Khan M.U.

Okui Ken-ichi

University of Toyama Repository

ve ntilatio n ofthe Pa rked Auto m obile u nde rBla zlngSu nHe ad oftheRe s e arch Prqje ct: Pr o†. OKUl, K･Repo rts ubmittedbyK HAN, M･U･ ･ Ventur eBu sin e s sLabo rato ry, Toya m aUnive rsity1. Lntrodu ctio nw he npa s e ngers e nter a Vehicle pa rked in the s u nfor a n extended periodr equ " es ther mal c omfort. At the s am e tim es e n sible car c ompon ents also requir edLimitedthe r m al Level to pe rfor m prope rly. To Limit the c a r c abinte mpe rature s everal re s e archerspr opo s e sdiffere nt te chniqu e sL T heir re s e a rch a redivided intotw o clas sific ation o n eis toprote ctthe c arfro mthe solar radiationbydiffere ntm ethods a nd a n otheroneisgLV] ngProperventilation into the c ar c abin. Adva n c ed window gla z[ng a ndther m alinsulatio n s a rethem ethodsto re stricts olarradiationintothe c a r c abin w hichinturn shelpsto[imit the c ar c abintempe rature. But the s etw o m ethods a r ebit expen sive anditals odiminishe s e xpo s u re ofthe c arbody. Se c o ndtype ofsolutionin clude s a mbie ntc o oling and ve nting syste m a ndfansyste mdriv e nbys olarbatte ryfor v e ntilation. In thelo ngr un the s etw o a r enots uitable withre spe cttofin a n cialandte chnic alpoint ofview IAt this stage, this re s e archinte ndedtoinvent a ve ntilation system which will befina n cial一y andte chnic ally s uitable･ To a chieve this go al te mpe rature ofthe c a r c abin,s uitable airflow r ate w a s m e a s ured andlo c atio n of the airinletw a s s e arched expe rim entallya nd num e ric ally･ A 托e rgetting s uitable airflow rate a ndLoc ation of the airinlet7itwilm akethe path to de sLgn the ve ntilations syste m･ T his pape r wi" de s cribe temperaturem e a sure m e nt and optimiz atio n of airflow rate to limit the c a r c abin te mperatur e withinc o mfo rtable range.2. Expe rim entout=ne ofthe e xperim e ntalset- upfo rte mpe rature m e a s u rem ent W a sShow n infigur el･ T his figure sho w sthe top view ofthe expe rim ental s et- UPI Tempe rature s w erem e a s u r edinthediffere ntlo c atio n s ofthe c ar c abin a nd show nbythebla ck and white circle.T-typethe r m o c o uple w a s u s edforthis pu rpo s e. Five a n alog m odule s w er us edfo rdataacquisition. Sa mpling r ate ofthe data a cquisitio n w a s1 sa mple s/min. Ac cur a cyofthem odule s w a s ±0.1% . This analogdata w a s c o n v e什edinto digital data by a n alog/digitalc on ve rte r･ Digitizeddata w a s an alyzed bythe co mputerLAtm o spheric air wa s u s ed fo rventilatio n. Tw odiffe r e ntLoc atio n sfo r airinlets w ereu s ed o n ew a s o nthetop ofthefro ntpa n eland othe r one w a s u s ed at thebotto m ofthefront98Fig, 1 Outline ofthe e xpe rim entals et-uppanel which w asinclin ed at35o with c a rflo o r. At the s am etim e,thelo cation ofthe ve nt forair outJet w as sho w nin figu re 1. Befo re entering into the c a rc abin, air flo w rate w a sm e a su red by the c o mbin ation of orific e and m a n o meter. Di肝e re nt rate of