THERMAL/FLUID CHARACTERISTICS OF 3_D WOVEN MESH STRUCTURES AS HEAT EXCHANGER SURFACES

Transcription

1 THERMAL/FLUID CHARACTERISTICS OF 3_D WOVEN MESH STRUCTURES AS HEAT EXCHANGER SURFACES R. A. Wirtz, Jun Xu, Ji-Wook Park and Dan Ruch Mechanical Engineering Department/MS 3 Univerit o Nevada, Reno Reno, NV Phone: (775) Fax: (775) rawirtz@unr.edu ABSTRACT The preent work demontrate the abrication methodolog o a 3-D, aluminum wire ilament, bonded meh deploed a a heat exchange urace. A model o the eective thermal conductivit o the meh i developed. Apparatu to meaure the coolant preure-drop and heat traner coeicient are decribed. Meaurement are reported or abricated tet ample o varing thickne. Meh Stanton number and riction actor correlation or a coolant with Prandtl number equal to 9.5 (chilled water) are reported. A heat exchanger perormance evaluation, comparing the 3D woven meh technolog to another exchanger urace technolog, i decribed. We have ound that the weaving/wire bonding proce mut be careull controlled to inure that target poroit, peciic urace area and eective thermal conductivit are achieved. Eective thermal conductivitie are ound to be at leat twotime larger than achieved in other comparable porou media coniguration. Meh riction actor and Stanton number are comparable to thoe achieved with other exchanger urace technologie. The exchanger perormance comparion how that exchanger having uperior perormance can be conigured. KEY WORDS: thermal-luid, heat exchange, woven meh NOMENCLATURE C luid peciic heat d wire diameter o meh D h hdraulic diameter o meh riction actor G luid ma velocit g tranorm actor h meh heat traner coeicient H height o meh j Colburn j-actor k thermal conductivit ke eective thermal conductivit M meh number ntu meh traner unit Pr Prandtl number q heat traner rate q heat lux r diameter ratio R perormance ratio Re meh Renold number S hape actor St meh Stanton number t thickne o meh T temperature U eective conductance o meh W width o meh β heat traner urace area to volume ratio P preure drop ε poroit ρ luid denit µ luid vicoit Subcript luid i, o inlet, outlet olid x,, z coordinate INTRODUCTION Ka and London [984] have pointed out that a mot eective wa to increae the perormance o a heat exchanger i to increae it urace area to volume ratio, β. Smallparticle packed bed and oamed metal are expanded material having large β-value. Unortunatel, due to the tortuoit eect in conjunction with the high poroit (ε) o thee material, their eective thermal conductivit (ke) i relativel mall o that much o the gain in perormance obtained b having a large β i lot b having a relativel mall ke. Tpical value o eective thermal conductivit in ued-particle packed bed are 0% - 5% o the particle thermal conductivit. Commerciall available metal oam uch a aluminum oam ha an eective thermal conductivit that range rom onl % to 6% o the bae metal value [Ahb et al, 000]. An aniotropic porou matrix having a large peciic urace area and a large eective thermal conductivit in a particular direction will reult in a ver eective heat exchange urace. A three-dimenional woven meh o heat conducting ilament can be conigured to have thee characteritic. Geometric equation how that thee porou matrice can be abricated to have a wide range o poroit and peciic urace area and a

