Note: Descriptions are shown in the official language in which they were submitted.
CA 02376163 2001-12-03
WO 01/06102 PCT/US99/16305
1
EFFICIENCY ENHANCED TURBINE ENGINE
Technical Field
This invention relates to an improved and efficiency
enhanced turbine engine.
Background of the Invention
Turbine engines are now well known, and the turbine
engine is now known to have several advantages not to be
found in engines such as, for example, piston type
internal combustion engines, although such engines have
useful features not heretofore incorporated in turbine
engines.
As is well known, the typical turbine engine utilizes
compression and combustion stages with fluid flow
established therethrough, utilizes near constant high
pressure at combustion (practical usable pressures, at
least in many turbine engines, are limited by reverse flow
through the compressor (i.e., compressed stall) and the
physical size of the several stages required to achieve
the necessary high pressures), and has a primary direction
of flow through the engine that is substantially parallel
to the axis of rotation (circumferential components may be
found in radial compressors, but these components do not
provide progress of the fluid between successive stages of
the engine).
It is known that the efficiency of heat engines is
directly related to the operating temperatures at which
heat is added, that increases in operating pressures
normally also increase operating temperatures, and that
heat engines can be made more efficient by constraining
the fluid during the heating process, all of which enhance
efficiency, and the foregoing have been found to be
applicable to heat engines in which heat is added by
combustion of, or in, the working fluid. While
constraining of working fluid to a near constant volume
during heating is common to the internal combustion
engine, for example, this feature has not heretofore been
utilized in now known turbine engines.
SUBSTITUTE SHEET (RULE 26)
CA 02376163 2001-12-03
WO 01/06102 PCT/US99/16305
2
Now known turbine engines normally cannot tolerate
pressure rises during combustion because of accompanying
temperature rises to unacceptable levels and/or because
pressure rises above the pressure at the outlet of the
compressor results in pressure flow back through the
compressor with such pressure back flow often stalling the
compressor.
While compressor/inlet stall has been prevented in a
pulse jet engine, for example, by interposing a barrier
between the combustion chamber and the compressor/inlet
during the combustion process to allow the temperature and
pressure to rise during combustion above that provided by
the compressor and thus provide an increase in operating
efficiency, and while this same general concept has also
been used in a piston driven internal combustion engine
through use of inlet and outlet valves with the piston
operated in such a manner as to provide a near fixed
volume during combustion to thus provide an increase in
operating efficiency, the foregoing has not heretofore
been utilized in now known turbine engines.
In turbine engines, the maximum operating
temperatures typically occur at the exit from the
combustor, which commonly is also the inlet of the turbine
portion of the engine, and the materials, or surfaces, at
the turbine portion are often continuously subjected to
temperatures at, or near, the maximum tolerable operating
temperatures.
Since the maximum tolerable temperature strength of
the materials in the turbine portion of now known turbine
engines is at least one of the primary determinants of
turbine efficiency, such engines are thus also now limited
in efficiency by the ability of the materials in the
turbine portion to withstand high temperatures (while
increased efficiency in now known turbine engines could be
realized by improving the high temperature strength of the
material at the turbine portion, this cannot always be
practically accomplished and/or is often quite an
expensive undertaking).
SUBSTITUTE SHEET (RULE 26)
CA 02376163 2001-12-03
WO 01/06102 PCT/US99/16305
3
Improvements in heretofore known turbine engines
(such as those illustrated in U.S. Patent Nos. 1,289,960,
4,693,075, 4,503,669, 3,877,219, and 3,685,287) to provide
efficiency enhancement not now found in the turbine engine
would therefore be found useful and/or is now needed.
Disclosure of the Invention
This invention provides an improved and efficiency
enhanced turbine engine and method for a turbine engine
having a rotor and a fluid flow path that extends through
l0 compression, combustion, and expansion or turbine stages
with fluid flowing through the fluid flow path driving the
rotor.
The turbine engine has one or more stator-rotor-
stator assemblies, and, in a now preferred embodiment of
this invention, a flat rotor disk with turbine blades is
utilized and provides fabrication simplicity as well as
simplifying establishing and maintaining clearances of the
turbine blades.
