Radiant energy power source structure

A radiant energy power source structure for providing electrical power to a jet aircraft is disclosed. The device comprises a plurality of inward facing longitudinal ribs arranged in an annular configuration positioned radially outward of the plurality of perforations in the combustion liner of a jet engine. The longitudinal ribs are attached to a base which are a part of the outer combustion casing in the combustion section of the jet engine. In addition to air passing over the longitudinal ribs, helically wrapped fuel passageways are additionally incorporated into the base. Interiorly to the channels formed by the longitudinal ribs are an upper and lower groove formed in each longitudinal rib, the lower of the two grooves adapted to receive a plurality of photovoltaic cells receiving the radiant energy, the photovoltaic cells arranged in a series electrical connection in the circular direction. The circular series is broken at one point to carry off the electrical power. Immediately inward of the photovoltaic cells in each formed channel is a protective plate securing the cell against dust particles carried by the incoming air and possible flame emission from the combustion liner. Means are further provided to bleed air into an air gap created between the cell and the protective plate in order to equalize air pressure on both sides of the plate.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The field of the invention is devices for providing electrical power aboard 
jet aircraft. The Government of the United States of America has rights in 
this invention pursuant to Grant No. DE-FG01-86CE-15301 awarded by the 
U.S. Department of Energy. 
2. Description of the Related Art 
The Applicant's prior U.S. Pat. No. 4,090,359 issued May 23, 1978 and 
entitled "RADIANT ENERGY POWER SOURCE FOR JET AIRCRAFT AND MISSILES" 
details a power source which derives electrical energy from the radiant 
energy emitted from a jet engine. This is accomplished by placing 
photovoltaic cells proximate the jet engine combustion liner and 
interiorly the jet engine combustion casing. 
Since the issuance of Applicant's prior patent, Applicant has continued to 
improve upon the basic underlying concept in respect of structural 
features encapsulating the radiant energy power source. 
Applicant herein details structural features which he believes 
substantially improves the utilization of his prior invention. 
SUMMARY OF THE INVENTION 
This invention relates to structure integrated into a jet engine or gas 
turbine utilizing its radiant energy for providing electrical power to the 
vehicle having the jet engine or gas turbine. More specifically, the 
subject invention comprises the center frame structure securing the 
radiant energy receiving photovoltaic cells into the outer combustion 
casing proximate the combustion liner of the jet engine or gas turbine. 
The photovoltaic cells receive radiant energy from the burning fuel via a 
plurality of perforations in the jet engine combustion liner surrounding 
the burning fuel. Additionally, it is entirely conceivable that the 
combustion liners in future jet engines may be composed of radiant energy 
transparent materials. These photovoltaic cells are integrated into an 
annular cylindrical structure having a plurality of longitudinal channels 
formed by spaced apart ribs throughout its interior periphery. 
The radiant energy power source structure containing the photovoltaic cells 
comprises firstly a base defining a cylindrical sleeve, the base having on 
its interior peripheral surface a plurality of inwardly protruding 
longitudinal ribs forming the photovoltaic cell channels therebetween. The 
longitudinal ribs are characterized by a pair of longitudinal grooves 
formed in the protruding ribs, one groove proximate the base adapted to 
receive and secure a plurality of photovoltaic cells in a fixed position, 
allowances being made however for physical expansion of the cells as a 
result of their increasing temperature during use. Photovoltaic cells 
completely blanket the interior peripheral surface of the radiant energy 
power source structure. The cells are connected in an annular or circular 
series by electrical wires attaching at opposite sides of each cell and 
passing through openings formed transversely in the longitudinal ribs 
immediately above the groove securing the photovoltaic cell. 
Immediately above the photovoltaic cell situated in a second elongated 
groove formed in each rib is a transparent protective plate adapted to 
protect the photovoltaic cell from dust and other particles in the air 
passing between the radiant energy power source structure and the outside 
peripheral shell of the combustion liner. Like the photovoltaic cell, 
means are implemented within the second groove to permit physical 
expansion of the transparent protective plate as its temperature rises 
when the invention is in operation. 
The base to which the longitudinal ribs are secured provides a heat sink 
for excess radiant heat energy received by the photovoltaic cells and the 
ribs. The base is further characterized by helical wound fuel passageways 
encapsulated within the base providing for heat in the base to be 
transferred to circulating jet engine fuel on its way to the fuel 
injectors which spray fuel into the combustion liner of the jet engine. In 
the preferred embodiment, the base is a part of the outer combustion 
casing of the jet engine for the engine's combustion section and may be 
one piece rather than a composition of various parts. 
