U.S. patent application number 11/111447 was filed with the patent office on 2005-09-01 for gas turbomachinery generator.
Invention is credited to Gozdawa, Richard Julius.
Application Number | 20050189827 11/111447 |
Document ID | / |
Family ID | 9904229 |
Filed Date | 2005-09-01 |
United States Patent
Application |
20050189827 |
Kind Code |
A1 |
Gozdawa, Richard Julius |
September 1, 2005 |
Gas turbomachinery generator
Abstract
A gas turbomachinery electricity generation apparatus includes a
gas turbomachinery arrangement having an associated rotary drive
take-off, an electricity generating arrangement which includes a
first generator stage including a first generator rotor and
generator stator arrangement; a second generator stage including a
second generator rotor and generator stator arrangement, at least
of the first and second generator stage rotors is driven by the
rotary drive take-off.
Inventors: |
Gozdawa, Richard Julius;
(Uxbridge, GB) |
Correspondence
Address: |
BLISS MCGLYNN, P.C.
2075 WEST BIG BEAVER ROAD
SUITE 600
TROY
MI
48084
US
|
Family ID: |
9904229 |
Appl. No.: |
11/111447 |
Filed: |
April 21, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11111447 |
Apr 21, 2005 |
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10747386 |
Dec 29, 2003 |
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6900553 |
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10747386 |
Dec 29, 2003 |
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09995152 |
Nov 27, 2001 |
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Current U.S.
Class: |
310/58 |
Current CPC
Class: |
F01D 25/12 20130101;
Y02E 20/14 20130101; H02K 1/32 20130101; F01D 5/08 20130101; F01D
15/10 20130101; H02K 7/1823 20130101; H02K 1/278 20130101; H02K
16/00 20130101 |
Class at
Publication: |
310/058 |
International
Class: |
H02K 009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 30, 2000 |
GB |
0029296.1 |
Claims
1. (canceled)
2. A rotor of an electric generator or motor, the rotor including
an airway extending generally in the direction of the rotor axis
permitting cooling air or other gas to be drawn along the
rotor.
3. A rotor according to claim 2, wherein the airway extends
adjacent the outer surface of the rotor.
4. A rotor according to claim 2, wherein the airway has an inlet
portion proximate an end of the rotor.
5. A rotor according to claim 2, wherein a shroud portion overhangs
the end of the rotor, defining an air gap between the rotor end and
the shroud.
6. A rotor according to claim 5, wherein the shroud portion
overhangs the airway inlet.
7. A rotor according to claim 2, further comprising an airway
outlet to permit the cooling air to vent from the rotor at a
position spaced longitudinally from the inlet.
8. A rotor according to claim 2, wherein the rotor comprises a
permanent magnet armature having one or more permanent magnets
positioned at the radial periphery of a rotor body.
9. A rotor according to claim 8, wherein the airway extends along
the rotor intermediate the permanent magnet and a rotor body.
10. A rotor according to claim 8, wherein a securing rim or annulus
extends around the magnet armature.
11. A rotor according to claim 2, wherein the magnet armature is
seated in a seat formed on a rotor body.
12. A rotor for an electric generator or motor comprising: a rotor
body having a rotor axis; an airway extending along said rotor body
generally in a direction of said rotor axis, said rotor body having
an air inlet and an air outlet to permit cooling air or other gas
to be drawn along said rotor body.
Description
[0001] The present application is a divisional of U.S. patent
application Ser. No. 10/747,386, filed Dec. 29, 2003, which is a
continuation of U.S. patent application Ser. No. 09/995,152, filed
Nov. 27, 2001.
FIELD OF THE INVENTION
[0002] The present invention relates to a gas turbomachinery
electric generator and particularly to a high speed gas turbine
electric generator.
DEFINITION OF THE INVENTION
[0003] According to a first aspect, the invention provides gas
turbomachinery electricity generation apparatus comprising:
[0004] a gas turbomachinery arrangement;
[0005] a rotary drive take-off associated with the turbomachinery
arrangement;
[0006] an electricity generating arrangement comprising:
[0007] i) a first generator stage including a first generator rotor
and generator stator arrangement; and
[0008] ii) a second generator stage including a second generator
rotor and generator stator arrangement;
[0009] wherein at least one of the first and second generator stage
rotors is driven by the rotary drive take-off.