2 unit cell Fig. Three-dimenional orthogonal tacked weave. highl aniotropic thermal conductivit vector can be achieved. Thee attribute allow or the deign o mall, highperormance ingle-luid parallel plate heat exchanger that are more univerall applicable than conventional heat exchanger becaue the meh can readil be made to conorm to complex urace. Becaue o the high thermal conductance achieved, exchanger can be deigned or application where patial temperature uniormit or high localized pot cooling i required. In order or the technique to be applicable to a wide range o application, the woven meh mut be tructured uch that high thermal perormance i maintained while coolant preure drop i held at reaonable level. It i believed that thi objective can be achieved through careul coniguration o the woven tructure. Tong and London [957] reported meaurement o riction actor and meh heat traner coeicient or air (Pr 0.7) lowing through inline plain-weave creen laminate and taggered cro-rod matrice (no interweaving). Thee reult are reported in Ka and London [984]. Park et al, [00] develop a two-energ equation model or heat traner in thin porou media. The conidered chilled water low (Pr 9.5) through in-line and taggered iotropic plain-weave creen laminate. The meaured riction actor and Colburn j- actor imilar to thoe meaured b Tong and London. The ound that creen-laminate baed heat exchange matrice could be conigured to have preure-drop and thermal perormance uperior to ued particle bed exchange matrice having the ame ma per volume. Xu and Wirtz [00] develop a model or the in-plane eective thermal conductivit o creen-laminate. The how that thee tructure can be conigured to have a large urace area to volume ratio, exceeding 6500 m -, and high eective thermal conductivit in a particular direction, with eective thermal conductivitie o aniotropic creen laminate approaching 78% o bae material value. The preent work demontrate the abrication methodolog o a 3-D, aluminum wire ilament, bonded meh deploed a a Fig. 3D tacked weave unit cell. heat exchange urace. A model o the eective thermal conductivit o the meh i developed. Apparatu to meaure the coolant preure-drop and heat traner coeicient are decribed. Meaurement are reported or abricated tet ample o varing thickne. Meh Stanton number and riction actor correlation or a coolant with Prandtl number equal to 9.5 (chilled water) are reported. A heat exchanger perormance evaluation, comparing the 3D woven meh technolog to another exchanger urace technolog, i decribed. THEORETICAL CONSIDERATIONS 3D Woven-Meh Geometr. Figure how a threedimenional orthogonal tacked-weave that conit o three eparate wire ilament o diameter dx, d and dz, having axe aligned with the coordinate, x, and z, repectivel. Coolant low i preumed to be primaril in the x-z plane. The -wire ilament diameter, d i larger than dx and dz o that the eective thermal conductivit in the -direction, ke i larger than ke x or ke z. In thi wa, heat i tranerred to the luid b conduction primaril along the -ilament; then to the x- and z-ilament, which act a in. The wire ilament are bonded at interection to acilitate conduction. We deignate the three-dimenional orthogonal weave hown in Fig. a tacked weave ince there i no interweaving o wire ilament in an o the three principal plane. Thi approach allow or a ver dene tructure. Figure how a unit cell o the weave o Fig.. The wire pitch in each o the coordinate direction are M, M and M z x (M i the meh number ). Conideration o thi unit-cell how that the poroit (ε) and peciic urace area (β) are given b the ollowing expreion: ( dx MMz + d MxMz dx MxM) π ε + () 4

3 ( dxmmz + dmxmz + dzmxm) β π () 7 The quantit (-ε) i the volume metal raction. For the current application, we require that wire ilament touch at all poible ilament interection o that ilament can be bonded to acilitate conduction within the meh. Then Mx M Mz (3) d + dz dx + dz dx + d 6 βd D weave Sphere r Furthermore, let dx dz, and deine the ilament diameter ratio, r d/dx. Equation () and () become π + r + r ε (4) 4 ( + r) 3 r r r where ( ) βd S ε (5) + r S 4r (6) + r + r i the hape actor. Equation (4) and (5) how that once we retrict our attention to bondable 3-D weave; the βdproduct and the poroit are unction o the ilament diameter ratio onl. Figure 3 plot βd o the 3D tacked weave veru metal raction or diameter ratio, 0 r. The igure how that bondable 3-D tacked-weave with r can be conigured to have metal