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An autonomous system for thermal convection of viscoelastic fluids in a porous layer using a thermalnonequilibrium model

Qi WEI, Xiaohui ZHANG

《能源前沿（英文）》 2010年 第4卷 第4期   页码 507-516 doi: 10.1007/s11708-010-0017-x

摘要： Thermal convection of viscoelastic fluids saturating a horizontal porous layer heated from below is analyzed using a thermal nonequilibrium model to take account of the interphase heat transfer between the fluid and the solid. The viscoelastic character of the flow is considered by a modified Darcy’s law. An autonomous system with five differential equations is deduced by applying the truncated Galerkin expansion to the momentum and heat transfer equations. The effects of interphase heat transfer on the thermal convection of viscoelastic fluids in a porous medium are analyzed and discussed. The results show that the weak interphase heat transfer tends to stabilize the steady convection.

关键词： thermal convection     porous media     viscoelastic fluid     thermal nonequilibrium model    

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A modified zone model for estimating equivalent room thermal capacity

Hua CHEN, Xiaolin WANG

《能源前沿（英文）》 2013年 第7卷 第3期   页码 351-357 doi: 10.1007/s11708-013-0254-x

摘要： The zone model has been widely applied in control analysis of heating, ventilation and air conditioning (HVAC) systems to achieve a high building efficiency. This paper proposed a modified zone model which is much simpler in the HVAC system simulation and has the similar accuracy to the complicated simulation model. The proposed model took into consideration the effect of envelop heat reservoir on the room indoor temperature by introducing the thermal admittance of the inner surfaces of the building enclosure. The thermal admittance for the building enclosure was developed based on the building thermal network analytical theory and transfer function method. The efficacy of the proposed model was demonstrated by comparing it with the complicated model — heat balance method (HTB2 program). The predicted results from the proposed model well agreed with those from the complicated simulation. The proposed model can then make the HVAC system dynamic simulation much faster and more acceptable for control design due to its simplicity and efficiency.

关键词： room model     thermal network analysis     transfer function     heating     ventilation and air conditioning (HVAC) system simulation    

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Carbon performance evaluation model from the perspective of circular economy—The case of Chinese thermal

Zhifang ZHOU, Jinhao LIU, Huixiang ZENG, Mengmeng XU, Shihui LI

《工程管理前沿（英文）》 2022年 第9卷 第2期   页码 297-311 doi: 10.1007/s42524-020-0143-z

摘要： Carbon emission reduction is the only way to alleviate environmental problems, such as global warming. Effective evaluation of carbon performance can help enterprises to carry out energy saving and emission reduction activities to a certain extent and promote sustainable development. This paper constructs a carbon performance evaluation index system that includes the four dimensions of carbon resource (energy) input, cycle, output, and carbon management by incorporating the principles of circular economy and the theory of resource value circulation from the perspective of the flow trajectory of carbon-containing resources in the circulation of enterprises combined with the production characteristics of thermoelectric enterprises. Subsequently, combined with the case study, this paper discusses the scientific and practical nature of the system and provides another way of thinking for carbon performance evaluation of micro-enterprises in other industries. This paper expands the application boundary of matter–element model and supplements the literature of carbon performance, which has certain theoretical and practical significance.

关键词： circular economy     carbon performance     comprehensive evaluation     thermal power enterprise    

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Research and development of a high-quality thermal-stress online monitoring model for the 600 MW turbine

ZHANG Hengliang, XIE Danmei, XIONG Yangheng, SUN Kunfeng

《能源前沿（英文）》 2007年 第1卷 第3期   页码 322-326 doi: 10.1007/s11708-007-0047-1

摘要： To monitor and control its thermal state, a rotor s temperature and thermal stress fields must be calculated in real time. After some reasonable assumptions and simplification, iterative models of the rotor s temperature and thermal stresses were obtained with an integral transform based on a two-dimensional axis-symmetry thermal conduction differential equation. The models can deal with some nonlinear factors such as material and boundary condition. An example is given to compare results computed by the finite element method (FEM) and one-dimensional models. The result shows that the analytical model gained has high quality and the computing course is very short. The iterative formulas could be used not only to analyze the rotor’s thermal states of turbine, but to monitor and control them online. The method adopted can be used to analyze the thermal state of other axis-symmetry objects having similar boundary conditions.
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Thermal fluid-structure interaction and coupled thermal-stress analysis in a cable stayed bridge exposed