Increases in pressure during combustion above the
pressure at the compressor, or compression stage, are
prevented from flowing back from the combustor, or
combustion stage, to the compressor to thus allow higher
usable pressure at the combustor and hence allow higher
temperatures to be utilized during combustion which
results in greater engine efficiency.
Fluid is substantially precluded from flowing back to
the compression stage from the combustion stage by
trapping fluid compressed at the compression stage between
turbine blades of the rotor in a constrained flow section
for achieving a valuing action between the compression
stage and the combustion stage to provide forward transfer
of the compressed fluid without reverse flow of pressure
whereby the fluid at the combustion stage is elevated in
temperature and pressure while being maintained at near
constant volume during combustion to provide still greater
efficiency enhancement. Constant volume combustion can be
further augmented by valuing and/or use of a constrained
flow region in the fluid path.
SUBSTITUTE SHEET (RULE 26)
CA 02376163 2001-12-03
WO 01/06102 PCT/US99/16305
4
Fluid flow is preferably in a circumferential
direction and the fluid passes, or reenters, the rotor a
plurality of times to provide cyclic exposure of the
moving parts of the turbine engine to different portions
of the engine cycle for substantially reducing the average
temperature to which the moving parts are subjected and
thereby allow higher compression ratios and combustion
temperatures to also yield higher efficiency.
The enhanced efficiency turbine engine includes a
unit having compression, combustion and expansion stages
and having a pressure difference existing during normal
operation between the compression and combustion stages,
the unit also including at least one stator having a
plurality of chambers and an adjacent rotor. A combustion
producer for causing combustion at the combustion stage is
provided and a fluid flow path extends through the
compression and combustion stages, the fluid flow path
extending between the stator and the adjacent rotor. The
rotor has blades disposed in the fluid flow path for
containing fluid between the blades and transferring fluid
contained between the blades between the compression and
combustion stages to thereby enable fluid to be maintained
at near constant volume during combustion.
The turbine engine unit may include first and second
stators, the fluid flow path configuration including a
first portion extending through the first stator, a second
portion extending through the second stator, and third and
fourth portions extending through the rotor. The fluid
passing through the third portion of the fluid flow path
is in the direction opposite to the direction of fluid
passing through the fourth portion of the fluid flow path
whereby the fluid moving along the fluid flow path passes
through the rotor a plurality of times for causing
movement of the rotor due to fluid flow along the path.
The compression and combustion stages have pressure
established thereat during normal operation, with the
pressure at the combustion stage being substantially
precluded from flowing to the compression stage during the
SUBSTITUTE SHEET (RULE 26)
CA 02376163 2001-12-03
WO 01/06102 PCT/US99/16305
combustion to thereby allow the pressure at the combustion
stage to be elevated to a pressure greater than the
pressure of the fluid at the compression stage during the
combustion.
5 The rotor positioned between the first and second
stators has first and second groups of turbine blades
positioned radially adjacent to one another on the rotor.
Fluid flow from the first and second stators passes
through the rotor to thereby engage each group of the
turbine blades a plurality of times.
The stators and rotor are preferably disks with the
rotor disk positioned between the first and second stator
disks and the rotor disk having turbine blades. An
adjustable spacing control is connected with the first and
second stator disks to enable adjustment of the
operational spacing between the disks.
An intermittent exposure controller is provided for
controlling exposure of the surfaces of the rotor to high
temperatures by achieving a mixed fluid flow through the
turbine engine.
The method of this invention for providing enhanced
efficiency in a turbine engine having a compression stage
and a combustion stage receiving fluid from the
compression stage includes providing fluid flow through
the compression and combustion stages of the turbine
engine, elevating the pressure of the fluid at the
combustion stage to a pressure greater than the pressure
of fluid at the compression stage, and preventing the
pressure at the combustion stage from flowing back to the
compression stage to thereby enable use of higher
pressures at the combustion stage.
As may be appreciated from the foregoing, it is an
object of this invention to improve and efficiency enhance
a turbine engine and related method by provision of the
foregoing advantages and advantageous effects .
