共查询到20条相似文献,搜索用时 140 毫秒
1.
近年来,天然气低氮燃烧技术层出不穷,然而单一低氮技术的控制效果始终有限。为实现天然气清洁燃烧和低氮排放,设计了一种集分级燃烧、旋流燃烧和烟气再循环等低氮技术于一体的新型低氮燃烧器,以降低燃烧过程中氮氧化物的生成和排放。建立了功率14 MW的燃烧器模型并对其进行数值模拟计算,分析了不同燃烧器结构和运行参数下燃烧器出口附近温度场、速度场以及氮氧化物(NO)浓度场,探究了混合气体旋流强度和二次风出口速度等因素对低氮燃烧性能的影响,优化该燃烧器的结构和运行参数使其达到最佳低氮性能。结果表明:优化前的燃烧器可使燃气在出口截面分布均匀并与空气充分混合,出口截面NO质量浓度已经低于30 mg·m-3的低氮排放标准;燃气支管数量优化为8根时,高温区的集中度和氮氧化物的排放量最低,出口截面NO质量浓度低至7.61 mg·m-3;一次风和燃气混合气体旋流强度S0优化为0.6时,出口截面NO质量浓度低至5.04 mg·m-3,S0越大,产生的旋流效果越好,炉膛内的烟气内循环效应越明显;二次风出口速度... 相似文献
2.
3.
4.
5.
6.
上海第二工业大学研制的螺锥状旋风式燃烧器(简称FKS燃烧器)在锻造炉上应用获得成功.在该燃烧器的鉴定会上,专家们一致认为FKS燃烧技术在室式锻造加热炉上应用是成功的,技术是先进的。FKS燃烧器是根据煤粉与空气旋转混流,内部风管排列一定角度和风割中快风升温的原理,采用多级多咀送导向结构设计的。生产时,煤粉与风量控制在一定适度,使煤粉在燃烧器內形成理想的旋转路线,从而达到充分燃烧、充分利用热能的目的。使用FKS燃烧器的锻造加热炉的结构如下图所示。 相似文献
7.
8.
9.
10.
11.
目的研究水热反应时间对氧化锌吸波性能的影响,以获得高性能吸波材料。方法通过控制水热反应时间,制备不同形貌的氧化锌半导体材料,并采用XRD、SEM、TEM等表征手段,分析水热反应时间对氧化锌半导体材料形貌及结构的影响。利用矢量网络分析仪测定该材料在2~18 GHz频率范围内的相对复介电常数和复磁导率,采用MATLAB模拟分析不同厚度下水热反应时间对氧化锌半导体材料吸波机制及吸波性能的影响。结果当水热反应时间为12 h时,氧化锌在高频率处可达到较好的吸波效果,最大回波损耗可达?52.86 dB。结论通过控制水热反应时间,可实现对氧化锌的形貌进行调控,进而得到吸波性能优异的氧化锌吸波材料。 相似文献
12.
浙江省县级单元建成区用地绩效评价及其地域差异研究 总被引:4,自引:1,他引:4
为评价浙江省县级单元建成区用地的绩效,并探讨其地域差异,论文采用AHP法、空间分析法,得到研究结果为:构建了基于经济、效益、效率和公平四个维度的土地绩效评价框架;经济绩效与效率绩效呈现较强的空间集聚特征;效益绩效与公平绩效的空间分布趋于离散;综合绩效呈现四种不同的空间模式;用地协调度并不与经济发展水平直接相关。由此得出结论:由于城市的规模报酬递增和工业化水平提高,子绩效中经济绩效与效率绩效呈现较强的空间集聚特征;而效益绩效与公平绩效则体现出相反的两极分化特征;在区域中心城市的产业梯度转移、辐射效应、周边地区的功能承接等机制影响下,H-H绩效和L-L绩效呈显著的空间集聚形态;产业结构升级提高了土地利用协调性,而欠发达地区的土地利用低水平自组织优化机制也可能具有较高的协调度。 相似文献
13.
采用统计分析方法研究了胞外聚合物(extra-cellular polymeric sub6tances, EPS)对浸渍式膜生物反应器(submerged membrane bioreactor, SMBR)中聚乙烯醇改性聚丙烯无纺布过滤性能的影响.结果表明,无纺布膜组件表面污泥的溶解性EPS(soluble EPS, EPSs)、EPSs,组成(protein/carbohydrate, P/C)以及相对疏水性(relative hydrophobicity, RH)对膜的过滤性能有显著影响,与膜污染阻力的皮尔逊相关系数(rp)分别为:0.868、0.840、0.890;改性无纺布膜组件能有效抑制EPSs,的吸附、降低EPSs组分中P/C的比率、减少活性污泥的沉积.表明聚丙烯无纺布通过亲水改性后,过滤性能得到明显改善,表现出一定的耐污染性. 相似文献
14.
目的 预测某型电连接器的剩余寿命。方法 以某弹用电连接器为研究对象,在分析导弹服役环境和电连接器失效机理的基础上,基于电连接器接触电阻性能退化特点,利用Wiener过程拟合电连接性能退化轨迹。然后,以Wiener过程的漂移参数为中间变量,采用广义Eyring模型,对温度、湿度应力进行建模,进而根据试验数据对性能退化数据似然函数的参数进行估计。最后,结合加速模型,推导得到正常应力水平下的漂移参数值,从而确定出电连接器的可靠度模型。结果 计算出样品电连接器的平均寿命,可进一步推断该型电连接器的其他寿命信息。结论 Wiener过程可以拟合湿热环境下电连接器的性能退化轨迹,温湿应力是开展弹上设备试验需重点关注的因素,考虑进一步提高类似环境载荷下的加速退化试验效率,可在一定程度上增大温度应力水平。 相似文献
15.
