US3188961A

US3188961A - Means for cooling structures that are periodically heated to elevated temperatures

Info

Publication number: US3188961A
Application number: US112676A
Authority: US
Inventors: David M Scruggs; Gordon D Pfeifer
Original assignee: Bendix Corp
Current assignee: Bendix Corp
Priority date: 1961-05-25
Filing date: 1961-05-25
Publication date: 1965-06-15
Anticipated expiration: 1982-06-15

Description

J 1965 D. M. SCRUGGS ETAL 3 188,961

9 MEANS FOR COOLING STRUCTURES THAT ARE PERIODICALLY HEATED TO ELEVATED TEMPERATURES Filed May 25, 1961 5 Sheets-Sheet 1 INTERMEDIATE COOL SIDE 5 E C T l O N EIE ;L

INVENTORS GORDON D. PFEIFER DAVID M. SCRUGGS. By.

% fTTOR/VEE.

June 15, 1965 D. M. SCRUGGS ETAL 3,1 8,96

MEANS FOR COOLING STRUCTURES THAT ARE PERIODICALLY HEATED TO ELEVATED TEMPERATURES Filed May 25. 1961 5 Sheets-Sheet 2 IE E INVENTORS GORDON D. PFEIFER. DAVID M. SCRUGGS.

E/MAW 311 June 15, 1965 o. M. SCRUGGS ETAL 3,188,961

MEANS FOR COOLING STRUCTURES THAT ARE PERIODICALLY HEATED TO ELEVATED TEMPERATURES Filed May 25, 1961 5 Sheets-Sheet 3 INVENTORS GORDON D. PFEIFER DAVID M. SCRUGGS. By" 7W a Arron/Vs June 15, 1965 D. M. SCRUGGS ETAL 3,188,961

MEANS FOR COOLING STRUCTURES THAT ARE PERIODICALLY HEATED TO ELEVATED TEMPERATURES Filed May 25. 1961 5 Sheets-Sheet 4 INVENTORS GORDON D. PFEIFER DAVID M. SCRUGGS.

I Arron/vex June 15, 1965 D. M. SCRUGGS ETAL 3,188,961

MEANS FOR COOLING STRUCTURES THAT ARE PERIODICALLY HEATED TO ELEVATED TEMPERATURES Filed May 25. 1961 s Sheets-Sheet s INTERMEDIATE COOL SIDE I TIP. SEC'TION. !SECTION.

/ Z a 4 g INVENTORS GORDON D. PFEIFER. DAVID M. SCRUGGS.

Arron/v5) United States Patent 3,188,961 MEANS FOR COOLING STRUCTURES THAT ARE PERIODIEALLY HEATED T0 ELEVATED TEM- PERATURES David M. Scruggs and Gordon D. Pfeifer, both of South Bend, Ind., assignors to The Bendix Corporation, South Bend, Ind., a corporation of Delaware Filed May 25, 1961, Ser. No. 112,676 13 Claims. (Cl. 10292.5)

The present invention relates as indicated to means for cooling structures that are heated to very high temperatures for short intervals of time; and more particularly to means for cooling re-entry structures, aircraft brakes, rocket nozzles andthe like.

It sometimes occurs in structures that are heated to elevated temperatures for short intervals of time, that only portions of the structure are heated above a critical temperature while other portions remain below the critical temperature.

An object of the present invention therefore is the provision of new and improved structure which will cause the hottest portion of the structure to be cooled by radiation,.and which will reflect or pass on this radiation to the cooler portions of the structure.

In some instances, however, more heat is generated in the hottest portions of the structure than can be absorbed or transmitted through the cooler portions of the structure;

and accordingly a further principle of the present invention is the provision of new and improved means for absorbing the heat which is in excess of that which can be absorbed or transmitted through the cooler portions of the structure.

A further object of the invention is the provision of new and improved structure of the above described type which is cooled by means of a material which goes through a change of state, and more particularly by means of a solid which melts to absorb the excess heat.