raction ranging rom to π/4 while.36 βd π. Our deign objective i to abricate a 3D tacked weave heat exchange matrix having r. The target metal raction i then (-ε) 0.6, and β 458m -. The target point, {r, (-ε) 0.6, βd 3.49} i alo hown in the in the igure. Furthermore, the peciic urace area ormula, Eq. (5) take the amiliar orm o other porou media. For example, the hape actor or an unconolidated bed o phere i S 6 [Coulon et al, 99] and Xu and Wirtz [00] have hown that iotropic plain-weave creen-laminate (ddz, MMz) have S 4. Thee unction are hown in the igure. The theoretical poroit o a packed bed o unconolidated phere depend on the packing arrangement [Kavian, 995]. It can range rom ε 0.6 or ace centered cubic packing to ε or imple cubic. However, the poroit o a packed bed i diicult to control. A tpical poroit or an unconolidated bed will range rom 0.35 to A a conequence, the metal raction can range rom 0.55 to 0.65 and βd will then range rom 3.3 to 3.9. The igure how that our target deign point will have a poroit and peciic urace area roughl equivalent to that o an unconolidated bed o phere. Larger diameter ratio, r will reult in larger achievable peciic urace area. Screen Laminate Xu and Wirtz, ( - ε) Fig. 3 Speciic urace area v. metal raction o porou material. Xu and Wirtz [00] how that iotropic plain-weave laminate can be abricated to have 0 (-ε) Under thee condition, 0 βd.3. The igure how that addition o a third ilament to create a 3D orthogonal weave allow or the tructuring o a meh having a larger metal raction and coniderabl larger peciic urace area. 3D Woven-Meh Eective Thermal Conductivit. Following Chang [990], we tranorm the x- and z-direction wire ilament o the unit cell (ig. ) into rectangular cro ection egment hown in Fig. 4. Each rectangular wire ilament ha thickne πd / 4g and width gd o that the cro ection area o each ilament i π d / 4. We urther require that the volume o the unit cell be preerved acro the geometric tranormation. Then g π / 4. The in-plane eective thermal conductivit in the -direction ma be determined b conidering the thermal circuit or conduction in the -direction acro the tranormed unit cell, hown in Fig. 5. Reerring to the tranormed unit cell: the parallel path (R,R) repreent conduction along the axi o the central d-ilament and urrounding luid; the erie path (R R+R) and (R3 R3+R3) repreent conduction acro dx- and dz-ilament and luid region above and below each ilament, repectivel; and, R4 repreent conduction acro the dx-dz ilament interection. 4( dx + d) d R dx dz dx dz π k 4km ( g) + + π + ( g) d d d d

4 T q Fig. 5 Thermal circuit or -direction conduction. 0.8 Fig. 4 Tranormed unit cell. dx k + dz k R (8) k k g dx [ dz( g) + d] dz k + dz k R3 (9) k k g dz [ dx( g) + d] dx + dz R4 (0) k ( g dx dz) where k and k are the thermal conductivit o the olid and luid phae, repectivel. I we deine the eective thermal conductivit in the -direction a ke ( dx + d)( dz + d) T q () dx + dz then r ( km ) + 4km[ r + ( g) ] + 8km r ( g) + 4g Keq π 4( + r) 4km g ( r + g) + () ( km + )( r + ) where ke and k Ke k. In mot cae the ratio k i k k mall; o, i k 0 the dimenionle eective thermal conductivit become a unction o diameter ratio, r onl, π r + π / 4 ( ) Ke (3) k 0 4 r + Figure 6 plot Ke (k 0) v the metal raction. Alo hown in the igure i the expected dimenionle thermal conductivit or a bed o ued phere, metal oam and that or a plane weave creen laminate. The igure how that or r, the dimenionle eective thermal conductivit o the 3-D weave Ke Screen Laminate Xu & Wirtz, 00 r r 3D WEAVES r r Foam, Calmidi & Mahajan, ε Fig. 6 Eective thermal conductivit o expanded material. can range rom 0.35 up to π/4 while the metal raction range rom up to π/4. The target deign point, {r, (-ε) 0.6} give Ke Thi i compared to a ued bed o phere, which i expected to have Ke (phere) 0.5. Furthermore, incorporation o a third wire