压力条件对不同尺寸条缝喷嘴换热的影响  

Influence of different pressure on heat transfer of nozzle with different sizes

作　　者：顾翰文 谢晶 王金锋[1,2,3,4] GU Han-wen;XIE Jing;WANG Jin-feng(Shanghai Engineering, Research Center of Aquatic Product Processing & Preservation , Shanghai201306, China;Shanghai Professional Technology Service Platform on Cold Chain Equi pm entPer f ortnam e and Energy Saving Evaluation ,Shanghai 201306,China;National Ej: peri mental TeachingDemonstration Center for Food Science and Engineering Shanghai Ocean University, Shanghai 201306,China;College of Food Science and Technology , Shanghai Ocean University , Shanghai 201306, China)

机构地区：[1]上海水产品加工及贮藏工程技术研究中心,上海201306 [2]上海冷链装备性能与节能评价令业技术服务平台,上海201306 [3]食品科学与工程国家级实验教学示范中心(上海海洋大学).上海201306 [4]食品学院上海海洋大学,上海201306

出　　处：《食品与机械》2019年第4期87-92,共6页Food and Machinery

基　　金：国家“十三五”重点研发项目(编号:2018YFD0400605);上海市科委平台能力建设项目(编号:16DZ2280300);上海市科委公共服务平台建设项目(编号:17DZ2293400)

摘　　要：以条缝喷嘴型的上下冲击式速冻机内部流场为研究对象,利用计算流体力学(Computational Fluid Dynamics,CFD)数值模拟和实地测试,对比了3种尺寸的喷嘴结构分别在不同压力(190,170,160Pa)条件下3种不同尺寸的喷嘴结构,条件下内部流场及换热特性的区别。结果表明:条缝喷嘴T_0在190Pa条件下的出口风速、努塞尔特数、均匀性比在170Pa条件下的理想,同时横流风速也低。条缝喷嘴T_1在170Pa条件下的出口风速、努塞尔特数、均匀性比在160Pa条件下的理想,但横流风速反而增加。条缝喷嘴T_2与T_0在同一入口压力下相比,只有横流风速较低。在换热强度方面,当入口压力为190Pa时,条缝喷嘴T_1所对应的钢带表面的局部努塞尔特数最大,而T_0与T_1的平均努塞尔特数相差不大。在换热均匀度方面,条缝喷嘴T_0在入口压力为190Pa时的不均匀度最低,换热最均匀。故当空气的质量流量相同时,入口压力为190Pa时所对应的条缝喷嘴T_0能更好地提升换热效率,有利于提升食品的冻结速率。Food industry is demanding higher anti higher (jualily of frozen food.anil the quickfreezer can well meet this requirement.In this siudy, the internal flow field of quick freezer with slit noz zle type was taken as I he research object.I'hree different sizes of nozzle structures based on inlet pressure of 190 Pa.170 Pa and 160 Pa.numerical simillation and field test of computational fluid dynamics (CFD) were used to compare the differences of internal flow field and heat transfer characteristics of three nozzle struc tures under different pressure conditions.The results showed that the outlet wind velocity.Nusselt number and uniformity of slit nozzle T,, at 190Pa were better than those at 170 Pa, and the cross-flow wind velocity was also lower.The exit wind velocity.Nusselt number and uniformity ratio of slit nozzle Pat 170 Pa weregood.but the crossing flow wind velocity increased.Com pared with T2, the slit nozzleTo had lower cross flow velocity at the same inlet pressure.In terms of heat transfer intensity, when the inlet pressure was 190 Pa, the local Nusselt number of st rip surface corresponding to slit nozzle Ti was the largest.while the average Nusselt number of T0 and T1 was not much differcni.In terms of heat transfer uniformity, the slit nozzle I', had the low est non uniformity anti the most uniform heat transfer when the inlet pressure was 190 Pa.Therefore, when the mass flow rate of air was the same? lhe slit nozzle T0 corresponding to the inlet pressure of 190 Pa could better improve the heat transfer efficien cy.and could increase the freezing rate of foods.

关 键 词：数值模拟 入口压力 喷嘴尺寸 冲击式速冻机 风速均匀度 换热特性 

分 类 号：TS203[轻工技术与工程—食品科学]