Leavitt - Do Water Arc Explosions Release Internal Water Energy - 2013

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Do water arc explosions release internal water energy? If so, what is

the source of the released energy?

Tucker Leavitt

Senior Project Advisor: Steve Smith

12thGrade Humanities

Animas High School

22 April 2013


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Section I: Abstract and Research Motivation

Abstract

This paper presents the results of an investigation into the phenomenon of !ater arc

e"plosions#$ in !hich an electrical arc is used to trigger the violent e"pansion of a small amount

of !ater% Prior research has suggested that firing a high&current pulse through li'uid !ater

releases energ( stored !ithin the !ater% This manifests as )inetic energ( and results in a verita*le

e"plosion# tearing the !ater apart into tin( fog droplets% +mpirical measurements have sho!n

that the e"plosions are much stronger than e"pected and that an e"plosion,s )inetic energ( can

even e"ceed the electrical energ( of the pulse that initiates it% -either the source of the

e"plosions, energ( nor the mechanism *( !hich it is released is !ell understood%

The purpose of this project !as to verif( that stored potential energ( is li*erated during a

!ater arc e"plosion and to determine the nature and source of this li*erated energ(% .ater

e"plosions !ere created *( discharging a high&voltage capacitor *an) through 3&/ m of !ater%

The e"plosions, energies !ere measured *( using them to launch a projectile into the air and

e"trapolating the e"plosion,s average velocit( from the height to !hich the projectile ascended%

t !as found that !ater e"plosions do in fact release energ( and can have efficiencies of greater

than unit( the energ( released during the e"plosions is li)el( due to the difference *et!een the

heat capacities of *ul) !ater and fog% These results allude to the possi*ilit( of harnessing !ater

e"plosions to perform useful !or)%

Research Motivation:

A *etter understanding of !ater arc e"plosions and their causes ma( pave the !a( for the

development of a novel ne! rene!a*le energ( source% Several recent papers Hatha!a( et al%#


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1445 Hatha!a( et al%# 144/ Graneau et al%# 20006 have reported that rapidl( dissociating li'uid

!ater into tin( fog droplets using a high&current# high&voltage pulse can release energ( stored

!ithin the !ater% The released energ( is supposedl( made up *( atmospheric heat & that is#

essentiall( *( solar energ($ !hen the fog droplets re&agglomerate into *ul) !ater Graneau et

al%# 2000# p% 1156% .ater e"plosions could therefore represent a method of converting

atmospheric heat into directed )inetic energ(# and since the e"plosions do not alter the !ater

chemicall( Hatha!a( et al%# 1445 Graneau et al%# 20006# the conversion process !ould *e

rene!a*le% The prospect of harnessing clean# rene!a*le *ond energ( in !ater is certainl(

note!orth(# especiall( since the !orld,s car*onaceous energ( resources are finite and their

consumption is harmful to the environment%


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Section II: Historical Context

n 2000# ph(sicist Peter Graneau of -ortheastern 8niversit( pu*lished several

e"traordinar( findings on !ater arc e"plosions% His paper# titled Arc&i*erated 9hemical

+nerg( +"ceeds +lectrical nput +nerg(#$ presents evidence demonstrating that the )inetic

energ( of a !ater arc e"plosion can e"ceed the electrical energ( of the current pulse used to

initiate it Graneau et al%# 20006% These unanticipated results# if accurate# clearl( re'uire that the

e"plosions release internal !ater energ(%

To create a !ater arc e"plosion# a short# high&current pulse# on the order of several

)iloamps over a duration of a fe! microseconds# is shot through a small 'uantit( of !ater# !hich

is usuall(# *ut not necessaril(# distilled% The pulse imparts )inetic energ( to the !ater and results

in a verita*le e"plosion% Previous research Graneau et al%# 2000 Hatha!a( and Graneau# 144/6

has sho!n that the !ater is ionied and torn into tin( fog droplets 1&100 ;m in diameter6 during

the e"plosion process%

ittle research on !ater arc e"plosions and their energ( efficiencies has *een done since