[0010] The gas turbomachinery arrangement preferably includes a gas
driven turbine stage or stages. The rotary drive take-off may be
associated with the gas driven turbine stage.
[0011] Beneficially, the turbomachinery arrangement includes a gas
compressor stage, preferably a rotary compressor stage including a
rotary impeller stage.
[0012] It is preferred that both the first and second stage
generator rotors are driven by the turbomachinery arrangement.
[0013] The first and second stage generator rotors are
advantageously driven by one or other of the compressor and/or
turbine stages.
[0014] In one embodiment, the compressor impeller and turbine rotor
are mounted upon a common shaft. In this embodiment it is preferred
that the first and second rotor stages of the electricity
generation arrangement are directly driven by the common shaft,
preferably being arranged in series, beneficially mounted upon a
common shaft (which may be the same shaft upon which the turbine
rotor and compressor impeller are mounted, or a shaft coupled
thereto).
[0015] In an alternative embodiment, the first and second rotor
stages of the electricity generation arrangement are mounted upon
separate, discrete shafts each preferably being drivingly
associated with one or other of the compressor impeller and the (or
a) turbine rotor.
[0016] In a further alternative embodiment, the first and second
rotor stages of the electricity generation arrangement are mounted
upon separate shafts each preferably being drivingly associated
with one or other of the compressor impeller and the turbine rotor.
In this embodiment shafts may be coupled by gear means or clutch
means.
[0017] The gas compressor stage may be mounted on or connected to
the take-off shaft of the turbine stage.
[0018] The turbomachinery arrangement preferably includes a
combustion stage for combustion of a gas/fuel mixture. The
combustion stage is, preferably provided intermediate compressor
stage and the turbine stage. The gas turbomachinery arrangement may
be arranged to burn a gas fuel or a liquid fuel at the combustion
stage. The combustion stage preferably comprises a combustion
chamber in which a working gas (typically air) is heated by
combustion of the fuel, which is then passed (with combustion
products) to a downstream turbine.
[0019] One of the first and second generator stages is preferably
more highly power rated than the other. The power rating ratio
between the two stages is preferably substantially in the range
1:1.5 to 1:9. More preferably the range is substantially 1:2 to
1:4, most preferably at or about 1:2.
[0020] Beneficially one or both of the generator rotors arranged to
be driven to initiate rotational operation of the turbomachinery
arrangement. In this situation the relevant stage is acting as a
motor rather than a generator. The apparatus therefore preferably
includes means for operating at least one of the generator stages
in motor mode. A control system and power supply means (typically
electrical battery means) are preferably provided for this purpose.
The control system preferably includes inverter means for the power
supply to the or each generator stage. The inverter means is
preferably arranged to charge maintain the start up power supply
battery. The relevant generator stage acts as a motor to bring the
relevant turbomachinery apparatus up to a rotational speed at which
the gas turbomachinery becomes fully self sustaining. Most
beneficially, the lower power rated stage rotor is arranged to be
driven to initiate rotational operation of the turbomachinery
arrangement This enables minimum power to be used to drive the
turbomachinery to a level at which combustion at the combustion
stage takes over.
[0021] Beneficially, the apparatus control system is capable of
selecting electrical power to be supplied by one or other or both
of the first and second generator stages dependent upon the output
requirement of the apparatus. Inverter means and output power
connections for both of the generator stages are provided for this
purpose. Each generator is preferably connected to its own inverter
that converts the high frequency current that is generated into a
conventional alternating current or direct current supply as may be
required.
[0022] Dependent upon the economics of the circumstances of the
operating profile of the generator a recuperator may be provided
for preheating the air by heat from the exhaust of the gas turbine
before the air passes to the combustion chamber or chambers. The
fuel may be a liquid hydrocarbon or a gas. A fuel supply system and
combustion chamber or chambers are provided as may be required by
the use of liquid fuel, by the use of gas or for dual fuelling. (In
one embodiment exceptionally the compressor might be multistaged
and the turbine has a high-pressure and a low-pressure stage.)