ilament reult in a dramatic increae in the eective thermal conductivit relative to that obtained with creen laminate tructure. Heat Exchanger Implementation. Figure 7 how a woven meh implemented a a heat traner urace in a parallel plate exchanger. The meh i hown in edge-view in a channel having hal-height H. Heat (q) i conducted rom the heated plate (at temperature T b ) into the meh, and then b convection to the luid lowing through the meh. The meh wire ilament axe are arranged o that the -ilament are perpendicular to the channel wall o that conduction rom the wall i acilitated. G i and T i are the coolant approach ma. Fued Sphere

5 ( ρ, G, µ, d, r, β, t, ε ) h (8) Dimenional anali give Fig. 7 Heat exchange implementation o creen laminate and Schematic o tet ection. velocit and temperature, repectivel. P i the preure drop acro the exchange matrix. Thermal Perormance Model. The meh act a a porou wall o poroit, ε and thickne, t. The heat traner rate i given b q U( tw )[ T b T i ] (4) where U i the eective conductance o the porou wall and (tw) i the bae area. The porou wall eective conductance, U can be related to the thermal and phical characteritic o the woven tructure. The luid low path length through the porou wall i hort and low rate are relativel high, o local thermal equilibrium between the luid and olid phae i probabl not achieved; a two energ equation model i called or. Park et al. [00] aume that the olid phae temperature i onl a unction o ; and, the local heat lux between the luid and olid phae i characterized b Newton cooling law [ ( ) T ( x, ) ] q h T (5) where h i the meh heat traner coeicient. Eq. (5) couple the olid and luid phae energ equation. The porou wall conductance can then be related to the thermal and phical characteritic o the woven tructure a ollow: where U H mh tanh ke ( mh ) ntu ( ) (6) mh Gˆ i e (7) cg H Gˆ i i i a dimenionle coolant upericial ma ke t velocit and βt ntu St i the number o traner unit o the ε meh. St i the meh Stanton number, St h / c G, where G G i /ε i the internal low ma velocit. Meh Preure-Drop And Stanton Number Correlation. We potulate that the meh heat traner coeicient, h i unctionall related to luid and low propertie a ollow: p d St n(re, Pr, r, ε, ) (9) t where GD Re h i the meh Renold number with 4ε D h µ β the meh hdraulic diameter. In a imilar wa, we potulate that the preure drop acro the meh, P, i unctionall related to luid and low propertie a ollow: P n( ρ, G, µ, β, t, r, ε ) (0) Then dimenional anali give where n(re, r, ε) () ρ P i the riction actor. G β t EXPERIMENTAL CHARACTERIZATION Experiment are perormed to meaure the preure drop and porou wall eective conductance. Then, the meh Stanton number i determined rom Eq. (6). The unctional orm o Eq. (9) and () are then determined. Experimental Setup and Procedure. Preure drop and heat traner experiment to determine meh Stanton number and riction actor correlation are done in two dierent channellow apparatu. A chematic o the tet ection or either apparatu i hown in Fig. 7. The igure how an edge view o a 3D weave, o thickne t, located in a rectangular cro ection channel, which i approximatel 8 mm high x 00 mm wide. A luid, at ma velocit (G i ) and temperature (T, i ) pae through the tet article. In the cae o the preure drop experiment, the channel i o open-loop, induced-drat deign. Laborator air pae through a honecomb low traightener; the woven-meh tet article; a econd low traightener; a plenum chamber and uitabl long pipe to a laminar low element, which meaure the volumetric low rate; and, then to a variable peed exhauter. The preure drop acro the woven-meh tet article (meaured at our uptream/downtream wall preureport pair) i meaured with an electronic manometer having ±4% accurac. The laminar low element ha ±3% accurac. Heat traner experiment are conducted in a cloed loop chilled water-low apparatu. The tet rig conit o a pump/luid reervoir, low control valve, and the tet ection. The low ma low rate i meaured b a turbine low meter, and a rerigerated recirculator/heat exchanger hold the inlet low temperature contant at about C. Thi reult in experiment with the Prandtl number, Pr 9.5. The heat traner tet ection i imilar in deign to the one ued in the preure-drop experiment. Flow traightner are located uptream and down tream rom the tet article. Copper-contantan thermocouple meaure the uptream luid

