Experimental Investigation on Ignition and Lean Blow-out Performance of a Multi-sector Centrally Staged Combustor

Improvement on extinction and pollution emission have become one of the most prominent research topics in gas turbine.It is widely recognized that the fuel/air mixture distribution in the recirculation zone is a critical factor in improving lean blow-out(LBO) and ignition.This paper proposed a new low emission scheme with fuel staged centrally and hybrid injector to improve flameout and emission.A relative small amount of fuel enters into central pilot airblast atomizer burner and then atomized by inner swirl air.The remaining majority of fuel is directly injected into vane channels of the primary swirler through a series of holes located on the sidewall of the main stage.Only pilot stage is fueled under ignition and lean flameout condition.The uniformity of fuel/air mixture distribution in the primary zone of the new design decreases NOX emission,meanwhile the fuel air mixture in pilot recirculation zone is locally rich to improve flameout and ignition.Experimental investigation was conducted to compare the new scheme with baseline design of dual-swirler in terms of LBO and ignition characteristics under the same condition in a multi-sector combustor.It is found that the fuel-air ratio of ignition limit and LBO decrease with the reference velocity increasing.The experimental results also show that the new scheme successfully improve lean blow-out and broaden the operation range of the combustor.The experimental results indicated that the centrally staged scheme can widen the operation boundary of the combustor and can provide guidance for design and optimization of combustion chamber.

Growth Performance of Different Cross Combinations of Quality Lean Type Pig

Ten healthy weaning piglets of Landrace x Yorkshire （LY） in good body condition with body weight of （24 ± 1.27） kg were selected, and ten weaning piglets of Berkshire × LY （BLY） and Duroc × LY （DLY） with similar situation were also selected respectively to study the growth performance of different cross combinations. Three groups of experimental pigs were bred with conventional diet. The results showed that the average dry matter intakes of combinations of BLY and DLY were slightly decreased by 4.97% and 5.47% compared with the combination of LY, while average daily gain was significantly increased by 3.13% and 1.14%, and feed-weight ratio was decreased by 7.94% and 6.35%, respectively; economic benefit per pig was increased by 0.61 and 0.41 yuan, respectively. The combinations of BLY and DLY have better growth performance, which can be promoted in the production.

The Impact of Lean Transformation on the Organizational Performance: The Case of Public Utilities in Greece

Purpose: Lean Management concerns a strategy or philosophy aiming at saving resource practices and curtailment of public expenses, with ultimate objective of the enhancement of the organizational performance. By extension, the successful integration of the Lean Management leads to positive organizational results, such as higher quality, along with improved financial, environmental and business market performance. Although a lot of studies related to the effect of Lean production on the organizational performance have been conducted, empirical findings that examine the case of the public sector are absent. Additionally, there is no precise mechanism through which the Lean Management determines the organizational performance of the public utility companies. The above mentioned research gap is examined with this research, given that it investigates the influence of the Successful Lean Management on the Organizational Performance (Environmental Performance, Financial Performance, Business Performance) in public utilities in Greece. Research Methodology: The research method combines bibliographic research and empirical—with quantitative method—through a case study. More specifically, via quantitative approach, which was based on sample research with standardized questionnaire, performed in two of the biggest and most important public utilities in Greece, the Public Power Corporation S.A. (PPC S.A.) and the Athens Water Supply and Sewerage Company (EYDAP S.A). Findings: Quantitative findings from this illustrated that the successful transformation towards the Lean principles/saving resources affects positively the Business Market Performance, the Environmental and the Financial Performance. Limitations: Main restrictions of the current study are the capitalization of random sample and the strict focus on Greek public utilities that function under conditions of competition. Consequently, whichever generalizations for the whole Public Sector as well as for businesses of the private sector it would be better to be avoided, as they differ concerning their structural and functional features and their organizational culture.

The Impact of Lean Manufacturing Practices on Sustainability Performance:A Natural Resource-Based View

Drawing upon a Natural Resource-Based View(NRBV),this paper aims to propose a quantitative model that could be used to investigate whether Lean Manufacturing(LM)practices/tools can improve the three aspects of corporate sustainability performance(economic,environmental,and social).This paper is based on a theoretical study to develop a new model by reviewing the literature and proposing new ideas according to the Natural Resource-Based View(NRBV).Reviewing the literature showed that there is a significant association between LM practices/tools implementation and the improvement on three aspects of corporate sustainability performance(economic,environmental,and social).This paper provides insights to manufacturing managers about the ability of LM practices to reduce cost of operations and maximize the value provided to customers.Further,it highlighted the importance of LM practices implementation to manage organizations’activities responsibly in terms of their environmental,social,and economic effects.By proposing such a quantitative model according to a NRBV,this study contributes to a broader understanding of how LM practices affect three pillars of sustainability.