It is still another object of this invention to
provide an improved turbine engine and method having
compression, combustion, and expansion or turbine stages
SUBSTITUTE SHEET (RULE 26)
CA 02376163 2001-12-03
WO 01/06102 PCT/US99/16305
6
with fluid flow therethrough in a manner such that
efficiency is enhanced.
It is still another object of this invention to
provide an improved and efficiency enhanced turbine engine
having a flat rotor disk.
It is still another object of this invention to
provide an improved and efficiency enhanced turbine engine
with one or more stator-rotor-stator assemblies with flow
therein in a circumferential direction and with the fluid
reentering the rotor a plurality of times to provide
exposure of the moving parts of the turbine engine to
different portions of the engine cycle.
It is still another object of this invention to
provide an improved and efficiency enhanced turbine engine
wherein fluid flow is controlled so that pressure is
substantially precluded from flowing back to the
compression stage to allow higher usable pressure at the
combustion stage.
It is still another object of this invention to
provide and improved and energy enhanced turbine engine
wherein fluid at the combustion stage is elevated in
temperature and pressure while being maintained at near
constant volume during combustion.
With these and other advantages and advantageous
effects in view, which will become apparent to one skilled
in the art as the description proceeds, this invention
resides in the novel construction, combination,
arrangement of parts and method substantially as
hereinafter described, and more particularly defined in
the appended claims, it being understood that changes in
the precise embodiments of the herein disclosed invention
are meant to be included as come within the scope of the
claims.
Brief Description of the Drawings
The accompanying drawings illustrate a complete
embodiment of the invention according to the best mode so
far devised for the practical application of the
principles thereof, and in which:
SUBSTITUTE SHEET (RULE 26)
WO 01/06102 CA 02376163 2001-12-03 pCT/US99/16305
7
FIGURE 1 is a perspective view of the turbine engine
of this invention having a single stator-rotor-stator
assembly:
FIGURE 2 is a side sectional view of the turbine
engine shown in FIGURE l:
FIGURE 3 is a perspective view of the rotor shown in
FIGURE 2:
FIGURE 4 is a top view of the rotor shown in FIGURES
2 and 3:
FIGURE 5 is a cross-sectional view of the rotor taken
through lines 5-5 of FIGURE 4;
FIGURES 6 and 7 are top views of the top and bottom
plates, respectively, of the rotor shown in FIGURE 2;
FIGURE 8 is a simplified top view sketch illustrating
fluid flow through the rotor and top and bottom stators
shown in FIGURE 2;
FIGURE 9 is an enlarged partial side view
illustrating the rotor and stators with a captured flow
region between the compression and combustion stages;
FIGURE 10 is a cut-away side view of a turbine engine
having a plurality of stator-rotor-stator assemblies with
valuing associated therewith;
FIGURE 11 is an end view fluid flow illustration of
the turbine engine shown in FIGURE 10 wherein fluid passes
through the rotor a plurality of times;
FIGURE 12 is a cross-sectional view taken through
lines 12-12 of FIGURE 11; and
FIGURES 13 through 15 are cut-away side views
(FIGURES 13 and 14) and end view (FIGURE 15) of a turbine
engine such as shown in FIGURE 10 but illustrating use of
intermittent combustion (FIGURE 13), flow diversion
(FIGURE 14), and mixed flow using circumferential
separation (FIGURE 15).
Modes For Carryinct Out The
Invention And Industrial Applicability
Since the efficiency of a turbine engine is directly
related to the temperature at which heat is added, turbine
engines can be made more efficient by increasing pressure,
SUBSTITUTE SHEET (RULE 26)
CA 02376163 2001-12-03
WO 01/06102 PCT/US99/16305
8
and therefore temperature, at combustion and/or by
constraining the fluid during the combustion process.
Improved and efficiency enhanced turbine engine 20 is
shown in FIGURES 1 through 9. As best shown in FIGURE 2,
engine 20 now preferably includes a single stator-rotor-
stator assembly 21, and as best shown in FIGURES 1 and 2,
the engine is small and compact with low mass.
As also best shown in FIGURE 2, turbine engine 20
includes top stator 23, bottom stator 24, and rotor 25
positioned between the top and bottom stators, with rotor
top plate 26 and rotor bottom plate 27 being positioned at
the opposite sides of the rotor. Rotor 25 also has a hub
28 connected therewith and constrained to rotation
therewith, with the hub being connectable with a
conventional output drive through load attachment nut 29.