Graneau,s 2000 paper# and no independent e"perimenters have (et confirmed Graneau,s results%

This paper presents a more in&depth anal(sis of the input and output energies of !ater arc

e"plosions# providing needed accreditation for Graneau,s results% Additionall(# this paper

proposes a theor( on the source of the energ( released during a !ater e"plosion and presents

e"perimental evidence supporting this theor(%


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amount of li'uid !ater is dissociated into fog# the fog must release energ( previousl( stored as

heat in the li'uid !ater%

The amount of energ( released is proportional to the difference in the heat capacities of

the !ater and fog% Procedurall(# this energ( + can *e calculated for a unit mass of !ater as

!here T is the !ater,s a*solute temperature and 9P and 9Pare the specific heat

capacities of li'uid !ater and fog# respectivel(% Tag 14/06 presents a more thorough discussion

of this relationship%

t is li)el( that onl( a small part of + contri*utes to the e"plosion )inetic energ( the

remainder !ould *e dissipated as heat to the environment%

This energ( + should also *e released !hen !ater is vaporied% n this case# the released

energ( !ould *e undetecta*le since it is small compared to the latent heat the !ater a*sor*s as it

evaporates% Ho!ever# it ma( also *e possi*le to li*erate + !ithout needing to suppl( the full

latent heat using directional i%e% non&thermal6 forces# such as those induced *( the high&current

arc in a !ater e"plosion% Here# the !ater is not vaporied it is merel( converted to fog6# *ut its

specific heat capacit( is still reduced Stretton# 20076% ?( this reasoning# there should *e a fog

droplet sie that ma"imies the released energ( *( *alancing the droplets, decreased heat

capacit( !ith their increased surface tension energ( related to the *rea)ing of intermolecular

*onds !hich is e'uivalent to the latent heat of vaporiation6% uture efforts to optimie a !ater

e"plosion,s output energ( might see) to achieve this optimal droplet sie%

f e'uation 56 is the reason for !ater arc e"plosions, high energies# then the energ(

released during an e"plosion should *e directl( proportional to the !ater,s temperature% igures

7 and < e"hi*it such a direct relationship *et!een e"plosion energ( and temperature# at least


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until a*out 30 N9% A*ove 30 N9# the !ater evaporated readil( !hile the capacitor *an) !as

charging and condensation could *e o*served around the sides of the accelerator *arrel% f

e'uation 56 governs !ater e"plosion *ehavior# greater evaporation !ould decrease e"plosion

strength# as the evaporation !ould dissipate stored energ( that could other!ise have contri*uted

to the !ater e"plosion% urther e"perimentation that controls for evaporation is needed to

determine the relationship *et!een e"plosion strength and temperature at higher !ater

temperatures%

Fn a molecular level# the release of energ( during a !ater e"plosion can *e understood as

a reorganiation of the !ater,s h(drogen *onding net!or)% nelastic neutron scattering

e"periments have revealed the e"istence of t!o different )inds of h(drogen *onds in !ater# each

*ond !ith a different strength i and oss# 14436% The strong$ and !ea)$ *onds have

vi*rational force constants of 32 me and 27 me# respectivel(# and e"ist in !ater in a strong&to&

!ea) ratio of a*out 2:1 Graneau# 144/6% Juring an e"plosion event# forces associated !ith the

high&current arc discharge tear the !ater into fog droplets% This consumes a certain amount of

mechanical energ(# !hich is stored as additional surface tension energ( in the fog% Ho!ever# the

molecules in the fog droplets no! have significantl( fe!er neigh*ors than the( did in the *ul)

!ater and can more easil( reorient themselves into lo!er energ( states% Thus# !ea) h(drogen

*onds can reform into strong h(drogen *onds# and an der .aals attractions can collapse into