[0023] As an example of the influence of economics upon the
provisions included in the gas turbine, should the turbine
generator be installed for the sole purpose of generating
electrical power then it becomes economic to maximise the
efficiency of generation by the provision of a recuperator. However
the case for the additional capital expenditure represented by the
provision of a recuperator is less strong if the turbine generator
is to be used in a combined heat and power scheme.
[0024] Bearing means are preferably provided to support the
generator rotors and rotational turbomachinery. Oil lubricated
bearings may be utilised that may be conventional shell bearings of
circular bore or shell bearings with fixed lands or tilting pad
bearings or rolling element bearings that are mist lubricated. A
tilting pad thrust bearing or bearings control the axial position
of the rotor or rotors.
[0025] An oil supply system and an oil cooler is preferably
provided to feed oil to the bearings for lubrication and for
cooling. The system preferably also provides that oil or other
coolant is passed through channels in the stators of the generators
to carry away heat produced by the electrical losses. In another
aspect of the invention the rotors of the generators may be
provided with channels for the passage of flows of cooling air or
other gas.
[0026] In one embodiment a compressor, a turbine stage and the
rotors of the first and second generating stages (but not
necessarily in that sequence) are coupled together on a common axis
to form a single line. The line may or may not contain means such
as a spline or a gear coupling to permit the axial length of the
line adjusting itself automatically to the demands of differential
expansion between the line stationary parts.
[0027] In an alternative embodiment, there may be two lines, with
the compressor, a turbine stage and a rotor of one of the
electricity generator stages coupled together (but not necessarily
in that sequence) on a common axis on a first line, and on a second
line on a common axis the rotor of the second electricity generator
stage coupled together with a turbine stage driven by an
appropriate fraction of products of combustion taken from the
turbomachinery arrangement of the first line.
[0028] Beneficially a respective rotor of the generator arrangement
includes an airway extending generally in the direction of the
rotor axis permitting cooling air or other gas to be drawn along
the rotor. Cooling air is drawn along the airway. This provides
significant benefit in aiding cooling of the rotor.
[0029] According a further aspect the invention therefore provides
a rotor of an electric generator or motor, the rotor including an
airway extending generally the direction of the rotor axis
permitting cooling air or other gas be drawn along the rotor.
[0030] The airway preferably extends adjacent the outer surface the
rotor. The airway preferably an inlet portion proximate an end of
the rotor. A shroud portion preferably overhangs the end of the
rotor, desirably defining an air gap between the rotor end and the
shroud. The shroud preferably overhangs the airway inlet.
[0031] An airway outlet is preferably provided to permit the
cooling air vent from the rotor at a position spaced longitudinally
from the inlet.
[0032] In one embodiment, the rotor comprises a permanent magnet
armature having one or more permanent magnets positioned the radial
periphery of the rotor body. The airway (typically formed a groove)
is preferably positioned to extend along the rotor intermediate the
permanent magnet and the rotor body. A securing rim or annulus
(preferably shrink fitted around the armature) extends around the
magnet armature. The magnet armature preferably seated in a seat
formed on the rotor body.
