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SUBMITTED BYNI V EDI T A KUMA R I

R A V I SH KHA N

SUNI DHI KUMA R I

DFT ( V I )

Moisture Vapor Transfer

Theor 

SUBMITTED T!" ASST# $ R! FFESER$ARNAV V!RA 

FABRI% !B&E%TIVE MEASUREMENT ASSI'NMENT

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  eat transfer

 Heat transfer is the study of energymovement in the form of heat which occurs

in many types of processes.  The transfer occurs from the HIGH TO THE

LOW TEMPE!T"E regions.

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Mass Transfer 

 This sort of transport of one su#stancere$ative to another ca$$ed mass transfer.

 Te%ti$es e%posed to a hot air stream may #e

coo$ed evaporative #y #$eeding waterthrough its surface.

Water vapor may condense out of damp aironto coo$ surfaces.

Heat wi$$ &ow through an air'water mi%ture inthese situations( #ut water vapor wi$$ di)usethrough air as we$$.

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Drin* of te+ti,es

*rying of te%ti$es is accomp$ished #y vapori+ingthe water and to do this the $atent heat ofvapori+ation must #e supp$ied.

 There are( thus( two important processcontro$$ing factors that enter into the process ofdrying,

-a Transfer of heat to provide the necessary

$atent heat of vapori+ation.-# Movement of water through te%ti$es and then

away from it to e)ect separation of water.

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Requirement in textiles

*rying the fa#ric or garment

/omfort to wear the garments and fa#rics

 To avoid c$inging property of garments.

Human #ody produce moisture in form ofperspiration .

It transfer to outside environment through

fa#ric .It remove heat from the #ody through fa#ric.

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 This Information is use for

Information on the transmission of watervapor #y te%ti$es 0#ers is desira#$e for #etter

understanding of the pro#$ems of11comfort factor of garments

design for fa#rics in specia$ app$ications suchas protective c$othing( upho$stery( footwear(

immersion suits.

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MVTR

 2tands for MOI2T"E 3!PO T!425E !TE

It is the rate at which moisture vapor transferthrough the fa#ric $ayers.

6reatha#$e 5a#ric, When fa#ric a$$ow to movethe water vapor at faster rate then it is ca$$ed

#reatha#$e fa#ric or #reatha#i$ity. This shou$dmore scienti0ca$$y #e referred to as water

vapor permea#i$ity.62 789: , it is method used to chec; vapors

transfer through mu$ti$ayer fa#rics.

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Human Skin

Sweat

Fabrics

If water vapor nottransfer to Out side

Environment

Increase thermalconductivity of

airFabric

 becomes

uncomf ortable

MVTR

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Hypothermia

Hypothermia, In e%treme cases hypothermiacan resu$t if the #ody $oses heat more rapid$ythan it is a#$e to produce it.

If perspiration cannot evaporate and $i

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Heat energy produced by various activities and correspondingperspiration rates

 A-ti.it /or0 rate (1atts) $erspiration rate(*23a)

Sleeping 60 !0

"entle #alking 00 $600

Sitting %00 &!00

 'ctive #alking &00 %%(00

)a*imum work rate %000+%00 &!000+,(600

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! review of c$othing studies has shown thatmoisture co$$ection in co$d weather c$othing(even after heavy e%ercise( se$dom e%ceeds=9> #y weight of added water

One of the measurements are used toca$cu$ate va$ues re$ated to water vaportransmission properties is ?water vapor

resistance?.

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Water vapor resistance

 This is the water vapor pressure di)erenceacross the two faces of the fa#ric divided #ythe heat &u% per unit area.

Moisture egain is the mass of water presente%pressed as a percentage of the dry weightof the materia$.

/otton, @'@.A >

Po$yester , 9.B>

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Typical water vapor resistance(WVR) of fabrics

5a#ric( Outer -she$$ materia$ W3-mm sti$$air

4eoprene( ru##er or P3/ coated, =999'=899

/onventiona$ P3/ coated,C99'B99

Wa%ed cotton,=999D

Woo$ overcoating, '=C

Leather ,7'@

Woven micro0#er, C'A

/$ose$y woven cotton, 8'B

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Stage III and I. /ross sections of absorbent material at different regains#

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Transport phenomena for sweat

 The two most important characteristics offa#rics are water vapor transport and heattransport.

Water vapor transport is depend on watervapor resistance.

Wic;ing , How

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Wickin

It determines how

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!onclusion

It shou$d #e noted that the overa$$ watervapor and heat transport characteristics of a

fa#ric shou$d depend on factors such as the ,

the Type of 5i#ers.

 The Porosity of fa#ric

 *ensity of te%ti$e materia$

 Thic;ness of the fa#ric - mu$ti$ayer fa#rics