Nazim Abdul NARIMAN

《结构与土木工程前沿（英文）》 2018年 第12卷 第4期   页码 609-628 doi: 10.1007/s11709-018-0452-z

摘要： In this paper, thermal fluid structure-interaction (TFSI) and coupled thermal-stress analysis are utilized to identify the effects of transient and steady-state heat-transfer on the vortex induced vibration and fatigue of a segmental bridge deck due to fire incidents. Numerical simulations of TFSI models of the deck are dedicated to calculate the lift and drag forces in addition to determining the lock-in regions once using fluid-structure interaction (FSI) models and another using TFSI models. Vorticity and thermal convection fields of three fire scenarios are simulated and analyzed. Simiu and Scanlan benchmark is used to validate the TFSI models, where a good agreement was manifested between the two results. Extended finite element method (XFEM) is adopted to create 3D models of the cable stayed bridge to simulate the fatigue of the deck considering three fire scenarios. Choi and Shin benchmark is used to validate the damaged models of the deck in which a good coincide was seen between them. The results revealed that TFSI models and coupled thermal-stress models are significant in detecting earlier vortex induced vibration and lock-in regions in addition to predicting damages and fatigue of the deck due to fire incidents.

关键词： fire scenario     transient heat transfer     TFSI model     coupled thermal-stress     XFEM    

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动态热过程分析用建筑几何模型的构建

丁力行,何立群,陈祖铭,刘仙萍,季杰

《中国工程科学》 2010年 第12卷 第8期   页码 88-93

摘要：

建筑墙体表面的太阳直射辐射投影及辐射强度随时间发生很大变化，该变化在已有的动态热过程算法框架内很难直接计算。根据建筑传热模型特点和计算机图形学原理，构建了动态热过程的建筑几何模型，该模型将建筑空间抽象为由矢量平面围成的空间区域的集合；提出了建筑几何模型的核心计算方法，即三维空间内直线与表面的矢量运算。该建筑几何模型能解决建筑动态热过程中直接计算建筑墙体表面之间的太阳直射辐射换热和太阳直射辐射投影等问题，并对空气流通、楼房之间的相互遮阳和光污染等问题的研究也具有实际意义。

关键词： 建筑热过程     几何模型     太阳辐射    

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Key point selection in large-scale FBG temperature sensors for thermal error modeling of heavy-duty CNC

Jianmin HU, Zude ZHOU, Quan LIU, Ping LOU, Junwei YAN, Ruiya LI

《机械工程前沿（英文）》 2019年 第14卷 第4期   页码 442-451 doi: 10.1007/s11465-019-0543-0

摘要： Thermal error is one of the main factors that influence the machining accuracy of computer numerical control (CNC) machine tools. It is usually reduced by thermal error compensation. Temperature field monitoring and key temperature measurement point (TMP) selection are the bases of thermal error modeling and compensation for CNC machine tools. Compared with small- and medium-sized CNC machine tools, heavy-duty CNC machine tools require the use of more temperature sensors to measure their temperature comprehensively because of their larger size and more complex heat sources. However, the presence of many TMPs counteracts the movement of CNC machine tools due to sensor cables, and too many temperature variables may adversely influence thermal error modeling. Novel temperature sensors based on fiber Bragg grating (FBG) are developed in this study. A total of 128 FBG temperature sensors that are connected in series through a thin optical fiber are mounted on a heavy-duty CNC machine tool to monitor its temperature field. Key TMPs are selected using these large-scale FBG temperature sensors by using the density-based spatial clustering of applications with noise algorithm to reduce the calculation workload and avoid problems in the coupling of TMPs for thermal error modeling. Back propagation neural network thermal error prediction models are established to verify the performance of the proposed TMP selection method. Results show that the number of TMPs is reduced from 128 to 5, and the developed model demonstrates good prediction effects and strong robustness under different working conditions of the heavy-duty CNC machine tool.

