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Analysis of radiation heat transfer and temperature distributions of solar thermochemical reactor for

Bachirou GUENE LOUGOU, Yong SHUAI, Xiang CHEN, Yuan YUAN, Heping TAN, Huang XING

《能源前沿(英文)》 2017年 第11卷 第4期   页码 480-492 doi: 10.1007/s11708-017-0506-2

摘要: This paper investigated radiation heat transfer and temperature distributions of solar thermochemical reactor for syngas production using the finite volume discrete ordinate method (fvDOM) and P1 approximation for radiation heat transfer. Different parameters including absorptivity, emissivity, reflection based radiation scattering, and carrier gas flow inlet velocity that would greatly affect the reactor thermal performance were sufficiently investigated. The fvDOM approximation was used to obtain the radiation intensity distribution along the reactor. The drop in the temperature resulted from the radiation scattering was further investigated using the P1 approximation. The results indicated that the reactor temperature difference between the P1 approximation and the fvDOM radiation model was very close under different operating conditions. However, a big temperature difference which increased with an increase in the radiation emissivity due to the thermal non-equilibrium was observed in the radiation inlet region. It was found that the incident radiation flux distribution had a strong impact on the temperature distribution throughout the reactor. This paper revealed that the temperature drop caused by the boundary radiation heat loss should not be neglected for the thermal performance analysis of solar thermochemical reactor.

关键词: solar thermochemical reactor     incident radiation flux     temperature distribution     radiation absorptivity     radiation emissivity     thermal performance analysis    

Numerical solution, simulation and testing of the thermal dynamic characteristics of ball-screws

XIA Junyong, HU Youmin, WU Bo, SHI Tielin

《机械工程前沿(英文)》 2008年 第3卷 第1期   页码 28-36 doi: 10.1007/s11465-008-0007-4

摘要: This research focuses on the characteristics of how a ball-screw changes its temperature corresponding to the periodic change of the end-most heat source. Based on the theory of heat transfer, this paper supplies a numerical solution to the non-homogeneous equation of heat transfer through the group explicit (GE) finite difference approach. The temperature distribution for the ball-screw at different times and directions is shown. By simulating and modeling the temperature field and thermal deformation of the ball-screw under periodically varying heat sources, this paper describes the thermal dynamic characteristics of the ball-screw under such conditions. By testing the thermal dynamic characteristics of the ball-screw, the numerical solution is validated.

关键词: numerical solution     temperature corresponding     temperature distribution     end-most     ball-screw    

墙角火灾环境下钢构件温度分布及响应行为的实验研究

陈长坤,姚斌,杨昀,蔡昕,张和平,万玉田

《中国工程科学》 2005年 第7卷 第9期   页码 70-75

摘要:

利用ISO9705标准火灾实验系统,模拟墙角火灾环境,以薄壁方管钢梁为研究对象,对钢构件在热、力耦合作用下的行为进行实验研究。对火灾的热释放速率与室内温度场,钢构件及其表面气体的温度、构件在火灾作用下的挠度进行测量,分析真实火灾下钢构件温升及温度分布的特点与火灾发展对构件挠度的影响。研究结果表明钢构件在长向上存在着很大的温差,而构件的挠度变化也并不对称,这说明以往研究中往往假设钢构件在长向上温度一致并不恰当,这种非均匀温度场对构件的行为有着重要影响,它使得构件高温区部分更易发生局部屈服而失效,在相同规模的火灾环境下,与均匀温度场相比,这种墙角火灾所导致的非均匀温度场更不利于钢构件的安全。

关键词: ISO标准火灾实验系统     钢构件     墙角火     温度分布    

Heat flux distribution on circulating fluidized bed boiler water wall

LU Junfu, YUE Guangxi, YANG Hairui, ZHANG Jiansheng, YU Long, ZHANG Man, YANG Zhongming

《能源前沿(英文)》 2008年 第2卷 第2期   页码 134-139 doi: 10.1007/s11708-008-0027-0

摘要: The future of circulating fluidized bed (CFB) combustion technology is in raising the steam parameters to supercritical levels. Understanding the heat flux distribution on the water wall is one of the most important issues in the design and operation of supercritical pressure CFB boilers. In the present paper, the finite element analysis (FEA) method is adopted to predict the heat transfer coefficient as well as the heat flux of the membrane wall and the results are validated by direct measurement of the temperature around the tube. Studies on the horizontal heat flux distribution were conducted in three CFB boilers with different furnace size, tube dimension and water temperature. The results are useful in supercritical pressure CFB boiler design.