6 Woven/bonded rope EDM-cut exchange matrix egment Fig. 8 Three-D woven/bonded meh abrication equence. temperature and the bae temperature o the woven meh ample (our location each). The approach low temperature i monitored at our location acro the channel pan at midheight about H uptream rom the tet article. The 3D woven ample i heated mmetricall with two guarded lat-plate heater [Ruch, 00]. The heating rate i applied o that o Tb T, i 0 C. In thi cae we meaure the overall conductance, U, and ue Eq. (5) to back-calculate the meh heat traner coeicient, h. We etimate that temperature meaurement are accurate to ±0. C, and q i meaured to ±4%. Meh Fabrication. Our deign objective i to abricate three 3D tacked weave heat exchange matrixe that are approximatel 0mm high x 00mm wide with t 6.35mm, 9.53mm and.7mm, repectivel. The meh i to have d 0.76 mm (0.030 ), dx dz 0.38mm (0.05 ) o that r. The target metal raction i (-ε) 0.6, and β 458m -. The target eective thermal conductivit in the -direction i 84 W/mK. The proce involve weaving a wire meh rope o peciied wire ilament diameter and meh number in the three coordinate direction, braze-bonding the wire ilament at their interection point, and cutting (via the wire-edm proce) and braze-bonding meh egment together to orm the heat exchange matrix. Figure 8 ummarize the proce. Aluminum wire meh ample (Allo 00) were woven on a commercial loom. The large diameter wire ilament (d) ormed the warp (weave) direction, and dx-wire and dz-wire ilament made up the hut and ill direction. The loom retricted the 3D weave to a product that wa approximatel 35mm wide x 5mm thick. The woven rope wa dip-brazed to bond wire ilament at their interection point. The proce involve impregnating the woven tructure with a lurr o al/i eutectic allo in lux, heating the article to the lux activation temperature, and then immering the article in a alt bath at 590 C. Table Three-dimenional meh characteritic. Parameter Target Achieved % dx, dz, d [in] 0.05, , Mx, Mz [/in] M [/in] Poroit β [/m] 4580(eq 5) 3840 (eq. ) -6. ke [W/m K] 84 (eq. 3) Since the d-wire ilament are in the warp-direction, and the height (-direction) o the meh tet article i 0mm, twent mm long egment o the woven/bonded rope had to be cut, rotated 90, and then bonded together to orm the tet article. Thi wa accomplihed via wire-edm. Table ummarize reult o the abrication proce. The table lit target and achieved meh phical and thermal attribute. Detail regarding meaurement procedure are documented a ollow: [phical dimenion, poroit; [Ruch, 00], eective thermal conductivit; [Xu, 00]. The Table how that there wa light wire diameter growth, caued b a combination o wire tretching during the weaving and metal addition due to the brazing proce. More igniicant i the decreae in weave meh number, indicative o a looer meh than targeted. Thi i due to the inabilit o the weaver to maintain a tight weave, caued b the tine o the metal wire ilament and their breakage i too much tenion i applied to the wire ilament during the weaving proce. The looening o the meh reult in an increae in poroit, and a decreae in the number o wire interection that can be brazed together. It wa ound that about 80% o wire ilament interection are atiactoril/partl bonded. The remainder are either unbonded, or the bond contain ault [Ruch, 00]. The reduction in metal raction and wire interection bond give rie to a reduction in heat traner urace area (β), and eective thermal conductivit (ke ). RESULTS Meh Friction Factor And Heat Traner Coeicient Correlation. Figure 9 compare meaured riction actor, and j-actor, P G βt ρ () / 3 j St Pr (3) or the preent 3D tacked weave [ε 0.49] with correlation or phere [ε 0.39] and iotropic plain-weave creenlaminate [Park et al, 00, 0.53 < ε < 0.84]. Ninet-ive percent (95%) conidence level error bar are hown on the igure. The preent data la intermediate to thee two other coniguration. The riction actor i correlated a ε (4) Re ε

