Energy saving using heat exchangers covered with porous coatings (Oszczędność energii przez zastosowanie wymienników ciepła z pokryciem porowatym)

&UDFRZ3RODQG

HPDLOWPZRMFLN#DJKHGXSO

ENERGY SAVING USING HEAT EXCHANGERS

COVERED WITH POROUS COATINGS

A b s t r a c t

([SORLWDWLRQRIWHFKQLFDOGHYLFHVLVDOZD\VUHODWHGWRWKHHQHUJ\FRQVXPSWLRQ7KXVLIPRUHHI¿FLHQWKHDWH[FKDQJHUVDUH used as part of mechanical systems, it is possible to save energy. The paper presents possible ways of producing more HI¿FLHQWKHDWWUDQVIHUVXUIDFHVZRUNLQJXQGHUWKHQXFOHDWHERLOLQJPRGH:KHQSRURXVFRYHULQJVDUHXVHGVLJQL¿FDQW UHGXFWLRQRIWHPSHUDWXUHGLIIHUHQFHVLVQRWLFHGDWWKHVDPHKHDWÀX[,WOHDGVWRKLJKHUHQHUJ\HI¿FLHQF\

Keywords: boiling, porous coatings

1. Introduction

In thermodynamic cycle the temperature differences between the evaporator section and the heat source, and between the condenser and the heat sink, are VRXUFHVRILUUHYHUVLELOLW\7RREWDLQKLJKFRHI¿FLHQWVRI performance, the temperature differences need to be as VPDOODVSRVVLEOH)RUH[DPSOHLQDUHIULJHUDWLRQV\VWHP WKHUHGXFWLRQLQWHPSHUDWXUHGLIIHUHQFHIURPo_{C to}

o_{C results in the reduction of required work by about}

>@7KDWOHDGVWRHQHUJ\VDYLQJ6XFKDUHGXFWLRQ LQWHPSHUDWXUHGLIIHUHQFHVLQKHDWH[FKDQJHUVFDQEH achieved due to introduction of porous coverings on the surfaces. In boiling, they might dissipate the same heat ÀX[DVVPRRWKVXUIDFHVEXWDWVLJQL¿FDQWO\ORZHUHG temperature differences. Such microstructures might be used in many industrial applications – in refrigeration, chemical engineering. Orman discussed their possible DSSOLFDWLRQ LQ DXWRPRWLYH KHDW H[FKDQJHUV >@ RU LQ heating and ventilation systems [8].

2. Boiling heat transfer augmentation

7KHKHDWHUVXUIDFHFDQEHPRGL¿HGZLWKURXJKQHVV or the application of microstructures of different JHRPHWU\0HFKDQLFDOPL[LQJRIWKHÀXLGRULQGXFLQJ vibrations is also possible [1, 2]. Microstructures can be produced on the heater surface by deposition or by mechanical means. There are many kinds of such VWUXFWXUHV>@7KHLUDSSOLFDWLRQPLJKWOHDGWRD VLJQL¿FDQWHQKDQFHPHQWRIKHDWWUDQVIHU

=KDQJDQG=KDR>@GLVFRYHUHGWKDWERLOLQJKHDW WUDQVIHU FRHI¿FLHQWV IRU WKH VXUIDFHV ZLWK SRURXV coatings produced with the thermal spraying

WHFKQLTXH ZHUH  ±  WLPHV KLJKHU WKDQ IRU WKH VPRRWKVXUIDFH±WKHFRYHULQJVRIPPPP DQGPPKHLJKWZHUHXVHG=KDQJDQG&KHQ>@ investigated water and ethanol boiling on a horizontal surface covered with porous layer of sintered bronze SRZGHU 0LFURVWUXFWXUH KHLJKW ZDV  ±  PP ZKLOHWKHJUDLQGLDPHWHUUDQJHGIURP±PP +HDWWUDQVIHUFRHI¿FLHQWRIVXFKDVXUIDFHZDVWR 10 times higher than of the smooth surface. For the VDPH KHDW ÀX[ WKH WHPSHUDWXUH GLIIHUHQFH ZLWK WKH XVHRISRURXVOD\HUVZDVPXFKORZHU)RUH[DPSOH ZDWHUWHVWUHVXOWVLQGLFDWHGWKDWIRUKHDWÀX[RI W/cm2 _{the required temperature difference for the}