Proposal of a Conceptual Model to Analyse the Influence of LARG Practices on Manufacturing Supply Chain Performance

The main objective of this paper is to propose a conceptual model about the influence of lean, agile, resilient, and green （LARG） practices on supply chain operational, economic and environmental performance. This model is based on the literature review about the four supply chain management paradigms and also performance measurement systems. This paper contributes to the literature by introducing a new model to improve the leanness, agility, resilience, and greenness of manufacturing supply chains. Among the suggested LARG practices, the ones influencing more the supply chain performance are the just in time and also the supplier relationships. Also the supply chain performance measures with more LARG practices influencing them are the inventory levels and the time, that is, the supply chain＇s operational performance is the most affected by the simultaneous paradigms deployment in the supply chain.

Assessing Enabling Competence of Leagile Manufacturing Model and Its Impact on Performance of Small and Medium Factories in Uganda

Purpose: Leagile manufacturing is one of the time-based manufacturing practices used to improve factory performance. It is a practice that combines initiatives of Lean and agile manufacturing under certain enabling competences. Therefore, the purpose of this study is investigate the combinative nature of time-based manufacturing practices under unique enabling competences and their impact on performance of factories in Uganda. Methodology: Firstly, the underlying factor structure of competences and time-based manufacturing was examined was conducted using Principal Component Analysis (PCA). Enabling competences and time-base manufacturing practices were modelled and validated for each using confirmatory factor analysis, particularly composite reliability, average variance extracted and convergent validity. A fully fledged structural equation model was used to test the impact of leagile manufacturing on performance of factories. Findings: The study results revealed that time-based manufacturing of lean, and leagile are related but differ, in terms of their enabling competences and philosophical orientation. The findings also revealed that when small and medium factories in Uganda adopt leagile practice, they are likely not improve their performance. This is perhaps due to the fact that small and medium factories have inadequate resources. Practical Implications: The study findings shed more insights on the factors that enable adoption and implementation of time-based manufacturing practices. The extent to which these competences are orchestrated determines the benefits derived from the time-based manufacturing practices. In addition, small and medium enterprises should keenly make a choice on the appropriate practices that purposely reduce their lead time and cost of conversion. Originality: This study investigated the combinative nature of time-based manufacturing practices under unique enabling competences and their impact on performance of factories in Uganda. It is among the few studies that provide evidence on the leagile model anchored in the appropriate enabling competences in the context of developing countries. The empirical survey was done on small and medium factories to validate a leagile manufacturing model and tested its impact on factory performance.

企业—用户互动、敏捷开发与数字产品创新绩效

数字技术的可重新编程性、开放性等特征增强了市场需求的不确定性,企业通过与用户互动进行敏捷开发以提升数字产品创新绩效,成为获取竞争优势的关键。基于精益创业理论和利益相关者理论,深入分析企业—用户互动、敏捷开发与数字产品创新绩效间的作用机理。结果表明:企业—用户互动通过敏捷开发积极影响数字产品创新绩效,且组织创新氛围将增强三者间的作用关系。研究有助于丰富对于数字情境下企业—用户互动创新的理解,推动敏捷开发研究的发展,为解释数字产品创新绩效差异化提供有价值的研究思路,也为数字产品创新绩效的提升提供重要的管理启示。

不同叶顶弯曲对离心叶轮性能影响机理

面对现代发动机对离心叶轮性能需求不断提高的背景,叶顶弯曲具备有效改善离心叶轮气动特性的能力,本文通过数值模拟的方式对不同叶顶弯曲方向、弯曲形式、弯曲程度的压气机性能进行预测,基于仿真结果对不同流动状态下压气机内部流场进行分析,给出了叶顶弯曲压气机性能变化机理。结果显示:负弯叶轮有助于提升压气机峰值效率,提高压气机堵塞流量。正弯叶轮则在损失部分效率的情况下,使压气机失速裕度得到提升。弯曲叶轮主要通过改善叶顶前缘载荷,重构叶轮通道内静压分布,从而削弱激波强度、减少二次流损失、抑制低能涡发展,达到提升压气机性能的目的。本文研究结果可为离心压气机叶片改型设计提供参考。

精益管理方法在医院耗材管理中的应用效果

精益管理在于通过一系列的方法和工具,将精益的理念融入到医院的日常运营中,从而提升医疗服务的质量、效率和患者满意度,最终实现医院的可持续发展。本文首先概述了医院耗材管理的特点,总结精益管理的内涵,建立精益管理方法在医院耗材管理中的应用体系,并提出相关管理配套措施:建立全院性的质量控制体系、规范耗材管理流程管理、推进耗材信息化建设与管理、制订合理的绩效考核制度。

