Sustainable pneumatic transport systems of cereals

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1 Proceedngs of he 3 Inernonl Conference on Enronen, Energy, Ecosyses nd Deeloen Susnble neuc rnsor syses of cerels Mrn Pnescu,, Gbrel Son Durescu,b, Andre Alexndru Scu,c Deren of Engneerng Scences n Mechncl nd Enronenl Feld Consn Mre Unersy Consn, Ron rnn@yhoo.co b onfebrure@yhoo.co c ndre.scu@gl.co Absrc Technologcl neuc rnsor nsllons re desgned o oe erls fro one lce o noher n rous hses of he roducon rocess. For exle: lodngunlodng erls (cerels) usng rl nd rne rnsor, r unnel conner rnsor, sulyng cobuson nsllons wh burnng col dus. The n reer n neuc rnsor nsllons s he elocy of r. For he rege of oon wh erl rcles n susenson, for gen flow erl, he hgher he elocy s he greer he ressure loss wll be nd hus he energy consuon for rnsoron wll ncrese. In horzonl es he begnnng of oon flow we he coc rege, nd hen due o decrese r elocy connuous lyer rege s forng. Ths s he ren oon n wch he ressure losses ncrese wh he decrese of elocy. y reducng he r elocy he hckness of he deosed erl ncreses nd he rel r ssge secon decreses nd herefore he rel r elocy ncreses, whch exlns he ncrese n ressure loss. In ercl es f he r elocy decreses below he lower l of oln rnsor, fer crcl re of nsbly, rnsoron fludzed bed s esblshed, he ressure losses beng uch lrger hn he rcles n susenson ode. If he elocy furher decreses he rcles cn no be enrned n he r. Keywords rnsor, neuc, susnble, nsllons, cerel, sron, slo, cyclone, elne. I. INTRODUCTION In neuc rnsor nsllons [] he r crculon s done n order o rnsor sold erls under dync ressure effec of he r flow n es. Trnsoron of erls cn be echnclly (coneyors, bucke, ec.), hrough neuc elnes usng r s he crrer or cobned echncl nd neuc. The uns conss of wo rs: dece for ckng u he erl (long wh he r) n rnsoron nework nd renng dece (seron) of he erl rnsored. The erl us fulfll nuber of reureens o be rnsored n good condon: o resen sze cooson nd densy for whch he rnsor nd he seron should be econocl, no o dhere o he surfce of he es, no o degrde by crushng durng rnsor, he reured eerure for rnsor should no ffec he ressnce of es nd of he euen used, no o e exlose or corrose ors, do no chnge her checl roeres durng rnsor. Pneuc rnsor s bsed on he rncle of enrnng sold erl rcle by curren of r or oher gs ong wh cern elocy hrough e. Wh hs ye of nsllons we cn rnsor sold ny eleens: whe, corn, os, brley, sh, cly, ceen, wood chs, swdus, cellulose. Mong of erl s de on horzonl lne oer dsnce of 35 4 or on ercl lne oer dsnce of 45. II. PNEUMATIC TRANSPORT SYSTEMS uldng neuc rnsor syse nd s reure euen long wh econoc ndcors ry fro one uns o noher deendng on syse ressure. Fro he ressure on of ew we cn dsngush: syses wh dschrge low, edu or hgh ressure; syses wh sron (fg..); cobned syses (x) - oen or closed syses. In neuc rnsor syses by sron (Fg. ), he erl s rnsored wh he hel of exhuser ouned he end of neuc un end so h les enrely on r deresson. The exhuser roduces deresson of,5,6 br necessry for rnsor of erl. Grnulr erl wh s sucked long wh he r hrough he sucon hed nd rnsored o he slo dschrge e. Seron of grn ls r s enrned n cyclone. Adusng deresson s by nure, grn sze nd frcon losses h occur long he enre lengh of he nsllon. Pneuc coneyng sron s effece n downlodng erls fro crs, lfors, rlers ec. A dsnces u o, Fgure Pneuc rnsor syse wh sucon [] - sucon hed, - Condor rnsor 3 - Slo, 4 - cyclone, 5 - exhuse. III. MATHEMATICAL MODELING OF THE PROCESS A. The seed of erl n r rnsor es In he elne he erl rnsored behes dfferenly fro r, eseclly due o s hgher ss. The forces exered 9

