Name: design and optimization strategies of a high-performance vented box
Uploaded: 2023-06-09T14:00:00
Description: Watch this Scientific Journal Video about Design and Optimization Strategies of a High-Performance Vented Box at JoVE.com

本研究由温州市科学技术局资助（温州市重大科技创新项目，批准号：ZG2020029）。该研究由温州市科学技术协会资助，批准号为KJFW09。本研究由温州市重点科学与研究计划（ZN2022001）资助。

1. 预仿真处理
注意：考虑到管道阵列，使用三维软件建立通风箱模型的三维下半部分和上半部分，并将其保存为X_T文件，整体尺寸如图 1所示。配置显示在材料表中。
<ol><li>运行仿真软件并将 网格 组件从“组件系统”拖动到“项目原理图”窗口。将其命名为“底部”。右键单击 几何 图形，然后单击 浏览 </...

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	<li>Villa-Rodriguez, J. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Maintaining+antioxidant+potential+of+fresh+fruits+and+vegetables+after+harvest.">Maintaining antioxidant potential of fresh fruits and vegetables after harvest.</a> Critical Reviews in Food Science and Nutrition. 55 (6), 806-822 (2015).</li><li>Mozaffari, H., Lafreni&#232;re, J., Conklin, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Does+eating+more+variety+of+fruits+and+vegetables+reduce+risk+of+cancer?+Findings+from+a+systematic+review+and+meta-analysis.">Does eating more variety of fruits and vegetables reduce risk of cancer? Findings from a systematic review and meta-analysis.</a> Current Developments in Nutrition. 4, 339-339 (2020).</li><li>Wu, S., Fisher-Hoch, S. P., Reininger, B. M., Lee, M., McCormick, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fruit+and+vegetable+intake+is+inversely+associated+with+cancer+risk+in+Mexican-Americans.">Fruit and vegetable intake is inversely associated with cancer risk in Mexican-Americans.</a> Nutrition and Cancer. 71 (8), 1254-1262 (2019).</li><li>Nan, M., Xue, H., Bi, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Contamination,+detection+and+control+of+mycotoxins+in+fruits+and+vegetables.">Contamination, detection and control of mycotoxins in fruits and vegetables.</a> Toxins. 14 (5), 309 (2022).</li><li>Alothman, M., Bhat, R., Karim, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+radiation+processing+on+phytochemicals+and+antioxidants+in+plant+produce.">Effects of radiation processing on phytochemicals and antioxidants in plant produce.</a> Trends in Food Science &amp; Technology. 20 (5), 201-212 (2009).</li><li>Ayala-Zavala, J. F., Wang, S. Y., Wang, C. Y., Gonz&#225;lez-Aguilar, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+storage+temperatures+on+antioxidant+capacity+and+aroma+compounds+in+strawberry+fruit.">Effect of storage temperatures on antioxidant capacity and aroma compounds in strawberry fruit.</a> LWT-Food Science and Technology. 37 (7), 687-695 (2004).</li><li>Piljac-&#381;egarac, J., &#352;amec, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antioxidant+stability+of+small+fruits+in+postharvest+storage+at+room+and+refrigerator+temperatures.">Antioxidant stability of small fruits in postharvest storage at room and refrigerator temperatures.</a> Food Research International. 44 (1), 345-350 (2011).</li><li>Lal Basediya, A., Samuel, D. V. K., Beera, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaporative+cooling+system+for+storage+of+fruits+and+vegetables+-+a+review.">Evaporative cooling system for storage of fruits and vegetables - a review.</a> Journal of Food Science and Technology. 50 (3), 429-442 (2013).</li><li>Sandhya, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modified+atmosphere+packaging+of+fresh+produce:+Current+status+and+future+needs.">Modified atmosphere packaging of fresh produce: Current status and future needs.</a> LWT-Food Science and Technology. 43 (3), 381-392 (2010).</li><li>Bassey, E. J., Cheng, J. H., Sun, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+nonthermal+and+thermal+pretreatments+for+enhancing+drying+performance+and+improving+quality+of+fruits+and+vegetables.">Novel nonthermal and thermal pretreatments for enhancing drying performance and improving quality of fruits and vegetables.</a> Trends in Food Science &amp; Technology. 112, 137-148 (2021).</li><li>Mieszczakowska-Fr&#261;c, M., Celejewska, K., P&#322;ocharski, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+innovative+technologies+on+the+content+of+vitamin+C+and+its+bioavailability+from+processed+fruit+and+vegetable+products.">Impact of innovative technologies on the content of vitamin C and its bioavailability from processed fruit and vegetable products.</a> Antioxidants. 10 (1), 54 (2021).</li><li>Xue, Z., Li, J., Yu, W., Lu, X., Kou, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+nonthermal+preservation+technologies+on+antioxidant+activity+of+fruits+and+vegetables:+A+review.">Effects of nonthermal preservation technologies on antioxidant activity of fruits and vegetables: A review.</a> Food Science and Technology International. 22 (5), 440-458 (2016).</li><li>Olaimat, A. N., Holley, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Factors+influencing+the+microbial+safety+of+fresh+produce:+a+review.">Factors influencing the microbial safety of fresh produce: a review.</a> Food Microbiology. 32 (1), 1-19 (2012).</li><li>Caleb, O. J., Mahajan, P. V., Al-Said, F. A. J., Opara, U. