chemical physics of discharges - Argonne National Laboratory

+xiip.ni +xmi.ng ca iscity of trie appai,atus after W-LiCii, tile
Ti. ?.I.. e b::s reducer:,'.p;- chaibing the electrode area
r .to, give a .f.urther-.reauc!,ion in product residence
t.irJiei. %'i+ly a d.C. '. paral'lel electroae react& was we'd '.
in ,:w,yicn t.le discharge waveform characteristicg;,werd
altered'. so that only a s:iort activating pulse.; was 'supplidd
, to 'the reactarit in tne eiectrode gap as it passed throqh;,
.. . the ., reaat,or.
,in .a:
flowing gas train. Commercially 'pure amon5d.uas fed ihto
the raeasurinf. section of the ap::aratus via a'reduction
valve, &d- a reigxlating needle .vzlve. The flow rjte: was '.
measured on a rotaJ:ieter wriich had been previsusly calibrated
under operating coilditions by us- a soap film manometer.
Gas te:.lperatures an6. 1.ressures.. also were uie:?.sL.red before the
dischar,,;e reactor. The hycirazine formed in t iie discharge
was absorbed in ethylerie glycol either in situ or in a
separate absorrition trLin. Hydrazine was determined using
the spectrophoiietric method of' W a t t ' and 'cLr?sp (11).
Vacuum control. 'was acuie'ved by a Cartesian manostat located
..
before the 'vacuuh-.puunp.-
The A.C. radio frequency power (1.2meg c/s) to-the
A- and B-type reactors was supplied by a modified C-12
Radyne generator -of law rated output. 3easurement of the
power dissipat,e.d.. in the. aischarge was acnieved by firstly
'.determining t.h,e, power factor directly. on%uitable osc.il10-
'sc3pe. This value in conjunction with the direct
-readings of an X.iG.S. voltmeter (Airmec 314) and a radio '
. frequency ammeter- (.Cambriuge , Unipivot ) . enabled a reasonably
accurate .d,etermination of the power in the discharge .to be
-achieved. The D.C. power for the C-type reactor was
provided by a specially engineered 8KW generator. Measure- .
:merit of the'actual discharge power was made using a
,combination of an oscilloscope trace and the appropriate
meter .r.eadinga.' , . . ,
The vaxioue types of diqcharke reactors used 'in this
work are illustrated schen&%ically in Fig.1. Other essent.ia1
geopetric details of these reactors and their operating data
are given In Table 1. The A-type seriqs of reactors
consisted of a precision silica tube (which acted as the
capacitive barrier) with the high tension electrode attached.
wound the outeide. The inper electrode was a spinning
cylinder so constructed that ,absorbent liqukd could be
eprayed onto the ineide of the tube to flow-down through the
m,ular diecharge gap. Co-current gas and liquid flow was
'. 'reactor 'set brtueen measur mg and analysing sec%,i.ons
: , -;'
\ ..
The apparatus conshod esse:;tially of t-b discharge , : '
employed; : . .
The B-type eerie6 of reactors were of -similar. conetruction
except tllat a central wire electrode vae used and the
absorbent liquid was fed into the incornin@; gas a8 a epray.
Dieperpion of, the liquid vas, achieyed ylt,raeonically using a
vibratory gemrator. The apray was fed into fhe kae atream
through on annular orifice placed at a euffieient dietanbe
, ,, _. ..
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