FZ/T 97042—2023《经编展纤整经机》标准解读

阐述FZ/T 97042—2023《经编展纤整经机》标准的制定过程,包括多方参与和反复论证。分析其适用范畴,涵盖不同规模和类型的生产场景。探讨整经机的形式和主要参数,为设备选型提供了依据。研究设备控制系统的要求,以保障整经过程的稳定性和高效性。强调整经质量的严格要求,确保产品符合高品质标准。最后,深入剖析该标准发布对行业发展的意义,为高性能纤维经编织造行业的健康发展提供了有力支撑。

Numerical and Experimental Investigation on the Performance of Lean Burn Catalytic Combustion for Gas Turbine Application

This manuscript presents our numerical and experimental results regarding the performance characteristics of lean bum catalytic combustion for gas turbine application. The reactant transport was assumed to be controlled by both bulk diffusion as well as surface kinetics, implemented by means of an approximate reaction rate equation and empirical coefficients to incorporate reaction mechanism. Experimental and numerical results were compared to examine the effects of methane mole fraction, inlet temperature, operating pressure, velocity and hydrogen spe- cies on combustion intensity. The results indicate that inlet temperature is the most significant parameter that im- pacts operation of the catalytic combustor and the most effective methods for improving the methane conversion are increasing the inlet temperature and increasing the methane mole fraction. Simulations from ID heterogene- ous plug flow model can capture the trend of catalytic combustion and describe the behavior of the catalytic mo- nolith in detail. The addition of hydrogen will provide heat release by the exothermie combustion reaction so that the reactants reach a temperature at which methane oxidation can light-off.

Numerical and Performance Analysis of one row Transonic Rotor with Sweep and Lean angle

In this study,aerodynamic behaviors of swept and leaned blades were investigated.Axial and tangential blade curvatures impacts on compressor's operating parameters were analyzed separately.A commercial CFD program which solves the Reynolds-averaged Navier-Stokes equations was used to find out the mentioned impact and the complicated flow field of transonic compressor-rotors.The CFD method that was used for solving flow field's equation was validated by experimental data of NASA Rotor 67.The results showed that the compressor with curved rotors had higher efficiency,rotor pressure ratio and stable operating range compared to the compressor with un-curved rotors.Using curved rotors mostly had higher impact on the overall stable operating range compared to the other operating parameters.Operating range involves choking point and stall point that were changed separately by using of bended blade.For finding the detailed impact of sweep and lean angle on transonic blades,various forms of lean and sweep angles were exerted to basic rotor.It was found that sweep angles increased overall operating range up to 30%,efficiency up to 2%and pressure ratio up to 1%.Leaning the blades increased the safe operating range,the pressure ratio and efficiency by 14%,4%and 2%respectively.

旋流器构型对全环燃烧室性能的影响

为研究旋流器构型对燃烧室性能的影响,针对配装双级轴向旋流器和双级径向旋流器的全环燃烧室开展了实验研究。结果表明,在本文研究范围内,地面点火状态下,轴向方案和径向方案点火油气比分别为0.011~0.022和0.015~0.026,轴向方案比径向方案具有更宽的点火边界。轴向方案贫油熄火油气比为0.009~0.020,径向方案贫油熄火油气比为0.006~0.019,径向方案比轴向方案具有更宽的贫油熄火边界。在地面慢车和空中慢车状态下,轴向方案比径向方案具有更好的出口温度分布品质。轴向旋流器对应的燃烧室压力脉动强度显著强于径向涡流器:油气比为0.011时,轴向方案和径向方案的燃烧室主频分别为525 Hz和555 Hz,相对压力脉动分别为1.9%和0.3%;油气比为0.018时,轴向方案的燃烧室主频为475 Hz,相对压力脉动为1.1%,而径向方案无明显主频。

绩效驱动的造船精益供应链管理体系

当前造船业尚未形成造船供应链管理理论共识,一般的供应链管理理论和方法不适用于造船供应链管理,大部分船厂仍采用项目管理的理论和方法管理造船供应链。对此,基于造船供应链管理的特点,系统性构建造船精益供应链管理体系理论框架和管理方法;在此基础上,以供应链绩效评价和分析为驱动,从体系构建、数据收集和分析等方面不断循环迭代,持续对该体系进行改善。通过该体系,各造船企业可根据自身资源配置情况和精益水平调整评价指标体系的权重,并进行分析改善,形成具有自身特色的以绩效驱动的造船精益供应链管理体系。

Requirements in performance measurement systems of construction projects from the lean production perspective