关键词: horizontal     different furnace     temperature     FEA     measurement    

新型PB-PSOI器件表面电场和温度分布模型研究

孙伟锋,高珊,陆生礼,陈军宁

《中国工程科学》 2009年 第11卷 第11期   页码 82-87

摘要:

根据泊松方程和热扩散方程提出了新型PB-PSOI 器件漂移区的二维表面电场分布模型和温度分布模型,模型计算结果与Medici模拟结果相一致。根据所提出的模型,重点研究了埋氧化层厚度及长度对漂移区表面电场分布和温度分布的影响,最后给出了PB-PSOI 器件的埋氧化层厚度和长度的优化设计方法。

关键词: PB-PSOI     表面电场     温度分布     埋氧化层    

Investigation on available wind energy at Tungku beach

M. G. YAZDANI, M. A. SALAM

《能源前沿(英文)》 2012年 第6卷 第3期   页码 275-279 doi: 10.1007/s11708-012-0194-x

摘要: In this paper, wind velocities and directions (sea and land) are recorded in different days and times. The data collected were compared with the weather data from the Brunei Darussalam Meteorological Service (BDMS) and the findings of other researchers and were found to be in good agreement. The potential of wind energy is predicted from the available data collected. The average generated power (forenoon and afternoon) is found to be 25 (mean) and 18 W (median), 101 (mean) and 73 W (median), 912 (mean) and 660 W (median), 10137 (mean) and 7331 W (median) for a rotor with a diameter of 2.5, 5, 15 and 50 m, respectively. The power density for wind farming is found to be 0.26 (mean) and 0.19 (median), 0.31 (mean) and 0.22 (median) for the rotor whose diameter is 2.5 and 50 m, respectively, while the average values are found to be 0.28 (mean) and 0.2 (median) for the rotor whose diameter is 5 and 15 m.

关键词: wind velocity     temperature     tower height     power density     Raleigh distribution     electrical power    

CFD Simulation of thermal hydraulic characteristics in a typical upper plenum of RPV

Mingjun WANG, Lianfa WANG, Yingjie WANG, Wenxi TIAN, Jian DENG, Guanghui SU, Suizheng QIU

《能源前沿(英文)》 2021年 第15卷 第4期   页码 930-945 doi: 10.1007/s11708-021-0728-1

摘要: A comparative computational fluid dynamics (CFD) study was conducted on the three different types of pressurized water reactor (PWR) upper plenum, named TYPE 1 (support columns (SCs) and control rod guide tubes (CRGTs) with two large windows), TYPE 2 (SCs and CRGTs without windows), and TYPE 3 (two parallel perforated barrel shells and CRGTs). First, three types of upper plenum geometry information were collected, simplified, and adopted into the BORA facility, which is a 1/5 scale system of the four-loop PWR reactor. Then, the geometry, including the upper half core, upper plenum region, and hot legs, was built using the platform. After that, an unsteady calculation to simulate the reactor balance operation at hot full power scenario was performed. Finally, the differences of flowrate distribution at the core outlet and temperature distribution and transverse velocity inside the hot legs with different upper plenum internals were compared. The results suggest that TYPE 1 upper plenum internals cause the largest flowrate difference at the core outlet while TYPE 3 leads to the most even distributed flowrate. The distribution and evolution pattern of the tangential velocity inside hot legs is highly dependent on the upper plenum internals. Two counter-rotating swirls exist inside the TYPE 1 hot leg and only one swirl revolving around the hog leg axis exist inside the TYPE 2 hot leg. For TYPE 3, two swirls like that of TYPE 1 rotating around the hot leg axis significantly increase the temperature homogenization speed. This research provides meaningful guidelines for the future optimization and design of advanced PWR upper plenum internal structures.

