输电线路架线施工计算软件开发与应用

青海送变电工程公司在以往工程计算数据的基础上,利用计算机软件编程技术发展快、操作简单、运算快、精度高的优点,开发了涵盖牵张力和牵引力计算、弧垂计算、连续爬坡弧垂修正计算、布线计算等10项计算模块的张力放线计算软件,通过在张力放线计算软件中设置各计算参数计算公式,设计人性化的操作界面,按设定计算功能快速准确得出计算结果,在架线施工中得到了广泛应用,有效减少技术人员复杂繁琐的计算过程,提高了计算效率。     

采暖年耗热量的计算及应注意的问题

本文强凋执行《城市热力网设计规范（GJJ34—2002）》．介绍了采暖热负荷计算方法。选用热指标应注意的问题。介绍了采暖全年耗热量计算方法及计算应注意的问题。 本文给出了5个全年耗热量计算的例题．并对计算例题进行了分析。 本文还介绍了按室外不同计算温度所持续时间计算全年耗热量的计算方法。计算举例与《城市热力网设计规范》规定的方法进行了比较，并提出应按设计规范的计算方法，计算采暖全年耗热量。 本文供热电厂设计参考。     

基于到达时间的云闪定位计算模型仿真研究

针对雷电定位系统中的云闪定位问题,基于雷电到达各探测站的时间建立了云闪定位计算模型,给出了云闪定位的计算方法和精度评定,利用模拟的云闪观测数据,通过不同数目探测站的组合对云闪定位的计算模型进行了仿真计算,并对仿真过程中迭代计算的收敛性和初值的确定方法进行了分析。结果表明,云闪定位计算模型合理、有效,且计算稳定、计算量小。     

关于循环流化床锅炉热力计算中几个问题的探讨

对循环流化床锅炉热力计算进行了探讨。对炉膛热力计算，飞灰浓度和飞灰量计算、内热平衡计算、返料回灰焓计算，二次分离器前后烟焓计算及ｑ４和ｑ６计算提出了计算方法。     

锅炉部件和系统可靠性的计算模型

提出了电站锅炉部件及系统的可靠性计算模型,包括承压部件强度的可靠性计算模型、非承压部件的可靠性计算模型和锅炉系统的可靠性计算模型.锅炉承压部件的可靠性计算,考虑了设计量离散性的影响,使用概率设计法计算承压部件强度设计的可靠性.锅炉非承压部件的可靠性计算,使用了历史寿命数据统计法和非参数法的计算模型.锅炉系统的可靠性计算采用了串联系统的可靠性计算模型.给出了电站锅炉承压部件、锅炉易损件、锅炉耐用件、锅炉子系统、锅炉主机和锅炉系统的可靠性计算公式与计算实例.实现了在设计阶段定量计算锅炉部件和系统的可靠性.为电站锅炉的可靠性分析、可靠性设计与可靠性改进提供了依据.     

全网供电可靠性指标合成研究

开发了一种供电可靠性计算软件,该软件可用于农村电网和城市电网的可靠性计算,在保证计算精确度的同时大大降低了计算时间,节约人力资源.同时,针对分区可靠性计算不能灵活组合合成的问题,提出全网供电可靠性指标的合成方法,并以实例计算验证了该软件计算可靠性指标的准确性.     

基于P2P的电力潮流的冗余计算模式

阐述了P2P的网络计算模式的优点,计算模式采取灵活的对等式和动态交互式调度管理。针对潮流计算的特点,提出了基于P2P的冗余计算模式,这种冗余计算实现形式虽然也是对同一个问题进行计算,但不是进行同样的处理,而是对不同的划分方案采取主方案和辅助方案的方式同时进行计算,可以提高计算准确性,还可起到容错性效果。算例的计算结果表明了这种计算模式的有效性。     

热电厂短路电流计算的心得体会

绍了电厂设计中短路电流计算的基本步骤：包括基本参数的描述、电路元件标么值的计算、短路点短路电流的计算;并介绍了短路电流的计算方法：如基准值的选取、短路阻抗标么值计算、等值阻抗图的简化等。通过短路电流计算的基本步骤和计算方法的介绍使电气设计人员对纷繁复杂的短路电流计算有了清晰的思路和可靠的方法,解决了电气设计人员在短路电流计算时无从下手的困难。     

再热汽轮机性能试验系统修正方法研究

依据《ASME PTC6—1996汽轮机性能试验规程》,深入研究了再热汽轮机性能试验系统修正计算的两种方法,给出了两种计算方法的实现过程,分析了两种计算方法的差别。通过一个算例考察了两种计算方法对计算结果的影响,在此基础上推荐了一种修正计算方法。     

大功率汽轮机通流部分热力参数的简化计算方法

针对传统汽轮机变工况计算方法所需热力参数较多、测量时有不准、通流部分几何参数难以获取等问题,拟定了大功率汽轮机通流部分热力参数的简化计算方案.该计算方案是一种基于少量监测参数即可实施的简化计算方法,具有操作简便,计算快捷的特点.以某300MW汽轮机为对象,对简化计算方案进行了实施,完成了多个变工况下的热力计算,将计算结果与制造厂提供的数据进行了对比,结果显示:计算结果能很好地满足工程计算精度和实用性的要求.     