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modified+atmosphere+packaging+technology+of+fresh+and+fresh-cut+produce+and+the+microbial+consequences-a+review.">Modified atmosphere packaging technology of fresh and fresh-cut produce and the microbial consequences-a review.</a> Food and Bioprocess Technology. 6 (2), 303-329 (2013).</li><li>Waghmare, R. B., Mahajan, P. V., Annapure, U. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modelling+the+effect+of+time+and+temperature+on+respiration+rate+of+selected+fresh-cut+produce.">Modelling the effect of time and temperature on respiration rate of selected fresh-cut produce.</a> Postharvest Biology and Technology. 80, 25-30 (2013).</li><li>Praeger, U., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Airflow+distribution+in+an+apple+storage+room.">Airflow distribution in an apple storage room.</a> Journal of Food Engineering. 269, 109746 (2020).</li><li>Praeger, U., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+room+layout+on+airflow+distribution+in+an+industrial+fruit+store.">Influence of room layout on airflow distribution in an industrial fruit store.</a> International Journal of Refrigeration. 131, 714-722 (2021).</li><li>Berry, T. M., Delele, M. A., Griessel, H., Opara, U. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Geometric+design+characterisation+of+ventilated+multi-scale+packaging+used+in+the+South+African+pome+fruit+industry.">Geometric design characterisation of ventilated multi-scale packaging used in the South African pome fruit industry.</a> Agricultural Mechanization in Asia, Africa, and Latin America. 46 (3), 34-42 (2015).</li><li>Dehghannya, J., Ngadi, M., Vigneault, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mathematical+modeling+of+airflow+and+heat+transfer+during+forced+convection+cooling+of+produce+considering+various+package+vent+areas.">Mathematical modeling of airflow and heat transfer during forced convection cooling of produce considering various package vent areas.</a> Food Control. 22 (8), 1393-1399 (2011).</li><li>Dehghannya, J., Ngadi, M., Vigneault, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transport+phenomena+modelling+during+produce+cooling+for+optimal+package+design:+thermal+sensitivity+analysis.">Transport phenomena modelling during produce cooling for optimal package design: thermal sensitivity analysis.</a> Biosystems Engineering. 111 (3), 315-324 (2012).</li><li>Delele, M. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combined+discrete+element+and+CFD+modelling+of+airflow+through+random+stacking+of+horticultural+products+in+vented+boxes.">Combined discrete element and CFD modelling of airflow through random stacking of horticultural products in vented boxes.</a> Journal of Food Engineering. 89 (1), 33-41 (2008).</li><li>Ilangovan, A., Curto, J., Gaspar, P. D., Silva, P. D., Alves, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CFD+modelling+of+the+thermal+performance+of+fruit+packaging+boxes-influence+of+vent-holes+design.">CFD modelling of the thermal performance of fruit packaging boxes-influence of vent-holes design.</a> Energies. 14 (23), 7990 (2021).</li><li>Gong, Y. F., Cao, Y., Zhang, X. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Forced-air+precooling+of+apples:+Airflow+distribution+and+precooling+effectiveness+in+relation+to+the+gap+width+between+tray+edge+and+box+wall.">Forced-air precooling of apples: Airflow distribution and precooling effectiveness in relation to the gap width between tray edge and box wall.</a> Postharvest Biology and Technology. 177, 111523 (2021).</li><li>Guo, R., Li, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heat+dissipation+analysis+and+optimization+of+lithium-ion+batteries+with+a+novel+parallel-spiral+serpentine+channel+liquid+cooling+plate.">Heat dissipation analysis and optimization of lithium-ion batteries with a novel parallel-spiral serpentine channel liquid cooling plate.</a> International Journal of Heat and Mass Transfer. 189, 122706 (2022).</li><li>Chen, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimization+of+geometric+parameters+of+hydraulic+turbine+runner+in+turbine+mode+based+on+the+orthogonal+test+method+and+CFD.">Optimization of geometric parameters of hydraulic turbine runner in turbine mode based on the orthogonal test method and CFD.</a> Energy Reports. 8, 14476-14487 (2022).</li><li>Yun-De, S., Hai-Dong, Q., Sun, B., Li, Z. Z., Cao, K. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flow+analysis+of+fresh+vegetable+box+based+on+multiporosity+material.">Flow analysis of fresh vegetable box based on multiporosity material.</a> International Journal of Education and Management Engineering. 2 (1), 29 (2012).</li><li>Elansari, A. M., Mostafa, Y. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vertical+forced+air+pre-cooling+of+orange+fruits+on+bin:+Effect+of+fruit+size,+air+direction,+and+air+velocity.">Vertical forced air pre-cooling of orange fruits on bin: Effect of fruit size, air direction, and air velocity.</a> Journal of the Saudi Society of Agricultural Sciences. 19 (1), 92-98 (2020).</li></ol>

由于其高性能和复杂的结构，本研究基于建模软件构建了一种通风箱。我们通过仿真软件分析了内部流动。仿真软件以其先进的物理建模功能而闻名，其中包括湍流建模、单相和多相流、燃烧、电池建模、流固耦合等。本文采用的样品选择方法为正交实验设计方法，因其方法科学、操作简单、节约成本、效果显著，适用于机械生产等领域。范围分析法可以通过简单的计算得到实验的一级和次级因?...