关键词： thermal error     heavy-duty CNC machine tools     FBG     key TMPs     prediction model    

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Thermal and hydraulic characteristics of a large-scaled parabolic trough solar field (PTSF) under cloud

Linrui MA, Zhifeng WANG, Ershu XU, Li XU

《能源前沿（英文）》 2020年 第14卷 第2期   页码 283-297 doi: 10.1007/s11708-019-0649-4

摘要： To better understand the characteristics of a large-scaled parabolic trough solar field (PTSF) under cloud passages, a novel method which combines a closed-loop thermal hydraulic model (CLTHM) and cloud vector (CV) is developed. Besides, the CLTHM is established and validated based on a pilot plant. Moreover, some key parameters which are used to characterize a typical PTSF and CV are presented for further simulation. Furthermore, two sets of results simulated by the CLTHM are compared and discussed. One set deals with cloud passages by the CV, while the other by the traditionally distributed weather stations (DWSs). Because of considering the solar irradiance distribution in a more detailed and realistically way, compared with the distributed weather station (DWS) simulation, all essential parameters, such as the total flowrate, flow distribution, outlet temperature, thermal and exergetic efficiency, and exergetic destruction tend to be more precise and smoother in the CV simulation. For example, for the runner outlet temperature, which is the most crucial parameter for a running PTSF, the maximum relative error reaches −15% in the comparison. In addition, the mechanism of thermal and hydraulic unbalance caused by cloud passages are explained based on the simulation.

关键词： parabolic trough solar field (PTSF)     thermal hydraulic model     cloud passages     transients    

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A building unit decomposition model for energy leakage by infrared thermography image analysis

Yan SU, Fangjun HONG, Lianjie SHU

《能源前沿（英文）》 2020年 第14卷 第4期   页码 901-921 doi: 10.1007/s11708-020-0679-y

摘要： A quantitative energy leakage model was developed based on the thermography image data measured for both external and internal building surfaces. The infrared thermography images of both surfaces of doors, windows, and walls of an office building in the Hengqin Campus of University of Macao were taken at various times in a day for four seasons. The transient heat flux for sample units were obtained based on measurements of the seasonal transient local temperature differences and calculations of the effective thermal conductivity from the multiple-layer porous medium conduction model. Effects of construction unit types, orientations, and seasons were quantitatively investigated with unit transient orientation index factors. The corresponding electric energy consumption was calculated based on the air conditioning system coefficient of performance of heat pump and refrigerator cycles for different seasons. The model was validated by comparing to the electric meter records of energy consumption of the air conditioning system. The uncertainties of the predicted total building energy leakage are about 14.7%, 12.8%, 12.4%, and 15.8% for the four seasons, respectively. The differences between the predicted electric consumption and meter values are less than 13.4% and 5.4% for summer and winter, respectively. The typical daily thermal energy leakage value in winter is the highest among the four seasons. However, the daily electric energy consumption by the air conditioning system in summer and autumn is higher than that in winter. The present decomposition model for energy leakage is expected to provide a practical tool for quantitative analysis of energy leakage of buildings.

关键词： heat conductivity     heat coefficient     heat &fllig     ux     infrared thermography     thermal image    

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Microdamage study of granite under thermomechanical coupling based on the particle flow code

《结构与土木工程前沿（英文）》   页码 1413-1427 doi: 10.1007/s11709-023-0953-2

摘要： The thermomechanical coupling of rocks refers to the interaction between the mechanical and thermodynamic behaviors of rocks induced by temperature changes. The study of this coupling interaction is essential for understanding the mechanical and thermodynamic properties of the surrounding rocks in underground engineering. In this study, an improved temperature-dependent linear parallel bond model is introduced under the framework of a particle flow simulation. A series of numerical thermomechanical coupling tests are then conducted to calibrate the micro-parameters of the proposed model by considering the mechanical behavior of the rock under different thermomechanical loadings. Good agreement between the numerical results and experimental data are obtained, particularly in terms of the compression, tension, and elastic responses of granite. With this improved model, the thermodynamic response and underlying cracking behavior of a deep-buried tunnel under different thermal loading conditions are investigated and discussed in detail.

