浮顶储油罐传热系数的变化规律及影响因素研究

目前国内外常用的地上大型原油储罐主要是浮顶罐,研究其传热系数的变化规律对于降低储罐生产能耗,节约成本具有重要的现实意义。在建立浮顶罐内原油理论模型基础上,为避免由于平均温度的不当选取,使得计算误差不断得到放大,采用分步集总参数法计算浮顶储油罐的传热系数,通过对浮顶类型、储罐液位、储罐体积、外界环境温度、风速等影响因素的分析,总结浮顶罐罐底、罐壁、罐顶以及总传热系数变化规律,为准确预测大型浮顶储油温降提供了理论依据。     

基于红外测温的双盘式浮顶储油罐散热损失分布规律研究

采用红外热像仪、表面温度计等对双盘式浮顶储油罐的表面温度场进行测试。结果表明:罐顶表面温度呈轴对称分布,径向温度梯度远高于周向,且距离罐中心越远,表面温度越高。油蒸汽挥发导致浮顶和罐壁间的一二次密封处散热损失明显升高,使其成为罐顶表面温度最高的区域。浮舱隔板、桁架和椽子等结构形成了热桥,使局部位置的表面温度升高,增大了罐顶的散热损失。罐壁周向表面温度梯度低于轴向,并且受油温影响较大,在罐壁保温结构的结合部位、局部保温结构破损位置的表面温度较高,散热损失较大。基于表面温度法,结合环境温度和风速测试结果,采用强迫对流换热关联式计算得到储罐不同部位的散热损失。结果表明:对于双盘式浮顶储油罐,罐顶散热损失最大,约占储罐总散热损失的67%,罐壁散热损失约占25%,罐底散热损失约占8%。     

内浮顶油罐浅析

内浮顶罐是近几年发展起来的，有一部分是新建的，有一部分是利用立式圆柱形拱顶油罐，在罐中加建内浮盘而改建的，内浮顶罐有钢板、铝板制成的，也有用玻璃纤维增强聚脂及环氧物、硬泡沫、塑料或各种复合材料建造的。浮顶结构有隔仓式、浮船式、浮盘式等多种。１内浮顶罐...     

大港油田储罐保温现状及太空隔热涂料的应用

通过对液体隔热保温涂料的应用和分析,优选出了一种新型太空隔热保温涂料,并在储罐保温中推广应用。新型太空隔热涂料综合了涂料和保温材料的双重特性,具有传热系数低、反射率高、整体密封性好和防腐等特点,其在油田储罐保温中的应用,改变了传统的保温模式,避免了因保温材料吸水造成的保温效果下降和外壁腐蚀等问题,同时解决了浮顶罐罐顶不能保温的问题,为浮顶罐罐顶保温提供了一条有效的途径。     

新型节能内浮顶在轻质油罐中的应用

全新型的储油罐内浮顶—金属骨架泡沫塑料浮子组装式内过顶是深圳求实技术开发公司专利产品,曾在1988年北京国家发明博览会和首届国际专利及新技术展览会上获得铜牌奖,1989年获国家发明银奖,1992年6月该浮顶在我厂143、144、145、203罐(原为无力矩罐)上应用获得成功.金属骨架泡沫塑料浮子组装式内浮顶是由金属的周边框架和槽型支承梁组成,Dx—40铝合金复合盖板材料复盖在框架的上方,整个结构支承在铝管支腿上,外圈是密封胶带与精壁紧贴在一起,从而更有效地起到密封作用.该浮顶大大节省了钢材和金属材料,而其支持强度却毫不逊色,且可防止油品的蒸发损耗、保护油质、保护环境.     

大型储罐用钢板SPV4902焊接裂纹的分析及处理

2005年9月，某石油储备基地300×10 4m2原油储罐建造工程开工，当地锅检所对全部储罐现场制造安装进行了监督检验。2006年5月，锅检所对施工单位已完成自检的T101、T103、T105、T106和T201等5台10×104 m3双盘浮顶储罐纵环焊缝进行第三方无损检测抽查时，     

直膨系统顶排管换热性能实验研究

顶排管作为冷冻冷藏库内常用的冷却设备之一,在冷库降温过程中具有诸多优势。但其自然对流换热过程复杂性,整个换热过程包括导热、对流以及辐射3种形式,导致对自然对流条件下的冷却排管理论分析求解比较困难。文中分别研究了不同库温、不同换热温差共12组工况下,顶排管的换热性能,得出了传热系数的变化情况及最佳工况点。     