新鲜蔬菜和水果在人类食物消费中所占比例很高，不仅因为它们味道好，形态诱人，而且对人们获得营养和保持健康有很大的好处1。许多研究表明，新鲜水果和蔬菜在预防许多疾病方面发挥着独特的作用2，3。在新鲜果蔬的贮藏过程中，真菌、光照、温度和相对湿度是其变质的重要原因4，5，6，7，8。这些外部条件通过影响内部代谢或化学反应来影响储存的新鲜水果和蔬菜的质量9。
水果和蔬菜的常见处理技术包括非保温和保温。其中，热预处理对干燥过程有积极作用，但也会对产品质量产生不利影响，如营养成分损失、风味和气味变化、颜色变化等10，11。因此，近年来，产品的非保温从研究角度受到关注，以满足消费者对生鲜产品的需求。目前主要有辐射处理、脉冲电场、臭氧处理、食用涂料、密相二氧化碳等非保温技术来贮藏果蔬，但这些技术往往存在缺点，如设备要求大、价格高、使用成本高等12.因此，设计结构简单、成本低廉、控制方便的保鲜设备对食品工业非常有意义。
在水果和蔬菜的储存环境中，适当的空气循环系统有助于消除产品本身产生的热量，减少温度梯度，并保持其所在空间的温度和湿度。适当的空气流通还可以防止由于呼吸和真菌感染引起的体重减轻13，14，15。已经对不同结构内的气流进行了大量研究。Praeger等人16，17通过传感器测量了仓库中不同风扇运行功率下不同位置的风速，发现由于垂直高度不同，风速可能相差七倍，每个位置的风速与风扇运行功率呈正相关。此外，一项研究考察了货物排列和风扇数量对气流的影响，得出的结论是，增加一些风扇位置的距离，合理选择风扇数量有助于改善效果。Berry等人18研究了不同果实贮藏环境中气流对包装盒气孔分布的影响。利用仿真软件，Dehghannya 等人 19，20 研究了包装壁上不同通风面积、数量和分布位置的包装内强制预冷空气的气流状态，并获得了各参数对气流状态的非线性影响。Delele等人21应用计算流体动力学模型来研究随机分布在不同形式的通风箱中的产品对气流的影响。他们发现，产品尺寸、孔隙率和箱孔比对气流的影响更大，而随机填充对气流的影响较小。Ilangovan等人22研究了三种包装结构之间的气流模式和热行为，并将结果与参考结构模型进行了比较。结果表明，由于通风口的位置和设计不同，箱内的热量分布不均匀。Gong等人23优化了托盘边缘与容器壁之间的间隙宽度。
本文中使用的技术包括仿真和优化方法。前者的原理是使用有限体积方法21对控制方程进行离散化和数值求解。本文中使用的优化方法称为正交优化24。正交检验是一种典型的多因素多水平分析方法。使用该方法构建的正交表包含均匀分布在设计空间中的代表性点，可以直观地描述整个设计空间并进行检查。即代表全因素检验的点数较少，大大节省了时间、人力、物力和财力。正交试验已广泛应用于电力系统、化学、土木工程等领域的实验设计25.
本研究的目的是设计和优化高性能通风箱。通风箱可以定义为原始箱，包括气体控制装置，该装置将气体均匀地分散在箱内。速度均匀性是指空气流过通风箱的均匀程度。Yun-De等人26 先前已经表明，多孔材料的性质对新鲜蔬菜箱的速度均匀性具有重要影响。在一些实验中，在测试室的顶部和底部都留下了一个增压室或调制室，以保证强制或诱导空气的均匀分布27。本文设计的通风箱包含带有锯齿形孔的管道阵列。控制通风箱中的气流分布是主要的保存策略。在通风箱的左右两侧平行设置两个相同尺寸的进气口，在通风箱的上侧设置一个出口。设计通风箱的内部结构是本研究的关键。换句话说，管道和孔的数量是改变通风箱内部结构的重要参数。参考模型有 10 个管道。两个中间管道各有 10 个孔，这些孔在管道上交错排列。从中间到外管的孔数一次增加两个。
也就是说，当我们保持新鲜的蔬菜、水果等产品时，持续稳定的气流可以减少产品的呼吸，减少乙烯等有害物质用于产品保鲜，降低产品本身产生的温度。由于通风箱的参数不同，不容易获得所需的气流状态，这会影响通风箱的保存性能。因此，该项目以通风箱的内部气流速度均匀性为控制目标。对通风箱的结构参数进行了敏感性分析。采用正交实验设计筛选样品。我们使用范围分析来优化三个结构参数的组合。同时，验证了优化结果的可取性。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Hardware</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>NVIDIA GPU</td>
			<td>NVIDIA</td>
			<td>N/A</td>
			<td>An NVIDIA GPU is needed as some of the software frameworks below will not work otherwise. https://www.nvidia.com</td>
		</tr>
		<tr>
			<td>Software</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ansys-Workbench</td>
			<td>ANSYS</td>
			<td>N/A</td>
			<td>Multi-purpose finite element method computer design program software.https://www.ansys.com</td>
		</tr>
		<tr>
			<td>SOLIDWORKS</td>
			<td>Dassault Systemes</td>
			<td>N/A</td>
			<td>SolidWorks provides different design solutions, reduces errors in the design process, and improves product quality 
			www.solidworks.com</td>
		</tr>
		<tr>
			<td>SPSS</td>
			<td>IBM</td>
			<td>N/A</td>
			<td>Software products for statistical analytical operations, data mining, predictive analysis, and decision support tasks software.https://www.ibm.com</td>
		</tr>
	</tbody>
</table>