A fluid flow path 31 is established through the
turbine engine, with fluid being inserted into the path
through fluid inlet, or intake, 33 and discharged from the
path through fluid outlet, or exhaust, 34. Combustion
producer 36 is provided at top stator 23 and, as
indicated, may include a fuel inserter, or injector, 38
and an ignitor 39.
As also best indicated in FIGURE 2, rotor 25 is
preferably a flat rotor disk (the disk may be ceramic)
positioned between top and bottom stators 23 and 24
(stators 23 and 24 may also be disks) and the stator disks
are maintained in spaced relationship with respect to one
another by a retaining ring 41. Spacing between the
stator disks is controlled by spacing control 43, shown to
include jack screws 45 (in FIGURE 2) controlled by a gap
control drive 46 (in FIGURE 1).
In the embodiment of the invention as shown in
FIGURES 1 through 9, rotor 25 is the only part that moves
at engine speeds. As shown in FIGURE 2, rotor 25 is
mounted on two internal high speed bearings 47 that
provide the rotational axis. The bearings are supported
by stationary stator shaft 49 which may be integrally
formed with top stator 23 or otherwise attached to the top
SUBSTITUTE SHEET (RULE 26)
WO 01/06102 CA 02376163 2001-12-03 pCT/US99/16305
9
stator. The vertical position of the rotor is supported
by air bearing operation of the rotor disk top and bottom
surfaces.
Fluid flow path 31 is shown in FIGURE 2 to include a
first portion 51 that extends through top stator 23, a
second portion 52 that extends through bottom stator 24,
and third and fourth portions 54 and 55 that extend
through different areas, or portions, of rotor 25.
As indicated in FIGURES 3 and 4 (FIGURE 3 being a
semi-transparent trimetric perspective view illustrating
only the outer peripheral portion of the rotor and FIGURE
4 being a top view also illustrating only the outer
peripheral portion of the rotor), rotor 25 has two groups
57 and 58 of turbine blades therein with the blades being
disposed in inner and outer rings 60 and 61 near the outer
periphery of the rotor so that each group of turbine
blades passes through different ones of third and fourth
paths 54 and 55.
The turbine blades are configured, or shaped, as
indicated in FIGURE 5, to react to fluid flow and provide
an impediment to fluid flow unless the blades are rotated.
The opposite ends, or edges, of each of the turbine blades
are mounted on, and attached to, top and bottom plates 26
and 27 to reduce stress levels, with turbine blade group
57 (at inner ring 60) being mounted at an angle so that
upward circumferential flow through portion 54 of fluid
flow path 31 drives the rotor in a clockwise direction,
and with turbine blade group 58 (at outer ring 61) being
mounted at an angle opposite to the angle used to mount
turbine blade group 57 so that downward circumferential
flow through portion 55 of fluid flow path 31 also drives
the rotor in the clockwise direction.
In the single stator-rotor-stator assembly embodiment
of the turbine engine (as shown in FIGURES 1 through 9),
an entire engine cycle, including compression, combustion,
and expansion, occurs continuously and/or intermittently
during each revolution of the rotor. Fluid (normally air)
flow through the top and bottom stators is best indicated
SUBSTITUTE SHEET (RULE 26)
CA 02376163 2001-12-03
WO 01/06102 PCT/US99/16305
by arrows in FIGURES 6 and 7, and the combined flow is
best indicated by arrows in FIGURE 8, with FIGURE 8 also
specifically indicating compression stage 63, combustion
stage 65, and expansion stage 67 in relationship with
5 fluid flow from intake 33 to exhaust 34.
Fluid flow enters the engine at intake 33 at bottom
stator 24 and flows upward through the inner ring, or
portion, ~~4, of rotor 25 continuing in a spir~~l pattern in
the circun.ferential direction through top stator 23
10 forward and downward through the outer ring, or portion,
55 of rotor 25, and then forward and upward through bottom
stator 24. The progress of the fluid is in a spiral with
flow in the circumferential direction outwardly in top
stator 23, as indicated in FIGURE 6, and inwardly in
bottom stator 24, as indicated in FIGURE 7.
