NASA-SP-5027-1967 Thermal insulation systems a survey《隔热系统的研究》.pdf

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1、t,-li-ll_ _ICi_-t31 _ a NASA SP-5027CA$_ FILECOPYTHERMALINSULATION SYSTEMSA SURVEYNATIONAL AER()NAUTICS AND SPACE ADMINII ;TRATIONv_!. r ,v - r “_- _: t “ _L _l,“ L2L (.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Provided by IHSNot for ResaleNo r

2、eproduction or networking permitted without license from IHS-,-,-NASA SP-5027THERMALINSULATION SYSTEMSA SURVEYBy Peter E. Glaser, Igor A. Black,Richard S. Lindstrom, Frank E. Ruccia,and Alfred E. WechslerPrepared under NASA Contractby Arthur D. Little, Inc.Cambridge, MassachusettsTechnology Utilizat

3、ion DivisionOFFICE OF TECHNOLOGY UTILIZATION“ 1967NATIONAL AERONAUTICS AND SPACE ADMINISTRATIONWashington, D.C.- Zr_w.i-1 L -_Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NOTICE This document was prepared under the sponsorship of theNational Aeron

4、autics and Space Administration. Neither the United StatesGovernment nor any person acting on behalf of the United States Govern-ment assumes any liability resulting from the use of the information con-mined in this document, or warrants that such use will be free from privatelyowned rights.For Sale

5、 by the Superintendent of Documents,U. S. Government Printing O/_ce, Washington, D. C. 20402Price 60 centsLibrary oJ Congress CaJalog Card Number 67-60053_tt, ,. _!- _-“Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ForewordThermal insulation system

6、s are extending the range of tem-peratures attainable and maintainable in industrial operations.The exploration of space has necessitated acceleration of devel-opment of materials and combinations of materials to shield menand machinery in both extremely cold and extremely hot envi-ronments.The info

7、rmation and data acquired by National Aeronauticsand Space Administration researchers and contractors also canbe used in a multitude of other ways. This is a guidebook tothis new resource, prepared by Dr. Peter E. Glaser and his col-leagues at Arthur D. Little, Inc., for the space agencys Officeof T

8、echnology Utilization. It is one of a series of such publica-tions intended to help persons who are not engaged in aerospacework benefit from the advances in technology resulting fromsuch work.There have been many advances in thermal insulation in whichNASA has had no part; this book focuses attenti

9、on on thoserelated to the space agencys programs.GEORGEJ. HOWlCK, Director,Technology Utilization DivisionNational Aeronautics and Space Administration r Tr_ I_IIIProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AcknowledgmentsThe authors would like t

10、o acknowledge the assistance of thefollowing persons and organizations in preparation of thissurvey:B. T. Ebihara, NASA LeRC, for technical assistanceP. Ordin, J. Barber, P. Perkins, NASA LeRC, for reviewingthe manuscript and rendering useful suggestionsR. L. Long and R. B. Newcomb of Missile and Sp

11、ace SystemsDivision, Douglas Aircraft Co.; R. Nixon and T. Seitz of SpaceInformation Systems Division, NAA; G. Fairbairn, J. Lieb, andK. Smith of Rocketdyne Division, NAA; and Dr. J. W. Lucasand E. Christiansen and W. Hagemeyer, Jr., for valuable dis-cussions.We also greatly appreciate the cooperati

12、on of Technology Uti-lization officers at all NASA centers, at Western OperationOffice, and at JPL.IvWp“- - ,nw- 1. - - “ - ,.r w r-, w- _ .r“. W“ WProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Contentsx_PageCHAPTER 1. INTRODUCTION . 1CHAPTER 2. AP

13、PLICATIONS OF THERMAL INSULATIONS 5General Applications . 5Liquefaction of Natural Gas 5Generation and Transmission of Electricity 6Electronic Equipment 7Manufacturing Processes 7Medicine 8Other Applications 8Typical Specific Commercial Applications 8Crystal Oven 8Liquid-Hydrogen Transporter 9Transp

14、ortable Cryogenic Liquid Storage Vessel 10CHAPTER 3. PRINCIPLES OF THERMAL INSULATION SYSTEMS 13Definitions 13Functions . 14Heat Transfer 15Solid Conduction 16Gas Conduction . 16Radiation Heat Transfer 18Laboratory Measurement Techniques . 19Density 19Specific Heat . 20Thermal Conductivity and Therm

15、al Dffusivity . 20Prototype Tests 32Simulation of Operational Environments 33Environment.Simulation Chambers 35CHAPTER A. CRYOGENIC INSULATION SYSTEMS 39Placement of Insulation Systems . 39External Insulation . 39Internal Insulation 39Jettisonable Insulation . 40Materials for Insulation Systems 40Mu