VPRRWKVXUIDFHZDVDERXW.ZKLOHIRUWKHSRURXV FRYHULQJRIPPKHLJKW±DERXW.)RUHWKDQRO DQGWKHVDPHKHDWÀX[WKHWHPSHUDWXUHGLIIHUHQFHIRU the smooth surface amounted to about 16 K while for WKHPLFURVWUXFWXUH±RQO\VRPH.&LHĞOLĔVNL>@ analysed water boiling on horizontal surfaces coated HOHFWURFKHPLFDOO\ZLWKD±PPSRURXVOD\HU of copper, aluminum and silver. The heat transfer FRHI¿FLHQW IRU WKH SRURXV FRDWLQJ WXUQHG RXW WR EH HYHQ  WLPHV KLJKHU WKDQ IRU WKH VPRRWK VXUIDFH 5DLQH\DQG<RX>@H[SHULPHQWDOO\DQDO\VHG)& ÀXRULQHUW±DGLHOHFWULFÀXLGERLOLQJRQWKHFRSSHU [PPVXUIDFHFRYHUHGZLWKPPZLGHVTXDUH SLQ±¿QV7KHUHZHUH[SLQVRQWKHVXUIDFHORFDWHG 1 mm apart from each other. The height of the pins ZDVDQGPP)RUWKHVDPHKHDW ÀX[RI:FP2 _{the temperature difference required}

IRUWKHVPRRWKVXUIDFHZDVDERXW.ZKLOHIRUWKH PLFUR±¿QQHGVXUIDFHDERXW.

Another type of microstructural coatings are PHWDO ¿EURXV SRURXV VWUXFWXUHV 7KH FRQVLGHUDEOH LQFUHDVHLQKHDWWUDQVIHUFRHI¿FLHQWGXHWRDWWDFKPHQW WR WKH VXUIDFH RI WKH KHDW H[FKDQJHU PHWDO ¿EURXV porous structures was reported by Wójcik in [19]. +H SUHVHQWHG WKDW WKH KHDW WUDQVIHU FRHI¿FLHQW DPRXQWHGWRā:P2.IRUWKHKHDWÀX[RI

W/m2 ZDWHU SRURVLW\  WKLFNQHVV  PP ,Q

the boiling process there is a strong dependence of ERLOLQJ KHDW WUDQVIHU FRHI¿FLHQW IURP WKH VWUXFWXUDO SDUDPHWHUVSRURVLW\WKLFNQHVV7KHPD[LPXPYDOXH RIWKHKHDWWUDQVIHUFRHI¿FLHQWZDVUHFRUGHGZKHQWKH covering was 0.6 – 0.8 mm thick. The heat transfer DXJPHQWDWLRQ IRU VXFK VWUXFWXUHV ZDV FRQ¿UPHG E\ Orzechowski and Orman [10]. Moreover, for the VDPHKHDWÀX[RIDERXWN:P2 _{the temperature}

difference for the smooth surface was 12 K, while for the porous layers 9 K (for water). In the case of the VDPHKHDWÀX[IRUHWKDQROERLOLQJWKHVPRRWKVXUIDFH WHPSHUDWXUHGLIIHUHQFHDPRXQWHGWRDERXW.DQG DERXW.IRUWKHSRURXVVWUXFWXUHV

Quite common are also wire mesh microstructures >@ 7KH GDWD SUHVHQWHG LQ >@ SURYHV WKDW KHDW transfer augmentation is possible with the application of such structures. A coating consisting of three copper mesh layers of wire diameter 0.18 mm and PHVKDSHUWXUHPPZDVXVHG+HDWÀX[IRUWKH mesh structure was even a few times higher than for WKHVPRRWKVXUIDFH)RUWKHKHDWÀX[RIN:P2

the required temperature difference for water boiling KHDWWUDQVIHURQWKHVPRRWKVXUIDFHZDVDERXW. ZKLOHIRUWKHPHVKFRYHULQJ.ZKLOHIRUHWKDQRO DERXW.DQG.IRUVPRRWKDQGSRURXVVXUIDFHV respectively. Orzechowski and Orman [12] also H[SHULPHQWDOO\ DQDO\VHG ERLOLQJ KHDW WUDQVIHU IURP mesh structures consisting of two mesh layers – each from a different material: copper and stainless steel – sintered together on a copper heater surface.

