Development of a thermal diode heat pipe for the advanced thermal control flight experiment /ATFE/

Swerdling, B.; Kosson, R.; Urkowitz, M.; Kirkpatrick, John P.

doi:10.2514/6.1972-260

Cited by 7 publications

(17 citation statements)

References 1 publication

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“…The 6°C gradient between the PCM and the diode transport section (T-002) indicates that the diode is fully shut off, with liquid blockage extending through the "low-k" and at least part of the transport section [1]. The -55°C temperature in the FCHIP transport (T-005), and the 82°C gradient between it and the PCM is indicative of gas blockage back into the FCHP evaporator.…”

Section: Flight Performancementioning

confidence: 98%

ATS-6 Flight Performance of the Advanced Thermal Control Flight Experiment

Kirkpatrick

Brennan²

1975

IEEE Trans. Aerosp. Electron. Syst.

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The Advanced Thermal Control Flight Experiment (ATFE) was launched aboard the Applications Technology Satellite-6 (ATS-6) on May 30, 1974. ATFE is designed to demonstrate the thermal control capability of a thermal diode (one-way) heat pipe, a feedbackcontrolled variable conductance heat pipe (FCHP) and a phasechange material (PCM). The experiment has been in almost continuous operation since launch. Flight data for the different operational modes are compared to ground-test data, and the performance of the individual components is analyzed. The system's performance with and without feedback control is also compared. Finally, the ATFE's behavior from launch through May 31, 1975, is presented.All thermal control components are performing as predicted for the existing flight environment. However, the daily reservoir and radiator temperatures during peak solar input are greater than those experienced in the ground acceptance tests. These increased temperatures have resulted in a loss of control by the FCHP for several hours around the period of maximum insolation. The higher temperatures are apparently due to contamination and/or degradation of the second surface mirrors which cover the reservoir and radiator.The Advanced Thermal Control Flight Experiment (ATFE) is providing the first zero-g flight data for the performance of a thermal diode heat pipe [9] and an electrical feedback-controlled heat pipe [6]1. The temperature stability derived from the melting and freezing of octadecane is also being evaluated. Experiment ObjectivesThe ATFE is designed to demonstrate the thermal control capability of a thermal diode (one-way) heat pipe, a phase-change material (PCM) for thermal storage, and a feedback-controlled variable conductance heat pipe (FCHP). The experiment permits evaluation of these components on an individual basis and as an integrated temperature-control system. In addition to developing flight-qualified hardware for future thermal control applications, specific ATFE performance objectives were as follows.1) Thermal diode: Demonstrate reverse-mode diode operation (determine shutdown energy and OFF conductance), determine effect of zero-g environment on diode shutdown characteristics, and demonstrate forward-mode heat pipe operation (determine forward-mode thermal conductance).2) Phase-change material: Demonstrate temperature stability derived from melting and freezing of a PCM, determinie the stability of the melting and freezing points in the zero-g environment, and evaluate the effect of the zero-g environment on the thermal conductance of the PCM package.3) Feedback-controlled heat pipe: Demonstrate the ability of the FCHP to provide temperature stability with variations in heat load and effective sink temperature, demonstrate the ability of the FCHP to perform as an ON/OFF thermal switch, and establish its variable conductance behavior in flight. Experiment Description

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Section: Flight Performancementioning

confidence: 98%

ATS-6 Flight Performance of the Advanced Thermal Control Flight Experiment

Kirkpatrick

Brennan²

1975

IEEE Trans. Aerosp. Electron. Syst.

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“…These are defined o n m n = J^ o) n G(o>) do) (1) for a bandwidth lying between any two frequencies wi and o)o(cjDi<o)o). Whitehouse and Archard 14 have shown that the profiles of many engineering surfaces have exponentially decaying autocorrelation functions, whose corresponding power spectral density function is 6(w ) = 4aa 2 /(a 2 +u> 2 ) (2) where a is the rms roughness and (a) is the constant of decay of the autocorrelation function.…”