[0033] The invention will now be further described in specific
embodiments, by way of example only and with reference to
accompanying drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] FIG. 1 is a schematic sectional view of an exemplary
turbomachinery generator according to the invention;
[0035] FIG. 2 is a schematic view of an alternative embodiment of
turbomachinery generator according to the invention;
[0036] FIG. 3 is a schematic view of a further alternative
embodiment of turbomachinery generator according to the
invention;
[0037] FIG. 4 is a schematic view of a rotor for a motor generator
in accordance with a further aspect of the invention;
[0038] FIG. 5 is an end view of the rotor of FIG. 4;
[0039] FIG. 6 is a detail view of a part of the rotor of FIGS. 4
and 5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0040] Referring to the drawings, one embodiment of the invention
is illustrated in FIG. 1. A monobloc rotor A has a generator
armature A.sub.1 of a generator of larger power rating and an
armature A.sub.2 of a lesser power rated generator. A thrust collar
A.sub.3 and the journals A.sub.4, A5 and A.sub.6 support the rotor
A. A.sub.7 and A.sub.8 are permanent magnets held by their shrunk
on sleeves (that are not shown in FIG. 1). Overhung from the
monobloc rotor but separate from it are the impeller B of the
centrifugal compressor and the impeller C of the inward radial flow
turbine. These impellers are assembled on the monobloc rotor by a
central tie bolt (not shown) and transmit torque to the monobloc
rotor via Hirth couplings or other forms of co-axial coupling
compliant of differential expansion between the elements they
connect (not shown). D.sub.1 and D.sub.2 are the stators of the
generators.
[0041] The casing of the generator comprises the casing E with its
flanges E.sub.1 and E.sub.2, the casing F with its flanges F.sub.1
and F.sub.2. The monobloc rotor runs in the journal bearings
G.sub.1 G.sub.2 and G.sub.3 and the axial position of the rotor is
fixed by the thrust bearing G.sub.4. The bearing G.sub.1 is unsplit
and its housing is bolted to the flange E.sub.1. The bearing
G.sub.2 is a bearing split on a diametral-axial plane and held by
the diaphragm H that is split on the same plane as its bearing The
bearing G.sub.3 and the thrust bearing G.sub.4 are split on a
diametral-axial plane and are held in a split housing bolted to the
flange F.sub.2.
[0042] Bolting is provided such that H may be positioned and bolted
to E.sub.2 before the casing F is bolted to E.sub.2.
[0043] The inlet to the compressor comprises the inner cone J.sub.1
that is supported by casing F at X (and by its flange that is
bolted to the flange F.sub.1) and the outer cone J.sub.2 that is
supported by its flange J.sub.3. The flange J.sub.3 is held to the
flange E.sub.1 by the columns K.sub.1. The support at X is a
sliding support. The separation of the inner and outer cones is
maintained by the struts L.sub.1 and L.sub.2 that are of
aerodynamic section. Some or all of these struts are hollow provide
conduit for the electrical leads the stators D.sub.1, and D.sub.2.
The inlet is provided with the variable inlet guide vanes whose
angle is varied by one of the mechanisms well known in the art. Air
enters the compressor inlet via the filter M that encircles the
columns K.sub.1.
[0044] The casing of the compressor comprises the out casing
N.sub.1 and the inner casing N.sub.2; with an inner annular upstand
N.sub.3, and an outer annular upstand N.sub.4. The inner casing
bolt by the flange J.sub.4 to the outer cone J.sub.2 the inlet to
the compressor The inner and outer casings are held together by the
spacers K the vaneless space and by the volute (not shown).
[0045] The casing of the turbine comprises the outer casing P.sub.1
and the inner casing P.sub.2. The inner casing is bolted at Z to
the inner annular upstand N.sub.3 of the inner casing of the
compressor. At the radius of this bolting there is little
differential expansion between the two inner casings. But because
of differential expansion the casings must not be bolted together
at the outer annulus and there their separation maintained by the
outer annular upstand N4 that rests at Y against the inner casing
of the turbine. Contact will be maintained at Y because the
temperature gradient across P.sub.2 will tend to make P.sub.2
concave wit its concavity facing the inner casing N.sub.2 the
compressor.
[0046] The inner and outer casings of the turbine are held together
by the spacers G that should it be necessary can be cooled by a
bleed of air from the exhaust of the compressor.
[0047] The casings of the compressor and of the turbine are
supported entirely by the cone J.sub.2. Consequently the rigidity
of this cone and the rigidity of its mounting with relation to the
casings of the generators are of great importance. To increase the
rigidity of its mounting the flange E.sub.1 is provided with
stiffening webs either internally, externally or in both positions.