Means are also provided to utilize the incoming air passing between the 
combustion liner and the invention to enter into the gap between the 
photovoltaic cells and the transparent protective plate in order to 
equalize the air pressure on both sides of the protective plate to protect 
against damage caused by stress that may be placed upon the protective 
plates and photovoltaic cells. Additional means are detailed to protect 
the entrance into the air gap between the protective plate and 
photovoltaic cell in such a way as to exclude dirt particles or other 
debris in the incoming air from clogging the air passageway communicating 
the incoming air into the air gap. 
It is an object of the subject invention to provide a structure integrated 
into a jet engine for securing the photovoltaic cells receiving radiant 
energy from the engine for conversion to electrical energy and use by the 
aircraft. 
It is another object of the subject invention to provide means to protect 
the photovoltaic cells surrounding a jet engine combustion liner from 
damage due to particles in the incoming air. 
It is still another object of the subject invention to provide means to 
electrically interconnect the photovoltaic cells to conduct the generated 
electrical power to the aircraft. 
It is still further another object of the subject invention to provide a 
structure to secure photovoltaic cells surrounding a jet engine combustion 
liner which renders relatively easy access to and replacement of the 
photovoltaic cells. 
Other objects of the invention will in part be obvious and will in part 
appear hereinafter. The invention accordingly comprises the apparatus 
comprising construction, combination of elements, and arrangement of parts 
which are exemplified in the following detailed disclosure and the scope 
of the invention which will be indicated in the Claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to FIG. 1, a partially sectioned view of the prior art 
combustion section 10 of a jet engine is shown in perspective. Proceeding 
from the outside inward, annular elongated combustion section 10 comprises 
an outer combustion casing 11 supporting within its annular envelope 
combustion liner 13. Current combustion liners 13 are perforated with a 
plurality of openings (although transparent combustion liners may become 
available in the future), these openings permitting the transfer of 
radiant energy to the subject invention (which is not shown in FIG. 1). 
Combustion liner 13 comprises an elongated cylindrical shell enclosing an 
elongated annular volume, much like a donut stretched out in its axial 
direction, into which the jet fuel is sprayed and then burned. Turbine 
blades 16 are to the immediate rear of combustion liner 13. Immediately 
interiorly to the innermost cylindrical surface of combustion liner 13 and 
in concentric alignment is the inner combustion casing 14, also having an 
elongated cylindrical surface. Continuing to proceed radially inwardly, 
shaft shield 15 protects a centrally located elongated rotating shaft (not 
shown) which connects an air compressor (not shown) immediately forward of 
the combustion section 10 to the first stage of the turbine partially 
shown with blades 16. 
The air compressor (not shown) immediately forward of the combustion 
section 10, which would be to the left of FIG. 1, compresses incoming air 
and drives it into the somewhat pointed leading edge of the combustion 
liner 13, the air dividing into three directions, i.e., between the 
combustion liner 13 and outer combustion casing 11, between the combustion 
liner 13 and inner combustion casing 14, and interiorly into the 
combustion liner 13 through the forward located openings shown in FIG. 1. 
The air which enters the forward located openings of the combustion liner 
13 is mixed with a spray of jet fuel to be ignited and burned within it. 
Air which passes between the combustion liner 13 and the outer combustion 
chamber 11 and between combustion liner 13 and the inner combustion casing 
14 serves to cool the combustion liner. It is this air passing between the 
combustion liner 13 and the outer combustion casing 11 that the subject 
invention depends upon, in part, to cool the invention from the heat 
resulting from the reception of the high intensity radiant energy 
generated interiorly to combustion liner 13 and passed through the 
plurality of openings in the outer portion of the shell comprising 
combustion liner 13. 
FIG. 2 is a front sectioned view of the new modified outer combustion 
casing 12 taken along the engine longitudinally with Applicant's invention 
in place (replacing outer combustion casing 11 shown in FIG. 1). Flanges 
12a and 12b in FIG. 2 replace flanges 11a and 11b shown in FIG. 1. In the 
preferred embodiment, Applicant's inventive structure is incorporated into 
the outer combustion casing on a jet engine and becomes a part of the 
original construction of an engine. Alternately, the inventive structure 
may be attached to a modified outer combustion casing and may replace the 
originally manufactured outer combustion casing 11 of an existing jet 
engine. In the view shown, the inventive structure is incorporated into an 
original outer combustion casing 12, manufactured as one piece, and one of 
the protruding longitudinal ribs 26 of the subject invention is shown 
facing inward towards the combustion liner 13 (FIG. 1). In the outside 
(top) portion of the new outer combustion casing 12 are also shown the 
plurality of fuel passageways 23 which permit the circulation of cold jet 
engine fuel helically around the modified outer combustion chamber prior 
to being injected into the combustion liner 13 volume (FIG. 1). The jet 
fuel passing through fuel passageway 23 serves the function of providing a 
heat sink for the invention in order to carry off heat which the invention 
receives during operation, also as later described. 