7 ε ε ε j ε t d j Table Three-dimenional orthogonal meh characteritic. Characteritic 3D Weave Screen-Laminate t 3.75mm, H t, 4t, 8t External Aluminum, Allo 00 Characteritic Coolant i 300K (Pr 0.69) Internal Geometric d 0.4 mm r, ε tacked Md ε d dz 0.35 mm in-line laminate β [m - ] 8589,Eq. (5) 6073 Ke [W/mK] 84, Eq. (3) 44 W/mK P [Pa] Eq. (4) h [W/m K] Eq. (5) Park et al. correlation [00] Fig. 9 Modiied riction actor and Colburn j-actor. The irt term o Eq. (4) repreent the inertial contribution to the preure drop; and, the econd term repreent the vicou contribution. Equation (4) reproduce the data that generated it with a tandard error o 4.4%. The j-actor i correlated with a power-law j.89 Re 0. ε d (5) ε t 0.44 Equation (5) reproduce the data that generated it with a tandard error o 0.7%. Meh Perormance Evaluation. Three-dimenional tacked weave oer coniderable deign lexibilit. Adjutment o the wire diameter ratio, r allow or control o the tructure poroit, heat traner urace area to volume ratio, and eective thermal conductivit. However, the riction actor and Stanton number o the heat exchange matrix are comparable to thoe o other heat traner urace. The quetion that mut be addreed i: under what condition doe the 3D-weave technolog oer uperior perormance. Recognizing that Park et al. [00] have hown that creenlaminate can generall be conigured to out-perorm ued particle tem, in the ollowing we decribe a ixed outer geometr comparion [Webb, 994] o the perormance o a 3D-weave exchange matrix with a creen-laminate exchange matrix o the ame volume and ace area. The two tem are deploed a in a ingle-luid parallel-plate heat exchanger uch a a cold-plate or low-through module. Table ummarize the characteritic o the two tem. Both exchange matrice are made o aluminum (allo 00). The have the ame thickne, ace area and plate-to-plate pacing (three pacing are conidered). The coolant i air. Conideration o higher Prandtl number luid produce imilar reult. The 3D weave i made up o 0.4mm/0.0mm (6mil/8mil) wire (r ) reulting in an exchange matrix with a poroit o 0.385, peciic urace area o 8589 m - and eective thermal conductivit o 84 W/mK. The tightet weave achievable with an iotropic plain-weave ha the product Md [Xu and Wirtz, 00]. Thi reult in a poroit o A meh number equivalent to the 3d weave ha M 6.4 cm -. Then, the wire diameter mut be 0.35mm (0.04 in). With no interleaving o adjacent creen laer, the peciic urace area become 6073 m -, and the eective thermal conductivit i 44 W/mK, roughl hal the value achieved with the 3D weave. Eective Conductance, U [kwatt/m K] 0 Figure 0 plot the eective urace conductance o the 3D tacked weave (U, eq. 4) a a unction preure drop. Reult or three plate-to-plate pacing are hown. Alo hown in the igure i the upericial velocit, V i, a a unction o applied preure drop. At P 50 Pa (5 in H O), the conductance exceed 6500 W/m K, a value normall aociated with liquid-low turbulent convection or phae-change heat traner. At thi preure drop, the upericial coolant velocit i approximatel.7 m/ec. We deine the preure drop ratio and heat dut ratio a R P H 6.35 mm H.6 mm H 5.4 mm Vi [m/ec] r, d 0.4mm Aluminum allo Preure Drop [Pa] Fig. 0 Eective conductance and upericial coolant velocit o 3D tacked weave. Coolant i air at 300K. P(3D weave), P( creen la min ate) R q V i G i/ρ U(3D weave) (6) U( creen la min ate)

