ρc T, t = (k T)+q (1) (1) Fluent15.0 q=h(tw, [13~14] -T f ), (2) ( Tw ) T f ( ),K [15~16] (2),,Tfoodbotom (x,y,z)= 1 Tban(x,y,z)=243K 1.1 (3) 1

Size: px

Start display at page:

Download "ρc T, t = (k T)+q (1) (1) Fluent15.0 q=h(tw, [13~14] -T f ), (2) ( Tw ) T f ( ),K [15~16] (2),,Tfoodbotom (x,y,z)= 1 Tban(x,y,z)=243K 1.1 (3) 1"

阡纪
5 years ago
Views:

33 7 2017 7 Vol.33,No.7 Jul.2017 DOI10.13652/j.issn.1003-5788.2017.07.

1 Vol.33,No.7 Jul.2017 DOI /j.issn Stimulationandtheoreticalanalysisofheattransferduringthe freezingprocesssimulationofbeef 1,2 1,2 1,2 1,2 TANG Wan 1,2 WANG Jin-feng 1,2 LI Wen-jun 1,2 XIE Jing 1,2 (1., ;2., ) (1.ShanghaiEngineering Research Centerof Aquatic ProductProcesing & Preservation,Shanghai201306,China; 2.Colegeof Food Scienceand Technology,ShanghaiOcean University,Shanghai201306,China) [1-2] (CFD),, [3], (T1 T2 T3 T4 T5) 5.45%,3.90%,5.80%, Pham Q T [4] 4.24%,9.60% 1.79, BeckerB R [5] ; ; ; AbstractFreezingisrecognizedasoneoftheimportanttechnologyin foodpreservation.consideringthechangeofphysicalcharacteristics inbeefundertheprocessofthefreezing,theequivalentheatcapacity methodwasutilizedtoprocesslatentheatinphasechange,andthen thecomputationalfluiddynamics (CFD)numericalsimulationtech- dictthebeeftofreezetimewel. nologywasappliedtosimulatethefreezingprocessandestablishthe diferentialequations ofthree dimensionalfoodfreezing process. Through the numerical simulation of freezing time,the error betweeneachexperimentalmeasuringpoint (T1,T2,T3,T4and T5)valueandsimulationcalculationoffreezingtimeweredetectedto be5.45%,3.9%,5.8%,4.24%,5.8%,respectively,andeach pointtemperaturereal-timesimulation oftheaverageerror was 1.79.Theresultsshowedthatthenumericalsimulationcouldpre- Keywordsnumericalsimulation;freezingtime;foodfreezing;re- frigerator ( 2016YFD ); ( 16DZ ) [11], (1968 ), jxie@shou.edu.cn ( ) CFD [6-7], [8] [9], C Pham Q T [10] 3,, [12] [13], Basic 117

2017 7 ρc T, t = (k T)+q (1) (1) Fluent15.

1 (3) 1 2,, Ts[S(t),t]=Tl[S(t),t]=T p, (3) KK25F55TI ( 400 mm 400mm 130mm) 100mm 100mm 70mm 1 1.

0, k-ε,, 2 (cm), Figure2 Foodputthepositionofthemainview 10-6,, Z, -9.81m/s 2 1.2, ( ) Fluent15.

2 ρc T, t = (k T)+q (1) (1) Fluent15.0 q=h(tw, [13~14] -T f ), (2) ( Tw ) T f ( ),K [15~16] (2),,Tfoodbotom (x,y,z)= 1 Tban(x,y,z)=243K 1.1 (3) 1 2,, Ts[S(t),t]=Tl[S(t),t]=T p, (3) KK25F55TI ( 400 mm 400mm 130mm) 100mm 100mm 70mm Figure1 Thefreezerandputfood 100 mm 100 mm 70mm, CAD, Gambit Fluent15.0, Fluent15.0, k-ε,, 2 (cm), Figure2 Foodputthepositionofthemainview 10-6,, Z, -9.81m/s 2 1.2, ( ) Fluent s, ;2,, ; s -18,, ;4 3 ( 1050kg/m 3 );5 118 λs Ts Tl x =λl x +h ρ ( 4) Ts Tl T p λs,w/(m K); λl,w/(m K); h,kj/kg; ρ, kg/m 3 Tfood(x,y,z)=T0 = K,, ;6 XOY 5 ( 4), X 0.00,0.02, 0.04,-0.01,-0.03m