The combined flow, as indicated in FIGURE 8, is
upward at the intake (marked 1), downward (marked 2) on
the outer ring, upward (marked 3) and so on through the
compressic:n stage in the circumferential direction and
with ever increasing compression and pressure toward the
combustion stage. After the combustion stage, expansion
progresses in the expansion stage in a similar manner
through progressively larger passages, as indicated in
FIGURE 8, until the fluid is exhausted through the exhaust
port.
While not specifically shown, it is meant to be
realized that appropriate valuing could be utilized in the
top and/or bottom plates of the rotor to control fluid
flow and/or cause fluid by-pass where needed.
During both compression and expansion, th.e fluid flow
is kept to the lowest practical velocities in order to
keep the passages as large as possible. An aerodynamic
calculation illustrates the above features of fluid (air)
flow and these calculations show that under conditions
wherein f=_ow through the turbine is at a low constant
velocity in the normal direction for compression and less
than 200 n.eters per second in the expansion process, the
CA 02376163 2001-12-03
WO 01/06102 PCT/US99/16305
11
area of the flow passage is proportional to the volumetric
compression.
For a given inlet area and fixed flow velocity, there
is a point in a continuous compression process, in which
the volume of the flow is the same as the free volume
within the rotor, i.e., the volume between the blades
times the velocity of the blades is equal to the flow
volume. With appropriate design choices, that condition
arrives at the same point of the flow in which the desired
compression ratio is achieved.
FIGURE 9 illustrates that fluid flow can then be
swept into a captured, or confined, flow region by the
motion of the rotor. In the confined flow region, the
stators fit the rotor and the blades sufficiently tightly
so as to prevent the trapped fluid (air) from leaking out
at any substantial rate. This confined region also
separates the combustion process from the compression
process so that any desired combustion process can be
utilized without generating back flow of additional
loading of the compressor stage.
Near constant volume combustion can be achieved by
causing combustion to occur, such as by injection of fuel
and ignition, during the time the flow is trapped between
the blades, or, if slower combustion is desired, as
indicated in FIGURE 9, after the confined region the
passage can be expanded into a combustion chamber having a
cross section as required to achieve the desired
combustion time.
In the embodiment of this invention utilizing a
single stator-rotor-stator assembly (as shown in FIGURES 1
through 9), there are four surfaces requiring special
precision in fabrication. The top and bottom of the rotor
and the interfacing surfaces of the top and bottom of
stators must be air bearing precision flat, and must be
stiff enough to maintain that flatness in the region near
the combustion process over time and temperature. The
significance of the problem is reduced by the fact that
the flat rotor disk has a short dimensional path (about 1
SUBSTITUTE SHEET (RULE 26)
CA 02376163 2001-12-03
WO 01/06102 PCT/US99/16305
12
cm) and the area under high pressure is very small
(roughly 40 cm2 or six square inches in a 100 HP design).
By providing forward threads on the outer edge of top
stator 23 and reverse threads on bottom stator 24, the gap
between the stators and the rotor can be reduced to air
bearing clearances by rotating the retaining ring.
Rotation of the retaining ring relative to the stators in
one direction will bring the stators closer together, and
rotation in the opposite direction will increase engine
clearances.
By use of jack screws 45, as shown in FIGURE 2, and
gap control 46, as shown in FIGURE 1, retaining ring
motion during operation is made practical. By this means,
the only critical engine tolerance, i.e., clearance
between the rotor and stators, can be adjusted over the
life of the engine to compensate for wear, and during
operation to provide higher performance if desired. The
remainder of the tolerances in the engine do not
significantly affect performance and may therefore utilize
standards common to the engine industry.
The outlet of the combustion stage can pass through a
second confined region, or could be ported directly into
the exhaust turbine. As long as some flow is allowed from
the combustion process into the exhaust turbine, the
engine will generate torque at zero speed. The low speed
torque is limited by the low compression state of the flow
presented to the combustion process, but still is a
substantial portion of the energy available from a
constant volume combustion process at any effective
compression ratio/speed. At low speed, the compression
stage generates very little pressure, and thus requires
little energy, and since frictional losses are low,
essentially all of the available torque is shaft output
power.