16、ltilayer Insulations 41Foams . 61Powders and Fibers 73Composite Insulations 7.5Other Materials . 87CHAPTER 5. STRUCTURAL AND NONINSULATING CRYOGENIC SYSTEM COMPONENTS 89Attachments and Supports 89Insulation Attachment Methads-Multilayer Insulations 89Structural Supports 96ryr.fL)-.Provided by IHSNot

17、 for ResaleNo reproduction or networking permitted without license from IHS-,-,-THERMAL INSULATION SYSTEMSPagePenetrations 103Buffer Zones in Multilayer Insulations 103Penetration Through Multilayer Insulation With Metal-Coated Plastic Shields 105Use of Vapor Cooling |07Evacuation and Purging 108Flo

18、w of Gases Through Insulotions 108Hazards of Condensed Air 109Evacuation Techniques . 110Purge Techniques . 111Vapor Barriers 112Vapor Barrier Materials . 112Physical Properties of Vapor Barrier Materials . 113Applications of Vapor Barrier Materials 114Protective Enclosures 114Protective Enclosure N

19、ot Exposed to Aerodynamic Heating 115Protective Enclosure Exposed to Aerodynamic Healing i16Adhesives 116Adhesives for Cryogenic Application 117Applications of Adhesives 119CHAPTER 6. HIGH-TEMPERATURE THERMAL PROTECTION SYSTEMS 121Introduction 121High-Temperature Protection Systems for Spacecraft St

20、ructures 121External Insulations 123Internal Insulations . 132Structural Components 133Thermal Protection Systems for Thrust Chambers andOther Spacecraft Components 138Practical Applications for High-Temperature Insulations 140REFERENCES 143it-* _ _ _ _ r v _-V- - ,r- _ W-Provided by IHSNot for Resa

21、leNo reproduction or networking permitted without license from IHS-,-,-density range: 2 to 5 lb/ft _(0.03 to 0.08 g/cm2)t f_Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-INTRODUCTION 3used now in industry and are shortening the normal time asso-cia

22、ted with new product development.Information on thermal insulations developed in the course ofspace research programs has been made available to scientists andengineers in the aerospace industry through contractor reportsand technical articles in professional journals. This informationhas not yet be

23、en fully exploited, primarily because relevant partsof it have been difficult to extract. Much of it is fragmented inthe various reports that describe the development of space ve-hicles, their components, and the research that supports suchdevelopments. Hence, there has been insufficient awareness t

24、hatvaluable information, which can be applied in commercial prod-uct areas, has been generated.In the following chapters we discuss possible uses of thermalinsulation systems in industry; the principles of thermal protec-tion systems; insulation components for such systems; and theirintegration, ins

25、tallation, and performance in typical applications.In this discussion we assume that the reader has a basic knowl-edge of the principles of heat transfer.A Aw-rr- r-V-rProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Provided by IHSNot for ResaleNo re

26、production or networking permitted without license from IHS-,-,-CHAPTER 2Applications of Thermal InsulationsGENERAL APPLICATIONSThe development of thermal insulations and their dramaticimpact on advances in technology can be seen most readily inthe aerospace industry, where applications include the

27、wholerange of thermal insulations for space-vehicle cryogenic fuelstages, engine components, instruments, space suits, and elec-tronic devices. However, much industrial cryogenic work remotefrom the space effort also requires very effective thermal insula-tion systems. For example:Liquefaction of Na

28、tural GasThe availability of liquefied natural gas has dramatically al-tered the industrial potential of countries deficient in fossil fuelsand has increased the utilization of the worlds natural gas re-serves. Only a few years ago, natural gas was burned as a wasteproduct of oil wells, gasfields, a

29、nd refineries. It is now liquefiedand transported to distant points for use as fuel-liquefied-methane tankers, for example, supply England with fuel fromNorth Africa. Oceangoing tankers have used thermal insulationssuch as PVC-type foam, glass wool, balsa wood, and perlite.The discovery of natural g

30、as in the North Sea promises tohave an important effect on the neighboring countries. Becauseof the relatively short distances involved, carrying liquefied nat-ural gas to major distribution points via pipelines is now beingconsidered. To reduce boiloff losses such pipelines could be insu-lated with

31、 evacuated powder or multilayer insulations.During World War II gasoline shortages, methane was usedas a fuel for London buses. Increased availability of liquefiednatural gas may make such uses of methane more competitive.Methane has also been considered as a fuel for commercial super-sonic aircraft

