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Theoretical and Experimental Analysis of Heat Transfer and Condensation in Micro-Ribbed Tubes

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Fluid Dynamics & Materials Processing 2023年第6期19卷 1411-1424页

作者： daoming shen Jinhong Xia Chao Gui Songtao Xue Xinxiang University Xinxiang453000China Department of Architecture Tohoku Institute of TechnologySendai982-8577Japan

The thermal transmission coefficient for a micro-ribbed tube has been determined using theoretical relationships and the outcomes of such calculations have been compared with experiments conducted using a R1234yf refrigerant undergoing condensation.In particular four theoretical single-phase flow and three multi-phase flow models have been used in this regard.The experimental results show that:the Oliver et al.criterion equation overestimates the experimental results as its accuracy is significantly affected by the specific conditions realized inside micro-fin tubes;the Miyara et al.criterion equation prediction error is less than 15%;the Cavallini et al.approach gives the highest prediction accuracy;the Goto et al.model overestimates the test data.Such results are critically discussed and some indications for the improvement of such models are provided.

关键词： Micro-ribbed tube flow condensation thermal transmission coefficient dimensionless criterion equation

A New Model for the Characterization of Frozen Soil and Related Latent Heat Effects for the Improvement of Ground Freezing Techniques and Its Experimental Verification

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Fluid Dynamics & Materials Processing 2019年第1期15卷 63-76页

作者： daoming shen Hua Si Jinhong Xia Shunqun Li Xinxiang University 191 Jinsui AvenueXinxiang453000China Tianjin Chengjian University 26 Jinjing RoadTianjin300384China

The correct determination of thermal parameters,such as thermal conductivity and specific heat of soil during freezing,is the most important and basic problem for the construction of an appropriate freezing method.In this study,a calculation model of three stages of soil temperature was established.At the unfrozen and frozen stages,the specific temperatures of dry soil,water,and ice are known.According to the principle of superposition,a calculation model of unfrozen and frozen soils can be established.Informed by a laboratory experiment,the latent heat of the adjacent zone was calculated for the freezing stage based on different water contents in the temperature section.Both the latent and specific heat of water,ice,and particles were calculated via superposition of the weight percentage content.A calculation model of the specific heat of the freezing stage was built,which provides both guidance and theoretical basis for the calculation of the specific heat of frozen soil.

关键词： Freezing construction latent heat frozen soil specific heat

Experimental Analysis of the Performances of Unit Refrigeration Systems Based on Parallel Compressors with Consideration of the Volumetric and Isentropic Efficiency

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Fluid Dynamics & Materials Processing 2020年第3期16卷 489-500页

作者： daoming shen Chao Gui Jinhong Xia Songtao Xue College of Civil Engineering and Architecture Xinxiang UniversityXinxiang453000China Research Institute of Structural Engineering and Disaster Reduction Tongji UniversityShanghai20092China Department of Architecture Tohoku Institute of TechnologySendai982-8577Japan

The performances of a refrigeration unit relying on compressors working in parallel have been investigated considering the influence of the compressor volumetric efficiency and isentropic efficiency on the compression ratio.Moreover,the following influential factors have been taken into account:evaporation temperature,condensation temperature and compressor suction-exhaust pressure ratio for different opening conditions of the compressor.The following quantities have been selected as the unit performance measurement indicators:refrigeration capacity,energy efficiency ratio(COP),compressor power consumption,and refrigerant flow rate.The experimental results indicate that the system refrigeration capacity and COP decrease with a decrease in evaporation temperature,increase of condensation temperature,and increase in pressure ratio.The refrigerant flow rate increases with the increase in evaporation temperature,decrease in condensing temperature and increase in pressure ratio.The compressor power consumption increases with the increase in condensing temperature and increase in pressure ratio,but is not significantly affected by the evaporation temperature.