2 Proceedngs of he 3 Inernonl Conference on Enronen, Energy, Ecosyses nd Deeloen on he rcle (e.g. frcon wh he e wlls, he c of rcles one wh noher, s sn, wegh, drg, ec.) roduce cceleron or slowng down of he erl, so h o nn he reured seed rnsor s necessry n ddonl energy consuon. ) oerng seed of he erl - s he seed l h he rcles n dync eulbru he. The relonshs re clculed for rrefed flow (oln rnsor). For rele seeds: r nd Re> 5, he relon s : λ Fr [ βfr βfr ( ) + ] Fr Fr λ Fr () For hgh seed rnssson, when consdered β, he relon becoes: λ Fr ( ),5,5 () n whch:, elocy of r nd erl n he e [/s]; - flong elocy of he erl [/s]; l - nl frcon coeffcen deendng on he erl rnsored; b - coeffcen of frcon beween he ong erl rcles nd elne; b for ercl es; b / for horzonl e; Fr Froude creron, s Fr /(gd) s Fr /(gd); D - deer of he e []. For ll yes of rcles, ncludng for dus, he deful relon s recoended: ' r ψ ψ λ β gd (3) where ψ' nd ψ re he erodync drg coeffcens. b) elocy of he erl durng cceleron - beween e of lcng erl n neuc elne nd chee s oerng elocy, here s erod of cceleron of he erl, whch s corresonds lengh of cceleron. Uon he rcle s cng he scenson (F A ) force (fg.) nd he gry (G) force, he reenon force due o collsons beween rcles (F). All of he forces cree resuln whch reresens he Newonn cceleron force (F cc ). F A r c S ; (4) G g; (5) F n whch: c - coeffcen of drg; ; F d d cc (6) S he secon of rcle [ ]; Fg.. The con of he forces of cceleron on he rcle[] r -,rele seed [/s]; - he r densy [kg/ 3 ]; - ss of erl rnsored [kg]; - coeffcen of c, deendng on he sze nd nure of he rcle. Vercl roecon of forces eulbru euon s obned: F F G F (7) cc + A d r + c S g (8) d ( ) c S + g+ (9) If noe: c S A ; + c S ; C c S + g; Dfferenl euon cn be wren s: d A + C () Adng h s consn, we cn sere he rbles nd hen negre he: d A + C Afer negron s obned he followng: d () 3

3 Proceedngs of he 3 Inernonl Conference on Enronen, Energy, Ecosyses nd Deeloen A ln A K + () The lue of consn K s obned by nroducng he nl lues: ; K + (3) Relcng n euon () K wh s forul, we obn: 4AP ( ln ) C ( + ) C (4) Euon s soled wh he noons: ϕ ; δ Merl resulng n cceleron seed: e β δe ϕ + ϕ ϕx ϕx (5) (6) Acceleron e s deerned fro he relonsh generlly beng n nerse funcon of elocy: τ cc δ β ln ϕ β (7) The lengh of he cceleron resulng fro he negron of he euon: l cc τ cc (8) Lengh of srgh elnes for cceleron s deerned by he e reured for he elocy of erl o rech 95% of he oerng elocy. Pressure dfference reured o ccelere he erl s deerned by he relonsh: G (9),785D n whch: G -ss flow of erl [kg/s]; V, V - nl elocy, fnl elocy (fer cceleron) of he erl [/s]; D - he deer of he rnsor []. c) elocy of he erl n cured elnes In cured elnes cenrfugl force due o r erl seron occurs, he rcles for lyer lnng on he ouer wll of he elne wll due o frcon, he lyer of erl s slowed down drsclly, he elocy decreses bu he ressure chnges ery few ercenge loss due o clen r ssge. Afer he cured elne he erl hs o be ccelered on he srgh secons of elne. The forces cng on he rcle (Fg. 3) re: norl force he e wll (N), he frcon force (F f ), nerl force (F ) (ss x cceleron). Forces resulng fro he roec: where d F ; N η R F f η () For n eleen of lengh ds Rdϕ, R d. Subsung no he euon nd nroducng slfcon nd ung boundry condons, we obn: ϕ d η dϕ; ln η ϕ ; ηϕ e () n whch: f cure ngle [rdn]; h he coeffcen of frcon of he erl of he e wll, exerenlly deerned; R rdus []. e ηϕ () Noe h he elocy he ex of cure does no deend on he rdus of curure nd s een lower wh boh frcon coeffcen s hgher, whch s why hese lns re no llowed o cure segens re shown cures enel or oher rocessng o reduce he coeffcen of frcon. Velocy s een sller he hgher he oenng ngle of he cure s, whch leds o he recoendon on he cooson of se of wo cures 45 whch s nsered beween srgh secon h wll foser nd reurn o oerng seed cored o sngle cure of 9. Fg. 3. Prcle oon n horzonl elbow [] 3