design and optimization strategies of a high-performance vented box

本研究旨在通过恒能耗通风箱内部结构设计，解决通风箱内气流分布不均匀导致通风箱气流混乱、性能差的问题。最终目标是均匀分布通风箱内的气流。对3个结构参数进行了敏感性分析：管道数量、中间管道孔数和从内管到外管的每个增量数。采用正交实验设计，共确定了16组随机阵列，共3个结构参数，4个水平。商业软件用于为选定的实验点构建3D模型，该数据用于获得气流速度，然后用于获得每个实验点的标准偏差。根据范围分析，对3个结构参数的组合进行了优化。也就是说，建立了一种考虑通风箱性能的高效、经济的优化方法，可以广泛用于延长生鲜食品的储存时间。

按照协议，前三个部分是最重要的，包括建模、网格划分和仿真，所有这些都是为了获得流速的标准偏差。然后，通过正交实验和距离分析完成了通风箱的结构优化。协议中使用的模型是参考通风箱模型，它是从参考获得的初始模型。图4显示了参考通风箱模型流线型流程的结果，图5显示了用于灵敏度分析的模型之一通风箱流线型的结果。...

Watch this Scientific Journal Video about Design and Optimization Strategies of a High-Performance Vented Box at JoVE.com

Design and Optimization Strategies of a High-Performance Vented Box

在这里，我们提出了范围分析方法，以优化正交实验设计产生的采样点，以确保新鲜食品可以通过调节气流模式长时间存放在通风箱中。

高性能通风箱的设计与优化策略

This study aims to solve the problems of air flow chaos and poor performance in a vented box caused by the heterogeneous distribution of airflow through ...