Section: Theorymentioning

confidence: 99%

“…The asperities responsible for these contacts will be so large that we can presume that all of the asperities of this size will be in contact; i.e., the summit density D (the number of summits per unit area) will be equal to the contour area density: D = 3/(ird 2 /4) (6) The summit density is related to the moments by15 D = (1/67T/3) mii/nfc (7) Now, from Eqs. (4) and (5), !ll = a 2 (ft 3 /3 -ft+ tan" 1 ft) (8) ra 2 ft-tan" 1 …”

Section: Theorymentioning

confidence: 99%

“…If the resulting radius of curvature exceeds appreciably the length of the specimen, the contact face will take up approximately the same curvature as the elemental disk. The curvature at the interface is then given by the expression 1/P = q (ot/k) (1) If two specimens of different a/k ratios are in contact under an infinitesimally small holding load and subjected to an axial heat flux, then the magnitude of the interfacial gap at any radial position may be expressed as -! !i\ (2) I L-V / 2 for a peripheral contact due to a heat flux from material 1 to material 2 where Ot 1 /k 1 > a 2 /k 2 , and…”

Section: Theoretical Analysismentioning

confidence: 99%

“…When a set of resistance measurements is interpreted in terms of a change of dominant bandwidth from waviness to roughness, the transition point agrees well with theory. Nomenclature A = autocorrelation function decay constant of protosurface a = decay constant of exponential autocorrelation function b = flow channel radius D = area density of summits d = diameter of nominal contact area E = elastic modulus E 1 = Hertzian elastic modulus G(o)) = power spectral density function k = harmonic mean thermal conductivity of contacting solids…”

Section: XIImentioning

confidence: 99%

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Heat Transfer with Thermal Control Applications

Yovanovich¹,

Aiaa²

1975

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XIVcritical locations on space shuttle orbiter-type vehicles. Schneider has developed a general correlation for section weight of passive and ablative insulators used in mild aerodynamic heating environments. Performance of ablator materials in ramjet environments is the subject of the last paper by Cohen, Couch, and Murrin.A number of individuals played key roles during the preparation of this volume, and to them I owe a debt of gratitude. AbstractThe nature of thermal rectification which occurs at certain contacts due to induced thermal stresses has been investigated. The distortions produced are not only detrimental to joint conductance but also frustrate the design of thermally predictable assemblies. The analyses presented indicate the factors that must be considered when the intention is to produce a joint with high heat-transfer characteristics and low local stresses. The study has highlighted the pitfalls that can be encountered unknowingly by measuring techniques. Where necessary, experimental evidence is presented to corroborate the presented theory. Nomenclature a = radius of a microcontact, ym c = radius distinguishing contact and noncontact regions,m g( ) = constriction alleviation factor g f ( ) = first derivative of g( ) i= index relating to heat flow direction k = thermal conductivity, wnT 1 K" 1 Abstract Conduction shape factors for a disk on an insulated half-space with arbitrary surface heat flux prescribed have been calculated. The solution of the differential equation was obtained by formulating the problem numerically in the oblate spheroidal coordinate system. The uniform heat flux case and that corresponding to a uniform disk temperature were solved to test the stability and convergence of the numerical solution scheme. Dimensionless resistances were found to be 0.2716 and 0.2507, respectively, which agree to within 1/2% of the analytically known values. In both cases a 40 x 20 grid was chosen,and solutions converged uniformly to the stated accuracy in less than 50 sec IBM 360/75 computing time. Five additional cases were run^and dimensionless resistance values were obtained which lie above and below the bounds formed by the two classical solutions cited previously* Abstract This paper describes the equipment, procedure, and results of an experimental investigation on the overall thermal resistance of sphere-flat contacts. Two spherical specimens having diameters of 1 and 2 in. in elastic contact with relatively smooth flats were examined. Tests were conducted with air and argon, pressures ranging from atmospheric conditions to 10~5 mm jjg. The effect of a lubricant, with and without air present, also was studied. Mechanical loads were varied from 3.6 to 160 Ib, thereby producing contact radii varying from 4.34 x 10"3 to 1.53 x 1CT 2 in. The experimental results are in good agreement with the theory previously published by these authors. AbstractAn analysis is presented for predicting the local contact conductance of a woven metallic wire screen contacting two smooth solids under vacuum co...

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