4 Proceedngs of he 3 Inernonl Conference on Enronen, Energy, Ecosyses nd Deeloen IV. NUMERICAL SIMULATION OF THE PROCESS USING FINITE VOLUME METHOD For he nuercl sulon we he used nuercl sofwre Ansys-Fluen.3.. Ths rogr s bsed on he fne olue ehod. The geoery creed s slr o Fg.3 nd hs he followng densons (Fg. 4): - he elnes rs lengh 3; - he elnes deer.6. Fg. 4 Geoery reresenon Afer he creon of he geoery we he dscresed he body no 459 dscreson cells wh 8836 nodes (Fg. 5). A secl enon ws gen o he r were he e bends, conssng n lrger nuber of cells, becuse here he r nd he whe chnges drecon nd fors eddes. Fg. 5 ody dscreson On one sde of he e eners he r nd whe wh olue frcon of 5% ech wh seed of 5 /s. The wo hses wll x nd wll rech he oher sde osherc ressure of,35 P. The densy of he r ws eul o.5 kg/ 3 nd he whe densy ws 8 kg/ 3. The elne s on horzonl lne so no gry s used. To clcule he wo-hse rnsoron (r nd whe) we he used he olue frcon ehod. The olue frcon ehod reles on he fc h wo or ore fluds re no nerenerng. For ech ddonl hse h s dded o he odel, rble s nroduced: he olue frcon of he hse n he couonl cell. In ech conrol olue, he olue frcon of ll hses su o uny. Thus, he rbles nd roeres n ny gen cell re eher urely reresene of one of he hses, or reresene of xure of he hses, deendng uon he olue frcon lues [5]. where: n ( ) ( ) α + α S + α s he ss rnsfer fro hse o hse nd s he ss rnsfer fro hse o hse ; α s he olue frcon of he hse nd S α s secfc consn. For urbulen odel k-eslon: we used he euon for urbulen knec energy k (3), dson eslon (4) nd he energy euon (5) [5]: µ, σ k µ, σε ( k) + ( k) k + G ( ε) + ( ε) ε ε + k k, ε ( C G C ε) lε ( E) + ( E+ ) where: G k, ε ( ) ( keff T Σ h J + ( τ ) eff + Sh N (3) (4) (5) α, (6) N N α α µ C k, µ ε, (7), (8) ( ( ) ) T + : k, µ,, (9) k eff s effece conducy; J flud dffuson flux ; S h he due o checl recon. In he euon (5) we he: E h + (3) h enhly; for del fluds (9) nd for rel flud () h Σ Y h (3) h Σ Y h + (3) 3

5 Proceedngs of he 3 Inernonl Conference on Enronen, Energy, Ecosyses nd Deeloen h, dt (33) T c T ref The elocy ron shows us ncrese of he elocy xure fro 5 /s o 7 /s when he xure chnges drecon.. Necessry deer of he e conduc d Q,6 (34) µ γ Q5 35 r flow of syse; γ,[kg/ 3 ] r densy; µ5 concenron of xure, for syses wh grn sucon; Tble. Clculon of necessry deer o rnsor he grns for cern r elocy Fg. 6 Velocy ron The densy reresenon shows cully he olue frcon dsrbuon of hses (Fg. 7). The blue color s ssoced wh r densy, whle he red color s ssoced wh whe densy. The green color shows h n h secfc regon he couer erged he densy lues h ws deendng on olue frcon of he hses. Fg. 6 Densy ron V. CALCULATION FOR PNEUMATIC GRAIN TRANSPORT SYSTEM A) INITIAL DATA : 4 r elocy [/s]; d: deer of rcle []; Q5 35 r flow of syse. ) RESULTS Nr. Cr. Q µ [/s] g [kg/ 3 ] d [] Trnsor elocy 8,4d 'γ k (35) γ Where, d 4-3 []- deer of rcle; k,57- she coeffcen; γ,[kg/ 3 ] r densy; γ 7 85 [N/ 3 ] secfc wegh of grn. Tble. Clculon of rnsor eloces for dfferen secfc weghs Nr. g [N/ 3 ] d [] g [kg/ 3 ] [/s] Necessry r flow o rnsor he grns - Q Q Q (36) 4,3µ Q5 35 r flow of syse 33

6 Proceedngs of he 3 Inernonl Conference on Enronen, Energy, Ecosyses nd Deeloen µ5 concenron of xure, for syses wh grn sucon; Tble 3. Clculon of necessry r flow o rnsor he grns for dfferen r flows of he syse Nr. Q µ Q Necessry ower of neuc rnsor nsllon kl η P [kw] (37) L Q ln [dn/s] (38) ho k,- coeffcen h kes ccoun of losses of lekge; h o ressure dro; Q r ss flow; η effcency of he u. We he clculed he necessry ower of neuc rnsor for ll cses of he necessry r flow, hus resulng bles. Th s wy we he resened here ll he frs wo bles nd he los one. VI. CONCLUSIONS We cn obsere h n ncrese of grn densons leds us n ncrese of elocy, for cern secfc wegh. Also we cn noce h he necessry ower of he syse ncreses wh ncresng r flow nd he elocy of rnsored erl lcly. Ths shows h you he o ke corose: wh elocy of rnsor should be chosen (he bgger, he beer) nd wh ower or energy we he hnd. Vryng hese reers we cn oze he rnsoron syse. References [] [] O. nce,, Indusrl enlon, Polehnc Publshng,Tsor, 9. [] []O.nce, Venlon nd r condon, lecure noes, Polehnc Publshng,Tsor,996. [3] [3] W. ARTH,Absezung, Trnsor und Federsufwrbelung on subförge Gu Lufsro. Chee Ing.Technc no.3/963. [4] [4] E.CARAFOLI, T.,OROVEANU, Fluds echncs, Ronn Acdey Publshng uchres,ol.i, ,95, ol.ii, , 955. [5] Ansys-Fluen. Theory gude, 7. Tble 4. Clculon of necessry ower for Q Nr. Q L [N/s] h k P [kw] Tble 5. Clculon of necessry ower for Q 4.38 Nr. Q L h k P [N/s] [kw] Tble 6. Clculon of necessry ower for Q Nr. Q L [N/s] h k P [kw]