In some types of structure with which we are concerned, the structure is gradually heated from a low temperature to its critical temperature over an appreciable period of time during which a certain amount of radiation or conduction to its environment outside of the structure takes place. According to further principles of the present invention new and improved means are provided whereby substantially no heat is transmitted to the internal heat absorbing structure during the period of time that the structure is being raised to its critical temperature; and after which time the transmission of heat to the heat absorbing structure increases markedly to maintain the temperature below its critical temperature. By so doing a maximum amount ofheat is dissipated to the surrounding environment outside of the structure, and only a minimum amount of heat is absorbed by the material which undergoes a change in state.

It is a property of radiating bodies that the amount of heat radiated is a function of the fourth power of absolute temperature; so that very little energy is radiated at low temperatures and a great amount of heat is radiated at elevated temperatures. Accordingly, a more specific object of the invention is the provision of new and improved structure of the above type wherein the structure which is to be cooled transmits its heat to the heat absorbing body solely by radiation; so that a maximum amount of heat will be transmitted from the body to be cooled to the surrounding environment outside of its structure and therefore will not be required to be absorbed by the heat absorbing body.

The invention resides in certain constructions and com binations and arrangements of parts; and further objects and advantages of the invention will become apparent to those skilled'in the art to which it relates from the following description of several preferred embodiments described with reference to the accompanying drawings forming a part of this specification, and in which:

FIGURE 1 is a fragmentary cross sectional view of a nose cone for a re-entry structure;

FIGURE 2 is a fragmentary cross sectional view of an aircraft brake embodying principles of the present invention;

FIGURE 3 is a plan view of an aircraft brake stator to be used in an aircraft brake of the type shown in FIG- URE 2, but which is constructed somewhat different;

FIGURE 4 is a fragmentary cross sectional view taken approximately on lines 4-4 of FIGURE 3;

FIGURE 5 is a fragmentary cross sectional view through a rocket nozzle showing how principles of the present invention can be utilized to maintain the throat of a rocket nozzle below its critical temperature; and

FIGURE 6 is a fragmentary cross sectional view of a nose cone using an internal heat reflector only.

As is indicated above, the principles of the present invention can be utilized in various types of structures which are periodically heated to elevated temperatures-one such structure is the nose cone shown in FIGURE 1. The nose cone shown in FIGURE 1 generally comprises a hollow envelope or shell 10 which is heated to elevated temperatures by air friction during its re-entry to the earths atmosphere. The envelope is generally dome shaped and is suitably bolted to the front end of the rocket structure 12 with a heat insulating structure 14 interposed therebetween. Various types of heat insulating structures can be used and as shown in the drawing, a thin layer of bubbled aluminum oxide 16 is machined out of a sheet of commercially available material, and is bolted to the outside surface of a support plate 18, which may be of any suitable super alloy, as for example Rent: 41. Bubbled aluminum oxide is a sintered aluminum oxide material which has had a foaming agent dispersed therethrough which causes bubbles to be produced throughout the aluminum oxide prior to its being sintered. Rene 41 is a vacuum cast nickel material containing small percentages of aluminum which form nickel-aluminide particles throughout to dispersion harden the nickel.

Any suitable material capable of withstanding high temperatures can be used for the envelope 10 provided that it also has good oxidation resistance. Materials such as molybdenum and tungsten oxidize quite readily at elevated temperatures, and therefore are not usable without being protected in some manner. In the preferred embodiment shown in the drawing, the envelope or shell 10 is preferably made from a chrome cermet capable of prolong use in oxidizing atmospheres at 3400 F. For a complete disclosure of this material reference may be had to the Scruggs application Serial No. 88,302, now abandoned.