关键词: pressurized water reactor (PWR)     upper plenum     internal structures     temperature distribution     computational fluid dynamics (CFD)    

Copper and zinc interaction on water clearance and tissue metal distribution in the freshwater mussel

Tianxiang XIA, Xuehua LIU

《环境科学与工程前沿(英文)》 2011年 第5卷 第2期   页码 236-242 doi: 10.1007/s11783-010-0218-8

摘要: Copper and zinc interaction on clearance from water and distribution in different tissues was investigated for the freshwater mussel, , under laboratory conditions. Clearance rate of Cu or Zn from water was highly dependent on exposure concentration. Interaction effect was most evident at 300 μg·L Cu exposure and depressed the Zn clearance rate significantly ( <0.05). However, the presence of 100 μg·L and 300 μg·L Zn hardly affected the Cu clearance rate. The 300 μg·L Cu presence enhanced Cu accumulation in each tissue most significantly ( <0.01), but caused Zn content to decrease in the gills by 62% ( <0.05), viscera by 49% ( <0.05) and foot by 31% ( <0.05), and increase in the mantle by 97% ( <0.05) and the muscles by 243% ( <0.05) for different Zn exposure treatments. The response of metal accumulation in various tissues of the test mussels indicated that Zn transferred from the gills, viscera and foot to the mantle and muscles might be one of the important characteristics of the Zn regulatory mechanism by leading to a narrow range of Zn concentration in the different tissues.

关键词: interaction     mussel     copper     zinc     clearance     distribution    

Nitrogen distribution in the products from the hydrothermal liquefaction of sp. and sp.

《化学科学与工程前沿(英文)》 2022年 第16卷 第6期   页码 985-995 doi: 10.1007/s11705-021-2126-y

摘要: The high contents of nitrogen-containing organic compounds in biocrude obtained from hydrothermal liquefaction of microalgae are one of the most concerned issues on the applications and environment. In the project, Chlorella sp. and Spirulina sp. were selected as raw materials to investigate the influence of different reaction conditions (i.e., reaction temperature, residence time, solid loading rate) on the distribution of nitrogen in the oil phase and aqueous phase. Three main forms of nitrogen-containing organic compounds including nitrogen-heterocyclic compounds, amide, and amine were detected in biocrudes. The contents of nitrogen-heterocyclic compounds decreased with temperature while amide kept increasing. The effect of residence time on the components of nitrogen-containing organic compounds was similar with that of temperature. However, the influence of solid loading rate was insignificant. Moreover, it was also found that the differences of amino acids in the protein components in the two microalgae might affect the nitrogen distribution in products. For example, nitrogen in basic amino acids of Spirulina sp. preferred to go into the aqueous phase comparing with the nitrogen in neutral amino acids of Chlorella sp. In summary, a brief reaction map was proposed to describe the nitrogen pathway during microalgae hydrothermal liquefaction.

关键词: microalgae     hydrothermal liquefaction     biocrude     nitrogen distribution    

Thermodynamic models and energy distribution of single-phase heated surface in a boiler under unsteady

Xiyan GUO, Yongping YANG

《能源前沿(英文)》 2011年 第5卷 第1期   页码 69-74 doi: 10.1007/s11708-010-0117-7

摘要: A coal-fired power unit frequently operates under unsteady conditions; thus, in order to acquire scientific energy analysis of the unit, thermodynamic analysis of a single-phase heated surface in a boiler under such conditions requires investigation. Processes are analyzed, and distributions of energy and exergy are qualitatively revealed. Models for energy analysis, entropy analysis, and exergy analysis of control volumes and irreversible heat transfer processes are established. Taking the low-temperature superheater of a 610 t/h-boiler as an example, the distribution of energy, entropy production, and exergy is depicted quantitatively, and the results are analyzed.