《Journal of Cleaner Production》2006,14(6-7):661-671
By interacting with their suppliers and their customers, manufacturing organizations can potentially develop and implement more effective solutions to environmental challenges they are facing. This paper explores the outcome, in terms of operational performance, of green project partnership in the supply chain. Green project partnership, defined here as the degree of interaction between organizations in the supply chain regarding pollution prevention, can take place upstream with the suppliers and downstream with the customers. Using the data from a survey of the Canadian and United States package printing industry, the linkage between green project partnership and five performance indicators was tested. The results indicate that green project partnership with customers was positively linked to quality, flexibility and environmental performance while partnership with suppliers was associated with better delivery performance. 相似文献
16.
Daniel J. Thomas 《Journal of Manufacturing Processes》2009,11(2):97-105
The characteristic surface properties and internal workpiece transformations formed during the Abrasive Waterjet (AWJ) cutting process influences the formability and fatigue performance of steel cut-edges. This relatively established cutting technology is used in industry to generate specialist low production components, which may undergo continual loading cycles under operational service conditions. The fatigue performance of AWJ cut-edges can be critical since individual notch defects produced by the cutting process can act as initiation sites from where fatigue cracks can propagate. Due to the increased sensitivity of high strength structural steels to cut-edge fatigue, AWJ cut-edge defects have an ever more significant influence on fatigue performance. The relationship between the traverse cutting speed and the influence on the resulting properties of the cut-edge has been the critical area of investigation. The affects of traverse cutting speed on the surface roughness properties and cut-edge hardening through a process of plastic deformation of grains in the near edge region were observed to be influenced by the traverse cutting speed. It is these characteristic factors that were determined to influence the cut-edge ductility and fatigue performance of steel components. It is a combination of the AWJ properties that produces cut-edges, which are positive for the Hole Expansion Capacity (HEC) but negative for stress life and cyclic stress strain life fatigue performance of AWJ cut high strength steels. 相似文献
17.
Yoshihiro Sagisaka Tamotsu Nakamura Kunio Hayakawa Itaru Ishibashi 《Journal of Manufacturing Processes》2013,15(1):96-101
It is required to replace the aluminum fluoride coating, which is a popular lubricant for aluminum alloy cold forging in Japan, with environmentally friendly lubricants, because the aluminum fluoride coating has high environmental risks and needs much expense. Evaluations of lubrication performance are necessary before lubricant replacement. The authors proposed new friction test based on combined forward spline-backward can extrusion. It can realize large surface expansion, which is a characteristic of aluminum cold forging. In the present paper, a double-layer-type environmentally friendly solid lubricant film and the aluminum fluoride coating were applied to a precipitation hardened aluminum alloy. The lubrication performance was evaluated by the friction test. The double-layer-type lubricant showed superior performance enough for the replacement. The effect of surface treatment applied to workpiece on the lubrication performance was also investigated. The surface asperity generated by a wet-blasting showed high pickup resistance and low friction. 相似文献
18.
19.
固化/稳定化技术是一项在欧美等国家的污染场地修复中广泛应用的技术.在分析固化/稳定化修复效果常用的浸出试验方法和物理评价方法以及相对应的评价标准的基础上,发现我国固化/稳定化修复效果的评价方法仅有少量振荡浸出试验的方法,还缺少动态浸出试验的评价方法;浸出毒性测试普遍采用硫酸硝酸法浸出评估,忽略了As、Cr(Ⅵ)等含氧阴离子在中性至弱碱性pH下溶解度达到最大的情况;固化/稳定化修复效果的评价标准则主要借鉴固废毒性鉴别与管理方法,但该方法未规定污染土壤资源化再利用时的评价依据;另外,污染土壤和固体废物的自身特性也有一定的差异.提出了基于我国国情的污染土壤固化/稳定化浸出测试和评价标准体系:当污染土壤固化/稳定化后采用卫生填埋或一般工业固体废物贮存、处置场处置时,可参考固体废物填埋处置时的评价方法与标准;当污染土壤固化/稳定化后原址填埋时,则应增加绕流浸出方法或穿透浸出试验方法,其评价标准可参考GB/T 14848—1993《地下水质量标准》或根据关注点浓度的要求进行风险评估推算确定;当污染土壤固化/稳定化后再利用时,需根据再利用的具体情景选择相应的评价方法与标准. 相似文献
20.
Ming YangFaisal I. Khan Rehan SadiqPaul Amyotte 《Journal of Cleaner Production》2011,19(13):1513-1526
Activities in offshore oil and gas (OOG) that cause environmental impacts can be systematically managed through an environmental management system (EMS). Environmental performance evaluation (EPE) is an essential part of an EMS. However, previous studies on EPE indicate that existing lists of indicators little insight into how indicators are modified to more accurately assess environmental performance.In this paper, a way is proposed to identify and define specific environmental performance indicators on a case-by-case basis, which consists of five steps: (1) describing environmental requirements; (2) determining favourable outcomes corresponding to the requirements; (3) identifying required activities or issues to achieve the outcomes; (4) searching for proper measures of the activities or issues; and (5) generating a list of key indicators. Based on these steps, a quality function deployment (QFD) approach is developed to determine key indicators and evaluate environmental performance. To handle uncertainties in QFD, the decision makers’ evaluations are quantified through rough numbers using the concept of rough sets. The outputs of the proposed approach are different environmental performance indices. Using these indices, decision makers can easily determine whether an improved performance has been achieved through an EMS. The proposed approach is transparent and promising for use as a unified tool for EPE. An application of the proposed approach is demonstrated through a numerical example. 相似文献