关键词： Parallel compressor unit evaporation temperature condensation temperature pressure ratio refrigeration capacity energy efficiency ratio(COP)

A Water-Heat-Force Coupled Framework for the Preparation of Soils for Application in Frozen Soil Model Test

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Fluid Dynamics & Materials Processing 2021年第1期17卷 21-37页

作者： daoming shen Xia Zhang Jinhong Xia Shunqun Li College of Civil Engineering and Architecture Xinxiang UniversityXinxiang453000China School of Journalism and Communication Xinxiang UniversityXinxiang453000China College of Civil Engineering and Architecture Tianjin Chengjian UniversityTianjin300384China

The freezing of soil containing a liquid is a complex transient heat conduction problem involving phase change and release or absorption of latent heat.Existing efforts have essentially focused on theoretical research and numerical simulations.In the present study,the problem is approached from an experimental point of view using the so-called“freezing model test”method.In particular,in order to establish a precise relationship between the model and the prototype,a temperature similarity criterion is derived using the condition of an equal number of Kosovitch.Similarity is also established with respect to other aspects.A similarity criterion for the water field is determined on the basis of relevant partial differential equations.Analogous criteria for the stress field and load are derived using an elastic model.The validity of this approach is experimentally verified.The research results provide a practical and reasonable method for calculating the parameters for preparing model soils.They also constitute a theoretical basis and a technical support for the design and implementation of a water-heat-force similarity coupled framework.

关键词： Latent heat frozen soil temperature field water-heat-force coupled framework

Heat Transfer Enhancement Using R1234yf Refrigerants in Micro-Ribbed Tubes in a Two-Phase Flow Regime

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Fluid Dynamics & Materials Processing 2020年第6期16卷 192-205页

作者： daoming shen Xia Zhang Wei He Jinhong Xia Songtao Xue School of Civil Engineering&Architecture Xinxiang UniversityXinxiangChina Department of Architecture Tohoku Institute of TechnologySendai982-8577Japan

Experiments about heat transfer in the presence of a two-phase flow due to the condensation of a R1234yf refrigerant have been performed considering a smooth tube and two micro-fin tubes.The following experimental conditions have been considered:Condensation temperatures of 40℃,43℃ and 45℃,mass fluxes of 500–900 kg/(m^(2)·s),vapor qualities at the inlet and outlet of the heat transfer tube in the ranges 0.8–0.9 and 0.2–0.3,respectively.These tests have shown that:(1)The heat transfer coefficient increases with decreasing the condensation temperature and on increasing the mass flux;(2)The heat transfer coefficient inside the micro-fin tube is larger than that for the smooth tube;(3)The heat transfer enhancement factors for the micro-fin tube with a fin helical angle of 8°and 15°are 2.51–2.89 and 3.11–3.57,respectively;both are higher than the area increase ratio.These experimental results have been compared with correlations available in the literature:the Cavallini et al.correlation has the highest accuracy in predicting the heat transfer coefficient inside the smooth tube,the related percentage error and the average prediction error are±8%and 0.56%,respectively;for the micro-fin tube these become±25%and 6%,respectively.

关键词： R1234yf micro-ribbed tube heat transfer coefficient heat transfer enhancement factor

3种轨道结构下地铁引起多层住宅室内振动模拟与实测

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铁道科学与工程学报 2016年第10期13卷 2033-2041页

作者：申道明薛松涛新乡学院河南新乡453000 土木工程防灾国家重点实验室上海200092 日本东北工业大学日本仙台982-8577

由于土体与建筑物之间是弱耦合,忽略土-结构之间相互作用,解决了隧道-土体-建筑物模型对建筑物振动一般只分析到20 Hz以下振动的问题。分析DTⅢ-2扣件、弹性支承块轨道结构及Vanguard扣件下室内振动结果,将数值模拟结果与实测结果进行对... 详细信息