(The webs are not shown in FIG. 1.) The torsional stiffness with
which the columns K.sub.1 hold the cone J.sub.2 is also important
and is enhanced for example by diagonal struts connecting adjacent
columns K.sub.1 say in three equally spaced places.
[0048] The inlet guide vanes of the turbine are not shown nor the
combustion chamber or chambers that connect the exhaust of the
compressor with the inlet of the turbine.
[0049] Another embodiment of the invention is illustrated running
line is the centrifugal compressor D, a combined thrust and journal
bearing E, generator A, a journal bearing and the right hand
termination of the first shaft. The beginning of the second shaft
connected with the first by a spline or gear coupling G, generator
B, a combined journal and thrust bearing H, and the impeller of the
turbine J. C is the combustion chamber or chambers. In comparison
with the arrangement FIG. 1 this arrangement provides completely
unimpeded compressor entry and a greater space which to arrange the
combustion chamber or chambers. Its disadvantage is that the second
shaft is held at its left-hand end in a spline gear coupling G
rather than in a bearing.
[0050] Another embodiment the invention is diagrammatically FIG. 3.
It comprises two lines, a first line with generator B together with
a gas turbine D that also generates the gas that drives the power
turbine E of the second line with generator A. From left to right
the first line is a journal bearing followed by a centrifugal
compressor F that may be preceded by one more no axial compressor
stages G (or a centrifugal compressor with two centrifugal stages)
followed by thrust bearing H and also journal bearing should such
be needed, followed by generator B followed by a journal bearing I
followed by the radial inflow turbine stage D. The second line from
left to right is a journal bearing J followed by generator A
followed by a combined journal and thrust bearing K followed by the
radial inflow power turbine stage E. C is the combustion chamber or
chambers. The advantage of this arrangement that facilitates the
provision of additional compressor stages or an additional
compressor stage. The additional stage or stages would produce a
greater pressure ratio and improved turbine efficiency.
[0051] A means of cooling the armature of high-speed permanent
magnet motor or generator is illustrated in FIGS. 4 to 6. In the
figures A is the rotor, B is a permanent magnet, C is the band
shrunk around the magnets with such pre-strain as to keep the
magnets on their seats at the highest speed for which the rotor is
designed. D is a channel milled along the centre of each magnet
seat. (Two channels only are shown in the figure for clarity but
every seat is provided with a respective channel.) The channels
emerge the end of the magnets and sleeve as illustrated D.sub.1.
C.sub.1 is a lip formed as part of the sleeve or as otherwise
constructed. The rotor is cooled by a stream of cool air or other
gas flowing through the channels from the entrances of the channels
beneath the lip to their outlets D.sub.1. The air in the gap
between the inner surface of the lip and the end of the armature
will rotate substantially the speed of rotation of the rotor. The
centrifugal action will produce a greater pressure air or gas at
the entrances of the channels and because of that pressure rise air
or gas will flow through the channels the outlets D.sub.1. The flow
of air or gas will carry heat away from the rotor. (The pressure
rise for an armature cooled by air of 100 mm dia at 50000 rpm
approximately 0.34 bar.)
[0052] In the construction of a rotor the magnets are glued their
seats to hold them in position whilst the sleeve is being pressed
over them. To prevent the channels becoming blocked by adhesive
they are filled by plastic strips before the magnets are glued in
place and the strips are withdrawn after the sleeve has been
pressed over the magnets. Alternatively the channels are machined
with grooves to take the dovetail strip E as illustrated in FIG.
6.
[0053] It is a common practice to offset the magnets by a small
angle from the axial direction. In such an instance the channels
are milled on helical paths that keep them everywhere close to the
centre lines of the seats and their magnets.
[0054] The generator according to the invention is designed to
operate at high speed (50,000 rpm) and produce power output
typically in the range 50-60 KW. Because of its design, the
generator is highly compact and light for its power output. The
split generator arrangement enables power output to be tailored to
end use circumstances and also enables the lower rated generator
(10-15 KW) to be used as a motor to start up the generator. The
generator is potentially attractive as a local source of power in
situations where costly power lines would otherwise have to be
provided to give a connection to a distant supply grid.
* * * * *