Many techniques can be used to enhance heat transfer. Xiuling et al. [21] studied boiling of nitrogen RQDFRSSHU¿QQHGWXEH7KH¿QV¶KHLJKWZDVPP and an additional porous coating was sintered onto WKH¿QQHGWXEH7KLVFRYHULQJZDVPPKLJKDQG KDGSRURVLW\RI)RUWKHVDPHKHDWÀX[WKHKHDW WUDQVIHU FRHI¿FLHQW RI WKH ¿QQHG VXUIDFH ZLWK WKH coating was 6 – 8 times higher than of the smooth tube. It was also higher than of the tube without the ¿QVDQGRQO\ZLWKWKHSRURXVOD\HU

New methods of heat transfer augmentation are GHYHORSHG 5DGHN DQG 2UPDQ >@ H[SHULPHQWDOO\ analysed electro – spark deposition as a means of

ERLOLQJKHDWWUDQVIHUHQKDQFHPHQW6LJQL¿FDQWYDOXHV RIWKHKHDWWUDQVIHUFRHI¿FLHQWSURYLGHQHZJHQHUDWLRQ coverings investigated by Wójcik et al. [20]. These structures are sintered from copper powder with the DGGLWLRQRIFRSSHUR[LGHSRZGHU

3. Modelling boiling heat transfer for porous coatings Modelling of boiling heat transfer is of practical YDOXH±IRUH[DPSOHLQWKHGHVLJQRIKHDWH[FKDQJHUV One of the models has been proposed by Nishikawa HWDO>@+HDWLVDVVXPHGWREHWUDQVIHUUHGWKURXJK conduction from the heater surface to liquid according WRWKHHTXDWLRQIRUWKHKHDWÀX[

(1) where: G is the height of the porous layer, 'T is the difference between the temperature of the heater surface and the saturation temperature of the liquid (often referred to as wall superheat), O_m describes effective thermal conductivity.

O_m is calculated as:

(2) where: H is porosity of the microstructure, O_l and O_s conductivity values of liquid (l) and structure material (s), respectively.

The value of O_m is crucial for the model calculations. ,WXVXDOO\OHDGVWRHOHYDWHGKHDWÀX[HVXVLQJHTXDWLRQ LQFRPSDULVRQWRWKHH[SHULPHQWDOGDWD$FFRUGLQJWR [17] formula (2) describes the effective conductivity of the liquid – solid system if the solid elements are parallel to the heater. In the case of the perpendicular direction the following equation has been proposed in [17]:

 0RVW FRYHULQJV ± IRU H[DPSOH PHWDO ¿EHU VWUXFWXUHV KDYH D FRPSOH[ JHRPHWU\ DQG GR QRW VDWLVI\DVVXPSWLRQRIWKHSDUDOOHOVROLGKHDWÀRZ,Q the case of these microstructures another method of thermal conductivity calculation needs to be adopted according to the equation given in [17] as:

 7KLV FRQFHSW KDV EHHQ XVHG E\ 2UPDQ >@ WR GHWHUPLQHZLWKWKH¿WWLQJSURFHGXUHWKHFRHI¿FLHQW) IRUFRSSHUPHWDO¿EURXVVWUXFWXUHVZKLFKIRUZDWHU HTXDOOHG  )LJXUH  SUHVHQWV FRPSDULVRQ RI