airflow werepa s s ed intothe c ar c abin e.g･ 50, 7 5, 10 0, 1 25, 1 50, 200m3/hatstarting ofthe expe rim ent.Fo rthispurpo s e, orific ew a s c alibratedbefo r e experim ent.3. Experim e ntalr e sults3.1E #e ctofSolarradiatio nwithoutventilatio nFigu｢e 2 sho w ste mperature ofthetop of thefro ntpa n e一 andthe airte mpe ratu rene arthe drivers he ad withoutventilation. Ma xim um te mperature ofthe c ar cabin wa sfoundo nthefrontpane一a nd itw a s83 ℃. Air spa c etemperature n e a rdiver's he ad w a s6 7℃ .3･2 Com pa ris o nofeffe ctof diffe r entairflow rate o ntemperature mitigationlnfluenc e ofthe airflow r ate w a s sho w ninfigu re31 Te mpe r atu re variation ne a rthedrivershe ad w a s show ninthisfigure･ The s eimpliedthatairflo w ratefor50 and75m3/hc ans uppre s sthe tem pe raturebelow 5 5℃ . Airflow rate s10 0, 1 25, 150 and 20 0m3/hc ans uppre sthetem peraturebelow 50 ℃a nd the s ef一ow rate s show a一m ost s a m ebehavior ofte mpe｢atu｢ esuppres sion .995555587654(3o)a]nle]ad∈a11 0:00 1 1:00 12:00 1 3:00 14:00 1 5:00Tim e(hr)Fig. 2 Tem peratu re va riation with tim e atdifferentlo c ations(withoutc o oling)w 柑1 0 utV e ntibtbn(3しa)rqe)ad∈a170605040㌔ ㌔ ㌔ ㌔㌔ ㌔ ㌔ ㌔ ㌔T he 41r)Fig. 3 Tem peratu re v arition with tim e atdiffe rent flo wrates(m3/h)313 Compa ris on ofdiffer e nt Lo c ation ofairinleton ventilationFigure4 shows the c om paris o nbetw e en the effe cts of airinlet lo c atio n s on thetem perature suppre s sion ･ Fro mfigu re 3 itis evide nt that fro m l l:30a m to 1 2:30pmtem peratur efluctu atio n w as n ot s ev e re as itw as on thelater stage. For this re as on, toc alc ulatethete mperatu re mitigation, atfirsta v eragetempe rature ofthistim ewa stake nfromthe data of witho ut ve ntilatio n. Then itwa s s ubtra ctedfro mthe ave ragetemperatur e at100di斤e｢e n川 ow rate. Thiste mpe ratur edi庁e｢enc e o｢ a m ountofthetem pe｢atu｢e mitigation wa sals o c alc ulated fo rbothairinletlo c ations. Air atbelow frontpa n elsho w s m o r ete mpe raturemitigation then airinletatabovefro ntpanel.50505022ー一･-(Noドp)3)nle]ad∈81Pa)e6!)!Mirinlet at below frontpan el/ //暑r-･- - -一層 //し Airinlet at abovefr ontpa n el0 5 0 1 0 0 1 5 0 20 0 25 0F bw a te en3h)Fig. 4 Tempe ratu re mitigatio nwithdiffe r ent flow rate s atdifferentlo c ations ofairinlets4. Nu m e ric alsim ulation4.1Sim ulatjonte chniqu eThre edim e n sio n al Na vie rs-Stoke s equatio n sw ere u s edfor Nu meric alsim u一ation.Finite volum e m ethod w a s u s ed a s sim ulatio nte chnique. M ultトdis c[plin aryCF Dand he attransfe r s o冊ware CF D 2000w a s u s edfo r nu m e ric a一sim ulatio n. Bo u ndaryfittedc o-ordinatesystem wa s ap pliedto buildthe c a r m odel whichdim ensions w ere s am e a sthe c ar us edinthe expe rim ent. Outline ofthe sim ulatio n m odel w a s show ninfigu r e5. Me sh n umbers w e re37x2 5x31. He at w a sradiated fro mthe r o of,window s a nd s e ats. Lo c ation of theinlet a ndFig. 