Estimation of heat transfer coefficient and friction factor in the transition flow with low volume concentration of Al2O3 nanofluid flowing in a circular tube and with twisted tape insert

Experiments to evaluate heat transfer coefficient and friction factor for flow in a tube and with twisted tape inserts in the transition range of flow with Al₂O₃ nanofluid are conducted. The results showed considerable enhancement of convective heat transfer with Al₂O₃ nanofluids compared to flow with water. It is observed that the equation of Gleninski applicable in transitional flow range for single-phase fluids showed considerable deviation when compared with values obtained with nanofluid. The heat transfer coefficient of nanofluid flowing in a tube with 0.1% volume concentration is 23.7% higher when compared with water at number of 9000. Heat transfer coefficient and pressure drop with nanofluid has been experimentally determined with tapes of different twist ratios and found to deviate with values obtained from equations developed for single-phase flow. A regression equation is developed to estimate the Nusselt number valid for both water and nanofluid flowing in the transition flow Reynolds number range in circular plain tube and with tape inserts. The maximum friction factor with twisted tape at 0.1% nanofluid volume concentration is 1.21 times that of water flowing in a plain tube.     

Design of Fresnel lens with spherical facets for concentrated solar power applications

In this paper, a ray-tracing model is developed using MATLAB based on mathematical formulations used in the design of Fresnel lens with spherical facets. Further, a design chart for Fresnel lens with spherical facets is developed to determine aperture radius and design angle for a given focal length and focus size. Concentration ratio and spherical aberration for Fresnel lens with spherical facets are also compared with those of plano-convex lens and conventional Fresnel lens with triangular facets. Furthermore, the present mathematical model is validated with SolTrace model and with the experimental study conducted on a prototype of Fresnel lens with spherical facets fabricated using CO₂ laser cutting machine. Focal length for the proposed Fresnel lens with spherical facets is found to be the same. However, concentration ratio computed from the present ray-tracing model is in fair agreement with SolTrace model and experimental data with percentage deviations at focal length 5.4% and 12.4%, respectively.     

电机冷却用翅管换热器传热和阻力特性研究

研究了一种电机冷却用新型翅片开孔结构换热器的性能,对三种结构的翅片管换热器进行了换热和阻力性能测试,新型翅片换热器结构为翅片间距2.1 mm且翅片上具有开孔结构,对照组换热器分别为翅片间距2.1 mm无开孔换热器和翅片间距2.3 mm无开孔换热器。试验结果表明,相同Re数下,该种具有开孔结构换热器在所有换热器中换热性能最好,较2.1 mm无孔提升38%～39%,但同时压降损失也最大,较2.1 mm无孔提升41.9%～42.9%。采用j/f评价综合性能,结果显示,Re>6700时,新型翅片换热器性能优于同翅片间距无开孔换热器。文章还对这三种结构翅片管换热器进行了传热和阻力关联式拟合,可为相关理论研究和工程选用提供参考。     

柴油机椭圆孔喷嘴的实验研究

本文就椭圆孔喷嘴的雾化特点和对柴油机性能的影响进行了探讨。所得出的基本结论是：圆孔喷嘴并非是柴油机燃烧系统最理想的选择。在一定长短轴比情况下，椭圆孔燃油雾化的混合特性明显好于圆孔喷嘴，如果与柴油机燃烧系统匹配适当，可以使柴油机性能大幅度地提高。     

Experimental study of the effect of fuel types on the performance of spark ignition engine

Different fuels are being used daily in the city of Kirkuk, Iraq for operating vehicles with spark-ignition internal combustion engines. Aiming to address the effects of these fuels on both engines and the environment, this work conducts an experimental study where a single-cylinder, four-stroke small spark ignition engine is employed. Three types of benzene with different octane ratings (low with an additive [85.8%], medium [89.2%], and high [95.6%]) are utilized in the study as they are the most consumed fuel in the area of the study. Moreover, the low-octane fuel will be addressed with a commercial additive. In addition to engine performance, the exhaust gases and sound levels are analyzed as well. Through the outcomes, it is observed that the fuel with higher octane numbers relatively produces better engine performance and pollution. At normal engine speed, the fuel with a medium octane rating, however, has close engine performance results but with worse pollution effects. On the other hand, the engine fails to start with low-octane fuel without the additive. The additive improves the engine performance with the low octane fuel and surprisingly produces fewer pollution gases than the fuel with medium octane number. However, the engine still behaves worse than with the other fuels at normal engine speed.     

