1、 MIL-STD-221820 May 1992S UPERSEDINGMIL-STD- 23103A(AS)29 April 1971DEPARTMENT OF DEFENSEDESIGN CRITERIA STANDARDTHERMAL DESIGN, ANALYSIS AND TEST CRITERIAFOR AIRBORNE ELECTRONIC EQUIPMENTAMSC N/A AREA GDRQDISTRIBUTION STATEMENT A : Approved for public release; distribution is unlimited.Note: The co
2、ver page of this standard has beenchanged for administrative reasons. There are noother changes to this document.INCH-POUNDProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-sTD-2218FOREWORO1. This tnilitary standard is approved for use by al1 Depar
3、tments andAgencies of the Department of Defense.2. Beneficial comments (recommendations, additions, deletiens) and anypertinent data which may be of use in improving this document should beaddressed to: Commanding Officer, Naval Air Warfare Center AircraftOivision Lakehurst, Systems Requirements Dep
4、artment, Code SR3, Lakehurst,NJ 08733-5100 by using the self-addressed Standard izatjon DocumentImprovement Proposal (OD Form 1426) appearing at the end of this documentor by letter.3. This standard contains requirements for thermal design and coolinganalyses, thermal design verification tests and p
5、reproductionqualification tests for airborne electronic equipment. It also containsguidelines for test methods for verification testing of the thermal andcooling design, and for preproduct ion qualification temperature andhumidity tests.4. The requirements of this standard are oriented toward maximi
6、zing thereliability and minimizing the life cycle cost (LCC) of avionicsequipment by achieving component temperatures consistent with reliabi1ityand LCC goals.5. This standard is intended for use in conjunction with a detail equipmentspecification which will be used to tailor this document to fit th
7、e needsof the specific application. This document is appropriate to all phasesof an acquisition program, i.e., from concept formulation, throughdevelopment, to preproduction testing.iiProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-2218CONTEN
8、TSPARAGRAPH1.;:i1.32.2.12.1.12.1.22.23.4.4.14.24.2.14.2.24.2.34.2.3.14.2.3.24.2.3.34.2.44.2.4.14.2.4.1.14.2.4.1.24.2.4.1.34.2.4.1.44.2.4.1.54.2.4.24.2.4.2.14.2.4.2.24.2.4.2.34.2.4.2.44.2.54.2.5.14.2.5.24.2.5.34.2.64.2.74.2.84.2.94.2.104.2.114.34.3.14.3.2SCOPE Purpose Tailoring Thermal design dataAPP
9、LICABLE CIOCUMENTS .Government documents .Specifications, standards and handbooks Other Government documents, drawings, and publications .Order of precedence DEFINITIONS GENERAL REQUIREMENTS .General Thermal design requirements Cooling methods Cooling media impingement Design environment .Operating
10、Storage and non-operating Surrounding air pressure .Cooling requirements (forced cooled equipment) .Air cooled equipment .Conditioned air supply temperature .Ramair supply temperature .Airflow rate design Structural safety margin .Pressure drop Liquid cooled equipment Liquid supply temperature Liqui
11、d flow rate design Structural safety margin .Pressure drop Transient thermal requirements .Warm-up Temperature shock Temperature-altitude .Humidity requirements Ducting Air leakage Equipment heat dissipation .Thermal protection .Emergency operations .Thermal management .Thermal design and reliabilit
12、y interface .Component derating .E!w1i111:234444555:2:1:1010101010101011111111111112121212iiiProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-2218CONTENTSPARAGRAPH4.44.4.14.4.24.4.2.14.4.2.24.4.2.34.4.2.44.4.2.54.5:!5.5.15.1.15.1.25.1.35.1.45.