保温涂料在外浮顶油罐的应用

就国内一种新型的保温涂料在石化储罐上的应用实例进行分析计算,研究表明该涂料是一种高效保温涂料,尤其是在石化行业的外浮顶油罐上应用,节能效果十分显著。     

燃气涡轮篦齿叶顶流动传热特性的数值研究

以GE-E3型第一级叶栅为研究对象开展数值研究,基于高压涡轮常规凹槽叶顶提出新型叶顶结构。通过求解三维Reynolds-Averaged Navier-Stokes(RANS)和标准k-ω湍流模型研究了篦齿结构和布局对叶顶流动传热特性的影响。数值预测的平叶顶的流场分布与实验数据吻合良好,验证了数值方法的可靠性。研究结果表明:篦齿叶顶可以有效降低中弦处的叶顶泄漏损失,篦齿形状对泄漏强度影响较小。此外,篦齿叶顶显著降低叶顶平均传热系数和热负荷,相比常规凹槽叶顶,前缘斜篦齿叶顶的平均传热系数降低了22.39%。在研究的新型叶顶结构中,倒梯形篦齿叶顶(I-TIP)具有最低的叶顶平均传热系数,梯形篦齿叶顶(T-TIP)具有最低的叶顶热流量,前缘斜篦齿叶顶具有最佳的气热性能。在叶顶凹槽前缘布置篦齿结构可有效降低叶顶换热系数。     

滑动轴承顶轴油设计

介绍了滑动轴承顶轴油装置的结构特点,采用数值计算方法对顶轴油的压力分布以及在一定荷载下所需的顶轴油压力和流量进行了计算,并将计算结果与参考资料进行了比较,结果表明,采用该方法进行计算具有一定的精度,计算结果可为相关工程设计提供一定的参考。     

D.C. scanning thermal microscopy: Characterisation and interpretation of the measurement

The used Scanning Thermal Microscopy (SThM) probe is a thin Pt resistance wire acting as a heat source and as a detector simultaneously. Its energetic balance is investigated by the study of the temperature profile along the probe. A theoretical approach of the measurement, based on this investigation, is then proposed. Simulations with this modelling are shown to predict how the heat, electrically produced in the probe, is dissipated in the probe-sample system. In particular, it is shown that the steady-state of conduction losses to the thermal element support varies versus the thermal conductivity of the sample and can lead to bad interpretations of the measurement.     

Ground water level influence on thermal response test in Adana,Turkey

For optimum design of borehole thermal energy storage (BTES) and ground sources heat pump (GSHP) applications, determination of underground thermal properties is required. The design and economic feasibility (number and depth of boreholes) of these systems need thermal conductivity of geological structure, λ (W m^?1 K^?1), and thermal resistance of ground heat exchanger, R (K W^?1 m). Thermal properties measured in laboratory experiments do not coincide with data of in situ conditions. Therefore, in situ thermal response test equipment has been developed and used in Canada, England, Germany, Norway, U.K., U.S.A. and Sweden to ensure precise designing of BTES systems. This paper describes the results and evaluations of the Adana continual thermal response test measurements. Copyright © 2007 John Wiley & Sons, Ltd.     

活塞热疲劳分析

用Pro/E建立活塞几何模型,在ANSYS单元库里选取热结构耦合单元,对模型网格进行优化,并对活塞温度场进行标定,然后进行热机耦合分析计算,得到活塞温度场、热应力场和变形。计算结果表明,在低频热疲劳下,活塞循环次数最少约是1 120 000次,这为活塞的结构改进和优化提供了依据。     

甘肃海潮坝水库面板堆石坝的施工

海潮坝面板堆石坝在施工中调地制宜采用堆石料洞室爆破，级配符合设计要求。滑模用手动葫芦牵引，面板平整。对已成面板进行详细的检查，面板无贯穿性裂缝。工程进度快，质量优良。     

非共晶相变材料应用于太阳能吸热蓄热器的数值分析

通过计算分析发现对于目前的吸热蓄热器结构，采用相变发生在一个温度区间的非共晶熔盐混合物作为相变材料可以较好的提高吸热蓄热器的整体性能。主要表现在明显地提高相变材料的利用率、减小换热管工质出口温度波动、减小容器表面最大温度及容器表面温度变化，经过合理的设计还可以减小整体系统的质量。分析结果可以作为吸热器设计的参考。     