微通道壁面加热对甲烷空气预混火焰传播特性的影响

对于甲烷和空气预混合气在矩形微燃烧室内的燃烧过程,采用加热片加热,对比分析了在外部加热时,有无隔板对燃烧稳定性的影响,并分析了不同加热温度下隔板式燃烧室内火焰传播特性。实验结果表示,随着加热温度的提升,隔板型燃烧室稳定燃烧区域不断增大；加热温度高于600K,隔板型燃烧室的火焰吹熄极限有明显改善；高温加热利于提高隔板型燃烧室在较大流量情况下燃烧的稳定性。相较于单通道燃烧室,外部加热对隔板型燃烧室燃烧稳定性的改善更加明显。     

Modelling a hydropower plant with reservoir with the micropower optimisation model (HOMER)

Hydropower with water accumulation is an interesting option to consider in hybrid systems, because it helps dealing with the intermittence characteristics of renewable energy resources. The software HOMER (version Legacy) is extensively used in research works related to these systems, but it does not include a specific option for modelling hydro with reservoir. This paper describes a method for modelling a hydropower plant with reservoir with HOMER by adapting an existing procedure used for modelling pumped storage. An example with two scenarios in southern Brazil is presented for illustrating and validating the method explained in this paper. The results validate the method by showing a direct correspondence between an equivalent battery and the reservoir. The refill of the reservoir, its power output as a function of the flow rate and installed hydropower capacity are effectively simulated, indicating an adequate representation of a hydropower plant with reservoir is possible with HOMER.     

Impact of oxygen enrichment on the engine's performance,emission and combustion behavior of a biofuel based reactivity controlled compression ignition engine

Diesel engine with RCCI (Reactivity Controlled Compression Ignition) finds the next generation technology in engine research for combusting slow burning fuels such as vegetable oils and arriving extremely lower levels of smoke and NO (Nitric Oxide) emissions simultaneously. An attempt was made to operate a diesel engine on RCCI mode by injecting ethanol as low reactivity fuel at the intake manifold of the engine using sunflower based Waste Cooking Oil (WCO) as high reactivity fuel under oxygen enriched intake air. The influence of the combined effect of oxygen enrichment and RCCI mode on engine's behavior was studied using WCO as the high reactivity (main) fuel. Significant improvement (upto 33.5% with RCCI mode from 29.1% with neat WCO at peak power) in BTE (brake thermal efficiency) with drastic reduction in smoke (upto 48% with RCCI at the maximum efficiency point from 69% with neat WCO at peak power) and NO were achieved with injection of ethanol under RCCI mode when using WCO as base fuel mainly at high loads (power outputs). Combining oxygen enrichment with RCCI resulted in further improvement in BTE (upto 36.2%) and reduction in smoke (upto 37% at the maximum efficiency point), HC and CO emissions at all power outputs. Peak pressure and energy release rate were found to be superior with RCCI mode with EF (electronic fuel) injection of ethanol associated with oxygen enriched combustion. It is concluded that RCCI operation with injection of ethanol combined with oxygen enrichment could be preferred for very high BTE, lowest smoke and NO emissions using WCO as base fuel. The optimal level of low reactivity fuel blending with high reactivity WCO could be at the ethanol energy share of 25% for the highest thermal efficiency at peak load. The optimal oxygen concentration of 23% by volume could be preferred for best performance of the engine fueled with WCO as main fuel.     

Unsteady MHD natural convection flow past an infinite vertical porous plate with radiation absorption effects

In this paper, we have explored the unsteady hydromagnetic free convective flow over an infinite perpendicular porous plate with temperature resource and/or radiation absorption. The prevailing equations are subsequently resolved systematically by utilizing perturbation methodology. The velocity, temperatures as well as concentrations sketches are shown in graphics. The impacts in the flow area for dissimilar leading parameters have been explored. Also, the skin friction, Nusselt quantity along with Sherwood quantity are computed with different parameters and mentioned in the tables. The velocity diminishes with escalating in the chemically reacting parameter as well as improves with an increment in temperature resource parameters. The temperature field reduces with an augment in the Prandtl number, whereas it enlarges with an augment in temperature absorption parameters. The concentrations field is enhanced by an amplifying in chemically reacting variable, whereas it lessens with an amplifying Schmidt number.     

Mercury capture by native fly ash carbons in coal-fired power plants

The control of mercury in the air emissions from coal-fired power plants is an ongoing challenge. The native unburned carbons in fly ash can capture varying amounts of Hg depending upon the temperature and composition of the flue gas at the air pollution control device, with Hg capture increasing with a decrease in temperature; the amount of carbon in the fly ash, with Hg capture increasing with an increase in carbon; and the form of the carbon and the consequent surface area of the carbon, with Hg capture increasing with an increase in surface area. The latter is influenced by the rank of the feed coal, with carbons derived from the combustion of low-rank coals having a greater surface area than carbons from bituminous- and anthracite-rank coals.