Referring now to FIG. 3, a diagramic sectional front view (as if looking at 
the jet engine in FIG. 1 from the left hand side) is shown of the 
invention in place inside the new outer combustion casing 12. 
FIG. 3 has been reduced in size relative to that shown in FIG. 1 and 
represents a pictorial diagram of the different elements which comprise 
the invention and their location relative to the new outer combustion 
casing 12 which replaced outer combustion case 11 in the prior art. In 
addition, there is no attempt to represent in FIG. 3 the different 
elements of the invention and the engine in a true dimensional 
relationship, in fact, the dimensions of parts of the invention have been 
greatly enlarged in relationship to the outer combustion casing 12 in 
order to bring out the highlights of the invention. 
Proceeding from the central most portion outwardly, the outer periphery of 
the cylindrical surface of combustion liner 13 is shown represented by the 
innermost circle. This shell is perforated by a large plurality of 
openings as shown in FIG. 1. The invention is shown by Numeral 20 
completely surrounding, but not touching, the outer periphery of 
combustion liner 13. It is noted that the radiant energy power source 
structure 20 is the inner surface of the new outer combustion casing 12. 
Base 22 supports the elongated ribs later described and provides the heat 
sink for the photovoltaic cells. Shown in the figure is the helically 
wrapped jet fuel lines 23 (here a circle) which convey the cold jet fuel 
from the jet aircraft fuel tanks to the fuel injectors which spray fuel 
interiorly to the combustion liner. These fuel lines run helically in base 
22 and transversely to longitudinal ribs 26. 
The end view of the subject radiant energy power source structure 20 in 
FIG. 3 shows various individual and longitudinal ribs 26 completely 
encircling the interior of the modified outer combustion casing 12 in a 
spaced apart orientation and it is intended that the radiant energy power 
source structure 20 should extend in outer combustion casing 12 over at 
least the full length of the perforations in its outer shell of combustion 
liner 13 (as shown in FIG. 1) in order that substantially all the radiant 
energy emitted through the plurality of perforations in the combustion 
liner 13 is captured by the invention's photovoltaic cells later 
discussed. Thus the invention comprises an elongated cylindrical shell 
which is spaced away from the perforated portion of the outer cylindrical 
shell of the combustion liner 13 adapted to capture radiant energy emitted 
from the combustion liner 13. It further has contained cooling means to 
carry off excess heat (in addition to the cooling provided by incoming air 
passing between the ribs 26 and combustion liner 13). 
FIG. 4 is a cross-sectional view of a small section of the subject 
cylindrical radiant energy power source structure 20 transversely severed 
and then laid in a straight line for illustrative purposes. The radiant 
energy power source structure 20 comprises base 22 upon which protrudes 
transversely a plurality of stacked "T" shaped longitudinal ribs 26 which 
have, situated between a pair of longitudinal grooves formed in the ribs, 
an elongated transparent protective plate 28 overlaying an elongated row 
of individual photovoltaic cells 30. When the term "transparent" is used 
to describe the elongated protective plates 28, the term is meant to 
define a plate which is transparent to the radiant energies of interest 
which, by definition, will be the radiant energies which are at least 
within the bandwidth of the radiant energy useful to the photovoltaic 
cells. Sapphire is suggested as a suitable transparent protective plate. 
For illustrative purposes, protective plate 28 and photovoltaic cell 30 are 
shown loosely spaced in longitudinal grooves formed in the longitudinal 
ribs 26, however, there is a requirement that the protective plate and the 
row of photovoltaic cells be held firmly in place, yet allowance be made 
for their increased temperature expansion. Therefore, the protective 
plates and photovoltaic cells do engage the horizontal portions of the 
grooves shown in the longitudinal ribs 26, and room for expansion is 
provided. This is illustrated in FIG. 5, infra. 
FIG. 5 is a more detailed cross-sectional view taken between two elongated 
ribs shown in FIG. 4. At the lower most portion of FIG. 5 is the outer 
combustion casing 12 and a longitudinal sectional view of one of the 
helically wrapped jet fuel passageways 23 showing the top and bottom 
internal surfaces of the passageway. In the preferred embodiment, the 
elements represented by numerals 22 (base) and 12 (outer combustion 
casing) are one solid piece with helical fuel passageway 23 circling 
interiorly. Inasmuch as base 22 contains the helical wrapped jet fuel line 
23 and all constitute the new outer combustion casing 12, heat energy 
collected by the invention (in addition to radiant light energy) is 
transferred to the jet fuel flowing through the passageway 23. It should 
also be remembered that air passing over the invention also draws off much 
heat. Rising above base 22, upward protruding longitudinal ribs 26 are 
seen with their oppositely situated longitudinal grooves 32 and 34. 
