大型固定管板式换热器管板稳态温度场及热应力场分析

采用有限元分析软件ANSYS,对某大型固定管板式换热器管板的稳态温度场和热应力场进行了三维有限元分析。采用APDL语言建立了包括管箱、筒体和2433根换热管在内的四分之一管板的参数化模型。分析了对流边界条件下管板的温度场和相应的热应力场,提出并论证了温度场和热应力场迭代计算的必要性,得到了该边界条件下管板温度场和热应力场的分布规律。     

某生产井旁通管断裂失效分析

采用宏观分析、力学性能、化学成分分析、金相分析、断口分析等表征手段,对某生产井旁通管的断裂原因进行了分析。结果表明:该旁通管材质符合L80钢的技术要求;旁通管螺纹连接部位未完全啮合,容易造成该处应力集中;同时,螺栓表面存在脱碳现象使材料表面弱化,大幅降低了其疲劳强度,易在振动的环境中产生疲劳裂纹。在下放过程中存在瞬间强应力作用,裂纹从旁通管的裂纹源开始扩展,使旁通管管壁局部首先开裂,在持续应力的作用下从裂纹源区沿管壁一侧沿螺纹延伸方向快速扩展,最终使油管完全断开。     

大型阳极保护浓硫酸冷却器应力分析

应用ANSYS软件,对某大型阳极保护浓硫酸冷却器建立了管板和壳体的有限元实体模型,得到了管板和壳体在工作状态下的温度分布。同时按照JB4732-1995《钢制压力容器——分析设计标准》分析了管板和壳体在5种工况下的应力状况,并进行了应力强度评定,找到了换热管最大拉脱力的位置。结果表明,该设备管板和壳体满足强度要求。     

合成氨变换净化冷却器失效分析

应用SW6-98管板分析设计软件,对合成氨变换净化不锈钢带膨胀节薄管板冷却器进行管箱、壳体、换热管和管板及膨胀节的应力分析计算,进行失效原因分析,提出改进意见。     

机械式胀管器损坏原因的初步分析

通过在多年的胀管实践中的经验和理论分析,对机械式胀管器损坏的原因进行探讨分析。     

急冷锅炉炉管内管失效分析

针对某急冷锅炉炉管内管发生失稳堵塞的问题,对堵塞炉管内管进行材料组织检测分析、管壁腐蚀检测分析和内管的高温强度检测分析,讨论了炉管内管的材料损伤状况以及高温性能情况,得出急冷锅炉炉管发生失效的主要原因是由于内管强度不足,建议增加内管的壁厚,以提高其承载能力。     

废热锅炉薄管板的三维机械应力分析

运用有限元分析软件ANSYS,对废热锅炉建立了考虑筒体和换热管影响的管板真正实际结构的三维模型,对其进行机械应力分析,得出管板的变形和应力分布云图.将分析结果进行应力线性化处理,按照JB4732-95<钢制压力容器--分析设计标准>中的应力分类和评定方法对管板进行了评定.     

固定管板式换热器的温差热应力数值分析

建立由管板、壳体和换热管组成的有限元分析简化模型,利用通过CFD数值模拟得到的各个相应壁面温度数据拟合而成的温度-距离函数关系式,在ANSYS软件中对固定管板式换热器的换热管、壳体和管板表面加栽进行结构热分析,得到了温度分布模型。还将所得的节点温度作为热载荷加栽到结构时应点上计算换热器的整体温差热应力,着重分析管板与管子及壳体连接处附近的热应力分布,并给出了沿管板径向和厚度方向上的热应力变化曲线。     

换热器异型管板应力分析及强度校核

利用ANSYS有限元分析软件对某型号换热器异型前管板进行分析,得到了异形管板温度载荷与压力载荷同时作用下结构的应力场,同时考虑了换热管对管板的加强作用。按照ASME规范进行了强度校核,为异型管板的强度设计和安全评估提供了可靠依据。     

固定管板换热器节能计算分析

结合在用固定管板换热器的运行参数，对相同构造的换热器在采用普通无缝钢管作换热管和采用螺旋槽管作换热管的情况下，分别计算换热器的传热系数，并对计算结果进行分析比较，表嚼采用螺旋槽管作换热管所起的强化传热作用对于固定管板换热器产生的节能效果明显，可以为企业带来较好的节能效益。     

Inversion Temperature and Pinch Analysis,Ways to Thermally Optimize Drying Processes

This work studies the compatibility and suitability of a combined inversion temperature and pinch analysis with the process selection for air and superheated steam spray drying of milk solids. The inversion temperature is a good starting point for an energy analysis because it is a simplified rate-based approach to comparing the steam and air drying systems. pinch analysis enables process integration, at least on a heat recovery and heat exchanger network level.