关键词: thermodynamic model     energy distribution     boiler     unsteady conditions    

Estimation of distribution algorithm enhanced particle swarm optimization for water distribution network

Xuewei QI,Ke LI,Walter D. POTTER

《环境科学与工程前沿(英文)》 2016年 第10卷 第2期   页码 341-351 doi: 10.1007/s11783-015-0776-z

摘要: The optimization of a water distribution network (WDN) is a highly nonlinear, multi-modal, and constrained combinatorial problem. Particle swarm optimization (PSO) has been shown to be a fast converging algorithm for WDN optimization. An improved estimation of distribution algorithm (EDA) using historic best positions to construct a sample space is hybridized with PSO both in sequential and in parallel to improve population diversity control and avoid premature convergence. Two water distribution network benchmark examples from the literature are adopted to evaluate the performance of the proposed hybrid algorithms. The experimental results indicate that the proposed algorithms achieved the literature record minimum (6.081 M$) for the small size Hanoi network. For the large size Balerma network, the parallel hybrid achieved a slightly lower minimum (1.921M?) than the current literature reported best minimum (1.923M?). The average number of evaluations needed to achieve the minimum is one order smaller than most existing algorithms. With a fixed, small number of evaluations, the sequential hybrid outperforms the parallel hybrid showing its capability for fast convergence. The fitness and diversity of the populations were tracked for the proposed algorithms. The track record suggests that constructing an EDA sample space with historic best positions can improve diversity control significantly. Parallel hybridization also helps to improve diversity control yet its effect is relatively less significant.

关键词: particle swarm optimization (PSO)     diversity control     estimation of distribution algorithm (EDA)     water distribution network (WDN)     premature convergence     hybrid strategy    

Hazard and vulnerability evaluation of water distribution system in cases of contamination intrusion

Kunlun XIN, Tao TAO, Yong WANG, Suiqing LIU

《环境科学与工程前沿(英文)》 2012年 第6卷 第6期   页码 839-848 doi: 10.1007/s11783-012-0409-8

摘要: In this paper, it proposed an index system for hazard and vulnerability evaluations of water distribution networks, based on the simulation of contamination events caused by pollutant injections at different junctions. It attempted to answer the following two questions in the case of contamination events: 1) Which are the most hazardous junctions? 2) Which are the most vulnerable junctions? With EPANET toolkit, it simulated the propagation of the contaminant, and calculated the peak concentration of the contaminant and mass delivered at different nodes. According to types of consumers, different weights were assigned to the consumer nodes for assessing the influence of the contaminant on the consumers. Using the method proposed herein, both the hazard index and vulnerability index were calculated for each node in the pipe network. The presented method was therefore applied to the water network of the city of Zhenjiang, which contains two water plants, two booster pump stations with storage tanks. In conclusion, the response time, the relationships between the peak concentration of contaminant and the total absorption are the most important factors in hazard and vulnerability evaluation of the water distribution network.

关键词: water distribution network     hazard     vulnerability     contaminant accident    

Calculation method of load distribution on pipe threaded connections under tension load

Shoujun CHEN, Lianxin GAO, Qi AN

《机械工程前沿(英文)》 2011年 第6卷 第2期   页码 241-248 doi: 10.1007/s11465-011-0219-x

摘要:

This paper presents a new calculation method that can calculate the load distribution on pipe threaded connections under tension load. On the basis of elastic mechanics, the new method was developed by analyzing each thread tooth, and a new deformation and covariant equation by making a mechanics analysis on each thread tooth was obtained. Compared with the traditional method proposed by the previous references, the new deformation and covariant equation could be used to describe the relation between the previous and the next thread tooth. By applying the new method on the sample of P-110S pipe threaded connection, the obtained results show that the load on thread tooth mainly concentrates on the four or five threads engaged and the middle teeth were not utilized well to bear the loads. The model offers a new way to calculate the loads carried on the thread teeth under tension load.