WKHH[SHULPHQWDOUHVXOWVRIZDWHUERLOLQJRQDFRSSHU ¿EHU SRURXV VWUXFWXUH RI  DQG  PP WKLFNQHVV according to data by Wójcik [18] with the calculations performed using the Nishikawa model – original DQG ZLWK D PRGL¿HG FRQGXFWLYLW\ YDOXH DFFRUGLQJ WR HTXDWLRQ  DQG )   7KH UHVXOWV DUH graphically presented as so called “boiling curves” – GHSHQGHQFHVRIKHDWÀX[YVZDOOVXSHUKHDW )LJ%RLOLQJFXUYHVIRUZDWHUIRUWKHFRSSHU¿EURXV VWUXFWXUH±H[SHULPHQWDOGDWD>@±FDOFXODWLRQVZLWK WKHRULJLQDO1LVKLNDZDPRGHO±FDOFXODWLRQVZLWKWKH PRGL¿HG1LVKLNDZDPRGHOZLWK)  ±FDOFXODWLRQVZLWKWKHQHZ)YDOXHRI 7KHFDOFXODWHGKHDWÀX[YDOXHVEDVHGRQWKHRULJLQDO 1LVKLNDZDPRGHODQGWKHPRGHOPRGL¿HGE\2UPDQ >@ ZLWK D GLIIHUHQW HIIHFWLYH WKHUPDO FRQGXFWLYLW\ YDOXH FXUYHV  DQG  UHVSHFWLYHO\ RYHUSUHGLFW WKH H[SHULPHQWDO GDWD ,Q >@ WKH FRHI¿FLHQW YDOXH RI  ZDV GHWHUPLQHG IRU D SRURXV VWUXFWXUH RI SRURVLW\  DQG WKLFNQHVV  PP ,Q >@ WKH geometrical parameters of the coating are different. Consequently, a different value of F should be H[SHFWHG+DYLQJFRQVLGHUHGWKLVFDOFXODWLRQVKDYH been preformed to determine a new value of F for the analysed microstructure. It has been calculated as 7KHUHVXOWVDUHSUHVHQWHGDVWKHFXUYH1R DQGDUHDOPRVWLGHQWLFDOZLWKWKHH[SHULPHQWDOGDWD 4. Discussion

$OWKRXJK SRURXV FRDWLQJV RIIHU VLJQL¿FDQW possibilities in heat transfer enhancement and reduce WKHWHPSHUDWXUHGLIIHUHQFHIRUWKHVDPHKHDWÀX[WKH knowledge of the physical processes inside porous VWUXFWXUHVLVVWLOOLQVXI¿FLHQW&RQVHTXHQWO\WKHUHDUH FRQVLGHUDEOHGLI¿FXOWLHVLQFUHDWLQJDPRGHOWRSUHGLFW

KHDWÀX[RUKHDWWUDQVIHUFRHI¿FLHQWEDVHGRQSK\VLFDO and chemical properties of the microstructure. In the case of smooth surfaces more is known. In [6] the discussion of this issue is presented.

)RU SRURXV OD\HUV GXH WR WKH FRPSOH[LW\ RI WKH structures and different production methods, it is YHU\GLI¿FXOWWRSURSRVHDVDWLVIDFWRU\FRUUHODWLRQRU a model. However, the concept presented here (based RQPRGL¿HG1LVKLNDZDPRGHOPLJKWEHLQWHUHVWLQJ to consider. A method of calculating the F value, which seems to be related to the structural properties of the porous covering, could be a new approach. 7KDWPLJKWEHIXUWKHUGHYHORSHGERWKH[SHULPHQWDOO\ and theoretically.

References

[1] Bergles A.E., (1997): Enhancement of pool boiling, ,QW-5HIULJHUDWLRQ9ROSS

[2] Bergles A.E., (1998): Techniques to Enhance

Heat Transfer, in Handbook of Heat Transfer, ed.

Rohsenow W.M., Hartnett, J.P., and Cho, Y.I., McGraw-Hill, New York.

>@ &LHĞOLĔVNL -7  An experimental study

RI QXFOHDWH SRRO ERLOLQJ KHDW WUDQVIHU IURP D ÀDW horizontal plate covered with porous coatings,

$UFKLYHRI7KHUPRG\QDPLFV9RO1RSS 69-76.

>@ 1LVKLNDZD.,WR77DQDND.Augmented

heat transfer by nucleate boiling on a sintered metal layer. Heat Transfer – Japanese Reseach, Vol. 8, pp.



