基于MATLAB的煤质元素分析通用计算模型研究

在研究元素分析和工业分析指标相关性的基础上,利用MATLAB对全国126个矿井的无烟煤煤质分析数据进行了多元线性逐步回归分析,推导出了元素分析和工业分析关联方程组和关联矩阵,并对其进行了验证,从而实现了由工业分析指标对元素分析指标的通用计算模型.新模型将关联矩阵推广到全国范围内无烟煤的使用,具有一定的实用价值.     

600MW亚临界锅炉水冷壁爆管原因分析

通过宏观分析、化学成分分析、机械性能测试、金相分析等方法对600 MW亚临界机组锅炉水冷壁爆管的原因进行了分析,分析结果表明,水冷壁爆管为氢损伤所致,并提出了相应的预防措施。     

柴油机气缸盖振动信号特征提取方法的研究

研究了基于短时AR分析、小波多分辨率分析和小波包分析的故障特征提取和识别方法,分析了柴油机气缸盖振动信号特征提取方法。得出了两条重要结论:基于短时AR分析的柴油机气缸盖振动信号整循环特征提取方法特别适合于短序列数据的分析;利用小波多分辨率分析和小波包分析以及Kllback-Leibler信息量最小,对柴油机表面振动信号进行分解与分析,确定各故障状态的特征频带,进而可用频带的时间序列的时序模型作为特征矢量,实现对柴油机运行状态故障的诊断。     

固体生物质燃料特性检验标准的研究

详细简要介绍了欧盟CET/TS、美国ASTM关于生物质燃料检测分析标准,并同我国生物质燃料分析检测标准进行比较,重点分析了三种检测分析标准的差异,并就主要检测分析标准内容进行了说明,为我国生物质燃料检测分析标准的完善作些有意义的工作。     

基于双向流固耦合的缸体缸盖温度场模拟分析与试验研究

为了研究发动机缸体缸盖表面的温度,基于双向流固耦合分析的方法对某汽油机的缸体缸盖进行了温度场分析。首先进行CFD分析得到温度以及换热系数边界,利用ABAQUS软件进行发动机的温度分析,再把结构温度作为下一次CFD计算的边界反复迭代。最终得到准确的温度场分布。并且通过试验的手段对分析结果进行验证分析,结果表明试验结果基本与分析结果相符。     

蓄电池酸性电解液分析项目的改进

针对铁路机务化验项目中蓄电池酸性电解液的测定分析过程过于繁琐和复杂这一问题 ,对密度的测定、硫酸含量的测定和铁含量的测定三个主要分析项目测定过程中的部分环节 ,进行了一些补充和完善 ,使酸性电解液的化验分析在达到分析结果准确、可靠的前提下 ,改善了测定分析的操作全过程 ,缩短了分析时间 ,提高了分析效率     

生物质发电应重视经济可行性研究

正生物质发电项目普遍存在重技术可行性分析,轻经济效少,缺少敏感性分析。造成影响生物质发电的健康持续发展。益可行性分析的问题,涉及盈利预测和效益分析的比重相当     

AutoPSA与CAESARⅡ在管道应力分析中的比较

结合实际的工程例题,比较了AutoPSA与CAESARⅡ的计算结果。考虑到管道静力分析中的难点如单向约束、埋地管道等问题,探讨了AutoPSA的非线性分析功能。针对管道动力分析中的模态分析、谐波分析、谱分析、时间历程分析,采用合适的方法保证了AutoPSA分析结果的稳定可靠。在管道应力分析中,AutoPSA精度很高、通用性强,能够满足电力、石化、化工等行业的工程应用。算例表明AutoPSA与CAESARⅡ分析结果非常吻合,并在某些方面有所超越。     

固体生物质燃料特性检验标准的研究

介绍了欧盟CEN/TS、美国ASTM关于生物质燃料检测分析标准,并同我国生物质燃料分析检测标准进行比较。重点分析了3种检测分析标准的差异,并就主要检测分析标准内容进行了说明,为我国生物质燃料检测分析标准的完善做些有意义的工作。     

历史洪水对水文频率分析不确定性的影响

针对水文频率分析过程中因模型选择和数据资料短缺引起分析结果不确定性问题,基于Bayesian MC-MC模型,将史料记载的定性洪水资料应用于水文频率分析中,并以西江流域梧州水文站为例进行洪水频率分析。结果表明,数据资料长度对水文频率分析结果的不确定性影响很大,且该模型应用于水文频率研究不仅可定量评估分析结果的不确定性,还可利用历史特大洪水信息有效降低分析结果的不确定性。     

基于三维有限元法的碾压砼拱坝应力仿真计算研究

为防止大坝因局部拉应力过大而产生坝体拉裂现象,基于拱坝温度场和温度徐变应力场基本原理,以江西省萍乡市山口岩水利枢纽工程拦河坝为例,利用三维有限元法对拱坝施工期与运行期的温度场和应力场进行了仿真计算。结果表明,拱坝的施工与设计中未采取温控措施、不设置分缝,坝体拉应力过大,超出了碾压砼的抗拉强度,对大坝防裂稳定不利;对拱坝合理地设置横缝和诱导缝,采取温控措施,坝体高拉应力区的应力可得到有效改善,应力得到了释放,最大拉应力小于碾压砼的抗拉强度,有利于大坝防裂,为坝体稳定提供了保障。     

A review on bio-oil production from biomass by using pyrolysis method

The paper provides an updated review on thermal conversion of biomass for the production of liquid products referred as bio-oil. This technology is described focusing on the characterization of feedstock, reactor design, products formation and upgrading. For feedstock characterization is covered in terms of several pretreatment methods. The reactor designs are illustrated number of design ranging from fixed bed to circulating fluidized bed. The properties of bio-oil composition have caused increasingly extensive research to be undertaken to address properties that need modification and this area is reviewed in terms of physical, catalytic and chemical upgrading. The mechanism of the products formation is also illustrated by several chemical routes. Reactor parameters such as heating rate, temperature of pyrolysis, catalysts etc are reviewed.     