It is a property of re-entry structures generally that the front tip of the structure is heated to the highest temperature; that its side surfaces can be relatively cool; and that the intermediate section of the re-entry structure will be heated to intermediate temperatures. In some instances, depending upon the speed of re-entry etc., only the very tip of the structure will reach temperatures exceeding its critical temperature, and it will be possible therefore to provide a reflective structure internally of the envelope for reflecting radiant energy from the tip of the re-entry structure to the side surfaces where the heat can be dissipated without the temperature of the side surfaces exceeding the critical temperature. The amount of heat which can be reflected, absorbed and then re-radiated in the above described manner will of course be limited; so that in more severe applications it will not be possible to re-radiate all of the heat which is transmitted to its envelope. The nose cone shown in FlGURE l'is intended to be-used for these more severe applications.-

V mathematical design for the present invention simplified. -I It will now be apparent that the exact material 30 which cone is absorbed; according to furthenprinciples of the invention which will now be described.

' The structure A shown in the; drawing for dissipating" heat from the envelope without transmitting the same to the internal portion of the rocket structure 12, general- 7 'ly comprises a coritainerZtl which is made-iof a material which will withstand the elevated temperatures. which are involved. The container 20 maybe made of any suitable'material such as stainless steel, Rene 4l,'etc. and'as shown in the drawing 'is formed :of ,the'same' chrome -cermet material that has been previously described as being used' for the. envelope '10. The container is 'formed generally as a comically shaped cup having a bottom which is dished to be equidistant at. all points from the envelope '10. The top of the container20is provided with suitable threads 24 by means" of which it is fastened to a top'threaded plate 26 which is suitably bolted to the ou'ter surfaceof the layer of insulating material :16. 'The sidewalls of the container20 may be variously shaped, and

as shown in the drawing are formed conicallyl fo'r'reasons' which will later be described. The'inside'gof the ,COIP

tainer20 is filled with a solid material which has a, high latent heat of fusiomand'which melts at a predetermined temperature which-correspondsfgenerally 'andldoes not exceed the maximum temperature T which can be used to provide the necessary heat transfer rate from the en- -velope 10 to the material .30. The formula generally used to calculate this heat transferis generally stated "as:

f=some function '7 i V '40 Q=heat transfer rate Kzconstant A=bottom surface of container 20 e V e =emissivity of the tipportion of the container 10 e =emissivity of the surface of the bottom of the conis used in the container 20, will have to be selected so that, its melting pointdoes not exceed the maximum T temperature, which can be utilized, and in the embodiment shown in the drawing, the material 30 is metallic beryllium which has a high-latent heat of fusion and which m'e'lts'at approximately 2400" F. V

'It'further occurs in 'the' embodiment shown in the drawingpthat the, heat which is generated upon the intermediate section-of the nose cone can be safely reflected and emitted from the cooler side section of the cone;

and accordingly the sidewalls 28 {of the container 20 have been properly shaped to reflect 'the heat from the interme diate section onto the cooler side section of the nose cone.

The sidewall sections 28'willhave to be variously shaped in order to provide 'their reflective function depending upon the shape ofthenose-cone; and in the embodiment shown in the drawing are comically shaped. To improve the reflectivity of the outer surface of the sidewalls 28,

'ateflectiveycoating' of zirconia is provided. 1 Zirconia meltsat 4700 P. so that 'it'itselfwill not be damaged by the temperature of the surface which'it sees; and it further serves the purpose of ,d-iminishingyas much as possible, the heat flow' from, the intermediate sections of the envelope-10w the material 30. Itcan now be seen "that the structure-A shown inthe drawing, 'cools'the intermediate sections of the nose ,conepby refiecting'radiant energy therefrom to the cooler side section of the nose cone so that neither section exceeds the critical temperature of which it is made; and it'will further be seen that it efficiently absorbs only that portion of the heat from the tip which is'necessaryto keep its temperature below the critical temperature of the material from which it is made. Structure A thereforecauses the'envelope 10 to radiate a maximum amount of heat to the surrounding environment; and it only absorbs that portion which is nemsar'y to maintain the .tip ata safetempera-ture.