>@ 2UPDQà-$QDOL]DHIHNW\ZQHMSU]HZRGQRĞFL

FLHSOQHMPLNURSRNU\üSRURZDW\FK$QDO\VLVRIHIIHFWLYH WKHUPDOFRQGXFWLYLW\RISRURXVPLFURFRDWLQJV, Proc.

RI&RQIÄ7HURWHFKQRORJLD´=HV]\W\1DXNRZH nr 11, Nauki Techniczne: Budowa i Eksploatacja 0DV]\QSS

>@ 2UPDQà-Nucleate boiling heat transfer on

DVPRRWKVXUIDFHRID¿Q, Proc. of XII Int. Symposium

RQÄ+HDW7UDQVIHUDQG5HQHZDEOH6RXUFHVRI(QHUJ\´ +756(±SS

>@ 2UPDQ à-  Possibilities of heat transfer

enhancement in automotive heat exchangers, Proc.

RIth,QW&RQIÄ7UDQVSRUW0HDQV´.DXQDV

University of Technology, Lithuania, pp. 116-119. >@ 2UPDQà-Possibility of the application of

microstructures in heating and ventilation systems,

Structure and Environment, Kielce University of 7HFKQRORJ\9ROSS

>@ 2UPDQ à- 2U]HFKRZVNL 7  Analysis of

WKH LQÀXHQFH RI WKH VXUIDFH URXJKQHVV RQ WKH KHDW transfer from extended surfaces, Science Report,

CEEPUS Project PL-127: Measurement Technology in Advanced Machine Manufacturing Systems.

General Editors: S. Adamczak, P.H. Osanna, Kielce 8QLYHUVLW\RI7HFKQRORJ\SS

>@ 2U]HFKRZVNL 7 2UPDQ à-  Boiling heat

WUDQVIHU RQ VXUIDFHV FRYHUHG ZLWK FRSSHU ¿EURXV microstructures, Proc. of XI Int. Symposium on

Ä+HDW7UDQVIHU DQG 5HQHZDEOH 6RXUFHV RI (QHUJ\´ +756(±6]F]HFLQSS

>@ 2U]HFKRZVNL72UPDQà-Mikropowierzchnie

VWUXNWXUDOQHZZ\PLDQLHFLHSáD0LFURVWUXFWXUHVLQKHDW WUDQVIHUHQJLQHHULQJ3URFRI&RQIÄ7HURWHFKQRORJLD

´ =HV]\W\ 1DXNRZH QU  1DXNL 7HFKQLF]QH Budowa i Eksploatacja Maszyn, Kielce, s. 171-177. >@ 2U]HFKRZVNL 7 2UPDQ à-  Wymiana

FLHSáD SU]\ ZU]HQLX SĊFKHU]\NRZ\P QD ĪHEU]H ] GZXZDUVWZRZą VWUXNWXUą VLDWNRZą 1XFOHDWH ERLOLQJKHDWWUDQVIHURQWKH¿QZLWKDWZR±OD\HUZLUH PHVKVWUXFWXUH3URFRIÄ;,,,6\PSR]MXP:\PLDQ\

&LHSáDL0DV\´.RV]DOLQ±'DUáyZHNV >@ 3DOP%Enhancement of boiling heat transfer

by aid of perforated metal foils, Ph.D. Thesis, The

Royal Institute of Technology, Stockholm.

>@ 3RQLHZVNL 0(  :U]HQLH SĊFKHU]\NRZH QD

UR]ZLQLĊW\FK PLNURSRZLHU]FKQLDFK, Wydawnictwo

3ĝN.LHOFH

>@ 5DGHN 1 2UPDQ à-  Water boiling on

HOHFWURVSDUNGHSRVLWHGFRSSHUFRDWLQJȼȱɋɇɂɄ

SS

[16] Rainey K.N., You S.M. (2000): Pool boiling heat

WUDQVIHU IURP SODLQ DQG PLFURSRURXV VTXDUH SLQ ¿QQHGVXUIDFHVLQVDWXUDWHG)&, Journal of Heat

7UDQVIHU9ROSS

>@ 5DPYLU 6 .DVDQD +6  Computational

aspects of effective thermal conductivity of highly porous metal foams, Applied Thermal Engineering,