Positioned securely in the lower most longitudinal groove 32 of 
longitudinal ribs 26 is a row of photovoltaic cells 30, the cells so 
situated that a small portion of opposite sides of their top surface 
engage the upper side of groove 32. The cells bottom surfaces rest firmly 
upon base 22. In order to assure a good thermal contact, it is suggested 
that all voids between the bottom of photovoltaic cells 30 and base 22 be 
filled with a thermally conducting gel, shown by numeral 31. Photovoltaic 
cells 30 do not engage longitudinal grooves 32 in the horizontal direction 
to the full depth of grooves 32, but a void is created therein to allow 
for expansion of photovoltaic cells 30 within the grooves. 
Photovoltaic cells 30, prior to installation in the longitudinal grooves 
32, are constructed of an appropriate semiconductor material 29 (shown by 
a dark line) situated upon the top of an electrically insulative (but 
thermally conductive) substrate, such as alumina. Semiconductor material 
29 is electrically connected to leads 36 and 38 (later discussed), but 
does not physically touch ribs 26. 
Immediately above photovoltaic cell 30, protective plate 28 is held between 
opposite upper longitudinal grooves 34 of oppositely situated longitudinal 
ribs 26 in a similar manner as cell 30 was held in lower longitudinal 
grooves 32 with the exception that only a small portion of each side of 
the bottom surface of protective plate 28 is held within longitudinal 
groove 34. It is intended that a secure fit of cell 30 and of protective 
plate 28 be accomplished in the longitudinal grooves of the longitudinal 
ribs. Thermal expansion of the protective plates 28 is permitted by a gap 
between the sides of the cell and plate and the vertical bottoms of the 
longitudinal grooves 34. 
Separating cell 30 and protective plate 28 is an air space, nominally about 
20 mils (20/1000 inch), created between the top of cell 30 and the lower 
surface of transparent protective plate 28. As explained later, into this 
space air will be injected in order to equalize the pressure on both sides 
of protective plate 28. 
Lastly shown in FIG. 5 are electrical wires 36 and 38 connected to opposite 
sides of semiconductor material 29 at connection points 37 and 39 
respectively on photovoltaic cell 30. Each of the electrical wires 36 and 
38 connect to the circularly adjacent photovoltaic cells located in 
adjacent channels formed by adjacent longitudinal ribs 26. It is noted 
that the electrical wires 36 and 38 pass through openings 40 and 42 
respectively formed transversely across longitudinal ribs 26 and across 
from each other, and immediately above the cells 30. Electrical wires 36 
and 38 carry insulation in their passage through openings 40 and 42. 
As shown in FIG. 5, photovoltaic cells 30 are shielded by transparent 
protective plates 28 from the air passing through the jet engine between 
the outer surface of combustion liner 13 and the top of radiant energy 
power source structure 20. This air often contains particles of matter, 
such as suspended dirt and water vapor, which are a source of concern to 
the photovoltaic cells. In addition, there is the possibility of a 
momentary flame exiting out of one or more of the plurality of openings in 
the combustion liner 13, which is also a source of potential problems to 
the photovoltaic cells. 
Further, photovoltaic cells 30 are fully protected against the absorption 
and retention of excessive heat by their direct thermal connection to base 
22, which has contained within it the heat removing fuel circulating on 
its way to the injectors passing through helically wrapped jet fuel lines 
23. Mathematical calculations tend to indicate that it may not be 
necessary for fuel in the helically wrapped jet fuel lines in the outside 
base portion 22 of outer combustion casing 12 to remove large amounts of 
heat since the largest part of heat generated by the combustion liner is 
carried away by the incoming air which surrounds the combustion liner. In 
such case, the base 22 may be sufficient heat sink for the inventive 
radiant energy power source structure 20 without circulating fuel. 