' It will be apparentlthat principles ofthepresent invention will have use in 'still'other types of structuresone of which will be'friction producing devices such as aircrafit brakes. The aircraft brake shown'in FIGURE 2 generally comprises a strut. 32 having, afshafit' 34 about I which is ,rotatably journaled a wheel structure 36. The

tainer'20 which sees the tip portionof the'envelope 10 T =average absolute temperature of the tip portion of the envelope 10 r T =absolute temperatureat which the material 30 changes state I V While insome instances the'bottom 22 of the container '20 may touch the tip ofthe envelope'lo'so that there ,is direct conduction of heat fro'rn'the envelope 10to the material 30, in the preferred embodiment shown in the drawing a sufiicient gap is provided sothat substantially all of the heat which reaches the material 30 .must be transmitted byjradiationaccording' to the above given formula. From this formulait will be seen that very little heat will be transmitted to the material 30 at low values of T --which it; should be pointed out must be. kept below the critical. or recrystallization I or softening temperature of the material from which the envelope 10 is made. It will therefore be seen that for those temperatures below thecritical T temperature, very little of the heat will be transmitted to the, material 30, ."so that a maximum of the heat would be rejected to, the surrounding environment of the envelope ,10-.this is by reason of the fact that the heat radiated to the material 30 is a function of the fourth power of the absolute tempera- 'ture. Also by keeping Ti high as possible a maximum 7 amount of heat is transmitted to space. Inasmuch as the change of-state of" all pure materialsoccurs at .a con-.

stant temperature, it-will be seen-,that'the heat which is;

absorbed from the tip'of the envelope 10 will be absorbed constant, and the fact that T islvconstantymakes :the'

wheel structure 36 is provided with a plurality of keys 38 equally spaced around the outer flange 40 of the wheel.

The keys'38 are provided for the purpose of projecting into correspondingly positioned keyways which are formed 'into'the outerperiphery of annular rotor members 42;" The strut 32 is provided'with a rigid flange 44 to which is suitably bolted a stationary support structure ,46 to which the stationary or

stator elements

48 and 50 of the brake "are suit'ably fixed. 'The intermost stator element 52 is bolted rigidlyto the support structure 46, and the

stator elements

48 and 50 are formed as annuluses having suitable keyways on theirinn'er surface sc that they are free to move axially over the bolting structure154 of the stator element 52. It will'now be seen that the stator and rotor elements are free to move axially along their respective jkeyw'ays; and all of the elements are adapted/to be s'andwiched together bya plurality o1 pistons 56,] only one of which is'sh'own, which in turn i: actuated by means of hydraulic pressure'that' is communi cated'to its hydraulic inlet connection 58. The structure 'so far described is quite conventional, and for a morr complete-description and understanding of this type 0 structure, reference may'be had to the DujBois Paten 2,731,312.-

Each'ofrthe stator elements

48, 50 and 51 carry a pluralityof cup-shaped structures 60- which an filled with an inorganic friction material 62 of the typl describedin the Stedman etaL, Patent 2,784,125. Thi

f material 62 carriedtby, the stator membe rs is in tun l rubbed again'stthe side surface of the rotor members 41 'which'may be made of. any suitable high temperatun at a constant temperature. The factthat T must be held material as *for "example'xthe chrome cermet materia As is well known in the art, aircraft brakes are made to handle energy exceeding 41 millions of ft./lbs. during a stop, which energy for the most part cannot be rejected to the surrounding atmosphere because suflicient air flow cannot possibly be provided; and this heat therefore raises the temperature of the brake to exceedingly high temperatures. According to principles of the present invention solid materials which will undergo a change of state are incorporated into the brake structure for the purpose of absorbing this heat at a constant low temperature to thereby prevent any portion of the brake structure from exceeding the critical temperature of the materials from which the brake is made. Any suitable material undergoing a change of state can be used. The material may be placed so that it sees either of the rubbing surfaces of the stator or rotor members, or as shown in FIGURE 2, can be placed so that it sees the back side of one of the rotor or stator members.