8 R P R q.6.4. H 6.35 mm H.7 mm H 5.4 mm V i Fig. PEC 3D tacked weave v iotropic plainweave creen-laminate. Figure plot the preure drop ratio and heat dut ratio a a unction o upericial coolant velocit, comparing the 3Dweave to the creen laminate. In ever cae, the creen laminate preure drop i igniicantl lower than that o the 3D weave. However, the correponding heat dut ratio are greater than one, indicating that the 3D weave out perorm the creen laminate tem b about 50%. Figure how that the heat dut ratio increae with increaing upericial velocit. Thi i a conequence o the 3D-weave having a higher peciic urace area and meh heat traner coeicient. The igure alo how that the heat dut ratio alo increae with increaing arra height. Thi i a conequence o the igniicantl higher eective thermal conductivit achieved with the 3D-weave. CONCLUSION Three-dimenional tacked weave can be conigured to have a wide range o βd-product and poroit, which are unction o the wire diameter ratio onl. Metallic weave can be tructured to have eective thermal conductivit that i two, or more time greater than what can be achieved with other porou media. However, the weaving proce mut be careull controlled. Relativel mall error in meh number reult in igniicant change in poroit, peciic urace area and eective thermal conductivit. Meh heat traner coeicient and riction actor are comparable to thoe achieved with other expanded material. However, high β-value, coupled with high eective thermal conductivit reult in exchange matrice that out-perorm other exchange matrix coniguration. Three-dimenion weave etup i ver labor intenive. A a conequence, thi methodolog i probabl bet applied to ituation where large volume manuacture i anticipated. ACKNOWLEDGEMENT. The Miile Deene Agenc through the Air Force Oice o Scientiic Reearch, USAF, ponor thi work under contract number F The view and concluion contained herein are thoe o the author and hould not be interpreted a necearil repreenting the oicial policie or endorement, either expreed or implied, o the Miile Deene Agenc, the Air orce Oice o Scientiic Reearch, or the U.S. Government. The author would like to acknowledge Dr. Mathew Dunn (Fiber Architect, Inc, Philadelphia, PA) and Mr. Steve Clark (T.E.A.M. Inc, Slaterville, RI]) or their willingne to undertake the 3-dimenional weaving; and Mr. Jim Ludd (ThermoFuion Inc, Haward CA) or the dip-brazing o our rope ample. REFERENCES Ahb, M., Evan, A., Fleck, N., Gibon, L., Hutchinon, J., and Wadle, H., Metal Foam, A Deign Guide, Butterworth Heinemann., 000. Calmidi, V.V. and Mahajan, R.L. (999) The Eective Thermal Conductivit o High Poroit Fibrou Metal Foam, J Heat Traner, Vol., pp Chang, W.S. (990) Poroit and Eective Thermal Conductivit o Wire Screen, J. Heat Traner, Vol., pp Coulon, J.M. and Richardon, J.F. (99) Chemical Engineering, 4-th ed, Vol., Pergamon Pre, Oxord. Kavian, M. (995) Principle o Heat Traner in Porou Media, nd ed., Springer. Ka, W. M. and London, A. L. (984) Compact Heat Exchanger, 3 rd edn., McGraw-Hill. Park, J-W, Ruch, D and Wirtz, R.A. (00) Thermal/Fluid Characteritic O Iotropic Plain-Weave Screen Laminate A Heat Exchange Surace, AIAA Paper , AIAA Aeropace Science Meeting, Reno, NV, Januar 00. Ruch, D. (00) Thermal/Fluid Characteritic O 3-D Woven Meh Structure A Heat Exchanger Surace, MS Thei, M. E. Dept, Univ. Nevada, Reno NV Tong, L. S. and London, A. L. (957) Heat-traner and lowriction characteritic o woven-creen and croed-rod matrixe, Tran. ASME,, pp Webb, R. L. (994) Principle o Enhanced Heat Traner, John Wile and Son,. Xu, Jun (00) Eective Thermal Conductivit o Screen Laminate Compoite, MS Thei, M. E. Dept., Univ. Nevada, Reno, NV Xu, J. and Wirtz, R. A., (00) In-Plane Eective Thermal Conductivit o Plain-Weave Screen Laminate, Thermal Challenge in Next Generation Electronic Stem, Millpre, Rotterdam.