Referring now to FIG. 6, a top view of the front end of the inventive 
radiant energy power source structure 20 is shown. Proceeding from left to 
right, at the far left is head 27 which constitutes the front most portion 
of the radiant energy power source structure 20 and is constructed 
similarly to the elongated ribs 26 in that it protrudes upward from the 
base and does have a lower and upper groove on the part of the head which 
faces the protective plate and photovoltaic cells. Front end is defined to 
mean the end which first receives the incoming air passing through the jet 
engine. It would be located at the left most part of the jet engine 
combustion section 10 shown in FIG. 1. In FIG. 6 are shown the 
longitudinal ribs 26 whose upper and lower grooves join with the same 
named grooves of head 27, and which run a length substantially equal to 
the width of the perforated portions of the combustion liner 13 and which 
are terminated at their rear end with a tail similar to head 27. It is 
realized that either the head or the tail must be removable from base 22 
in order that the protective plates and the photovoltaic cells be 
initially placed into structure 20 or removed for replacement or repair 
and then re-inserted. For convenience, the tail was chosen as the 
removable part. 
Not seen in FIG. 6 because of their transparency are the transparent 
protective plates 28. It is intended that only one plate is needed for the 
whole length between two elongated ribs 26. Immediately underneath these 
transparent protective plates are the multiplicity of photovoltaic cells 
30 shown in FIG. 6. Obviously, electrical connections between adjacent 
cells by electrical wires 36, 38, and 41, must be accomplished before the 
insertion of the transparent protective plates. A portion of the 
electrical connections are shown which connect every circular row of 
cells. 
Because of the present physical constraints of the photovoltaic cells, 
there is a plurality of photovoltaic cells in each channel formed between 
two elongated ribs, and these individual cells 30 are shown in FIG. 6. 
Inasmuch as the energy at all points in a circle along any one location in 
the longitudinal direction of the combustion chamber is substantially 
equal, the photovoltaic cells 30 shown in FIG. 6 are connected serially in 
the annular or circular direction. In this manner, the current generated 
by each photovoltaic cell is equal, and the resultant collected voltage is 
the sum of each cell. This is shown in FIG. 6 by the electrical connection 
of wires 36, 38, and 41 (shown partially dotted and partially full) 
between the different adjacent photovoltaic cells 30. Shown also are the 
electrical connection points 37 and 39 on one photovoltaic cell as 
representative of each photovoltaic cell. At one point on each of the 
circular chains of electrical connections, the connection is broken and 
the electrical wires from each end then passed through base 22 to outside 
the engine to be used as the aircraft electrical system. 
It is noted that a number of openings 44 are shown in head 27 in FIG. 6. 
These are openings which allow the passage of air into the radiant energy 
power source structure 20 and more specifically, to the air gap 
(previously mentioned) created between the top of photovoltaic cell 30 and 
the bottom of protective plate 28. By bleeding air into this gap between 
the cells and the plates, excessive pressure differentials on opposite 
sides of protective plate 28 are avoided. These holes or openings 44 are 
placed in the front head 27 portion of the radiant energy power source 
structure 20 in order to intercept the incoming air passing between the 
combustion liner 13 and the outer combustion casing 12. Thus, with the 
rushing incoming air, air is forced into the gap between the cell and the 
plate which results in captive air pressure substantially equal to the air 
pressure on the top of the protective plate by the air passing over the 
invention. 
Since it is advantageous that the air passageway within head 27 which leads 
from opening 44 into the air gap between the cell and the plate be as 
immune as possible to clogging or plugging by a particle of matter, such 
as sand or the like, carried by the in-rushing air, a structure such as 
shown in FIG. 7 is suggested. In FIG. 7, a cross-sectional view is taken 
of head 27 showning opening 44 and the passageway 45 which communicates 
opening 44 with the air gap between protective plate 28 and photovoltaic 
cell 30. It is particularly noted that to discourage particles from 
entering opening 44 and lodging therein, the air passageway 45 slants 
backwards at an acute angle towards the direction from which the air comes 
before it enters into the air gap between the plate and the cell. Next, at 
the entrance of the passageway 45 into the air gap between the protective 
plate and the photovoltaic cell, the passageway is opened up with a 
spreading opening 46 which forms a beveled edge. In addition, the 
passageway tends to cool the incoming air. 
FIGS. 8 and 9 show an alternate embodiment of the opening 44 and connecting 
air passageway 48 which proceeds immediately downwards before it turns 
into the air gap between the photovoltaic cell 30 and the protective plate 
28. FIG. 8 is a cross-sectional side view of head 27, and FIG. 9 is a top 
view of a portion of head 27. Here again, the beveled opening 46 
characterizes the end of air passageway 48. To protect against matter 
lodging in the opening 44, a triangular shaped mound 50 is situated 
immediately forward of the opening 44 in head 27 to protect against and 
deflect solid matter which may be in the air stream. 
While a preferred embodiment has been shown and described, it will be 
understood that there is no intent to limit the invention by such 
disclosure, but rather it is intended to cover all modifications and 
alternate constructions falling within the spirit and the scope of the 
invention as defined in the appended Claims.