3 第３３卷第７期唐婉等牛肉冻结过程中模拟及热值传递理论分析由图４５可知牛肉底部换热最快温度降低得最快而牛肉顶部和侧面降温略慢这是因为在冻结过程中食品底部直接与蒸发盘管接触存在接触导热作用导热的热阻远小于对流换热的热阻而且蒸发盘管的温度要低于冷冻室内部环境的温度所以食品底部的温度下降较快２牛肉冻结过程中试验研究与结果分析２１试验研究选取新鲜牛肉准确切取１００ｍｍ１００ｍｍ７０ｍｍ规图３牛肉体最高温度分布曲线则的长方体形状用标定好的美国ＯＭＥＧＡ四氟测温线ＴＴ３ＣｈｈｍｐｄｂｏｎｖｇｇｈＴ３６型热电偶温度探头固定好测点位置置于恒温恒湿箱图４不同时刻牛肉内部各截面的温度分布云图４Ｄｎｍｂｗｈｎｈｏｎｍｐｄｂｏｎｎｈｏｄｇ图５牛肉垂直中心截面位置不同时刻牛温度分布云图５Ｖｎｏｎｏｏｎｂｍｐｄｂｏｎｎｈｄｎｍｏｄｇ１１９

4 d, (5 ) ( 6) 1d,, 30s Fluke2640A Excel 7 Figure7 Foodcentersectionoftheexperimentalvalueof measuringpoints, T2 T3, T2 T1 15mm,T2 25mm,T3,T4, 45 mm,t5 15mm, 7, 6 (cm) -1.0~-2.6,, Figure6 Experimentaltakediagram T4,CFD, T1, T3, T1, T5, 8(a)~(c) 8 Figure8 Beefexperimentalvalueandsimulationvalueofeachmeasuringpointtemperaturecontrast 120

5 33 7 [5]BECKERBR,FRICKEB A.Freezingtimesofregularlyshaped fooditems[j].internationalcommunicationsin Heat & Mass Transfer,1999,26(5) [6],,. [J].,2009,25(4) , [7],,.,, [J].,2009,30(2) ,128. [8],. [J].,2000,22(4) [9],. [J].,2004,23(4) (d) [10]PHAM Q T.Modelingheatandmasstransferinfrozenfoods areview[j].internationaljournalofrefrigeration,2006,29 8(e), (6) [11],,,. [J].,2015(4) [12]WANGZheng-fu,WU Han,ZHAO Guang-hua,etal.One-di- mensionalfinite-diferencemodelingontemperaturehistoryand (T1 T2 T3 freezing time of individual food [J].Journal of Food Engineering,2007,79(2) T4 T5) [13]. [J]. 5.45%,3.90%,5.80%,4.24%,9.60%,2006,22(5) [14]UYAR R,BEDANE T F,ERDOGDU F,etal.Radiofrequ- 3 encythawingoffood productsa computationalstudy[j]., JournalofFoodEngineering,2015, [15],,,., CFD [J].,2005,39(1) [16]MORGAN V T.TheOveralConvective HeatTransferfrom, SmoothCircular Cylinders[J].Advancesin Heat Transfer, 14mm 1975, , (T1 T2 T3 T4 T5) ±10% 1.79 CFD,, [1],,. [J].,2008,24(2) [2],,. [J].,2016,32(10) [3],,,. [J].,2016,37(6) [4]PHAM Q T.Freezingtimeformulasforfoodswithlow moisture content,low freezing point and for cryogenicfreezing [J]. JournalofFoodEngineering,2014,127(4)

FZ1.s92

FZ1.s92 第一章服装制作工艺基础知识第一节服装术语服装术语是服装技术专用语, 如服装的每一个品种服装上的每一块裁片服装制作过程中每一种操作, 以及所使用的工具服装制作过程中出现的各种弊病和要达到的某些质量要求等, 都有其