共查询到19条相似文献,搜索用时 140 毫秒
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新型组合卸料器数值研究 总被引:1,自引:0,他引:1
目的与方法:提出一套新型组合卸料器——套管卸料器与高效分离器的组合;利用CFD技术对其三维两相流场进行模拟研究;结果:套管卸料器内的“短路流”几乎全部进入外排气管,改善了分离效果;套管的侧面排气方式有效利用排出气流的旋转动能,降低了不必要的损失;整套组合卸料器使实际的分离操作一步到位,具有重要的工程实用价值。 相似文献
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<正> 星形锁气器又称关风器或闭风器,在食品和发酵工业的风送装置中,它往往和卸料器配合使用,即保证卸料器卸下的物料能连续顺利地排出,又能防止外部的空气过多地从排料口吸入负压的卸料器,从而保证卸料器的分离效果。 相似文献
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奥克利姆公司离心卸料器压损特性及性能研究 总被引:1,自引:0,他引:1
为全面了解意大利奥克利姆公司生产的离心卸料器的性能,测定了空载时卸料器的阻力系数和重载时不同工况下卸料器出口阀及卸料器本身的阻力,分析了卸料器的分离性状,并同国内常用的卸料器的性能进行了分析比较,得出了意大利奥克利姆公司生产的离心卸料器的阻力系数同国内的60型、50型卸料器阻力系数接近,但分离效果稍差的结论. 相似文献
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在粮油食品及饲料的生产中 ,叶轮式卸料器 (又称关风器 )用途广泛。在用于风运、除尘风网配料系统的卸料器时 ,如果粮质较纯 ,不管是粒状、粉状都能正常工作 ,效率高 ;在初清风网中 ,作为刹克龙的卸料器使用 ,效果不理想。初清设备中未清出的纤维状杂质 ,如茎叶、麻绳长于两片叶轮之间的圆周距离时 ,由于叶轮和关风器外壳有不到 0 .0 5mm的间隙 ,容易缠绕在叶轮面上造成过载 ,烧坏电动机 (如图 1)。风运大米厂砻谷机下的谷壳 ,用刹克龙作为卸料器 ,经叶轮式关风器排入大糠房时 ,虽是片状物 ,少量稻壳仍然容易嵌入关风器叶轮和外壳之间 ,增… 相似文献
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为探究双槽形熔喷模头喷气孔端面对空气流场特征和纤维拉伸工艺的影响,对熔喷三维流场进行数值分析。采用Gambit建立了双槽形熔喷模头的结构模型,应用Fluent软件对熔喷三维气流场进行数值计算,分析流场中的速度、温度和压强分布规律及喷气孔端面对纤维制备的影响。结果表明:喷气孔端面对流场分布有一定影响,若远离流场中心,纺丝线上的速度和温度开始下降,而静压值变化较小;流场中心附近处纺丝线上的速度、温度和压强分布差别很小,靠近喷气孔端面的纺丝线上的温度、速度和静压最低;双槽形模头流场不同位置纺丝线上速度、温度和压强的不同导致制备的熔喷纤维在性能等方面存在差异。 相似文献
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目的:针对市场上缺少小型连续核桃烘干设备的现状,设计一种小型的核桃带式连续烘干机。方法:基于气固传热理论,建立烘干装置内部热流固耦合模型,并利用Fluent进行二维和三维仿真分析,获得烘干装置内部气体温度场的分布情况和核桃的温度场分布情况及变化规律;通过将烘干室的顶部由平顶改为有30°的角度倾斜,传送带两端的核桃掉落处改为圆弧过渡,箱体内壁用保温材料等措施,对机械结构进行优化设计,并搭建烘干试验平台,验证模型的有效性。结果:试验完成了最大烘干量为360 kg/h核桃带式连续烘干机设计,仿真优化之后烘干室内部压力场和温度场空间分布较均匀,烘干介质场层间的涡流消失,烘干室边界与内部中心位置温差很小,温度分布更均匀。结论:优化烘干装置结构可明显改善流场和温度场分布,提升烘干效果。 相似文献
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目的:分析新型双圆弧齿轮泵内部流场脉动特性的影响因素,采用合理参数以提高齿轮泵输出效率。方法:建立齿轮泵的二维流场仿真模型,采用计算流体力学软件Fluent进行仿真分析,研究不同齿顶间隙、不同齿轮偏心距、负载及转速对齿轮泵出油口瞬时流量、流量脉动、流场特性的影响。结果:随着齿顶间隙增大,齿轮泵出口流量逐渐减小,当齿顶间隙为0.09 mm时,出口流量脉动系数最小为0.135,为该结构参数下齿轮泵最佳齿顶间隙;受负载压力和转速的影响,齿轮泵中心轴线产生偏差,随着齿轮泵转子中心轴线偏心距增加,齿轮泵出口流量逐渐增大,当偏心距为0.05 mm时,齿轮泵出口流量比无中心偏差时增加了5.09%,提高了流量输出。结论:齿轮泵流量特性主要影响因素为转子转速和齿顶间隙,中心偏差的影响较小。 相似文献
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Gianpiero Pataro Beatrice SenatoreGiorgio Donsì Giovanna Ferrari 《Journal of food engineering》2011,105(1):79-88
The effects of both the electric and flow parameters on the lethality and energy efficiency of a pulsed electric fields (PEF) treatment were studied. An experimental plan was designed in order to study the microbial inactivation of Saccharomyces cerevisiae and Escherichia coli cells inoculated in a buffer solution. The following process parameters were taken into consideration: electric field strength (13-30 kV/cm), total specific energy input (20-110 J/mL), flow rate of the processed stream (1-4 L/h) and number of passes through the chamber (up to 5).The results showed that, at a fixed flow rate (2 L/h), microbial inactivation of both microbial strains increased with increasing field strength and applied energy input. The maximum inactivation level (5.9 Log-cycles for S. cerevisiae and 7.0 Log-cycles for E. coli) corresponded to the more intensive PEF treatment (30 kV/cm and 110 J/mL). However, for any given field strength applied, the inactivation rate decreased by increasing the energy input. This behavior was attributed to the presence of heterogeneous treatment conditions due, for example, to a different morphology (size and shape) or cell membrane (composition, structure), a local variation of the electric field strength in the treatment chamber, the tendency of microbial cells to form clusters, or a non-uniform distribution of the residence time of the product in the PEF chamber.A more effective stirring of the microbial suspensions which was achieved, at a fixed field strength (18 kV/cm), either by increasing the flow rate with a single pass operation through the PEF chamber, or by operating in re-circulating mode at a constant flow rate, provided a significant increase in the effectiveness and energy efficiency of the pulse treatment.A mathematical model based on the Weibull distribution adequately described the inactivation kinetics of both microbial strains under different flow dynamic conditions. 相似文献
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《Innovative Food Science and Emerging Technologies》2007,8(2):205-212
A pulsed electric field (PEF) system was designed and constructed using modern IGBT technology. The main focus of this work was to design a new PEF treatment chamber that operate at high electric field intensities with limited increase in liquid temperature and limited fouling of electrodes. Four multi-pass treatment chambers were designed consisting of two stainless steel mesh electrodes in each chamber, with the treated fluid flowing through the openings of the mesh electrodes. The two electrodes are electrically isolated from each other by an insulator element designed to form a small orifice where most of the electric field is concentrated. Dielectric breakdown inside the chambers was prevented by removing the electrodes far from the narrow gap. The effect of PEF treatment on the inactivation of gram-negative Escherichia coli ATCC 25922 suspended in simulated milk ultra-filtrate (SMUF) of 100%, 66.67% and 50% w/w was investigated. Treatments with the same electrical input power but with higher electric field strengths provided larger degree of killing. The effect of PEF treatment using suspensions at different flow rates and different pulse frequencies was also investigated. In general, the inactivation rate of E. coli increased with increasing electric field strength, treatment time and processing temperature. More than 6 log reductions in E. coli suspended in SMUF was achieved using electric field intensity in the range of (37.2–49.6 kV/cm) with a treatment temperature not exceeding 38 °C.Industrial relevanceThis paper presents an innovative pulsed electric field system for non-thermal pasteurisation of liquid food. The system design provides uniform distribution of electric field and minimum fouling of electrodes. This PEF system can be scaled up to any industrial size, making it attractive for industrial applications. 相似文献
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研究了在入口风速不变的条件下,通过改进结构和改变冻品参数,增大流场气流平均速度,达到降低装置能耗、提高冻结效率的目的。建立二维紊流模型,采用SIMPLE算法,对未放冻品原有结构的流场、开孔和增设隔板后的流场、食品不同摆放密度的流场以及不同食品高度的流场进行模拟计算分析,结果表明:网带的对螺旋塔内流场的平均速度影响小。增设隔板和开孔有利于提高流场内气流的平均速度,增加热交换的充分性。冻品摆放密度增加需要综合考虑气流平均速度、压力、和风机功率等因素。冻品高度在满足不超过孔的位置高度下,增高能增加气流平均速度。 相似文献
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为探究凝聚槽类型对转杯内气流场的影响,采用Solidworks建立三维转杯纺纱通道的几何模型,应用Fluent流体计算软件对纺纱通道内气流场进行数值模拟,并根据计算结果分析纺纱通道内气流场的分布,包括压力场分布和速度场分布。模拟结果表明:以U型槽为例,转杯内静压绝大部分处于-8 287.91~-2 370.92 Pa之间,输棉通道出口与凝聚槽交汇处存在一小部分高压区;输棉通道内的气流呈加速运动,并在出口处达到最大值,约为220 m/s;在相同工艺条件下,V型槽内的速度与静压均高于U型槽,凝聚须条纤维间抱合力较U型槽更紧密,捻度更易于传递,所纺纱线强度更高。 相似文献