SS

>@ :yMFLN70Boiling on cylindrical surfaces

with thick – layered porous covering, Proc. of X

,QW 6\PSRVLXP RQ Ä+HDW 7UDQVIHU DQG 5HQHZDEOH 6RXUFHVRI(QHUJ\´+756(±SS [19] Wójcik T.M. (2006): ,QWHQV\¿NDFMDZ\PLDQ\FLHSáD

GOD ZU]HQLD %RLOLQJ KHDW WUDQVIHU HQKDQFHPHQW,

,QĪ\QLHULDL$SDUDWXUD&KHPLF]QD1RLQ 3ROLVKSS

>@ :yMFLN703RQLHZVNL0']LDGRĔ$'HSF]\ĔVNL W. (2008): Experimental investigation of boiling

heat transfer on new porous coverings, Proc. of XII

Int. Symposium on “Heat Transfer and Renewable 6RXUFHVRI(QHUJ\´+756(±SS [21] Xiuling Y., Hongji X., Yaozhen S., Dongji C.,

<XZHQJ = +RQJ]KDQJ 4  ([SHULPHQWDO

research of nucleate pool boiling heat transfer from compound enhanced porous surface in liquid nitrogen,

&U\RJHQLFVYRO6XSSOHPHQWSS >@ =KDQJ+-&KHQ/Pool boiling heat transfer

on the sintered porous surfaces, T. Nejat Verizoglu

(ed), Particulate Phenomena and Multiphase 7UDQVSRUW+HPLVSKHUH9ROSS

>@ =KDQJ+-=KDR;%Experimental research

on pool boiling heat transfer from a spraying porous surface, Preprints of 7th _{Int. Heat Pipe Conf., Minsk,}

SS 7DGHXV]0:yMFLN

2V]F]ĘGQRŒýHQHUJLLSU]H]]DVWRVRZDQLH

Z\PLHQQLNyZFLHSâD]SRNU\FLHPSRURZDW\P

:VWĘS :\PDJDQH UyĪQLFH WHPSHUDWXU\ Z Z\PLHQQLNDFK FLHSáDPDMąZSá\ZQDZ\GDMQRĞüWDNLFKXNáDGyZ:\- ND]DQRĪHZSU]\SDGNXV\VWHPXFKáRGQLF]HJR]UHGX-NRZDQLHUyĪQLF\WHPSHUDWXU\]o&GRo&SURZDG]LáR

GR]PQLHMV]HQLDZ\PDJDQHMSUDF\RRNRáR>@ :NRQVHNZHQFMLSURZDG]LWRGRRV]F]ĊGQRĞFLHQHUJLL 7DNLHREQLĪHQLHZ\PDJDQHMUyĪQLF\WHPSHUDWXUZZ\-PLHQQLNDFKPRĪQD]UHDOL]RZDüSRSU]H]]DVWRVRZDQLH SRNU\ü SRURZDW\FK GR NRQVWUXNFML SRZLHU]FKQL

Z\-PLHQLDMąF\FKFLHSáR:SU]\SDGNXZU]HQLDPRJąRQH RGSURZDG]DüWDNLHVDPHJĊVWRĞFLVWUXPLHQLDFLHSáDFR SRZLHU]FKQLH JáDGNLH DOH SU]\ ]QDF]QLH PQLHMV]\FK UyĪQLFDFK WHPSHUDWXU 7HJR W\SX SRNU\FLD ]QDMGXMą V]HURNLH]DVWRVRZDQLHSU]HP\VáRZH

,QWHQV\ÀNDFMDZ\PLDQ\FLHSâDSU]\ZU]HQLX

3RZLHU]FKQLĊJU]HMQąPRĪQDPRG\¿NRZDüSRSU]H] jej chropowacenie lub zastosowanie mikrostruktur. =KDQJDQG&KHQ>@EDGDOLZU]HQLHZRG\LHWDQROX

