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Transport phenomenon in jet impingement baking.

机译:射流冲击烘烤中的运输现象。

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摘要

In food industry, hot air jet impingement ovens are used to bake pizza shells, crackers, cookies, and to toast ready-to-eat cereals. Despite its significant applications and advantages (faster processing and better quality products) in food processing industry, there is a very limited understanding of detailed transport processes (heat and mass transport) involved in jet impingement baking.;To develop quantitative understanding of transport processes during jet impingement baking, we have modeled the flow field and its associated thermal transport phenomenon for a cookie shaped and a hot dog geometry using numerical simulation and have validated it using experimental data. To predict temperature and moisture distribution during baking, we have developed four different baking models based on coupled heat and mass transfer. These models differ based on coupling of heat and mass transport terms, vapor transport, thermodiffusion and stages of a baking process.;Results of flow field and its associated thermal transport studies demonstrated that numerical simulation approach can be used to predict both flow field and thermal transport during jet impingement baking. The results highlight that local and average surface heat transfer coefficient values are a function of nozzle to plate spacing, jet inlet velocity and geometry of target product. Comparison of temperature and moisture profiles among the models show significant differences in temperature and moisture profile. Based on comparison of these models, we established that vapor transport process is important for modeling of a baking process, while thermo-diffusion process does not make a significant contribution to moisture transport. The results also demonstrate that introduction of stages in baking based on empirical approaches can introduce artificial steps in temperature-time profile. Comparison of numerically predicted center point temperature with experimental measurements in a potato disk shows that modified model II (with vapor transport and a single stage baking process) provides the best match with the experimentally measured data. In summary, we have modeled the complete transport process during jet impingement baking, which can predict the baking time, crust thickness, temperature and moisture distributions within the food for a given jet velocity and air temperature.
机译:在食品工业中,热风冲击式烤箱用于烘烤披萨壳,饼干,饼干,以及烘烤即食谷物。尽管其在食品加工业中具有重要的应用和优势(加工速度更快,产品质量更高),但对于喷射冲击烘焙涉及的详细运输过程(热和大量运输)的了解非常有限。射流冲击烘烤,我们使用数值模拟对曲奇形状和热狗几何形状的流场及其相关的热传递现象进行了建模,并使用实验数据对其进行了验证。为了预测烘焙过程中的温度和水分分布,我们基于传热和传质的关系开发了四种不同的烘焙模型。这些模型基于传热和传质条件,蒸汽传递,热扩散和烘烤过程的阶段而有所不同。;流场的结果及其相关的热传递研究表明,数值模拟方法可用于预测流场和热量喷射冲击烘烤过程中的运输。结果表明,局部和平均表面传热系数值是喷嘴到板间距,射流入口速度和目标产品几何形状的函数。模型之间温度和湿度曲线的比较显示温度和湿度曲线存在显着差异。通过对这些模型的比较,我们确定蒸气传输过程对于烘焙过程的建模非常重要,而热扩散过程对水分传输没有显着贡献。结果还表明,基于经验方法在烘焙阶段中引入阶段可以在温度-时间曲线中引入人为步骤。将数值预测的中心点温度与马铃薯圆盘中的实验测量值进行比较表明,改进后的模型II(具有蒸汽传输和单阶段烘烤过程)与实验测量数据最匹配。总而言之,我们对射流冲击式烘烤过程中的完整运输过程进行了建模,可以在给定的射流速度和空气温度下预测烘烤时间,外壳厚度,温度和水分在食品中的分布。

著录项

  • 作者

    Nitin, Nitin.;

  • 作者单位

    Rutgers The State University of New Jersey - New Brunswick.;

  • 授予单位 Rutgers The State University of New Jersey - New Brunswick.;
  • 学科 Agriculture Food Science and Technology.;Engineering Agricultural.;Engineering Mechanical.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 271 p.
  • 总页数 271
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 农产品收获、加工及贮藏;农业工程;机械、仪表工业;
  • 关键词

  • 入库时间 2022-08-17 11:37:51

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