关键词： thermomechanical coupling effect     granite     improved linear parallel bond model     thermal property     particle flow code    

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液体调速离合器中摩擦副热效应分析

洪跃,刘谨,王云根

《中国工程科学》 2003年 第5卷 第9期   页码 55-60

摘要：

液体粘性调速离合器是利用多个摩擦圆盘间的油膜剪切力来传递动力，并通过改变油膜厚度实行无级调速。由于近来工程中广泛采用聚α-稀烃型、聚酯型等合成油作润滑剂，液体粘性调速离合器在调速范围内，其摩擦副往往工作在流体润滑、混合润滑、边界润滑直到直接接触的工况。基于这些特点，笔者采用了幂律型非牛顿流体模型、Patir-Cheng的平均流量模型、GT两粗糙平面接触模型、计入油膜的惯性影响、平均能量方程、热传导方程，建立了热效应研究模型，推导了相应的计算方程式，并在流体润滑、流体混合润滑状态下，进行了数值计算与分析。

关键词： 液体调速离合器     热分析     雷诺方程     非牛顿流体     表面粗糙度    

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卫星主动控温回路的设计模型与算法

李运泽,杨娟,宁献文,王晓明,石晓波

《中国工程科学》 2008年 第10卷 第7期   页码 48-50

摘要：

使用电加热器的卫星主动控温回路是一种重要的主动热控措施，通过简明扼要的机理分析建立起该主动控温过程中受控对象温度变化的动态方程，得出了稳态控温、瞬态控温两种基本的控温模式下主动控温回路电加热器功率需求的计算表达式，给出了进行主动控温回路电加热器热功率设计计算的一般流程，较详细地分析了一个具体设计算例，为卫星主动控温回路设计计算提供了简便的计算模型和方法。

关键词： 卫星     主动热控制     主动控温回路     模型与算法    

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Influence evaluation of loading conditions during pressurized thermal shock transients based on thermal-hydraulics

Jinya KATSUYAMA, Shumpei UNO, Tadashi WATANABE, Yinsheng LI

《机械工程前沿（英文）》 2018年 第13卷 第4期   页码 563-570 doi: 10.1007/s11465-018-0487-9

摘要：

The thermal hydraulic (TH) behavior of coo-lant water is a key factor in the structural integrity assessments on reactor pressure vessels (RPVs) of pressurized water reactors (PWRs) under pressurized thermal shock (PTS) events, because the TH behavior may affect the loading conditions in the assessment. From the viewpoint of TH behavior, configuration of plant equipment and their dimensions, and operator action time considerably influence various parameters, such as the temperature and flow rate of coolant water and inner pressure. In this study, to investigate the influence of the operator action time on TH behavior during a PTS event, we developed an analysis model for a typical Japanese PWR plant, including the RPV and the main components of both primary and secondary systems, and performed TH analyses by using a system analysis code called RELAP5. We applied two different operator action times based on the Japanese and the United States (US) rules: Operators may act after 10 min (Japanese rules) and 30 min (the US rules) after the occurrence of PTS events. Based on the results of TH analysis with different operator action times, we also performed structural analyses for evaluating thermal-stress distributions in the RPV during PTS events as loading conditions in the structural integrity assessment. From the analysis results, it was clarified that differences in operator action times significantly affect TH behavior and loading conditions, as the Japanese rule may lead to lower stresses than that under the US rule because an earlier operator action caused lower pressure in the RPV.

