openings in
said blades from one blade to the next, thereby establishing
communication among said air spaces;
pressure seals attached to said housing in circumferential
relationship to said blades across said turbine spaces, each seal
being contiguous around the turbine space periphery except at
openings defined for combustion gas nozzles;
a collection chamber defined by said housing about the periphery of
said air spaces for conducting air from said air spaces.
8. The gas turbine of claim 7 wherein said ducts and blade openings
communicating therewith are located contiguous with said shaft and
non-coincident with said shaft exhaust ports in said turbine
spaces.
9. A turbine comprising a casing and a rotor within said casing,
said rotor comprising a rotatable shaft and blades connected
circumferentially to said shaft, said blades defining first and
second pluralities of alternating spaces therebetween, said first
plurality of alternate spaces having means for generally centrally
receiving a low temperature cooling fluid and said second plurality
of alternate spaces having means for peripherally receiving a high
temperature working fluid, means on said casing for peripherally
collecting the cooling fluid from said first plurality of spaces,
means on said rotor for exhausting the working fluid from said
second plurality of spaces, and means on said casing and on said
rotor for isolating said first plurality of spaces from said second
plurality of spaces whereby each of said blades receiving the
working fluid across one side thereof correspondingly receives a
cooling fluid, in substantially counterflow relationship, across an
opposite side thereof.
10. A turbine comprising a casing and a rotor within said casing,
said rotor comprising a central rotatable shaft and blades
connected circumferentially to said shaft, said blades defining
first and second pluralities of spaces therebetween for alternately
receiving a low temperature cooling fluid in said first plurality
of spaces and a high temperature working fluid in said second
plurality of spaces, means on said casing for isolatingly
delivering the working fluid peripherally into said second
plurality of spaces, means on said rotor for exhausting the working
fluid, means on said rotor for isolatingly delivering the cooling
fluid generally centrally to said first plurality of spaces, and
means on said casing for peripherally collecting the cooling fluid
whereby each blade receiving the working fluid across one side
thereof correspondingly receives the cooling fluid across an
opposite side thereof.
11. The turbine of claim 10 wherein said working fluid delivering
means comprises nozzles on said casing for introducing working
fluid into said second spaces and circumferential sealing means on
said casing adjacent opposing blades which define each space of
said second plurality of spaces for peripherally closing said
spaces and isolating said spaces from said adjacent alternate first
spaces, said sealing means being contiguous around each turbine
space periphery except at openings defined for the nozzles.
12. The turbine of claim 10 wherein said exhausting means comprises
an axial exhaust gallery within said shaft and radial orifices
defined in said shaft in communication with each space of said
second plurality of spaces.
13. A turbine comprising a casing and a rotor within said casing,
said rotor comprising a central rotatable shaft and blades
connected circumferentially to said shaft, said blades defining
first and second pluralities of spaces therebetween for alternately
receiving a low temperature cooling fluid in said first plurality
of spaces and a high temperature working fluid in said second
plurality of spaces, means on said casing for isolatingly
delivering the working fluid to said second plurality of spaces,
means on said rotor for exhausting the working fluid, means on said
rotor for isolatingly delivering the cooling fluid to said first
plurality of spaces, said last-named means including hollow spacers
each sealingly connected to opposite blades defining each of said
second plurality of spaces and orifices defined in each of said
blades adjacent said spacers for placing cooling fluid in
communication with each of said first plurality of spaces but
excluding the cooling fluid from said second plurality of spaces,
and means on said casing for collecting the cooling fluid, whereby
each blade receiving the working fluid across one side thereof
correspondingly receives the cooling fluid across an opposite side
thereof.
Description
BACKGROUND OF THE INVENTION
The invention relates to gas turbines, and more particularly to a
Tesla-type spiral flow turbine having a gas regenerator.
The basic Tesla turbine is described in Tesla U.S. Pat. No.