In low compression engines, a compromise engine
clearance setting can be utilized over a number of cycles
of engine use. For engines operating at high compression
ratios,. compressor stall during engine start is a
SUBSTITUTE SHEET (RULE 26)
WO 01/06102 CA 02376163 2001-12-03 pCT/US99/16305
13
significant problem. Compressor stall arises because the
latter stages of the compressor cannot achieve the
required mass flow until high pressures are achieved at
high speed. At low speed, the mass flow capabilities of
the low pressure stages exceeds that of the latter stages
and the early stages of the compressor stall preventing
further pressure rise.
Active gap control (such as can be provided, for
example, by automatically controlling gap drive 46, such
as, for example, by use of a computer program or a timer)
can overcome this difficulty by loosening the engine
clearances during startup and at low engine speed. The
loose engine clearances will allow the excess flow
capacity to be dissipated through leakage thereby
preventing compressor stall. As the speed and pressure
rise, increasing the mass flow capabilities of the latter
portion of the compressor, the clearances can be
progressively tightened to achieve optimum performance.
The embodiment of the invention, as shown in FIGURES
1 through 9, is simple, having only four major components,
four precision flat surfaces, and simple accessories, as
well as being light in weight (about 75 pounds for a 100
HP engine. The engine also has an estimated practical
thirty percent thermodynamic advantage over the best known
engine's today operating at the same compression ratio,
very low frictional losses, continuous torque, zero speed
torque, low turbine stress, material thermal advantages,
and fabrication simplicity.
The thermodynamic advantage arises from near constant
volume combustion and expansion back to ambient pressure,
and the very low frictional losses arise from use of air
bearing seals. The engine is inherently balanced and can
provide continuous torque from a single combustion chamber
requiring only a single fuel injector and ignitor.
The confined flow region separating the combustion
chamber from the compressor also has an effect on the
nature of the engine cycle including generation of
significant zero speed and low speed torque. At low
SUBSTITUTE SHEET (RULE 26)
CA 02376163 2001-12-03
WO 01/06102 PCT/US99/16305
14
speed, the compressor requires little energy, thus with
low frictional losses essentially all of the available
torque is shaft output power.
The turbine blades experience all portions of the
engine operation cycle and thus operate at the average
flow temperature (rather than the peak flow temperature
typical of now known turbine engines). Since the blades
are supported at both ends, the only critical dimension,
the sealing dimension, is both small and adjustable. The
small size of the dimension and the few parts involved in
creating the dimension provide for stability over both
temperature and time, and adjustability greatly simplifies
fabrication (the final finish on the air bearing surfaces
can be achieved by wear in during initial operation).
An improved and efficiency enhanced turbine engine
can also be realized using plural stator-rotor-stator
assemblies, particularly with respect to providing valuing
to prevent back flow of pressure from the combustion stage
to the compressor stage, constraining of fluid at the
combustion stage to effect near constant volume during
combustion, passage of fluid through the rotor of one or
more of the plural stator-rotor-stator assemblies a
plurality of times, and/or using an intermittent exposure
controller for achieving intermittent exposure of surfaces
to high temperature flows.
In the embodiment of the invention shown in FIGURE
10, turbine engine 70 has a plural (three as shown) stage
compressor, or compression stage, 72 having rotors 74 and
stators 75, a combustor, or combustion stage, 77, and a
plural (two as shown) turbine 79 having rotors 81 and
stators 82, along with a center body 84, a combustion
producer, or ignitor, 86, and a housing 88. A combustion
inlet valve 90 is also shown, as a combustion outlet valve
92.
Combustion inlet valve 90 allows fluid flow from
compressor 72 to combustor 77 when the compressor pressure
exceeds that of the combustor, and prevents reverse flow
from combustor 77 to compressor 72 when the pressure at
SUBSTITUTE SHEET (RULE 26)
CA 02376163 2001-12-03
WO 01/06102 PCT/US99/16305
the combustor exceeds that of the compressor, as occurs
during combustion. This allows high usable pressures at
the combustor and results in greater operating efficiency.