关键词: load distribution     calculation method     pipe threaded connections     tension load    

Numerical simulation of the heat flux distribution in a solar cavity receiver

Yueshe WANG, Xunwei DONG, Jinjia WEI, Hui JIN

《能源前沿(英文)》 2011年 第5卷 第1期   页码 98-103 doi: 10.1007/s11708-010-0019-8

摘要: In the solar tower power plant, the receiver is one of the main components of efficient concentrating solar collector systems. In the design of the receiver, the heat flux distribution in the cavity should be considered first. In this study, a numerical simulation using the Monte Carlo Method has been conducted on the heat flux distribution in the cavity receiver, which consists of six lateral faces and floor and roof planes, with an aperture of 2.0 m×2.0 m on the front face. The mathematics and physical models of a single solar ray’s launching, reflection, and absorption were proposed. By tracing every solar ray, the distribution of heat flux density in the cavity receiver was obtained. The numerical results show that the solar flux distribution on the absorbing panels is similar to that of CESA-I’s. When the reradiation from walls was considered, the detailed heat flux distributions were issued, in which 49.10% of the total incident energy was absorbed by the central panels, 47.02% by the side panels, and 3.88% was overflowed from the aperture. Regarding the peak heat flux, the value of up to 1196.406 kW/m was obtained in the center of absorbing panels. These results provide necessary data for the structure design of cavity receiver and the local thermal stress analysis for boiling and superheated panels.

关键词: solar cavity receiver     Monte Carlo method     heat flux distribution    

标题 作者 时间 类型 操作

Analysis of radiation heat transfer and temperature distributions of solar thermochemical reactor for

Bachirou GUENE LOUGOU, Yong SHUAI, Xiang CHEN, Yuan YUAN, Heping TAN, Huang XING

期刊论文

Numerical solution, simulation and testing of the thermal dynamic characteristics of ball-screws

XIA Junyong, HU Youmin, WU Bo, SHI Tielin

期刊论文

墙角火灾环境下钢构件温度分布及响应行为的实验研究

陈长坤,姚斌,杨昀,蔡昕,张和平,万玉田

期刊论文

Heat flux distribution on circulating fluidized bed boiler water wall

LU Junfu, YUE Guangxi, YANG Hairui, ZHANG Jiansheng, YU Long, ZHANG Man, YANG Zhongming

期刊论文

新型PB-PSOI器件表面电场和温度分布模型研究

孙伟锋,高珊,陆生礼,陈军宁

期刊论文

Investigation on available wind energy at Tungku beach

M. G. YAZDANI, M. A. SALAM

期刊论文

CFD Simulation of thermal hydraulic characteristics in a typical upper plenum of RPV

Mingjun WANG, Lianfa WANG, Yingjie WANG, Wenxi TIAN, Jian DENG, Guanghui SU, Suizheng QIU

期刊论文

Copper and zinc interaction on water clearance and tissue metal distribution in the freshwater mussel

Tianxiang XIA, Xuehua LIU

期刊论文

Nitrogen distribution in the products from the hydrothermal liquefaction of sp. and sp.

期刊论文

Thermodynamic models and energy distribution of single-phase heated surface in a boiler under unsteady

Xiyan GUO, Yongping YANG

期刊论文

Estimation of distribution algorithm enhanced particle swarm optimization for water distribution network

Xuewei QI,Ke LI,Walter D. POTTER

期刊论文

Hazard and vulnerability evaluation of water distribution system in cases of contamination intrusion

Kunlun XIN, Tao TAO, Yong WANG, Suiqing LIU

期刊论文

Calculation method of load distribution on pipe threaded connections under tension load

Shoujun CHEN, Lianxin GAO, Qi AN

期刊论文

Nikos Hatziargyrio:The Role of Data in Intelligent Distribution Grids(2022年6月6日)

2022年07月07日

会议视频

Numerical simulation of the heat flux distribution in a solar cavity receiver

Yueshe WANG, Xunwei DONG, Jinjia WEI, Hui JIN

期刊论文