1,061,206. Combustion gases or other pressurized working fluid
enter the turbine chamber through a nozzle directed generally
tangentially to the outer periphery of a plurality of spaced apart
flat disc-like turbine blades. The fluid travels in an inwardly
spiraling path while effecting rotation of the turbine blades, and
is axially exhausted from openings defined in the blades close to
the center of rotation. The efficiency of this type turbine lies in
its elimination of sudden changes in the velocity and direction of
movement of the fluid which generally occur with turbines having
conventional vanes or blades.
Gas regenerators, i.e., means for utilizing the heat present in the
exhaust gases from a turbine to heat intake air for combustion, are
well known. The regenerators, however, are generally external to
the turbine and merely effect a heat exchange between the gases
finally exhausted from the turbine and intake air for combustion.
See, for example, U.S. Pat. No. 2,784,552. Such a gas regeneration
system cannot utilize heat exchange to the full extent with a
Tesla-type turbine.
SUMMARY OF THE INVENTION
The invention provides an apparatus which utilizes heat exchange in
a Tesla-type turbine to increase nozzle output temperature, system
power output, and system efficiency. In addition to an external
regenerator, the apparatus includes a second regeneration system
amoung the turbine blades themselves. The system facilitates the
attainment of very high intake air temperatures at the entrance to
the combustion chamber while providing a means for cooling the
turbine blades. The cooling of the outer peripheral area of the
blades raises the maximum permissible working gas temperature at
the nozzle by protecting the blades from adverse effects of high
temperature such as melting. With higher gas temperatures at the
nozzles, greater power output and efficiency of the turbine is
achieved. With the regenerator parameters properly designed and
adjusted, cooling of the turbine blades can be accomplished without
appreciable cooling of the working gas exiting the nozzles.
According to the present regeneration and cooling system, a
plurality of flat, disc-like Tesla turbine blades are stacked in
spaced relation on a hollow cylindrical shaft which is mounted for
rotation on bearings. Spaces are thus defined between each pair of
adjacent blades. Turbine or combustion gas spaces alternate with
regeneration or air spaces. Each peripherally sealed turbine space
receives expanding combustion gases tangentially from a nozzle.
While driving the turbine, these gases spiral inwardly to exhaust
ports defined in the hollow rotor shaft. The gases are thus
exhausted axially through the rotor shaft toward the external
regenerator. Each turbine blade has oppositely disposed openings
adjacent the rotor shaft. Spacer ducts around these openings within
the turbine spaces provide air commmunication from one air space to
the next. Initially compressed air is caused to enter the first
such air space and is distributed amoung all the air spaces without
being intermingled with exhaust gases, which are sealed in the
turbine spaces between pairs of air spaces. The air thus
introduced, moves axially along the rotor shaft, then travels
spirally and radially outwardly in each air space, being heated as
it cools the turbine blades. The cooling of the outer periphery of
the blades is most important, since this is the area within the
turbine spaces where temperatures are highest. Each blade is cooled
from one side. The heated air of the air spaces is collected
circumferentially within the turbine housing for admission into an
external regenerator for further heating, by interaction with
exhaust heat. From the external regenerator, the hot air enters a
combustion chamber. In this way, fuel is conserved by the admission
of very hot air to the combustion chamber, while at the same time
the turbine blades are cooled to allow extra high gas temperatures
at the nozzles. With such higher temperatures possible, turbine
efficiency is generally increased along with power output.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partially sectioned elevational view of a gas
regeneration turbine engine according to the invention, indicating
gas and air flow paths;
FIG. 2 is a sectional view of the regeneration turbine engine taken
along the line 2--2 of FIG. 1, further indicating gas and air flow
paths;
FIG. 3 is an elevational view of the engine looking along the line
3--3 of FIG. 1;
FIG. 4 is a diagrammatic view of the turbine and rotor shaft,
indicating gas flow paths; and
FIG. 5 is a sectional view of the turbine and rotor shaft taken
along the line 5--5 of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, a gas regeneration turbine engine is
diagrammatically shown, generally indicated by the reference number
10. Atmospheric air first enters an air compressor 11 preferably
operably connected to a rotor shaft 12 where it is compressed at a
ratio of about 2:1. The compressor 11 also introduces a
circumferential whirling motion to the air.