本研究旨在通过设计通风箱内部结构，在能耗恒定的前提下，解决因气流分布不合理而导致通风箱气流混乱和性能不佳的问题。建立了一种考虑通风箱性能的高效、经济的优化方法，该方法易于用于延长生鲜食品的储存时间。本研究的目的是设计和优化一种高性能通风箱，其中包含带有锯齿形孔的管道阵列。在通风箱的左右两侧平行设置了两个相同大小的进气口，在通风箱的上侧设置了一个出口。参考模型有 10 个管道。两个中间管道分别有10个孔，这些孔在管道上交错排列。从中间到外管的孔数一次增加两个。考虑到管道阵列，使用三维软件建立通风箱模型的三维下半部分和上半部分，并将其保存为XT文件。运行仿真软件并将网格组件从组件系统拖动到项目原理图窗口。将其命名为底部。右键单击几何图形，然后单击浏览以导入底部的 XT 文件。右键单击几何图形，然后单击新建设计建模器几何图形以进入网格设计建模器窗口。单击“生成”以显示底部模型。右键单击上表面，然后单击命名选区以将其重命名为“通风框上部”。选择选择过滤器实体。右键单击底部模型以选择命名选择并重命名其底部。选择选择过滤器面，然后将选择模式切换到框选择。选择所有内曲面，然后单击鼠标右键以选择命名的选区，并将其重命名为外部内曲面，稍后定义为网格接口。返回到初始窗口。双击底部的网格。进入网格划分窗口。将物理首选项从机械更改为 CFD。单击更新以生成网格模型。返回到初始窗口。将网格组件从组件系统拖动到项目原理图窗口。将其命名为顶部。右键单击几何图形，然后单击浏览以导入顶部 XT 文件。右键单击几何图形，然后单击新建设计建模器几何图形以进入网格设计建模器窗口。单击“生成”以显示顶部模型。右键单击下表面，然后单击命名选区以将其重命名为下方的通风框。选择选择过滤器实体。右键单击顶部模型以选择命名选择并将其重命名为顶部。选择选择过滤器面。右键单击上曲面，然后单击命名选区以将其重命名为出口。返回到初始窗口。双击顶部的网格。进入网格划分窗口。将物理首选项从机械更改为 CFD。右键单击网格以在插入中选择尺寸。选择选择过滤器实体。选择图元大小的顶部模型和前 18 个模型。单击更新。返回到初始窗口。将网格组件从组件系统拖动到项目原理图窗口。将其命名为管道。通过单击几何图形导入管道 XT 文件。进入网格设计建模器窗口。通过单击生成再次显示管道模型。选取管道的两个端面，并将它们标记为入口 1 和入口 2。按主体选择的管道标记为管道。通过框选择的所有内表面都标记为内部内部表面，稍后定义为网格界面。返回到初始窗口。双击管道的网格。进入网格划分窗口。将物理首选项从机械更改为 CFD。可以通过单击更新来生成网格模型。返回到初始窗口。将仿真组件拖动到项目原理图窗口中。将三个网格组件链接到仿真组件并更新以进入。验证网格模型的质量。检查网格是否具有负体积。选择稳态因子、松弛因子、残差因子和时间尺度因子。选择默认值。进入粘性模型设置界面，选择K-ε模型。设置空气材料。将细胞区域的类型更改为流体。将通风箱上部、通风箱下部、外部内表面和内部内表面的类型从默认墙转换为界面。打开网格接口并进入创建/编辑网格接口窗口。将内表面外部与内部表面匹配。将通风盒上部与通风盒下部匹配。最后，在通风箱中创建两个网状接口，并分别命名为接口一和接口二。在速度入口窗口中将所有入口的气流速度设置为 8.9525 米/秒。在压力出口窗口中将出口的表压设置为零。在初始化之前，将解决方案初始化的样式设置为标准初始化。将迭代次数设置为 2000。单击“计算”开始模拟并返回到初始窗口，直到模拟结束。单击结果。进入差价合约发布窗口。单击工具箱中的流线型图标。选择出口从开始方向和向后方向。单击应用以生成通风箱的内部流程图。单击位置中的飞机。在方法中选择ZX平面，输入值0.6。单击“应用”（APPLY） 生成距底面 0.6 米的平面。单击工具箱中的轮廓图标。在位置中选择平面一。在变量中选择速度。在范围内选择本地。单击应用以生成速度等值线。导出上面生成的平面的流速数据。在Excel中获取流速的标准偏差。运行统计分析软件。单击数据，然后单击正交设计中的生成。在因子名称中输入管道编号，在因子标签中输入 A。单击添加并定义值，为管道数设置四个级别。单击继续并返回到生成正交设计窗口。在因子名称中输入孔号，在因子标签中输入 B。单击“添加”并定义值，为孔数设置四个级别。单击继续并返回到生成正交设计窗口。在因子名称中输入累积数，在因子标签中输入 C。单击添加并定义值以设置四个增量级别。单击继续并创建新数据文件以生成 16 个数组样本。单击变量视图以选择名义的度量和输入的角色。将其重命名为标准偏差乘以 100， 000。使用上面的采样点重复步骤 1.1 到 2.5。将得到的 16 个标准差乘以 100， 000 填充到样本列表中，以供以后优化。单击分析，然后单击一般线性模型中的单变量。将标准偏差乘以 100， 000 填充到因变量中，并将管道编号、孔数、累积数填充到固定因子中。单击模型和构建术语。将交互更改为主效果。将 A、B、C 填充到模型中。单击继续并返回到单变量窗口。单击 EM 均值并将 A、B、C 填充到显示均值中。单击继续并返回到单变量窗口。单击确定并获取优化结果。表中平均值列的最小值对应于最佳变量。双击表格。进入数据透视表窗口。单击编辑，然后单击创建图形中的条形以生成直方图。如图四和图五所示，由于通风箱的内部结构，后期通风箱的流线甚至比前者更凌乱。如图6和图7所示，作为灵敏度分析的模型之一的通风箱内的流速比较不均匀。为了更直观地了解通风箱内的流线分布，用这个公式计算标准差。表1显示了用于灵敏度分析的10组通风箱的流速标准偏差。较大的标准差表示大多数流速与其平均流速之间的较大差异。由此可见，改变通风箱的内部结构可以改变其内部流动，使流线更加合理。在设计正交试验时，本文中有三个设计变量。这三个变量中的每一个都有四个级别。如表所示，通过正交实验设计得到16组实验设计点。计算标准偏差。最后，将范围分析法作为求解最优结构参数组合的优化方法。图 8 显示了有关管道数量的结构参数的优化结果。由此，我们可以看到，当管道数为 14 时，获得最小值。图9显示了关于中间管道孔数的结构参数的优化结果。由此，我们可以看到，当中间管道中的孔数为 14 时，获得最小值。图 10 显示了结构参数的优化结果，该参数涉及从内管到外管的每个增量的数量。由此，我们可以看到，当从内管道到外管道的每个增量的数量为 4 时，获得最小值。以上分析表明，最佳组合是14号管、14号孔、累积4号。为了确认准确性，分析了最佳情况。图 4 和图 11 显示了参考模型与优化模型的流线型。图 6 和图 12 显示了参考模型内与优化模型的流速分布。表三显示了优化模型和参考模型之间的比较。可以看出，优化模型计算的标准差低于参考模型的标准差。表四显示了孔的数量从四个增加到六个，标准偏差几乎没有变化。本文通过优化通风箱结构来改善其内部环境，并通过标准差测量其内部环境的质量。标准差越小，通风箱内部气流越合理，表明本工作采用的优化方法是有效可行的。