13、1.55.1.65.25.2.15.2.25.2.35.2.45.2.55.2.65.2.75.2.85.2.8.15.2.8.25.2.9Thermal design, cooling and overtemperature protectionanalysis .Power dissipation and component selection Analytical thermal model Component operating temperature predictions Cold plate wall temperature predictions Forced cooling
14、analysis Overtemperature sensor locations .Temperature sensitive component analysis .Thermal analysis report Thermal design verification tests Preproduction qualification tests DETAILED TEST REQUIREMENTS AND PROCEDURES Thermal design verification tests Scope Test procedures Test configuration .Tempe
15、rature measurement Ambient cooled equipment .Forced cooled equipment Preproduction qualification tests Scope . General Equipment configurati”on Humidity test Entrained water test (air cooled equipment only) .Structural safety margin .Temperature and iiltitude tests .Temperature shock tests Ambient c
16、ooled equipment .Forced cooled equipment Failure criteria .NOTES Intended use .Data requirements Subject term (key word) 1isting p,:15161717171717;171717181818181919ivProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-FIGURES12mIMIL-STD-2218CONTENTSCool
17、ina airflow rate oer kilowattEmPreliminary design guidelines for al1owable junctiontemperature 12vProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-22181. SCOPE1.1 Purpose. This standard establishes requirements for thermal designand cooling an
18、alyses, thermal design verification tests, and preproductionqualification tests for airborne electronic equipment. These thermal designrequirements are provided to ensure that the equipment wi11 operatesatisfactori1y without manual adjustment under any mode of operation in theaircraft. It also estab
19、lishes gtiidelines for test methods for verificationtesting of the thermal and cooling design and preproduct ion qualificationtemperature and humidity tests to ensure that the equipment meets itsperformance requirements and reliability criteria. This document defines athermal design process establis
20、hing and validating the following:a. Equipment cooling methods and coolant flow requirements.b. Al1owable component temperature and component power, based onderating requirements to achieve lowest component temperaturesconsistent with reliability and 1ife cycle cost (LCC) require-ments.c. A thermal
21、design analysis which defines the temperatures! heatsources, heat paths and heat sinks of all temperature criticalcomponents for worst-case power, environmental temperature-altitude and coolant flow (where applicable) conditions.d. Thermal design, verification and preproduction qualificationtests.1.
22、2 Tailorinq. Application of this document is via tailoring.Department of Defense (000) policy is to selectively apply and tailorstandardization documents to ensure their cost-effective use in theacquisition process. Individual requirements (sections, paragraphs orsentences) shall be evaluated to det
23、ermine the extent to which they are mostsuitable for a specific acquisition and the modification of these requirementsto ensure that each achieves an optimal balance between needs and cost.Tailoring of data requirements consists only of the exclusion of thosesections, paragraphs or sentences in an a
24、pproved documents informationrequirement or Oata Item Oescription (OID). Each program office shouldcarefully consider within 000 and Service guidelines, the benefits and costsof imposing thi-sstandard on each specific acquisition. Contractors maypropose specific application and tailoring of this doc
25、ument and relatedinformation requirements (010s, etc.) as specified in 6.1.1.3 Thermal desiqn data. Oata associated with compliance to thisstandard shal1 be in accordance with 4.5 and 6.2.2. APPLICABLE DOCUMENTS2.1 Government documents.2.1.1 Specifications. standards and handbooks. The following spe
26、cifica-tions, standards and handbooks form a part of this document to the extentspecified herein. Unless otherwise specified, the issues of these documentsare those 1isted in the issue of the Department of Oefense Index of Specifica-tions and Standards (DODISS) and supplement thereto, cited in the s
27、olicitation.1Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-2218SPECIFICATIONSMILITARYMIL-E-5400MIL-T-18303STANOAROSMILITARYMIL-STD-454MIL-STO-785MIL-STO-810Electronic Equipment, Aerospace, GeneralSpecification forTest Procedures; Preproduct
28、ion, Acceptance, andLife for Aircraft Electronic Equipment, FormatforStandard General Requirements for ElectronicEquipmentReliabi1ity Program for Systems and EquipmentDevelopment and ProductionEnvironmental Test Methods and EngineeringGuidelinesHANDBOOKSMILITARYMIL-HOBK-217 Reliability Prediction of
29、 Electronic EquipmentMIL-HOBK-251 Reliability/Design Thermal Applications(Unless otherwise indicated, copies of federal and military specifications,standards and handbooks are available from the 000SSP Standardization DocumentOrder Oesk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19111 -5094.