由于土体与建筑物之间是弱耦合,忽略土-结构之间相互作用,解决了隧道-土体-建筑物模型对建筑物振动一般只分析到20 Hz以下振动的问题。分析DTⅢ-2扣件、弹性支承块轨道结构及Vanguard扣件下室内振动结果,将数值模拟结果与实测结果进行对比,分析结果表明二者吻合较好。将实测VLzmax结果与GB/T 10070及DB31/740的限值进行比较,提出对于不同振动要求的地区应采取相应的作为减振措施的轨道结构。对不同轨道结构下多层住宅室内振动分析有助于轨道交通部门采取合理减振措施来降低室内振动带来的影响。

关键词：地铁轨道结构室内振动多层住宅 1/3倍频程

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地铁引起二次噪声特性及评价量实测与探讨

土木建筑与环境工程 2013年第4期35卷 133-138页

作者：申道明张来栋薛松涛新乡学院土木工程与建筑系河南新乡453000 同济大学结构工程与防灾研究所上海200092 新乡职业技术学院建筑工程系河南新乡453000 日本东北工业大学建筑学科

针对地铁列车引起的建筑物二次辐射噪声进行了现场试验研究和评价量的探讨分析。从多个角度对试验数据进行了分析,总结了运行列车引起的室内二次辐射噪声特性。从分析频谱宽度、分析时间长度和背景噪声等几个方面研究了影响建筑物室内... 详细信息

针对地铁列车引起的建筑物二次辐射噪声进行了现场试验研究和评价量的探讨分析。从多个角度对试验数据进行了分析,总结了运行列车引起的室内二次辐射噪声特性。从分析频谱宽度、分析时间长度和背景噪声等几个方面研究了影响建筑物室内二次辐射噪声评价量的若干因素,并探讨了不同评价量之间的相关性以及中国现行标准中使用的评价量存在的不足。

关键词：二次辐射噪声 1 3倍频程主频分布评价量

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海上风电交通安全治理的实践与思考

水上安全 2022年第1期 53-58页

作者：沈道明刘建业郗林于冬青中华人民共和国南通海事局江苏南通226007

近年来,我国海上风电逐步进入快速发展期,规模化、集群化开发已成为海上风电新的发展趋势。笔者针对我国海上风电建设运营过程中涌现出的安全管理新问题、新矛盾、新风险,结合海上风电行业安全治理实践探索,提出了海上风电交通安全属性... 详细信息

近年来,我国海上风电逐步进入快速发展期,规模化、集群化开发已成为海上风电新的发展趋势。笔者针对我国海上风电建设运营过程中涌现出的安全管理新问题、新矛盾、新风险,结合海上风电行业安全治理实践探索,提出了海上风电交通安全属性概念,系统分析了海上风电交通安全存在的问题及原因,梳理阐述了南通海上风电交通安全治理的对策和举措,提出了针对性建议,以期对我国海上风电安全发展起到积极的促进作用。

关键词：海上风电交通安全属性治理实践思考

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《流体力学》教学模式课程思政的探索与实践

水利与建筑工程学报 2022年第3期20卷 237-240页

作者：韩洪兴申道明马芸桂超赵磊新乡学院土木工程与建筑学院河南新乡453003

在“互联网+”教育场景多元化应用的背景下,《流体力学》将思政课程教育有机融入到混合教学模式下,是一种以深度学习为目的新的教学模式。分析了《流体力学》混合教学模式下课程思政的可行性及评价效果,探讨了混合教学模式下的课程思政... 详细信息

在“互联网+”教育场景多元化应用的背景下,《流体力学》将思政课程教育有机融入到混合教学模式下,是一种以深度学习为目的新的教学模式。分析了《流体力学》混合教学模式下课程思政的可行性及评价效果,探讨了混合教学模式下的课程思政教学,初步构建《流体力学》混合教学-课程思政教学体系,将文化自信、工匠精神、民族自豪感等元素融入专业知识教学。

关键词：流体力学混合教学课程思政教学体系