design-and-optimization-strategies-of-a-high-performance-vented-box

Research

JoVE Journal

Engineering

Research and Development of High-performance Explosives

Developmental testing of high explosives for military applications involves small-scale formulation, safety testing, and finally detonation performance tests to verify theoretical calculations. For newly developed formulations, the process begins with small-scale mixes, thermal testing, and impact and friction sensitivity. Only then do subsequent larger scale formulations proceed to detonation testing, which will be covered in this paper. Recent advances in characterization techniques have led to unparalleled precision in the characterization of early-time evolution of detonations. The new technique of Photonic Doppler Velocimetry (PDV) for the measurement of detonation pressure will be shared and compared with traditional fiber-optic detonation velocity and plate-dent calculation of detonation pressure. In particular, the role of aluminum in explosive formulations will be discussed. Recent developments led to the development of explosive formulations that result in reaction of aluminum very early in the detonation product expansion. This enhanced reaction leads to changes in the detonation velocity and pressure due to reaction of the aluminum with oxygen in the expanding gas products.

Developmental testing of high explosives for military applications involves small-scale formulation, safety testing, and finally detonation performance tests to verify theoretical calculations. This paper will share typical development tests associated with the measurement of detonation velocity and detonation pressure.

高性能炸药的研究与发展

Developmental testing of high explosives for military applications involves small-scale formulation, safety testing, and finally detonation performance ...

科研

工程学

Probing C84-embedded Si Substrate Using Scanning Probe Microscopy and Molecular Dynamics

This paper reports an array-designed C84-embedded Si substrate fabricated using a controlled self-assembly method in an ultra-high vacuum chamber. The characteristics of the C84-embedded Si surface, such as atomic resolution topography, local electronic density of states, band gap energy, field emission properties, nanomechanical stiffness, and surface magnetism, were examined using a variety of surface analysis techniques under ultra, high vacuum (UHV) conditions as well as in an atmospheric system. Experimental results demonstrate the high uniformity of the C84-embedded Si surface fabricated using a controlled self-assembly nanotechnology mechanism, represents an important development in the application of field emission display (FED), optoelectronic device fabrication, MEMS cutting tools, and in efforts to find a suitable replacement for carbide semiconductors. Molecular dynamics (MD) method with semi-empirical potential can be used to study the nanoindentation of C84-embedded Si substrate. A detailed description for performing MD simulation is presented here. Details for a comprehensive study on mechanical analysis of MD simulation such as indentation force, Young&#39;s modulus, surface stiffness, atomic stress, and atomic strain are included. The atomic stress and von-Mises strain distributions of the indentation model can be calculated to monitor deformation mechanism with time evaluation in atomistic level.

Probing C84-embedded Si Substrate Using Scanning Probe Microscopy and Molecular Dynamics

This paper reports the nanomaterial fabrication of a fullerene Si substrate inspected and verified by nanomeasurements and molecular dynamic simulation.

探测ç<sub&gt; 84</sub&gt; - 嵌入式硅衬底利用扫描探针显微镜和分子动力学

This paper reports an array-designed C84-embedded Si substrate fabricated using a controlled self-assembly method in an ultra-high vacuum chamber. The ...

A High Performance Impedance-based Platform for Evaporation Rate Detection

This paper describes the method of a novel impedance-based platform for the detection of the evaporation rate. The model compound hyaluronic acid was employed here for demonstration purposes. Multiple evaporation tests on the model compound as a humectant with various concentrations in solutions were conducted for comparison purposes. A conventional weight loss approach is known as the most straightforward, but time-consuming, measurement technique for evaporation rate detection. Yet, a clear disadvantage is that a large volume of sample is required and multiple sample tests cannot be conducted at the same time. For the first time in literature, an electrical impedance sensing chip is successfully applied to a real-time evaporation investigation in a time sharing, continuous and automatic manner. Moreover, as little as 0.5 ml of test samples is required in this impedance-based apparatus, and a large impedance variation is demonstrated among various dilute solutions. The proposed high-sensitivity and fast-response impedance sensing system is found to outperform a conventional weight loss approach in terms of evaporation rate detection.

This paper presents an impedance-based apparatus for evaporation rate detection of solutions. It offers clear advantages over a conventional weight loss approach: a fast response, high-sensitivity detection, a small sample requirement, multiple sample measurements, and easy disassembly for cleaning and reuse purposes.

蒸发速率检测一种基于阻抗高性能平台

This paper describes the method of a novel impedance-based platform for the detection of the evaporation rate. The model compound hyaluronic acid was ...

Scalable Solution-processed Fabrication Strategy for High-performance, Flexible, Transparent Electrodes with Embedded Metal Mesh

Here, the authors report the embedded metal-mesh transparent electrode (EMTE), a new transparent electrode (TE) with a metal mesh completely embedded in a polymer film. This paper also presents a low-cost, vacuum-free fabrication method for this novel TE; the approach combines lithography, electroplating, and imprint transfer (LEIT) processing. The embedded nature of the EMTEs offers many advantages, such as high surface smoothness, which is essential for organic electronic device production; superior mechanical stability during bending; favorable resistance to chemicals and moisture; and strong adhesion with plastic film. LEIT fabrication features an electroplating process for vacuum-free metal deposition and is favorable for industrial mass production. Furthermore, LEIT allows for the fabrication of metal mesh with a high aspect ratio (i.e., thickness to linewidth), significantly enhancing its electrical conductance without adversely losing optical transmittance. We demonstrate several prototypes of flexible EMTEs, with sheet resistances lower than 1 &#937;/sq and transmittances greater than 90%, resulting in very high figures of merit (FoM) &#8211; up to 1.5 x 104 &#8211; which are amongst the best values in the published literature.