!ea) h(drogen *onds% This *ond reformation !ould# of course# release energ(# and could

conceiva*l( suppl( the )inetic energ( of a !ater e"plosion%

or a !ater e"plosion to release potential *ond energ(# as descri*ed a*ove# the post&

e"plosion fog must *e in a lo!er&energ( state than the pre&e"plosion !ater% The fog should then

a*sor* heat as it agglomerates *ac) into *ul) !ater% oo)ing at the last three columns of Ta*le 2#


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one can see that this is the case% or each shot measured# the thermal energ( of the !aterK*alsa&

!oodKtemperature&pro*e s(stem decreased significantl( over the course of the e"plosion event%

The difference *et!een the initial and final thermal energies !as a*out =< > on average# !hich is

sufficientl( large to account for the e"plosion )inetic energies reported in Ta*le 1% Ff course#

since not all the e"ploded fog !as captured in the *alsa !ood a*sor*er in an( of the shots

summaried in Ta*le 2# each reported value for O underestimates the total heat a*sor*ed *( the

fog upon reforming into !ater%

t is possi*le that evaporative cooling is partiall( responsi*le for the lo! values Tfseen in

Ta*le 2% Ho!ever# the evaporation of !ater from the *alsa !ood a*sor*er is thought to have *een

negligi*le !hile data !as *eing collected since the a*sor*er,s mass did not decrease significantl(

!hile its temperature !as *eing measured%

Since there is energ( released during a !ater arc e"plosion# it ma( *e practical to harness

the e"plosions to perform useful !or)% Fne could conceiva*l( create a !ater e"plosion engine$

*( replacing the gasoline e"plosions in an internal com*ustion engine !ith !ater e"plosions% The

engine !ould not produce car*on dio"ide or an( comple" h(drocar*ons# and ma( *e more

efficient than its petroleum&*urning counterparts%

.ater e"plosions ma( also *e used to drive magnetoh(drod(namic @HJ6 generators

and directl( produce electrical po!er% The generator,s electrical output energ( could e"ceed the

electrical input energ( if high enough efficiencies !ere achieved%

t ma( also *e possi*le to create a jet propulsion s(stem using !ater e"plosions% ?(

mounting an e"plosion cham*er on the *ac) of a *oat# su*marine# or similar vessel# so that !ater

from the surroundings can flo! freel( through the cham*er# the vessel could *e propelled

through the !ater *( the for!ard thrust from an e"plosion in the cham*er% The device !ould


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!or) much li)e a jet engine or @HJ propulsor# and ma( prove to *e more efficient than either of

these since the !ater itself !ould contri*ute energ( to the s(stem%

The creation of a device for harnessing the energ( of a !ater e"plosion is *e(ond the

scope of this project% Jesigning and testing such a device !ould *e a !orth!hile topic for future

research%


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.or)s 9ited

?arros# S% 20026% .ater atomiation *( high magnitude electrical impulses: a stud(%

nPowerLabs% etrieved >ul( 3# 2011

Graneau# -% 144/6% The anomalous strength of cold fog e"plosions caused *( high current !ater

arcs%IEEE# 70B1&70B3%

Graneau# -% -%# erdoold# S% S%# Fuda))er# G% G%# Qurteri# 9% 8%# R @arijnissen# >% @% 20116%

ene!a*le energ( li*eration *( nonthermal intermolecular *ond dissociation in !ater

and ethanol% >ournal Ff Applied Ph(sics# 10436# 03740/%

Graneau# -%# erdoold# S%# Fuda))er# G%# Qurteri# 9%# R @arijnissen# >% 2012# Septem*er 2


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i# >% R oss# J% L% 14436% +vidence for t!o )inds of h(drogen *ond in ice%'ature%

doi:10%103/B35une 236% Fn the diagnosis and conservation of energ( during

condensation%Journal of the t#ospheric *ciences# %# 237=&23

Documents

Leavitt - Do Water Arc Explosions Release Internal Water Energy - 2013