32、. Its use would enhance combustion efficiency, andits availability in many areas of the world would ease logistics -“ LV,_,- - v. yqr-, _r- ,q_G“L _.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-THERMAJ_ INSULATION SYSTEMSproblems. Analysis has sho

33、wn that a payload improvement up to31 percent and an operating cost reduction of up to 36 percentmight be realized with methane. A thermal protection systemwould have to be devised to allow liquefied methane to be car-ried in the wing of the aircraft. Among the systems consideredfor this purpose are

34、 evacuated powder, fiber glass, and multi-layer insulations (ref. 1).Thermal insulation is being applied to the inside of large-capacity concrete tanks designed to store liquefied natural gasfor peak load sharing in city gas supply systems during winter.Placing the thermal insulation on the inner su

35、rfaces of a tankprovides the advantage of rapid, low-loss-rate cooldown, smallerthermal expansion or contraction of the wall, and greater pro-tection from mechanical damage to the insulation during opera-tion. A flexible laminate of aluminum, Dacron, and Mylar formsthe protective cover for the insul

36、ation. This thermal insulationsystem can be compared with the approach used for the internalinsulation of the Saturn rockets S-IV stage for liquid hydrogen.It appears likely that techniques established for the space boostercan aid in applications of insulations to large terrestrial storagetanks.Gene

37、ration and Transmission of ElectricityThe consumption of cryogenic liquids by the electrical indus-try is expected to increase as developments of superconductorsfor electric motors, generators, transformers, and magnets reachthe practical stage. The use of superconducting materials, re-quiring tempe

38、ratures from 7 to 36 R (4 to 20 K) to be main-tained around conductors, will reduce the electrical power lossesin cables and the various devices. These low temperatures maybe achieved by the circulation of cyrogenic fluids, such as heliumor hydrogen, which, in turn, will require highly effective ins

39、u-lations to keep external heat inputs minimal.As power demands in large cities increase, cooling of under-ground electrical cables will become increasingly important. Con-ventional cables buried in the soil beneath city streets requirethat the subsoil absorb the heat generated within the cable andc

40、onduct it away at a rate sufficient to prevent overheating ofthe cables. With increased power requirements, this natural heattransfer is inadequate. Therefore cooling of electrical cables withfluids such as oil, Freon, nitrogen, hydrogen, or helium is beingconsidered. Such coolants will require the

41、installation of under-ground insulated fluid lines to maintain the desired temperaturesin the cables.r 7: -w- r _ - U“- r v-r- v_ _re- ,r-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-APPLICATIONS OF THERMAL INSULATIONSElectronic EquipmentThe maint

42、enance of low temperatures to diminish noise inelectronic devices such as communication antennas has consid-erable practical importance. To minimize the refrigeration re-quired to keep such devices at the desired low operating tem-peratures, effective thermal insulations, usually of the multilayerty

43、pe, have been used. In most instances the insulations are in-corporated in the overall design of the device and the associatedcooling system; one example is the cryodyne refrigerator.Effective insulations are also important in electrical devicesthat must operate over a range of temperatures and stil

44、l main-tain a closely controlled operating temperature; for example,crystal ovens which have to maintain a preset temperature evenwhen exposed to arctic environment. Multilayer insulations ap-plied to such ovens have reduced power requirements by a factorof 20 and at the same time have reduced the s

45、ize of the devices.A similar application for multilayer insulation was in a balloon-borne fuel cell which had to operate for extended periods of time.Thermal insulations have extended the unattended operatingperiods of remotely located instruments that rely on batterypower to control and maintain th

46、e desired operating tempera-ture. Examples include batteries designed for arctic use, gravim-eters for geophysica,1 explorations, oceanographic instrumentsplaced at great depths, and balloon-borne meteorological instru-ments.Manufacturing ProcessesIn manufacturing plants, the steadily increasing use

47、 of cryo-genic fluids has brought about the need for insulation of largestorage tanks and pipelines. Oxygen is used in a newly developedsteelmaking process. Uses of liquid nitrogen include the stiffen-ing of organic materials (e.g., rubber) to permit precise machin-ing and the cryogenic forming of m

48、etals to achieve high strength.In the future, liquid nitrogen also may be used to prepare scrapmetal for pulverization by cooling it to the low temperatures atwhich it becomes brittle.The use of liquid helium in manufacturing processes has in-creased since large centralized helium liquefaction plants havebeen built. Today, liquid helium rather than compressed gas isbeing used for many applications, for example, in the electronicsindustry. Shipment of helium has been made