This protocol describes a solution-based fabrication strategy for high-performance, flexible, transparent electrodes with fully-embedded, thick metal mesh. Flexible transparent electrodes fabricated by this process demonstrate among the highest reported performances, including ultra-low sheet resistance, high optical transmittance, mechanical stability under bending, strong substrate adhesion, surface smoothness, and environmental stability.

具有嵌入式金属网的高性能，灵活，透明电极的可扩展解决方案处理制造策略

Here, the authors report the embedded metal-mesh transparent electrode (EMTE), a new transparent electrode (TE) with a metal mesh completely embedded in a ...

Detecting the Water-soluble Chloride Distribution of Cement Paste in a High-precision Way

To improve the accuracy of the chloride distribution along the depth of cement paste under cyclic wet-dry conditions, a new method is proposed to obtain a high-precision chloride profile. Firstly, paste specimens are molded, cured, and exposed to cyclic wet-dry conditions. Then, powder samples at different specimen depths are grinded when the exposure age is reached. Finally, the water-soluble chloride content is detected using a silver nitrate titration method, and chloride profiles are plotted. The key to improving the accuracy of the chloride distribution along the depth is to exclude the error in the powderization, which is the most critical step for testing the distribution of chloride. Based on the above concept, the grinding method in this protocol can be used to grind powder samples automatically layer by layer from the surface inward, and it should be noted that a very thin grinding thickness (less than 0.5 mm) with a minimum error less than 0.04 mm can be obtained. The chloride profile obtained by this method better reflects the chloride distribution in specimens, which helps researchers to capture the distribution features that are often overlooked. Furthermore, this method can be applied to studies in the field of cement-based materials, which require high chloride distribution accuracy.

A protocol for obtaining a water-soluble chloride profile by using a high precision milling method is presented.

高精度水泥浆水溶氯分布的检测

To improve the accuracy of the chloride distribution along the depth of cement paste under cyclic wet-dry conditions, a new method is proposed to obtain a ...

Flow-assisted Dielectrophoresis: A Low Cost Method for the Fabrication of High Performance Solution-processable Nanowire Devices

Flow-assisted dielectrophoresis (DEP) is an efficient self-assembly method for the controllable and reproducible positioning, alignment, and selection of nanowires. DEP is used for nanowire analysis, characterization, and for solution-based fabrication of semiconducting devices. The method works by applying an alternating electric field between metallic electrodes. The nanowire formulation is then dropped onto the electrodes which are on an inclined surface to create a flow of the formulation using gravity. The nanowires then align along the gradient of the electric field and in the direction of the liquid flow. The frequency of the field can be adjusted to select nanowires with superior conductivity and lower trap density. 
In this work, flow-assisted DEP is used to create nanowire field effect transistors. Flow-assisted DEP has several advantages: it allows selection of nanowire electrical properties; control of nanowire length; placement of nanowires in specific areas; control of orientation of nanowires; and control of nanowire density in the device. 
The technique can be expanded to many other applications such as gas sensors and microwave switches. The technique is efficient, quick, reproducible, and it uses a minimal amount of dilute solution making it ideal for the testing of novel nanomaterials. Wafer scale assembly of nanowire devices can also be achieved using this technique, allowing large numbers of samples for testing and large-area electronic applications.

In this paper, flow assisted dielectrophoresis is demonstrated for the self-assembly of nanowire devices. The fabrication of a silicon nanowire field effect transistor is shown as an example.

流动辅助介: 一种低成本的制备高性能溶液可纳米线器件的方法

Flow-assisted dielectrophoresis (DEP) is an efficient self-assembly method for the controllable and reproducible positioning, alignment, and selection of ...

Developing High Performance GaP/Si Heterojunction Solar Cells

To improve the efficiency of Si-based solar cells beyond their Shockley-Queisser limit, the optimal path is to integrate them with III-V-based solar cells. In this work, we present high performance GaP/Si heterojunction solar cells with a high Si minority-carrier lifetime and high crystal quality of epitaxial GaP layers. It is shown that by applying phosphorus (P)-diffusion layers into the Si substrate and a SiNx layer, the Si minority-carrier lifetime can be well-maintained during the GaP growth in the molecular beam epitaxy (MBE). By controlling the growth conditions, the high crystal quality of GaP was grown on the P-rich Si surface. The film quality is characterized by atomic force microscopy and high-resolution x-ray diffraction. In addition, MoOx was implemented as a hole-selective contact that led to a significant increase in the short-circuit current density. The achieved high device performance of the GaP/Si heterojunction solar cells establishes a path for further enhancement of the performance of Si-based photovoltaic devices.

Here, we present a protocol to develop high-performance GaP/Si heterojunction solar cells with a high Si minority-carrier lifetime.