In the embodiment shown in FIGURE 2, a separate rotor member 42 is provided for each friction surface of the stator members 50; so that two rotor members 42 are positioned side by side with a space in between. An

, annular heat absorbing member 64 is positioned in this space and is keyed to the wheel structure 36 along with the rotor members 42, so that it rotates with the rotor members and no sliding occurs between the rotor and heat absorbing members. The heat absorbing members 64 shown .in the drawing are formed by radially inner and radially

outer rings

66 and 68 which hold the rotor members 42 spaced apart, and further include annular side plates 70 which are suitably welded to the inner and

outer rings

66 and 68. The annular side plates 70 are spaced apart from the rotor members 42, and are spaced apart from each other, so as to provide an internal chamber that is filled with the heat absorbing material 72 which undergoes a change of state. Any suitable heat absorbing solid material which undergoes a change in state at a sufliciently low temperature to keep the rotor member 42 below its critical temperature can be used. In the embodiment shown in the drawing, the heat absorbing material 72 is metallic aluminum, and the

rings

66 and 68 and side plates 70 are made of carbon steel. The rotor members 42 are made from the chrome cermet material disclosed in the Scruggs application 88,302. This material can stand a temperature of 3400 F., and the friction material 62 previously described can stand a temperature of approximately l800 F. It will now be apparent that the rotor members 42 are kept well below their critical temperature by the aluminum which melts at approximately 1100 F.; and that the aluminum absorbs its heat from the rotor members 42 principally by means of radiation through the air space 74 between the rotor and heat absorbing members. Inasmuch as the heat absorbing material receives its heat from the brake structure principally by radiation, the rotor and stator members are permitted to reach their elevated operating temperatures at which they work best, rather quickly and thereafter are maintained approximately at this temperature by reason of the principles discussed previously with respect to the structure in FIGURE 1.

FIGURE 3 of the drawings is a plan view of a stator member which is intended to be used in an aircraft brake structure similar to that shown in FIGURE 2. In the embodiment of brake structure utilizing the stator member 76 only one rotor member 42 is used between stator members so that the brake structure is conventional in this respect. Cooling of this brake structure is had by means of heat absorbing members 78 which are positioned between the friction material containing cups 62.

Heat absorbing members 78 are relatively thin compared to, the cup structures 60, so that they do not rub against the surface of the rotor members during the operation of the brake. As seen in FIGURE 3, the stator member is provided with alternate friction producing and heat absorbing members of about the same size so that the 6 rubbing surfaces of the rotor members are maintained at an even temperature.

The heat absorbing members 78 may be made in any suitable manner and of any suitable material and as shown in the drawing, are formed in the shape of small cylindrical disks or cookies having opposite end plates between which the heat absorbing material 72 is con-fined. The containers 80 shown in the drawing are made of carbon steel suitably welded together, and are inserted through openings 82 in the stator members 76, and are suitably Welded in place. The heat absorbing material may be of any suitable material as previously explained, and as shown in the drawing is metallic aluminum. With the embodiment shown in FIGURE 4, none of the heat absorbing members 64 need be provided, and only onehalf of the rotor members 42 as seen in FIGURE 2 are provided so that in some instances it may be possible to reduce the width of the brake structure from the Width which would be required by the embodiment seen in FIGURE 2.