关键词： structural integrity     reactor pressure vessel     pressurized thermal shock     thermal hydraulic analysis     pressurized water reactor     weld residual stress    

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Assessment indices for uniform and non-uniform thermal environments

ZHANG Yufeng, SUN Shufeng, ZHAO Rongyi

《能源前沿（英文）》 2008年 第2卷 第2期   页码 129-133 doi: 10.1007/s11708-008-0029-y

摘要： Different assessment indices for thermal environments were compared and selected for proper assessment of indoor thermal environments. 30 subjects reported their overall thermal sensation, thermal comfort, and thermal acceptability in uniform and non-uniform conditions. The results show that these three assessment indices provide equivalent evaluations in uniform environments. However, overall thermal sensation differs from the other two indices and cannot be used as a proper index for the evaluation of non-uniform environments. The relationship between the percentage and the mean vote for each index is established.

关键词： thermal sensation     proper assessment     relationship     equivalent     thermal acceptability    

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Liquid metal thermal hydraulics R&D at European scale: achievements and prospects

《能源前沿（英文）》 2021年 第15卷 第4期   页码 842-853 doi: 10.1007/s11708-021-0743-2

摘要： A significant role for a future nuclear carbon-free energy production is attributed to fast reactors, mostly employing a liquid metal as a coolant. This paper summarizes the efforts that have been undertaken in collaborative projects sponsored by the European Commission in the past 20 years in the fields of liquid-metal heat transfer modeling, fuel assembly and core thermal hydraulics, pool and system thermal hydraulics, and establishment of best practice guidelines and verification, validation, and uncertainty quantification (UQ). The achievements in these fields will be presented along with the prospects on topics which will be studied collaboratively in Europe in the years to come. These prospects include further development of heat transfer models for applied computational fluid dynamics (CFD), further analysis of the consequences of fuel assembly blockages on coolant flow and temperature, analysis of the thermal hydraulic effects in deformed fuel assemblies, extended validation of three-dimensional pool thermal hydraulic CFD models, and further development and validation of multi-scale system thermal hydraulic methods.

关键词： liquid metal     thermal hydraulics     Europe    

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标题 作者 时间 类型 操作

An autonomous system for thermal convection of viscoelastic fluids in a porous layer using a thermalnonequilibrium model

Qi WEI, Xiaohui ZHANG

期刊论文

A modified zone model for estimating equivalent room thermal capacity

Hua CHEN, Xiaolin WANG

期刊论文

Carbon performance evaluation model from the perspective of circular economy—The case of Chinese thermal

Zhifang ZHOU, Jinhao LIU, Huixiang ZENG, Mengmeng XU, Shihui LI

期刊论文

Research and development of a high-quality thermal-stress online monitoring model for the 600 MW turbine

ZHANG Hengliang, XIE Danmei, XIONG Yangheng, SUN Kunfeng

期刊论文

Thermal fluid-structure interaction and coupled thermal-stress analysis in a cable stayed bridge exposed

Nazim Abdul NARIMAN

期刊论文

动态热过程分析用建筑几何模型的构建

丁力行,何立群,陈祖铭,刘仙萍,季杰

期刊论文

Key point selection in large-scale FBG temperature sensors for thermal error modeling of heavy-duty CNC

Jianmin HU, Zude ZHOU, Quan LIU, Ping LOU, Junwei YAN, Ruiya LI

期刊论文

Thermal and hydraulic characteristics of a large-scaled parabolic trough solar field (PTSF) under cloud

Linrui MA, Zhifeng WANG, Ershu XU, Li XU

期刊论文

A building unit decomposition model for energy leakage by infrared thermography image analysis

Yan SU, Fangjun HONG, Lianjie SHU

期刊论文

Microdamage study of granite under thermomechanical coupling based on the particle flow code

期刊论文

液体调速离合器中摩擦副热效应分析

洪跃,刘谨,王云根

期刊论文

卫星主动控温回路的设计模型与算法

李运泽,杨娟,宁献文,王晓明,石晓波

期刊论文

Influence evaluation of loading conditions during pressurized thermal shock transients based on thermal-hydraulics

Jinya KATSUYAMA, Shumpei UNO, Tadashi WATANABE, Yinsheng LI

期刊论文

Assessment indices for uniform and non-uniform thermal environments

ZHANG Yufeng, SUN Shufeng, ZHAO Rongyi

期刊论文

Liquid metal thermal hydraulics R&D at European scale: achievements and prospects

期刊论文