As indicated in FIG. 1, and in more detail in FIG. 5, compressed
air next flows through an opening 3 in a stationary end disc 14 and
enters a plurality of spaces defined by turbine blades 15. The
turbine blades 15, of which only a few are indicated herein for
clarity, are flat, disc-like plates each having a central bore 16
for stacking the blades 15 on the central rotor shaft 12, as best
seen in FIG. 4.
Referring again to FIGS. 1 and 5, the turbine blades 15 define two
types of interblade spaces: air or regenerator spaces 20, and
turbine or expansion gas spaces 21. The air spaces 20 are in common
air communication through openings 24 defined in each blade 15,
best seen in FIGS. 4 and 5. There are preferably two openings 24
through each turbine blade 15. FIG. 5, showing a greatly reduced
number of interblade spaces 20 and 21 for simplicity, indicates
stationary end discs 14 and 25 each forming a boundary of an air
space 20, with a turbine blade 15 forming the opposed boundary. It
should be understood that in a working embodiment of the turbine
engine 10, a much larger number of blades 15, turbine spaces 21,
and air spaces 20 would be provided, with turbine blades 15 forming
both boundaries of all air spaces 20 except those adjacent the
stationary end discs 14 and 25.
The air interblade spaces 20 alternate with the turbine interblade
spaces 21, as best seen in FIGS. 1 and 5. To provide the required
communication amoung the air spaces 20 and to seal the air spaces
20 from the turbine spaces 21, spacer air ducts 26 are provided
within the turbine spaces 21 between adjacent blade openings 24.
FIG. 4 shows the spacer air ducts 26 in section. The spacer ducts
26 also act as spacers for the blades 15 in turbine spaces 21. They
are retained in aligned relationship by tie rods 27 which penetrate
the blades 15 as well as the spacer ducts 26.
Spacers are also interposed in the air spaces 20 to maintain proper
interblade spacing therein. These spacers, whose sole function is
to maintain the blades 15 in spaced relationship, not shown on the
schematic representations herein, since not enough air spaces 20
are shown for inclusion of spacers.
As the compressed air from the compressor 11 enters the air spaces
20, it flows spirally and radially outwardly, primarily due to its
compression and to a lesser extent to a minor propulsion effect
encountered between the rotating turbine blades 15. This propulsion
effect must be kept at a minimum in order to prevent a rapid rise
in the temperature of the cooling air as it moves through the air
spaces 20. In order to avoid the propulsion effect, the air spaces
20 between the blades 15 are made greater than the turbine spaces
21. This increase in space between the blades 15 reduces the
tendency of the blades to frictionally compress the cooling air and
inhibits a too-rapid velocity increase as the air moves toward the
periphery of the blades 15. The calculated temperature of the
compressed air as it enters the air spaces 20 is approximately
170.degree. F. This temperature increase above ambient air
temperature is caused primarily by the initial compression at the
compressor 11.
After the air from the air spaces 20 has had a cooling effect on
the blades 15 and passes the periphery of the blades 15, it is
directed into a circular path in a peripheral collection chamber
29, as best seen in FIG. 2. The air from the collection chamber 29
is directed through exit parts 30 and ducts 31 into an external
regenerator 32 for heat exchange with exhaust gases, as shown in
FIG. 3. Further heated in the regenerator 32, the air then passes
through ducts 33 and 34 to combustion chambers 36, where it is
mixed with fuel and continuous combustion occurs.