Combustion outlet valve 92, where utilized, is
5 controlled to close immediately prior to ignition to
constrain the fluid at the combustor to a near constant
volume during combustion (in conjunction with closing of
combustor inlet valve 90 to prevent back flow of fluid
when the pressure at the combustor exceeds that of the
10 compressor). This allows a rise in temperature and
pressure above that available using only the combustor
inlet valve. Closing combustion outlet valve 92 prior to
closure of inlet combustion valve 90 also provides
acoustic enhancement of the combustion pressure.
15 In addition, or as an alternative, to valuing, as
indicated in FIGURE 10, one or more of the stator-rotor-
stator assemblies shown in FIGURE 10 can have a fluid flow
path 94 configured to cause the fluid to pass through the
rotor a plurality of times, as is indicated in FIGURES 11
and 12. As shown by the arrows in FIGURES 11 and 12, the
fluid is caused to flow in a spiral in the circumferential
direction around the axis of the engine (i.e., the fluid
flow passes through the plane of the active stage a
plurality of times encountering the same active stage a
plurality of times). As can be appreciated, each of the
rotors could be fabricated as a single rotor with blades
trapped between stator plates and still provide multiple
stages of compression and power delivery.
By intermittent exposure of surfaces to different
temperature flows to thus reduce the overall average
temperature to which exposed surfaces are subjected and
thus enable use of higher temperatures than would
otherwise be possible with the same materials if subjected
only to high temperatures, such as combustion chamber
outlet temperatures, the efficiency of a turbine engine
can be enhanced. Intermittent exposure can be effected by
using at least one of intermittent combustion, use of flow
diversion by using flow exchange valves to intermittently
SUBSTITUTE SHEET (RULE 26)
CA 02376163 2001-12-03
WO 01/06102 PCT/US99/16305
16
exchange passage of hot and cooler bypass temperatures
through the engine, and mixed flow achieved by
circumferential separation.
Intermittent combustion can be achieved, as shown in
FIGURE 13, through use of a combustion producer 95, shown
as a fuel injector 96 and an ignitor 97, in a turbine
engine 70 such as shown in FIGURE 10 (with or without the
valuing as shown therein). Interruptions in ignition
cause termination of combustion, and this results in
cooler working fluid flow.
Flow diversion can also be achieved, as shown in
FIGURE 14, through use of flow exchange valves to
intermittently exchange the paths of the heat conductive
flow and the cool bypass flow as they pass through the
engine. As shown in FIGURE 14, the hot and cooler flows
are radially separated from one another through use of
internal housing 99 (separating the combustion flow 101
from the cooler bypass flow 102) and flow exchange valves
104.
The flow exchange valves provide either straight
through flow by maintaining the hot flow through the inner
portion and the cooler flow through the outer portion of
the exhaust turbine, or exchanged flow in which the hot
combustion flow is through the outer portion of the
exhaust turbine and the cool flow is through the inner
portion of the turbine.
Intermittent operation of the exchange valves
provides mixed flow through substantially all of the
exhaust turbine and thereby provides that all of the
surfaces in the exhaust turbine operate at a low average
temperature while allowing a very high temperature
combustion. In this embodiment, the bypass section of the
compressor is matched to the pressure at the outlet end of
the combustion chamber, thereby providing very low
operating pressure differentials to the flow exchange
valves.
Mixed flow can also be achieved by circumferential
separation of hot and cooler flows as indicated in FIGURE
SUBSTITUTE SHEET (RULE 26)
CA 02376163 2001-12-03
WO 01/06102 PCT/US99/16305
17
15. As shown, radial walls 106 allow combustion flow 108
and cooler bypass flow 109 in parallel to one another
along the same annular ring 111. Since the motion of the
turbine blades is in the circumferential direction, the
blades pass from a high temperature flow to a cooling flow
several times per revolution. Thus, the rota;.ing elements
of the turbine experience a low average temperature, even
in the intermittent presence of very high temperature
combustion. While this does not cool the stator elements,
the stators operate at lower stress levels and therefore
are better able to withstand the high temperatures.
As c~.n be appreciated from the foregoing; this
invention provides an improved turbine engine having
enhanced efficiency and an improved method for_ providing
enhanced efficiency in a turbine engine.