QDSRZLHU]FKQLSRNU\WHMZDUVWZąSRURZDWą]SURV]-NyZ VSLHNDQ\FK 'OD WDNLHJR XNáDGX ZVSyáF]\QQLN SU]HMPRZDQLDFLHSáDE\áRGGRUD]\Z\ĪV]\QLĪ GOD SRZLHU]FKQL JáDGNLHM 'OD WDNLHM VDPHM JĊVWRĞFL VWUXPLHQLDFLHSáDZ\PDJDQDUyĪQLFDWHPSHUDWXUSU]\ ]DVWRVRZDQLXSRNU\FLDSRURZDWHJRE\áDGXĪRQLĪV]D 1DSU]\NáDGZ\QLNLGODZRG\ZVND]XMąĪHSU]\JĊ-VWRĞFLVWUXPLHQLDFLHSáD:FP2Z\PDJDQDUyĪQLFD WHPSHUDWXUGODSRZLHU]FKQLJáDGNLHMVLĊJDáDRN. QDWRPLDVWGODPLNURVWUXNWXU\RZ\VRNRĞFLPP± RN.:SU]\SDGNXHWDQROXLWHMJĊVWRĞFLVWUXPLH- QLDFLHSáDUyĪQLFDWHPSHUDWXUGODSRZLHU]FKQLJáDG-NLHMZ\QRVLáDRN.DGODPLNURVWUXNWXU\±W\ONR ok. 1,8 K. Rainey and You [16] badali wrzenie FC ±QDSRZLHU]FKQLPLHG]LDQHMRZLHONRĞFL[ PP SRNU\WHM PLNURĪHEUDPL R V]HURNRĞFL  PP :\QLNLZVND]\ZDá\ĪHSU]\JĊVWRĞFLVWUXPLHQLDFLHSáD 1 W/cm2

Z\PDJDQDUyĪQLFDWHPSHUDWXUGODSRZLHU]FK-QLJáDGNLHMZ\QRVLáDRN.DGODPLNURĪHEHURN. ,QQ\PW\SHPSRNU\üVąVWUXNWXU\PHWDORZRZáyN-QLVWH :yMFLN >@ REVHUZRZDá ]QDF]ąF\ Z]URVW ZVSyáF]\QQLND SU]HMPRZDQLD FLHSáD Z SU]\SDGNX ]DVWRVRZDQLDSRNU\üPLHG]LDQ\FKZáyNQLVW\FK3R-WZLHUG]HQLH]QDF]QHMLQWHQV\¿NDFMLZU]HQLDGODWHJR W\SXXNáDGyZPRĪQD]QDOHĨüZSUDF\2U]HFKRZVNLH- JRL2UPDQD>@3RGDQRWDPĪHSU]\WHMVDPHMJĊ-VWRĞFL VWUXPLHQLD FLHSáD  N:P2 UyĪQLFD WHPSH-UDWXUGODSRZLHU]FKQLJáDGNLHMZ\QRVLáD.DGOD SRURZDWHMZáyNQLVWHM.GODZRG\:SU]\SDGNX HWDQROXLWHMVDPHMJĊVWRĞFLVWUXPLHQLDFLHSáDUyĪQLFD WHPSHUDWXUGODSRZLHU]FKQLJáDGNLHMVLĊJDáDRN. DGODSRURZDWHMRN. 'RĞüSRZV]HFKQHVąWHĪVWUXNWXU\VLDWNRZH:\QLNL ZSUDF\>@ZVND]XMąĪHLFK]DVWRVRZDQLHSURZDG]L GR]QDF]QHMLQWHQV\¿NDFMLZU]HQLD'ODJĊVWRĞFLVWUX- PLHQLDFLHSáDN:PZ\PDJDQDUyĪQLFDWHPSH-UDWXUSU]\ZU]HQLXZRG\QDSRZLHU]FKQLJáDGNLHME\áD RN.DGODSRZLHU]FKQLVLDWNRZHM.'ODHWDQR-OXE\áRWRRGSRZLHGQLRRN.L.2U]HFKRZVNL L2UPDQ>@EDGDOLWDNĪHZU]HQLHQDSRZLHU]FKQLDFK VLDWNRZ\FK]áRĪRQ\FK]GZyFKUyĪQ\FKPDWHULDáyZ± pokrycia ze spieczonych siatek: miedzianej i stalowej. 7UZDMą SUDFH QDG QRZ\PL PHWRGDPL LQWHQV\¿NDFML ZU]HQLD1SZ>@DQDOL]RZDQRSRZLHU]FKQLHSRRE- UyEFHHOHNWURLVNURZHM]DĞZ>@VSLHNDQH]PLHV]D-niny proszków miedzi i tlenku miedzi.