A review on thermal management techniques for lithium-ion battery

随着新能源汽车的广泛使用,动力锂离子电池的热安全性问题日益突出。本文以Bernardi生热机理为基础,耦合不同物理量,分别从电化学-热耦合模型、电-热耦合模型和热滥用模型来介绍单体电池的热特性。由于电池能量密度的增加与行驶工况复杂程度的提高,动力锂离子电池容易发生热量堆积,甚至造成热失控,对此,文中梳理了商用动力电池包的常用冷却方式。最后,根据对影响电池模组安全性的热失控蔓延机理及实测结果,介绍了阻断单体及基本模块热失控传播的有效方法。     

A mobile thermal battery resembling a solar receiver: Innovative design and performance assessment

An innovative design of a mobile thermal battery resembling the solar receiver is presented. A ternary salt mixture consisting of 52% KNO₃, 18% NaNO₃, and 30% LiNO₃ by wt% is used as the thermal energy storing medium inside the thermal battery. Since the thermal conductivity of the ternary salt mixture is low, aluminum meshes are introduced to create a thermal conduction tree inside the thermal energy storing medium. The actual field data are used in the simulations to resemble the solar irradiation emanating from the parabolic trough and focusing onto the thermal battery outer surface. To improve the uniform heating at the outer surface, the thermal battery rotation along the centerline of the trough is considered. The temperature parameter is introduced to assess the uniform‐like temperature distribution inside the ternary salt mixture. It is found that the use of aluminum meshes improves the heat diffusion in the phase change material of the ternary salt mixture; in which case, it acts like a thermal conduction tree inside the thermal battery. The rotation of the thermal battery results in uniform‐like temperature distribution across the thermal battery cross section and suppresses the excessive temperature rise because of the local heating in the close region of the thermal battery outer surface.     

A model study for cyclic thermal loading and thermal performance of a thermoelectric generator

Thermal cyclic loading influences the life cycle of the thermoelectric device pins because of the thermal stress developed in the pins. Although thermal efficiency improves for different geometric configurations of the device pins, development of thermal stresses limit the selection of pin geometry in practical applications, particularly under cyclic thermal loading. Consequently, in the present study, thermal stress analysis of thermoelectric pins under cyclic thermal loading is carried out. The influence of thermoelectric pin geometry on the stress levels is examined when the device is subjected to the thermal cyclic loading. The predictions of thermal stress distribution are validated with the data presented in the open literature. It is found that pin geometric configuration has a significant effect on the stress levels developed in the pin when subjected to cyclic thermal loading. The pin configuration R_A = 1 (parallel pins) results in the minimum value of the maximum von Mises stress in the pins as compared to that corresponding to other configurations. Copyright © 2014 John Wiley & Sons, Ltd.     

THERMAL RELAXATION TIMES EFFECT ON RAYLEIGH WAVES IN GENERALIZED THERMOELASTIC MEDIA

Rayleigh waves in a half-space exhibiting generalized thermoelastic properties based on Green-Lindsay (G-L), Lord-Shulman (L-S), and classical dynamical coupled (C-D) theories are discussed. The phase velocity of Rayleigh waves in the previous three different theories has been obtained. A comparison is carried out between the phase velocities of Rayleigh waves, displacements, stresses, and temperature as calculated from the different theories of generalized thermoelasticity. The C-D theory is recovered as a special case. It appears, in particular, that the results obtained from G-L theory tend to those of L-S theory as the values of the two relaxation times become closer to each other. The second relaxation time is well pronounced when it becomes larger than the first one. Furthermore, it is found that the thermal relaxation times decrease the speed of the elastic waves and modify the phase velocities of the Rayleigh waves. The results obtained and the conclusions drawn are discussed numerically and illustrated graphically. Relevant results of previous investigations are deduced as special cases.     

地源热泵岩土热物性测试简介与分析

地源热泵系统作为利用可再生能源的暖通空调技术,具有节能、环保等优点,在世界范围内被广泛使用。土壤作为地源热泵系统的冷热源,对整个系统有着至关重要的影响。不同建筑负荷特性要求系统对土壤的取放热量不同,二者的不平衡会使土壤的温度发生变化,影响整个系统的运行。对特定建筑地源热泵系统土壤的热物性测试是设计地埋管系统的重要依据。本文对热物性测试的理论依据进行了简单介绍,并对具体事例进行了分析计算,得出岩土体的导热系数等具体热物性参数,为地源热泵系统的精确设计提供了依据。