30、)2.1.2 . Thefol1owing other Government documents, drawings, and publications form a partof this document to the extent specified herein. Unless otherwise specified,the issues are those cited in the solicitation.PUBLICATIONSNAVMAT P 4855-1 Navy Power Supply Reliability Design and Manu-facturing Guide
31、lines, December 1982(Copies of the NAVMAT publication are available from DODSSP StandardizationDocument Order Desk, 700 Robbins Avenue, Building 40, Philadelphia, PA19111-5094.)2.2 Order of Isrecedence. In the event of a conflict between the text ofthis standard and the references cited herein, the
32、text of this standard shalltake precedence. Nothing in this standard, however, supersedes applicablelaws and regulations unless a specific exemption has been obtained.2Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-22183. DEFINITIONS3.1 The
33、following definitions shall apply:a.b.c.d.e.f.9.h.i.j.k.Abnormal operation - Al1 electronic equipment and devices arebeing operated through their normal duty cycles at maximumsupply voltages with,a loss of coolant or an increase in ambienttemperature or both for short periods of time not exceeding 1
34、0minutes.Adiabatic conduction interface - No heat transfer bettibencontacting surfaces.Ambient cooled equipment - Ambient cooled equipment dissipatesits heat to its ambient environment (without venti1ation inducedby the vehicle). Equipment containing fans or blowers tocirculate ambient air through t
35、he unit shall be classified asambient cooled.Ambient temperature - Ambient temperature is the temperatureimmediately surrounding the equipment.Component - A piece-part used in the production of an electronicsubsystem, such as an integrated microcircuit, diode,transistor, capacitor, flat pack, resist
36、or, relay, switch,transformer, etc.Continuous operation - A steady state condition under normaloperation.Design flow rate - Design flow rate is the minimum flow ratenecessary to maintain all components within the unit atspecified temperature requirements.Detail equipment specification - A specificat
37、ion thatestablishes the performance, design, development, instal1ation,test and demonstration requirements for the equipment and setsforth operational and environmental requirements for theequipment appropriate for its intended use.Forced (external1y) cooled equipment - Forced cooled equipmentis tha
38、t equipment designed to be cooled by gas, including airand ram air, or liquid, supplied by the aircraft vehiclesubsystems with sufficient pressure to flow through the unit andremove the dissipated heat.Ground operation - A normal operating condition at sea levelambient temperature and pressure.Inter
39、mittent operation - A transient condition. An abnormaloperating condition in which the characteristics of the ambienttemperature and external cooling provisions (if any) change fora specified period of time as specified in MIL-E-5400. Allelectronic components are being operated through their normald
40、uty cycles at nominal supply voltages.3Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-1.m.n.o.P.q-r.4. GENERALMIL-STD-2218Normal operation - Al1 electronic equipment and devices arebeing operated through their normal duty cycles at nominalsupply vol
41、tages.Sea level ambient pressure and temperature - Sea level ambientpressure is defined as 14.7 Esia + 5 percent. Sea level ambienttemperature is defined as 59 F f F (15C tlC).Stabi1ization - A stabi1ized thermal condition has been attainedwhen the indicated temperature of the”component with the 1ar
42、gestthermal time constant varies at a rate less than 3.6F (2”c) perhour.Standby operation - A steady state condition in which someelectrical power is continuously applied to some or al1,devicesand components.Start-up operation - A transient condition. Prior to start-up,all electronic components and
43、devices, and any external coolingprovisions, are shut off. In start-up operation al1 electroniccomponents and devices are being operated through their normalduty cycles at nominal supply voltages. The end of start-upoperation occurs when steady state conditions exist.Thermodynamicc requirements - Th
44、ermodynamicc requirements are theelectronic equipment ambient and component temperature, pressureand water content and, where applicable, the coolanttemperature, pressure drop, flow rate and water content.Water balance - Water balance is a mass conservation balance onall water entering and leaving t
45、he test system.REQUIREMENTS4.1 General . Time, temperature, moisture content, pressure altitudes,class deflnltlon and percentages 1isted herein are default values and shouldbe changed to be compatible to the envelope and cooling system of the aircraftin which the equipment will be installed as speci
46、fied by the detail equipmentspecification.4.2 Thermal desiqn requirements.4.2.1 Coolinq methods. It shall be analytically or experimentallydetermined if the equipment should be ambient cooled or forced cooled basedupon the ability of the cooling method to satisfy component temperature andreliability
47、 criteria. Single node analytical modeling is not sufficient. Allequipment shall, if practicable, be designed to be cooled by free convectionand radiation for the ambient conditions defined by the detail equipmentspecification. Airborne electronic equipment which is not amenable to ambientcooling sh
48、all be designed to be forced cooled with air supplied from theaircraft environmental control system. If cooling with air supplied from theaircraft environmental control system is not possible, alternate methods shal1be pursued. All analytical and experimental data determining the requirementsfor env
49、ironmental control system air cooling or alternate methods such asliquid, evaporative, change of phase material! heat pipes, or ram air shall besubmitted to the acquisition activity for review and approval. The selection4Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-2218of the cooling method shall be part of, and integrated