5 Outlin e ofthe sim ulatio n m odelandLo c ations ofobs ervation points101outlet ofthe airflow we r e s am e a sthe e xpe rim e ntbut airinlet at the botto m ofthefrontpa n el w a spa rallel with the flo or inste ad ofinclin ed airinlet. Consta nt velo city a ndte mpe ratu re air wa spa s s edthro ugh outside ofthe c ar･ Sim ulatio n w a s c arried outfo r50,1 0 0, 1 5 0a nd 200m3/h.4 .2 Nu m e ric alre s ults anddis cus sion sTe mperature distribution at diqe r e ntLo c atio n s of the c a r c abin w a s show n bytheFigu re6･ Te mpe rature o nthefrontpanel w a sfound8loC anditw a sm axim u mte m pe raturein the c a r c abin fo rwitho ut ventilation ･ Airte mpe ratur ene arthe driv e rs he ad w a s6 5oCIFigu r e7 shows theinfluenc e ofthe diffe r e nt airf一ow r ate s o nthete mperatu r emitigatio n･Am bie nt air w a spa s s edinside the ca r c abin at 50, 100, 1 50 a nd 200m3/hflow rate s･000076tL)4(3o)a]nlt!]ad∈¢1102Fig. 6 Te mpe raturedistributioninthe c a r c abin witho utc o oling(Se ctio nX- Y offigure 5)Tim e(min)Fig. 7 Te mpe r aturedistribution with tim e n e a rdriversh6adTem peraturede c r e a s e sbelow 400Cfor100, 1 50and200m3/h, which is5oK low e rthan theexperim e nt. W he ntheflow rate w a s50m3/hdiffere n c e sbetw e e n expe rim entand n u m eric alre s ult w a sl OoK. 1np｢a ctic alsituatio n c a r c abinis alw ays一e akings o m e a m ou ntofve ntilatedair. How eve rfo rn u merjc alsim ulation the r e w a s n o such lo s sin ventilatio n. T hat's whyn u m e ric alsim ulation showsbette rte mpe rature mitigation then expe rim ent.5 . Co n cluding rem arksCar c abin te mpe ratur e wa s m e a su red experim e nta"y a nd n u m e ricarly. Maxim u mte mpe ratu rew a sfo u nd on thefro ntpanefa nd itw a s8 3oC. Suitablelo c ationforthe airinletwa sfo und atthebotto m ofthefrontpanelwhich w a sin c=n ed withfloorofthe c ar at350. Forairffo w rate s1 00, 1 2 5, 1 50, 200m m3/hsho w ed s a m e a mount ofte mpe rature mitigatio nw hen airinlet w a satbotto m ofthe frontpa n el and the s e show s s uperior tem pe raturemitigatio nthe nthe airinletatthetop ofthefro ntpaneJ. Num eric alre s ults als o shows alm o stsimila rpatternof the experim entalr e s ult. Fro mthe s e expe rim e ntand nu m e ric aJr e sultitwa sc o n cluded that inclin ed airinletat the bottom ofthefrontpa neland airflow rate l OOm3/h iss uitab一efo r optim u m venti一ation syste mfo r comfo｢table c ar c abin.6. Futu r epla nTempe rature m e a s u re m e nt ofthe c ar c abin , s uitable airflow r ate andlo c ation ofthe ve=tilation syste m w e r e s earched･ At the s a m etim e, s ola rpow ered fan syste mdevelopm e nt w a s c a rrylng O ut. AfterdeveJop] ngthis syste m, pe rfor manc ete st willbeheldout inthisye ar. Ventilatio n syste m willbe evalu ated byin stallingitinthe c ar which wa s u s edfo rte mpe｢atu ｢e m e a s u re m e nt.Refere∩c e(1)Fr a nk K. , Principle s of He at Transfer, T hird ed. 197 6103

Ventilation of the Parked Automobile under Blazing Sun

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Ventilation of the Parked Automobile under Blazing Sun

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