Performance measurement(PM)generates useful data for process control,facilitates communication between different sectors,and helps to align efforts on the most important aspects of the business.Thus,PM plays a key role in the management of projects and organizations.PM is also important in the implementation of lean production principles and methods,such as reducing the share of nonvalue-adding activities,increasing process transparency,building continuous improvement into the process,and benchmarking.Moreover,the adoption of the lean production philosophy requires changes in PM.Despite its importance,limited studies have been conducted on the use of PM systems for assessing the impact of lean production programs in construction projects.In addition,studies on how lean companies(or projects)use performance measurement and to what extent the indicators adopted reflect the result of actions that have been undertaken are limited.This study proposes a set of requirements in PM systems of construction projects from the perspective of lean production and a taxonomy of performance metrics for lean production systems.Five empirical studies have been carried out on construction companies from South America involved in the implementation of lean production systems.The scope of this investigation is limited to the construction projects as production systems rather than PM at the level of construction organizations.

轻资产运营模式下服装企业的财务绩效分析——以太平鸟集团为例

文章探讨了太平鸟集团所采用的轻资产运营模式。通过数据分析,发现太平鸟集团通过精简实体资产投资,并充分发掘无形资产潜力,从而在品牌塑造、市场反应速度及财务绩效等多个方面取得了显著成就。此外,该集团通过实施数据驱动的全链路商品供应革新策略,实现了营销、生产、设计等多个环节的高效协同,进而提升了整体运营效率。

LPG用于小型点燃式发动机的性能优化与稀薄燃烧

介绍了将LPG应用在小型点燃式发动机上时 ,对燃烧系统参数优化和稀薄燃烧能力的影响。试验在一台四冲程、水冷 1 2 5ml单缸摩托车发动机上进行。研究结果表明 ,压缩比和点火提前角的增大有利于恢复发动机扭矩 ,火花塞间隙调整对扭矩影响不明显 ;提高压缩比。

三级旋流器旋流角匹配影响双环预混旋流燃烧室燃烧性能试验

为研究地面用燃气轮机以0号柴油为燃料时的燃烧特性,对装有值班级直射式喷嘴和5种旋流器组合方案的双环预混旋流(Twins Annular Premixing Swirler,TAPS)燃烧室的特性进行了实验测试,获得了5种旋流器组合方式下燃烧室的流阻性能和燃烧性能。研究结果表明:双环预混旋流燃烧室的总压恢复系数都在0.97以上,高于经典的单环腔燃烧室;值班级采用直射式喷嘴会导致燃烧室的点火和CO排放性能下降,点火油气比在0.04以上,CO排放高于36g/kg;随值班级旋流角增大,可改善点火性能,最低点火油气比可达到0.04左右,加宽贫油熄火边界,慢车贫油熄火边界可低至0.0058;燃烧室入口温度升高可以使燃烧室点火油气比下降30%,贫油熄火油气比下降35%;5种旋流器组合方式下,NO_x和UHC的排放最低达到了1.1g/kg和3.85g/kg,满足低排放燃烧室的要求,冒烟指数达到了无烟燃烧室的标准,CO排放最高达到了51.84g/kg远高于要求值,燃烧效率最高为0.987,低于先进燃气轮机对燃烧效率的要求。

几何参数对离心叶轮强度和气动性能影响的研究

使用有限元计算软件和内部流场计算软件对所设计的几个具有不同几何尺寸的离心压气机叶轮的强度和气动性能进行了计算。结果表明反弯叶片可降低叶轮出口处叶片根部附近的应力,但会造成叶片根部前缘区域应力集中,且反弯叶轮的气动性能和原型叶轮差别不大。前倾叶片能在很大程度上降低叶轮出口处叶片根部应力,前倾角越大出口叶根处应力减小越多;随前倾角增大,叶轮气动性能恶化程度加剧;叶轮的背盘形状对叶轮的应力影响较大,尤其是出口处的背盘厚度对出口处叶片根部区域的应力起主因作用。研究得出叶片几何及背盘形状因素对叶轮应力分布的影响规律,另外还得到了叶片几何形状对气动性能的影响规律,这些工作为叶轮的多学科优化设计提供良好的基础。

高寒地区的日光温室优化设计

通过对 3种不同高度、不同跨度的日光温室 ,在寒冷季节的光照、温度等性能比较 ,并通过秋冬番茄、越冬芹菜、春提前黄瓜的栽培试验。结果表明 :以跨度为 8m、高度为 3.7m的温室明显优于其它两种温室 ,在北纬40°以北的寒冷地区 ,发展日光温室应以高度 3.5～ 3.7m、跨度 8m为好 。