Stability Analysis of Distributed Parameter Systems on Temperature Measurement of Large-scale Objects

In this paper,the mechanical construction,thermal regulator design and temperature measurement system of alocal area were set up for large-scale linear measurement.Numerical analysis based on temperature correlatedcharacteristic is discussed to obtain optimal observation points for the measurements.The horizontal temperaturedistribution of the measured area is compared with the measurement of the variation of temperature at 15℃ and20~C over time,and characteristic of dynamic response is also discussed.In addition,the long-time stability ofmeasured temperature is analyzed by means of using the standard deviation.It characterizes the temperature dis-tribution performance of a large area and how it may impact the measurement of a large-scale object.     

基于数值模拟的排气歧管优化策略

在台架试验的基础上,采用一维发动机工作过程计算和三维CFD模拟技术研究了4缸柴油发动机各缸排气温度差异的影响因素.模拟结果表明:台架试验测量的各缸排温差异是受各缸工作过程、测量点位置和排气歧管结构的综合影响,其中排气歧管结构是主要的影响因素.排温测量点位置越接近排气门,越能反映缸内的热负荷状况.基于数值模拟结果,优化了原发动机排气歧管,并提出了排气歧管优化策略.     

温度变化对水电站地下厂房机墩组合中风罩应力的影响

风罩作为地下厂房机墩组合中的重要构筑物,在电站运行期受力特性及其复杂。主要研究温度荷载对风罩应力的影响特征,为结构体型优化及配筋设计提供依据。采用有限元数值模拟方法进行分析,模型选取了机墩根部至发电机层楼板的范围,考虑最不利情况下的运行状态。结果表明,对风罩这种薄壁结构,温度荷载是决定其应力的最主要因素,而且温度荷载不仅对应力的大小起决定因素,对应力的分布形式也有影响,应采取有效措施尽量减小风罩的内外温差,在结构和配筋设计时重视温度荷载的严重影响。     

300MW循环流化床锅炉外循环回料异常原因分析

循环流化床锅炉物料外循环异常的原因主要是煤种过多的偏离设计值,以及锅炉受热面的多次改造,导致整个炉膛温度场的改变,降低了物料的流化性,而排渣系统出力不足导致的长期高床压运行,加剧了炉膛的后燃现象,设计的先天不足及缺乏必要的温度监视手段,为外循环回路的低温结焦创造了条件,而针对性的技术改造和运行操作的标准化是解决问题的关键所在。     

Prospects and scopes of solar pond: A detailed review

Solar pond is an artificially constructed pond in which significant temperature rises are caused to occur in the lower regions by preventing convection. To prevent convection, salt water is used in the pond. Those ponds are called “salt gradient solar pond”. In the last 15 years, many salt gradient solar ponds varying in size from a few hundred to a few thousand square meters of surface area have been built in a number of countries. Nowadays, mini solar ponds are also being constructed for various thermal applications. In this work, various design of solar pond, prospects to improve performance, factors affecting performance, mode of heat extraction, theoretical simulation, measurement of parameters, economic analysis and its applications are reviewed.     

Numerical studies on the geometrical characterization of serpentine flow-field for efficient PEMFC

Geometrical characterization of the serpentine flow-field is one of the key issues to be solved to enhance the performance of PEMFC in relation to pressure drop, discharge of condensed water, maximization of cell voltage, and uniformity of current density over the entire surface area. Three different channel heights and widths were compared with the base flow-field design of the serpentine channel whose width is 1 mm and 0.34 mm in height, each through a detailed numerical study of the distribution of temperature, pressure, water content, and local current density. As the channel height increases higher than the base design, the total pressure drop decreases and results in reduced load of BOP and accumulation of liquid water at the outlet of both anode and cathode. The accumulation of anode liquid water at the outlet caused by back diffusion is accelerated as the channel height increases. As the channel width expands wider than the base design, the pressure drop is lowered and the removal rate of liquid water becomes faster. The effect of the channel width increase on the water removal is greater than that of the channel height increase. Which can influence the dehydration and temperature of the MEA and thus cell performance and lifetime of PEMFC. The results obtained in this work are expected to be applied in developing an efficient serpentine flow-field channel with sub-channels and by-passes.     

Modeling stresses in the separator of a pouch lithium-ion cell

The stress in a separator is mainly caused by the lithium diffusion induced deformation in the electrodes and thermal expansion differential between the battery components. To compute the lithium concentration distribution and temperature change during battery operation, multi-physics models have been developed previously. In this work, a macro-scale model for a pouch cell was developed and coupled with the multi-physics models. In this model, the porous battery components were treated as homogenized media and represented with the effective properties estimated using the rule of mixtures. The stress analysis showed that the maximum stress in the separator always emerged at the area around the inner corner of the separator where it wrapped around the edge of an anode and when the lithium-ion battery was fully charged. Numerical simulations were also conducted to investigate the influences of some design adjustable parameters, including the effective friction, electrode particle radii and thickness of the separator, on the stresses in the separator. The results provided the reference conditions for the improvement of separator materials and the design of lithium-ion batteries.     

参数变化对LiBr吸收式热泵性能的影响

针对溴化锂吸收式热泵的特点,在一定参数变化范围内研究驱动热源、冷媒水以及冷却水进出口变化对其性能的影响。结果表明,不同参数对COP及具体设备的热负荷、传热温差造成不同程度的影响,在热泵的设计过程中应综合考虑各参数的取值以获得最佳的效果。研究结果为热泵系统的优化设计提供理论支持和参考。