红外辐射加热干燥操作条件优化的研究

发布时间：2018-03-10 00:24

本文选题：红外干燥　切入点：温度场分布　出处：《天津科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：红外辐射干燥是一种新型的干燥方式,由于其具有高效、节能、卫生、便于调节和控制等特点,越来越受到人们的重视。随着红外辐射干燥的使用越来越广泛,人们对干燥过程中的操作条件优化提出了更高的要求,本文通过对红外辐射场温度分布规律的分析找到最佳辐射方案；通过物料干燥实验研究了不同操作参数对干燥过程的影响；最后建立物料干燥模型作为变温干燥实验设计的参考。在红外辐射干燥生产中,红外辐射器的选择关系到干燥的效率和节能问题,因此本文综合分析了几种目前比较常用的辐射器类型,并根据本次实验的特点选择乳白石英发射器作为红外发射器。红外辐射场的分布关系到干燥过程的一致性以及干燥设备的设计。在大规模生产和连续生产过程中,辐射场所起的作用尤为明显。通过实验获得了不同干燥功率和不同辐射器间距情况下的温度分布场,实验结果表明在特定的功率下辐射场温度分布均匀性与辐射器间距有关,并且在辐射器间距由小到大的过程中有最合适距离。通过仿真软件模拟了不同方向上红外辐射场温度的分布、不同数量辐射器的分布和在不同风速条件下辐射场温度分布,在无风条件下找到了满足温度分布均匀条件的最佳辐射器排布方案。不同的辐射角度和辐射功率、物料厚度都会影响红外辐射干燥的效率和产品品质,本文分析了不同条件下的物料干燥特性,然后通过变温干燥找到了最为节能高效的干燥方式：对于南瓜浆等多孔性状物料干燥,先采用中温干燥,达到约85%水分含量时,采用高温短时间快速干燥,待干燥速率开始下降时,采用低温降温干燥的方法,物料的干燥效果最好。干燥数学模型的建立可以帮助我们掌握干燥过程,利用不同功率条件下的实验数据,对不同干燥模型进行了验证,结果表明page模型、Logarithmic模型、Wang and Singh模型、Midilli-Kucuk拟合程度较好,并得出了Logarithmic模型中各个参数与输入功率的关系,得到了南瓜浆干燥模型,该模型作为可以为南瓜浆变温干燥设计的参考,进一步优化干燥进程。
[Abstract]:Infrared radiation drying is a new type of drying method. Because of its high efficiency, energy saving, hygiene, easy to adjust and control, more and more people pay attention to it. Higher requirements have been put forward for the optimization of the operating conditions in the drying process. In this paper, the best radiation scheme is found by analyzing the temperature distribution of infrared radiation field. The effects of different operating parameters on the drying process were studied through material drying experiments. Finally, the drying model of materials was established as a reference for the experimental design of variable temperature drying. The choice of infrared radiator is related to the efficiency and energy saving of drying, so this paper synthetically analyzes several types of radiators that are commonly used at present. According to the characteristics of this experiment, the white quartz emitter is selected as infrared emitter. The distribution of infrared radiation field is related to the consistency of drying process and the design of drying equipment. The temperature distribution field under different drying power and different radiator spacing is obtained by experiments. The experimental results show that the uniformity of radiation field temperature distribution is related to the radiator spacing under specific power. The temperature distribution of infrared radiation field in different directions, the distribution of different number of radiators and the temperature distribution of radiation field under different wind speed are simulated by simulation software. Under the condition of no wind, the optimal radiator arrangement scheme satisfying the condition of uniform temperature distribution has been found. Different radiation angle, radiation power, material thickness will affect the efficiency of infrared radiation drying and the product quality. In this paper, the drying characteristics of materials under different conditions are analyzed, and the most energy saving and efficient drying method is found by means of variable temperature drying. For the porous materials such as pumpkin pulp, the medium temperature drying is first used to reach about 85% moisture content. When the drying rate begins to decrease, the drying effect of the material is the best by using the method of low temperature cooling and drying. The establishment of the drying mathematical model can help us to master the drying process. Using the experimental data under different power conditions, different drying models are verified. The results show that the page model and the Wang and Singh model fit well, and the relationship between the parameters of the Logarithmic model and the input power is obtained. The drying model of pumpkin pulp was obtained. The model can be used as a reference for the design of pumpkin pulp drying at variable temperature, and the drying process can be further optimized.
【学位授予单位】：天津科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TS205

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