The resulting inversion temperature for the studied system was estimated as 182°C for the dryer inlet temperature. However, mass and energy balances showed that a minimum inlet temperature for spray drying of 184°C was required for the superheated steam dryer in order to ensure that the outlet solids temperature above the dew point temperature.

The inversion temperature is still very relevant in the early stages of a design process because it allows a quick assessment of which drying medium should result in a smaller dryer. It was evident that the steam system is better from an energy perspective because of the recoverable latent heat of the water vapor carried out of the dryer with the recycled steam. The steam system has between 82 and 92% of thermal energy recovery potential as condensable steam, compared with 13–30% energy recovery of the air system. However, other important design and operational factors are not discussed here in detail.

Combining the inversion temperature and pinch analysis suggests that superheated steam drying both gives better energy recovery and is likely to give smaller dryers for all operational conditions.     

Characterisation by thermal techniques

Differential thermal analysis and thermogravimetric analysis have been used to study EUROCAT-2 OXIDE (TiO₂–V₂O₅–WO₃). It has been found that water is removed at low temperature, and SO₂ removal and surface reduction (O₂ evolution) take place at high temperature, both for a fresh and a used catalyst.     

离子液体在分离分析中的应用

离子液体是在室温或室温附近温度下为液态且完全由离子构成的新型溶剂。具有很多独特的性质,已成功应用于分离分析的各个领域。文中综述了室温离子液体在气相色谱、液相色谱、光谱分析等领域的应用。     

The effect of heat history on thermal degradation of elastomers containing butadiene units

The aim of this research is to develop a new method for studying thermal degradation behavior of elastomers containing butadiene units by isothermal and anisothermal analysis. Accelerated aging such as isothermal thermogravimetry analysis shows that when BR, SBR and NBR elastomers are subjected to specific time and temperature condition in nitrogen atmosphere, an interchain reaction occurs. Experimental observations also show that thermal degradation mechanism of these elastomers depends on heating rate and time–temperature history. For these types of elastomers, the effect of time is similar to temperature and time–temperature superposition principle can be employed for studying the thermal degradation mechanism of elastomer containing butadiene units. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

热分析技术在高分子材料研究中的应用

论述了热分析技术在高分子材料物理化学性质研究中的具体应用 ,如玻璃化转变温度、熔点、氧化诱导期、分解温度以及化学组成含量等 ,并对样品的分析条件进行了探讨     

不同煤化度煤的热解动力学参数

用非等温热重分析对不同煤化度煤的热解动力学进行了研究，探讨了煤的热解活化能、热解特征温度与煤的挥发分、塑性温度之间的关系，并对结果作了解释。     

热油泵机械密封失效分析与对策

通过故障模式及影响分析方法,并采集实际机械密封失效数据进行验证,采用有限元建模分析不同转速、不同压力、不同材料下机械密封的温升情况。结果表明,温升异常是机械密封失效的最主要的原因,转速和压力与温升成线性正比关系;Si C作为密封材料时,温升较为理想。结合实际选型、安装、运行工况提出了改善机械密封的措施。     

Bayesian analysis for determination and uncertainty assessment of strength and crack growth parameters of brittle materials

To determine the strength and the crack growth parameters of brittle materials, the common approach is to first evaluate the strength and then the crack growth parameters. When the parameters are needed for different temperatures, the procedure is repeated for each temperature of interest. Since the number of test specimens is generally small, the separated analysis of strength and crack growth parameters for each tested temperature leads to large parameters uncertainty. In order to improve the accuracy of the parameters, we propose a Bayesian method that allows to combine all strength and lifetime data obtained at different temperatures and determine the distribution of all material parameters in a single analysis. The results obtained from the analysis of measured skutterudite data show that in comparison to the standard approach the presented method significantly reduces the material parameters uncertainty and therefore is well adapted for a reduced number of samples.     

脂肪醇聚氧乙烯醚气相色谱定性定量分析

采用毛细管气相色谱法分离测定脂肪醇聚氧乙烯醚混合物,对色谱条件进行了考察和优化,确定了最佳色谱条件:程序升温200℃(2 min),10℃/min,340℃(∞);气化室温度350℃;离子化室温度350℃;载气N2,流速30 mL/min;柱前压10 Psi(约69 kPa);氢气流速20 mL/min;空气流速300...