除尘器区低温省煤器烟道数值模拟

为实现除尘器区低温省煤器的节能改造,基于FLUENT6.3软件,对除尘器区低温省煤器烟道的流场进行数值模拟研究。研究结果表明:除尘器前烟道内流场严重不均,转弯处有明显的高速区与漩涡区,局部速度高达32 m/s;加装低温省煤器后,两低温省煤器内流场不均,最大速度偏差系数达79.3%,严重影响低温省煤器的换热效果,同时会磨损、冲刷低温省煤器管路,危及低温省煤器的安全;除尘器入口处出现大面积的低速区域,导致进入除尘器后流场紊乱、除尘器电耗高、除尘效率低等现象,除尘器前烟道内整流消涡可以根治除尘器工作效率的问题。     

对常规注水泥温度场预测方法的评价

为了对常规注水泥温度场预测方法进行研究评价,分析了API方法和一些常用的经验方法,并对API公布的数据和国内首次实测的大量井下循环温度实际数据进行了对比,结果表明:常规预测温度的方法其平均相对误差均高于5%;虽然对于不同井深和不同的循环时间条件可以采用不同的经验系数由地层静止温度(BHST)来估计井下循环温度,但该方法受到地区和各种因素的限制,时常与实际差别较大,不可能很好地满足钻井和固井施工的要求。要获取更准确的井下温度分布,应加强对本地区井下循环温度的实测和热交换过程的计算机模拟研究。     

DS18B20在油气井场温度监控系统中的应用

油气井场温度监控系统属于井场重要的安全保护装置,此系统用单片机+串行智能传感器来组成,广泛使用了串行芯片。介绍了系统硬件流程图,以及温度传感器芯片DS18B20的工作流程,详细说明了获取温度传感器序列号的ROM操作命令、存储器操作命令。     

船坞工程中坞墩施工关键技术

山船重工西区造船坞工程具有结构复杂、工程量大、工期紧迫等特点,为此在船坞坞墩施工过程中采取了一系列关键控制技术:具体包括坞墩结构合理分块、分层;混凝土施工时间与结构分层间歇期控制;减少结构侧面约束的模板工艺;坞墩混凝土内散热孔设置与块石埋设;混凝土养护与测温控制等。实施效果达到了整个船坞不渗、不漏、不裂,混凝土表观质量良好。     

井下节流气井的生产动态预测

以单井开采系统为研究对象,采用温度、压力解耦建模与数值耦合方式,以井口油压为控制条件,通过油嘴控制流量和下游温度,建立井下节流气井的井筒-气藏流动耦合的生产动态预测模型,利用试井解释结果或生产动态历史拟合,预测气井的生产流量、压力变化,同时描述生产过程中的井筒非线性温度剖面、压力剖面,从而全面掌握节流气井的生产动态,并可进一步扩展应用于多相流动和复杂井眼轨迹情况。     

Two preprocessing algorithms for climate time series

We propose two preprocessing algorithms suitable for climate time series. The first algorithm detects outliers based on an autoregressive cost update mechanism. The second one is based on the wavelet transform, a method from pattern recognition. In order to benchmark the algorithms'' performance we compare them to existing methods based on a synthetic data set. Eventually, for exemplary purposes, the proposed methods are applied to a data set of high-frequent temperature measurements from Novi Sad, Serbia. The results show that both methods together form a powerful tool for signal preprocessing: In case of solitary outliers the autoregressive cost update mechanism prevails, whereas the wavelet-based mechanism is the method of choice in the presence of multiple consecutive outliers.     

印刷车间再热的热回收节能策略

针对夏季印刷车间空气处理过程中,由于控制室内温湿度波动而采取再热措施造成冷热抵消的能源浪费现象, 根据空气处理过程焓湿图分析了西安某印刷车间夏季空气处理产生再热的原因,并在对印刷产生有机废气采用局部排 风进行有效收集处理的基础上,针对性地提出了利用热回收以补偿再热负荷的思路。比较了几种常见热回收装置的特 点,根据对印刷有机废气催化处理后排放尾气的温度,选择了热管式显热回收方式,进而分析了其传热量及显热回收效 率的计算过程,突出了其节能优势,最终达到充分利用废热节能的目的。     

基于ANSYS的热成形模具结构优化

基于冲压成型工艺试验分析系统,针对模具内材料受热膨胀将对模具导向装置及结构造成干涉的问题,利用有 限元分析软件ANSYS对模内温度场进行热力耦合分析,得出各部分材料的热膨胀程度。为基于正向压边模架的模内加 热装置提供可靠的实验参数和热力学设计依据,提高了模具结构设计的合理性,达到优化设计的目的。     

季节性冻土地区保温护道路基温度场数值模拟

研究路基及周围土体温度的分布规律是分析季节性冻土地区路基稳定性的重要基础,结合哈齐客专DK221+150断面3 a的现场监测数据,分析了天然地表及路基不同位置的地温分布规律;建立温度场的仿真模型,研究温度沿深度方向的变化规律;利用实测数据验证模型,分析保温护道高度对路基温度场的影响。现场监测和模拟计算结果表明：护道对路基的边坡下部和坡脚处影响较大,能够有效减小冻深,但对路基中心的温度场影响不大。     

Reanalysis of the DEMS Nested Case‐Control Study of Lung Cancer and Diesel Exhaust: Suitability for Quantitative Risk Assessment

The International Agency for Research on Cancer (IARC) in 2012 upgraded its hazard characterization of diesel engine exhaust (DEE) to “carcinogenic to humans.” The Diesel Exhaust in Miners Study (DEMS) cohort and nested case‐control studies of lung cancer mortality in eight U.S. nonmetal mines were influential in IARC's determination. We conducted a reanalysis of the DEMS case‐control data to evaluate its suitability for quantitative risk assessment (QRA). Our reanalysis used conditional logistic regression and adjusted for cigarette smoking in a manner similar to the original DEMS analysis. However, we included additional estimates of DEE exposure and adjustment for radon exposure. In addition to applying three DEE exposure estimates developed by DEMS, we applied six alternative estimates. Without adjusting for radon, our results were similar to those in the original DEMS analysis: all but one of the nine DEE exposure estimates showed evidence of an association between DEE exposure and lung cancer mortality, with trend slopes differing only by about a factor of two. When exposure to radon was adjusted, the evidence for a DEE effect was greatly diminished, but was still present in some analyses that utilized the three original DEMS DEE exposure estimates. A DEE effect was not observed when the six alternative DEE exposure estimates were utilized and radon was adjusted. No consistent evidence of a DEE effect was found among miners who worked only underground. This article highlights some issues that should be addressed in any use of the DEMS data in developing a QRA for DEE.