研制高性能的 gap-硅异构太阳能电池

To improve the efficiency of Si-based solar cells beyond their Shockley-Queisser limit, the optimal path is to integrate them with III-V-based solar ...

Optimization, Test and Diagnostics of Miniaturized Hall Thrusters

Miniaturized spacecraft and satellites require smart, highly efficient and durable low-thrust thrusters, capable of extended, reliable operation without attendance and adjustment. Thermochemical thrusters which utilize thermodynamic properties of gases as a means of acceleration have physical limitations on their exhaust gas velocity, resulting in low efficiency. Moreover, these engines demonstrate extremely low efficiency at small thrusts and may be unsuitable for continuously operating systems which provide real-time adaptive control of the spacecraft orientation, velocity and position. In contrast, electric propulsion systems which use electromagnetic fields to accelerate ionized gases (i.e., plasmas) do not have any physical limitation in terms of exhaust velocity, allowing virtually any mass efficiency and specific impulse. Low-thrust Hall thrusters have a lifetime of several thousand hours. Their discharge voltage ranges between 100 and 300 V, operating at a nominal power of &lt;1 kW. They vary from 20 to 100 mm in size. Large Hall thrusters can provide fractions of millinewton of thrust. Over the past few decades, there has been an increasing interest in small mass, low power, and high efficiency propulsion systems to drive satellites of 50-200 kg. In this work, we will demonstrate how to build, test, and optimize a small (30 mm) Hall thruster capable of propelling a small satellite weighing about 50 kg. We will show the thruster operating in a large space environment simulator, and describe how thrust is measured and electric parameters, including plasma characteristics, are collected and processed to assess key thruster parameters. We will also demonstrate how the thruster is optimized to make it one of the most efficient small thrusters ever built. We will also address challenges and opportunities presented by new thruster materials.

Here, we present a protocol to test and optimize space propulsion systems based on miniaturized Hall-type thrusters.

小型化霍尔推进器的优化、测试和诊断

Miniaturized spacecraft and satellites require smart, highly efficient and durable low-thrust thrusters, capable of extended, reliable operation without ...

A 100 KW Class Applied-field Magnetoplasmadynamic Thruster

Applied-field magnetoplasmadynamic thrusters (AF-MPD thrusters) are hybrid accelerators in which electromagnetic and gas dynamic processes accelerate plasma to high speed; they have considerable potential for future space applications with the significant advantages of high specific impulse and thrust density. In this paper, we present a series of protocols for designing and manufacturing a 100 kW class of AF-MPD thruster with water-cooling structures, a 130 V maximum discharge voltage, a 800 A maximum discharge current, and a 0.25 T maximum strength of magnetic field. A hollow tantalum tungsten cathode acts as the only propellant inlet to inhibit the radial discharge, and it is positioned axially at the rear of the anode in order to relieve anode starvation. A cylindrical divergent copper anode is employed to decrease anode power deposition, where the length has been reduced to decrease the wall-plasma connecting area. Experiments utilized a vacuum system that can achieve a working vacuum of 0.01 Pa for a total propellant mass flow rate lower than 40 mg/s and a target thrust stand. The thruster tests were carried out to measure the effects of the working parameters such as propellant flow rates, the discharge current, and the strength of applied magnetic field on the performance and to allow appropriate analysis. The thruster could be operated continuously for significant periods of time with little erosion on the hollow cathode surface. The maximum power of the thruster is 100 kW, and the performance of this water-cooled configuration is comparable with that of thrusters reported in the literature.

The goal of this protocol is to introduce the design of a 100 kW class applied-field magnetoplasmadynamic thruster and relevant experimental methods.

一个100千瓦级的应用场磁等离子体动力学推进器

Applied-field magnetoplasmadynamic thrusters (AF-MPD thrusters) are hybrid accelerators in which electromagnetic and gas dynamic processes accelerate ...

Structural Design and Manufacturing of a Cruiser Class Solar Vehicle

Cruisers are multi-occupant solar vehicles that are conceived to compete in long-range (over 3,000 km) solar races based on the best compromise between the energy consumption and the payload. They must comply to the race&#39;s rules regarding the overall dimensions, the solar panel size, functionality, and safety and structural requirements, while the shape, the materials, the powertrain, and the mechanics are considered at the discretion of the designer. In this work, the most relevant aspects of the structural design process of a full-carbon fiber-reinforced plastic solar vehicle are detailed. In particular, the protocols used for the design of the lamination sequence of the chassis, the leaf springs structural analysis, and the crash test numerical simulation of the vehicle, including the safety cage, are described. The complexity of the design methodology of fiber-reinforced composite structures is compensated by the possibility of tailoring their mechanical characteristics and optimizing the overall weight of the car.

In this work, several aspects related to the structural design process of a full-carbon fiber-reinforced plastic solar vehicle are detailed, focusing on the monocoque chassis, the leaf springs, and the vehicle as a whole during a crash test.

巡洋舰级太阳能车的结构设计与制造

Cruisers are multi-occupant solar vehicles that are conceived to compete in long-range (over 3,000 km) solar races based on the best compromise between ...