0RGHORZDQLHZU]HQLDQDSRZLHU]FKQLDFK]SRNU\FLHP porowatym 3UDZLGáRZH PRGHORZDQLH Z\PLDQ\ FLHSáD PD GXĪH ]QDF]HQLH SUDNW\F]QH ± QS Z SURMHNWRZDQLX Z\PLHQQLNyZFLHSáD-HGQ\P]SU]\NáDGyZMHVWPR-GHO 1LVKLNDZ\ L LQQ\FK >@ Z NWyU\P ]DNáDGD VLĊ ĪH FLHSáR MHVW SU]HZRG]RQH ] SRZLHU]FKQL JU]HMQHM GR FLHF]\ 0RGHO ]DZLHUD ]DVWĊSF]ą SU]HZRGQRĞü FLHSOQąNWyUHMZDUWRĞü]PRG\¿NRZDQRZSUDF\>@ GODSRZLHU]FKQLPHWDORZRZáyNQLVW\FKRSRURZDWR-ĞFLLJUXERĞFLPP1DSRGVWDZLHU\VXQNX PRĪQDVWZLHUG]LüĪHPRGHO1LVKLNDZ\SURZDG]LGR ]DZ\ĪRQ\FK ZDUWRĞFL JĊVWRĞFL VWUXPLHQLD FLHSáD Z odniesieniu do danych eksperymentalnych z [18]. Po-GREQLHPRGHO1LVKLNDZ\R]PRG\¿NRZDQHMZDUWRĞFL SU]HZRGQRĞFL ]JRGQLH ] UyZQDQLHP  L ZLHONRĞFL ) 'DQHHNVSHU\PHQWDOQH>@GRW\F]ąMHG-nak struktury o innych parametrach geometrycznych LPRG\¿NDFMDZDUWRĞFL)MDNRVSRZRGRZDáD EDUG]R GREUH GRSDVRZDQLH Z\QLNyZ REOLF]HĔ L GD-Q\FKSRPLDURZ\FKNU]\ZDQUU\V

4. Dyskusja

&KRFLDĪ SRNU\FLD SRURZDWH RIHUXMą ]QDF]ąFH PRĪOLZRĞFL LQWHQV\¿NDFML Z\PLDQ\ FLHSáD L RE-QLĪHQLD Z\PDJDQHM UyĪQLF\ WHPSHUDWXU GOD GD-QHM JĊVWRĞFL VWUXPLHQLD FLHSáD WR ZLHG]D QD WH-PDW SURFHVyZ ¿]\F]Q\FK ZHZQąWU] VWUXNWXU MHVW ZFLąĪ QLHZ\VWDUF]DMąFD : ]ZLą]NX ] W\P SR-MDZLDMą VLĊ WUXGQRĞFL Z VWZRU]HQLX PRGHOX PR-JąFHJR SU]HZLG\ZDü JĊVWRĞü VWUXPLHQLD FLHSáD w oparciu o parametry mikrostruktury. W przypadku SRZLHU]FKQLJáDGNLFKZLHG]DMHVWV]HUV]D:SUDF\ >@]DSUH]HQWRZDQRG\VNXVMĊQDWHQWHPDW

: SU]\SDGNX SRNU\ü SRURZDW\FK Z ]ZLą]NX ]LFK]áRĪRQąEXGRZąLUyĪQ\PLPHWRGDPLSURGXN-FML EDUG]R WUXGQR MHVW ]DSURSRQRZDü XQLZHUVDOQ\ PRGHOOXENRUHODFMĊ-HGQDNNRQFHSFMDZ\NRU]\VWDQD ZQLQLHMV]HMSUDF\ED]XMąFDQDPRG\¿NDFMLPRGHOX 1LVKLNDZ\ PRĪH E\ü LQWHUHVXMąFD V]F]HJyOQLH MHĞOL XVWDORQD]RVWDQLH]DOHĪQRĞüZDUWRĞFLSDUDPHWUX)RG parametrów pokrycia porowatego.