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RELEASE INTO THE SPACE OF EXCESS HEATTIT T =TT r- '- TF n TY F rIT ITT k T.Tr-T r T ITre

IN inHE rSPTIVE Hi rhL POWE1 PLATS

I.G.Panevin*, B.N.Baushev**, A.A.Koroteev**

Mo sco, w A o,', i nt/-_ itut Ru,'

Analysis of publications shows that the term "advanced power

plants" may refer to the following power plants (PP): high-powersteam turbine or gas turbine power plants (like SNAP-50),

j medium-range nuclear PP with thermionic or thermoelectric

conversion (like "Topaz" or SP-100) as well as some other types ofPP (for example, solar PP with energy concentrators).

For excessive power rejection into space from space powerplants (SPP) or thermal control systems of spacecraft (S/C) ortheir life support systems conventional radiators are used.flow-through radiators (finned tubes through which a liquid or

gaseous heat carrier flows) or heat pipes operating in autonomousmode.

The radiator inlet temperature may vary from T = 300 to 1200K The radiator specific mass dependence from Tb for conventionalradiators (both, in-use and advanced) was derived from thef American da a and is shown on Fig.l.

Mm :(T), mb - C-T4

This cependence is described by the formula:

b 1.3-101 T-4 (kg.T 4 ) kW,

w';icr means that ;he radiator mass Der 1 m2 ::DnsL: tutesa:.r :-imaely 1i-. : :': t.he entire emperacure range

:n act icr.. ::.;.tlial radia-:rs are sens-i: .'e to che

r t: e Ic ye.:'s somTe advanced racia or ,. like

- -3 - - deveL: ;ere be . DSrse'ch :s be:: c,::e s::al ly n :.e USA and in i:' ccurtrym -er [1: -;iea ;';-:: ;:-er: fundaren als and calcul ..- ion r.e-. hods

SDSR .in cr .is-para-.eer ceer.*eencies which ;ere developedb. gereralizing the uf.erical calcuiaLon results ob-.aiied at MAI.

SThese calcaafions, as well as the data from cther authors,

i

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indicate that the DSR specific mass (mb ) may be 1.5-2 (or evenmore) times less than that of conventional radiators

Besides, DSR are practically 100% meteor-proof. Here afterthere are presented some theoretical materials from [1] andexperimental data on droplet generation with jet nozzles obtainedat MAI.

A DSR scheme is given on Fig.2 with general designations. Thefollowing parameters are introduced:

Droplet concentration:

nr = 1 /b3 = 1/d3z , where z = b/ d

Droplet micro and macro cross-sections:

r, = fnV , Er = nro

- prcportionality factor according to the Mie theory.The stream albedo:

a, c

: 1- r

craracterizes the flow optical properties..me stream optical thickness:

r

Droplet stream transparencyv at the stream optical thickness betngS> . : is

Kb = Qb/Q, =0)

which is determined from numerical calculations (Fig.3).A DSR parameter is introduced:

'I"b '

18 c e T3

where P = r = ' KLPr Ln rr a o

Tnis para:e:er allows t calculate both c ically :ra: ren.= ; and non-Lranspare:. (< r) droolet flo,:s

(F X )

T= 2 = (P + 1)-2

radiator's efficiency:

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3 (1 7 2

71 T - 1 _2

radiiating power:

Q G*Cpr(TI T T2

mass of droplets In the stream:

b r r5dropletL speci-fic mass: rd

~r dr7b

toe eoeiene T _I- r ant P and - : fr7 snown3 2

erpe Le~r~ :~ s in the stream a' dif fere,,t.Idstances X >; frm te dropie- glenerator for- r: 1are preseltc"

co, pre .ners~v calo te a DS':aa&bult-rary vr cc2& t- S

Th-e dromlet vaporab ility depends c - h va o r e as ~I 'I

p. =f(Tr), dr and DSR operazion time t.

nhe evapora-x.r.D mass rate is:

P n

n nThe relt Lvmss evoporated liquid is:

AM - m n g tun3 ForI leod PYwt year and dr 2r Cr r 'D. D2m

7t r%. AM 145.> and 14-Q

C, A C S P- 1 7 e e1

Experimental study of droplet generation.

mSquare-edged I nlet nozzles wi th c yl Ind r ic al Channels of-

lengath 1 and diameter d a were uIsed.

Ia

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b~i'II :v ~suire lsse.~ doe to? I~;U.:: u. al exhol!os lOwer han the theor e:.I

C)S n= 2 Ap .

o character1ze the nozzle operatin the ve Iocity d' r

UTI , et narrowing coefficient anda Inczzle mass flow rate coefficient

Ga - = cp are introduced. I:; etc es p1 - 0.8; c = . . 8.

11oeZ 1- a detachment flow f Is -rV2'e 3£ - o~ , = i . = 6c 0 6 4I

cj~ D8U_~c thd a t In case of I jet

DC he case woen . . U a:lc dc

* . o er,

T § is >.. . . VacU-7d . s> .s j,.. -- l 3

21 .. .r- SUJ-eU- OlaF et' r U 0 3 mm. to:> wr'- t fre

r C , i* 0 apsp %'er 1- ;"e

-. c.,..., ' -n

1 77

u ! a. a.. . . -. e

u -e r c ..?A

e ~e n QTE-eI x d e- rip*-: r"ee......... . <cam3 ~ clareter c 3 tic. rate As Il

!~i_ ::~. ;i. j13 ::r.~Sa~: 1F ;~/elni~t ~ e~r ~~ _~~-.!i~ ~cC

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free collapse A = 4.5 d ):U decrease both the liquid volume per droplet and the (roplet size:

dr = d J1.5d

U 1where A - - -- --

c C

This relationship was proven experimentally. The collapsing

length for solid streams is much less than the DSR length L.

IReferences:

11. I.G Panevin. High-temperature heat exchangers for spacecraft

power plants (theory and calculations of droplet-stream radiators,

(in Russian). Moscow, MAI Publishing House, 199C 62 pages.

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