The principles of the present invention will have still other uses, one of which will be for the cooling of the throats of rocket nozzles, as shown, for example in FIG- URE 5. The rocket nozzle shown in FIGURE 5 generally comprises a throat section which may be made of any suitable material as for example wrought tungsten. The rocket nozzle shown is of the movable type whose axis can be moved to change the direction of the blast and includes a spherical section 92 which slides on a mating spherical surface 94 of the retainer plate 96. The retainer plate 96 is sealingly aflixed to the casing 98 of the rocket motor by means of any suitable structure; and the inner portion of the throat section 90 is protected from the intense temperature of the flame by means of a zirconium oxide layer 99. The trailing or diverging section of the nozzle 100 is not subjected to the intense temperatures of the flame, and to save weight is preferably made of Fiberglas reinforced or impregnated with a phenol formaldehyde plastic. The diverging section 100 is suitably bolted to the throat section 90; and in order to prevent pressure leakage through the movable joint between the

spherical surfaces

92 and 96, an annular sealing structure 102 resembling a tire is suitably posi tioned between the stationary retaining plate 96 and a removable flange 104 that is bolted to the throat section 90 along with the diverging section 100. The throat and diverging sections, can be moved in any suitable manner, and as shown in the drawing, is actuated by means of a plurality of hydraulic fluid pressure motors 106, only one of which is shown, in a manner which will be well understood by those skilled in the art.

According to principles of the present invention the throat section 90 is cooled by means of an annular heat absorbing body 108 which is spaced from and interpositioned between the throat section 90 and the sealing structure 102 to prevent the sealing structure 102 from being heated by radiation from the throat section 90. The heat absorbing member 108 is preferably made from a sheet, of the wrought chrome cermet material previously referred to, which is bent into an annular envelope and welded together in a manner which will be well understood by those skilled in the art. The envelope is provided with a flange 112 by which it is bolted to the throat section 90 in a manner assuring an air space 114 between the heat absorbing body and the throat section 90. The envelope is filled with a suitable solid material 116 which undergoes a change of state; and the preferred embodiment shown in the drawing is filled with metallic beryllium. The space between the heat sink 108 and sealing structure 102 is preferably filled with an insulating material 118 such as Fiberglas to prevent deterioration of the rubber from which it is made. It will now be seen that the throat section 90 is maintained at a temperature below its critical temperature by means of radiation to the heat absorbing body 108, which in turn absorbs the radiation, and prevents it from being re-radinozzle section 90. r

' perature.

ated'to the annular sealing structure 102, which would normally be damaged by the direct radiation from the FIGURE 6 of the drawings shows a nose cone similar to that seen in FIGURE 1, excepting that only aninternal reflector R is used to keep the external surface of the nose it mustbe: cooled at a predetermined rate, said side areas cone from exceeding its critical temperature. Those 'portions of FIGURE 6 which correspond to similar portions of FIGURE 1 are designated by a like reference numeral characterized further in that a prime mark is affixed thereto. The reflector R is generally. formed by a cone shaped supporting structure 120 made from any suitable; high temperature material such as Rene 41, and-a reflective layeror coating 122 of a suitable reflective material such as zirconia. The reflector may be held in place in any suitable manner, and is shown reentry structure 12. The reflective surface 124. of the as shown by the parallel dot-dash lines, and is-preferably a hyperbolic conoidal surface.

While the invention hasbeen bodiments shown and. described; and itis our, intention to cover hereby allnovel adaptations, modifications and arrangements-thereof whichcomewithin the practice of .those skilled in the art to which the invention relates; 7

We claim: 1. In heat dissipating structure: a first body which receives heatat a maximum rate for ashort interval of time and whose temperature must be kept below -a first predetermined temperature, and a second body spaced and positioned to receive heat energy from said first body substantially entirely by radiation at said maximum rate when saidsecond body is at a n elevatedsecond predetermined temperature, said second body including a solid which changes state at anelevatedtem-perature corresponding generally to said second predetermined temperature. I I H 2. In heat dissipating structure: a first body which receives heat at a maximurnrate for a short'interval of time ,andwhose temperature must be kept below a first predetermined temperature, and a second body shaped and positioned to receive heat energy from said first body substantially entirely by radiation at'saidmaximum rate when said second'body is at an elevated second pre- 7 in the drawing as clamped between the nose cone 10f, and the body of. the

I described in considerable detail, we do not wish to belimited to the particular em- 7 areas of said re-entry structure.