In the combustion chambers 36, the combustion gases encounter great
increases in temperature. In the preferred embodiment of the
present invention, the temperature of the combusted gases at the
nozzle exit is preferably 1900.degree. - 2000.degree. F. The
high-pressure, high-temperature gases pass through a plurality of
nozzles 37 in each combustion chamber 36, as indicated in FIGS. 1,
2 and 5. Each nozzle 37 is disposed at the periphery of a turbine
space 21, and is aimed preferably about 10.degree. below the
tangent of the turbine blades 15 at the gases' point of entry.
Pressure seals 38 are provided around the periphery of the turbine
spaces and are interrupted only by the nozzles 37. Thus, the
turbine spaces 21 are sealed so that expanding gases from the
nozzles 37 can only travel spirally inwardly in the turbine spaces
21. Although for clarity FIGS. 1 and 5 indicate only a single
turbine space 21, a much larger number are provided in practice as
discussed above.
The turbine blades 15 defining these turbine spaces 21 encounter
extremely high temperatures from the burned gases, especially in
the areas close to the outer periphery of the blades 15. The
primary purpose of the air spaces 20 is to cool each turbine blade
15 from one side, thus permitting, without damage to the blades 15,
higher gas exit temperatures at the nozzles 37. With higher gas
exit temperatures permissible, a higher rate of combustion may be
maintained in the chambers 36, thus facilitating higher gas
temperatures and pressures in the chambers 36, a higher gas exit
velocity from the nozzles 37, and greater engine power output. A
secondary purpose of the air spaces 20 is to effect heating of the
air as it passes through the air spaces 20 toward the collection
chamber 29 to additionally heat the air for combustion.
FIG. 4 schematically indicates the path of expanding combustion
gases. As the gases spiral through the turbine spaces 21 toward the
rotor shaft 12, they perform work on the turbine blades 15,
effecting their rotation. This principle is discussed in Tesla U.S.
Pat. No. 1,061,206. As distinguished from the Tesla turbine, the
spent, decelerated gases approaching the rotor 12 are not exhausted
through blade spaces. Instead, the rotor shaft 12 is hollow, with
exhaust ports 40 provided directly therein. Preferably two
oppositely disposed exhaust ports 40 are located in the rotor 12 in
each turbine space 21, between the spacer air ducts 26. Exhaust
gases entering the exhaust ports 40, as shown in FIGS. 1, 2, 4 and
5, flow axially through the rotor shaft 12 into an exhaust chamber
41 and duct 42 toward the regenerator 32, which is best seen in
FIG. 1. Here its heat is exchanged with air passing through the
regenerator 32 from the air spaces 20, as discussed above. The
cooled combustion gases are finally exhausted at 43.
As shown in FIGS. 4 and 5, keys 44 are provided in the outer
surface of the rotor shaft 18 for engaging the turbine blades 15,
which have complementarily shaped openings adjacent the rotor 12.
The keys 44 are not continuous along the rotor 12, but are
interrupted by the exhaust ports 40, so that they do not block
exhaust flow into the hollow rotor shaft 12. The keys 44 may be of
a "dove-tail" or "firtree" configuration for gripping the blades 15
against both circular and radial movement with respect to the rotor
12.
In addition to the pressure seals 38 provided around the periphery
of the turbine spaces 21, pressure seals must also be provided at
points 45 and 46 indicated in FIG. 1, to prevent loss of air or
pressurized gases from the system 10.
As shown in FIG. 1, the rotor shaft 12 is supported by bearings 48
which must be as remote as possible from the hot exhaust portion of
the rotor shaft 12. The rotor shaft may be somewhat cantilevered
from the support bearings 48, as shown in FIG. 1. However, it
should be understood that the various components of the turbine
engine 10 may be arranged in any convenient manner, FIG. 1
indicating only a preferred arrangement.
The above-described preferred embodiment provides a gas
regeneration turbine and turbine engine capable of operating at
very high temperatures without damage to the turbine blades, thus
generally increasing power output and efficiency over that of most
prior art turbine engines. Various other embodiments and
alterations to this preferred embodiment will be apparent to those
skilled in the art and may be made without departing from the
spirit and scope of the following claims.
* * * * *