.material 122 is designed to reflect heat from the tip of the 1 nose cone out of the cooler side surfaces of the nose cone receiving small amounts of heat and having a sufficiently ,-high-emissivity to keep it'stemperature well below'said .first'predetermined temperature, and said intermediate surface receiving anintermediate amount of heat to require only a small amount of cooling to hold its tempera- ..ture below said first predetermined temperature, a body positioned inside said hollow structure and having a front area spaced therefrom to receive radiant'energy at said predetermined cooling rate when its temperature is below a secondpredetermined elevated temperature, said body containing-a material which changes state at a temperature corresponding generally to-said second predeter- ,mined temperature, and said body also having reflective side surfaces for receiving said radiant energy from said intermediate surface areas and reflecting it to said side 6. In a nose cone and the like: .a hollow nose structure having. front, sideand intermediate surface areas which must be kept below a first predetermined temperature, saidjfront. area receiving large amounts of heat so that .it must becooled at a predetermined rate, said side areas receiving small amounts of heatand having a sufliciently high emissivity to keep its temperature well below said first predetermined temperature, and said intermediate surface receiving an intermediate amount of'heat to require only a small amount of cooling to hold its temperature below said first predetermined temperature, a body positioned insidesaid hollow structureand having a front 30.,

area spaced therefrom to receive radiant energy at said predetermined cooling rate when its temperature is below a secondpredetermined elevated temperature, said body containing a metalwhich melts at a temperature corresponding generally ,to'said second predetermined temperature, andsaidbody also having conoidal reflective side surfaces' forreceiving said radiant energyfrom said intermediate surface areas and-reflecting it to said side vareas ofsaid. re-entry structure. 7

7. "In a nose cone and the like: a hollow nose structure comprising a .s-intered mixture of approximately 94% chromiumand 6% magnesia having front, side and inter- 'mediatesurface areas which must be kept below approxi- .mately 3400? F., said front Tarea receivinglarge amounts I of heat so thatit must be cooled at a predetermined rate, "said side areas receiving smallarnounts of heat and having .a su'fi'iciently. high emissivity to keep its temperature well determined, temperature, said second body inc'luding a i a solid metal which melts at an elevated temperature corresponding generally to said second predetermined tem- 3. In re-entr y structure:

there being side areas of high emissivity and a considerably'lower temperature, a reflectivesurface inside said structure and spaced from said frontsurface area;.to

wreceive radiant energy only,: said reflective'surface being shapedto reflect heat from said frontsurface area .to said side areas.

I 4.- lu-anose cone of a a first predetermined of high emissivity anda-considerably lower temperature, and a hyperbolic conoidal reflective surface inside said 'structurejspacedsaid structure including a e ;front surface area which [receives heat at a maximum rate V for a short interval of time and'whose temperature must Y be kept below a first predetermined temperature, :and

below said first predetermined temperature, and said inter- .mediate surface receiving anintermediateamount ofheat to require only a small amountof eooling to hold. its temperature below said first predetermined temperature, a bodypositioned inside said hollow structure and having a front area spaced therefrom to receive radiant energy at 7 said predetermined cooling rate when its temperature is below a second predetermined elevated-temperature, saic body containing beryllium which changes. state at a tern perature corresponding generally to said second predeterfminedtemperature, and said body also having refiectivc side surfaces for receiving said radiant energy from saic intermediate surface-areas and reflecting it to said Sldt areas ofsaid re-entry structure.

8. In a friction producing'device': 'having'a pair 0 members havingsurfaces which are rubbed together t: generate heat at a predetermined rate and first predeter mined temperature,;a body spaced from one of said sur faces to receive heatv by radiation at said predeterminer ratewhen its temperature is below a second lower pre :determined temperature, saidbody'containing a materia which changes state at a temperature which does not ex from said front surfacearea to, receive'radiant energy V only, said reflective surface being shaped to; reflect heat from said front surface areato said side areas;

5. Ina nose cone. and. the like ahollow nosexstructure I having "front, side and" intermediate surface areas which ceed said second predetermined temperature.

9.'.In afriction producing device having rotor and sta tor members having-respectivesurfaces which-are rubbe togetherto generate heat at a predetermined rateand fir:

7 predetermined temperature, a' body spacedapart from on must be kept'below a first predetermined temperature;

.said front area'rec'eiving large amounts. ofheat so that p of said members on its side opposite to its heat-generatin surface to receive radiantenergy from said member at sai predetermined rate when its temperature is below a second predetermined temperature, said body containing a solid material which changes state at a temperature that does not exceed said second predetermined temperature.

10. In a friction producing device having rotor and stator members having respective surfaces which are rubbed together to generate heat at a predetermined rate and tfirst predetermined temperature, a body spaced apart from one of said members on its side opposite to its heat generating surface to receive radiant energy from said member at said predetermined rate when its temperature is below a second predetermined temperature, said body containing aluminum which melts at a temperature that does not exceed said second predetermined temperature.

11. In a friction producing device having generally parallel rotor and stator plates on one or" which are fastened spaced apart metallic cups containing a friction producing material which rubs against the surface of said other plate to generate heat at a predetermined rate and first predetermined temperature, said one plate having a body positioned between said cups in a manner which does not rub against said other plate but which receives radiant energy therefrom, said body containing a solid material which changes state at an elevated temperature to absorb heat from said surfaces.

1 2. In a friction producing device having generally parallel rotor and stator plates on one of which are fastened spaced apart metallic cups containing a friction producing material which rubs against the surface of said other plate to generate heat at a predetermined rate and first predetermined temperature, said one plate having a body positioned between said cups in a manner which does not rub against said other plate but which receives radiant energy therefrom, said body containing aluminum which melts at an elevated temperature to absorb heat from said surfaces.

13. A nozzle structure for handling fluids at predetermined elevated temperatures and comprising: a member forming a thin walled venturi section and made of a material which must be held below a first predetermined temperature, said venturi section radiating heat at a predetermined rate when it is at said temperature, and an annular body surrounding and spaced from said venturi section to receive radiant energy therefrom at said predetermined rate when its temperature is below a second predetermined temperature, said body containing a solid material which melts at a temperature that does not exceed said second predetermined temperature.

References Cited by the Examiner UNITED STATES PATENTS OTHER REFERENCES 1958 Missile Materials Review (Zaehringer et al.), Missiles and Rockets, vol. 3, No. 3, March 1958, pages 69-75.

Space Technology, Aviation, vol. 68, No. 16, Apr. 21, 1958, pages -59.

How We Have Progressed in Nose Cones, Missiles and Rockets, Apr. 4, 1960, pages 32 and 33.

BENJAMIN A. BORCHELT, Primary Examiner. ARTHUR M. HORTON, Examiner.

Claims

1. IN HEAT DISSIPATING STRUCTURE; A FIRST BODY WHICH RECEIVES HEAT AT A MAXIMUM RATE FOR A SHORT INTERVAL OF TIME AND WHOSE TEMPERATURE MUST BE KEPT BELOW A FIRST PREDETERMINED TEMPERATURE, AND A SECOND BODY SPACED AND POSITIONED TO RECEIVE HEAT ENERGY FROM SAID FIRST BODY SUBSTANTIALLY ENTIRELY BY RADIATION AT SAID MAXIMUM RATE WHEN SAID SECOND BODY IS AT AN ELEVATED SECOND PREDETERMINED TEMPERAURE, SAID SECOND BODY INCLUDING A SOLID WHICH CHANGE STATE AT AN ELEVATED TEMPERATURE CORRESPONDING GENERALLY TO SAID SECOND PREDETERMINED TEMPERATURE.