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ZnO nanorefrigerant in R152a refrigeration system for energy conservation and green environment

D. SENDIL KUMAR,R. ELANSEZHIAN

《机械工程前沿（英文）》 2014年第9卷第1期页码 75-80 doi: 10.1007/s11465-014-0285-y

摘要：

In this paper the reliability and performance of a vapour compression refrigeration system with ZnO nanoparticles in the working fluid was investigated experimentally. Nanorefrigerant was synthesized on the basis of the concept of the nanofluids, which was prepared by mixing ZnO nanoparticles with R152a refrigerant. The conventional refrigerant R134a has a global warming potential (GWP) of 1300 whereas R152a has a significant reduced value of GWP of 140 only. An experimental test rig is designed and fabricated indigenously in the laboratory to carry out the investigations. ZnO nanoparticles with refrigerant mixture were used in HFC R152a refrigeration system. The system performance with nanoparticles was then investigated. The concentration of nano ZnO ranges in the order of 0.1% v, 0.3% v and 0.5%v with particle size of 50 nm and 150 g of R152a was charged and tests were conducted. The compressor suction pressure, discharge pressure and evaporator temperature were measured. The results indicated that ZnO nanorefrigerant works normally and safely in the system. The ZnO nanoparticle concentration is an important factor considered for heat transfer enhancement in the refrigeration system. The performance of the system was significantly improved with 21% less energy consumption when 0.5%v ZnO-R152a refrigerant. Both the suction pressure and discharge pressure were lowered by 10.5% when nanorefrigerant was used. The evaporator temperature was reduced by 6% with the use of nanorefrigerant. Hence ZnO nanoparticles could be used in refrigeration system to considerably reduce energy consumption. The usage of R152a with zero ozone depleting potential (ODP) and very less GWP and thus provides a green and clean environment. The complete experimental results and their analysis are reported in the main paper.

关键词： ZnO nanorefrigerant reduced GWP COP pressure ratio green energy

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油压极值比与极值比效率

齐茂林

《中国工程科学》 2001年第3卷第4期页码 73-75

摘要：

文章应用基础公式，推导液压系统油压极值比与极值比效率之间的关系式。该式说明，油压极值比越大，极值比效率就越低。提出了油压极值比是可以设计和选择的。

关键词：油压极值比极值比效率液压系统

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节能环保工程水压爆破研究与应用

何广沂,段昌炎,荆山,王太超

《中国工程科学》 2003年第5卷第9期页码 43-48

摘要：

节能环保工程水压爆破是一种新的爆破技术，文章主要介绍该项技术提高炸药能量利用率和保护环境的理论分析和模拟试验，着重是创新突破点、关键技术和实际应用所取得的显著技术经济效果。

关键词：工程水压爆破模拟试验能量利用率

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Improvement of engine performance with high compression ratio based on knock suppression using Millercycle with boost pressure and split injection

Haiqiao WEI, Jie YU, Lei ZHOU

《能源前沿（英文）》 2019年第13卷第4期页码 691-706 doi: 10.1007/s11708-019-0621-3

摘要： In theory, high compression ratio has the potential to improve the thermal efficiency and promote the power output of the SI engine. However, the application of high compression ratio is substantially limited by the knock in practical working process. The objective of this work is to comprehensively investigate the application of high compression ratio on a gasoline engine based on the Miller cycle with boost pressure and split injection. In this work, the specific optimum strategies for CR10 and CR12 were experimentally investigated respectively on a single cylinder DISI engine. It was found that a high level of Miller cycle with a higher boost pressure could be used in CR12 to achieve an effective compression ratio similar to CR10, which could eliminate the knock limits at a high compression ratio and high load. To verify the advantages of the high compression ratio, the fuel economy and power performance of CR10 and CR12 were compared at full and partial loads. The result revealed that, compared with CR10, a similar power performance and a reduced fuel consumption of CR12 at full load could be achieved by using the strong Miller cycle and split injection. At partial load, the conditions of CR12 had very superior fuel economy and power performance compared to those of CR10.

关键词： high compression ratio knock Miller cycle split injection engine performance

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Effect of cutterhead configuration on tunnel face stability during shield machine maintenance outages

《结构与土木工程前沿（英文）》 2023年第17卷第4期页码 522-532 doi: 10.1007/s11709-023-0930-9

摘要： Owing to long-distance advancement or obstacles, shield tunneling machines are typically shut down for maintenance. Engineering safety during maintenance outages is determined by the stability of the tunnel face. Pressure maintenance openings are typically used under complicated hydrogeological conditions. The tunnel face is supported by a medium at the bottom of the excavation chamber and compressed air at the top. Owing to the high risk of face failure, the necessity of support pressure when cutterhead support is implemented and a method for determining the value of compressed air pressure using different support ratios must to be determined. In this study, a non-fully chamber supported rotational failure model considering cutterhead support is developed based on the upper-bound theorem of limit analysis. Numerical simulation is conducted to verify the accuracy of the proposed model. The results indicate that appropriately increasing the specific gravity of the supporting medium can reduce the risk of collapse. The required compressed air pressure increases significantly as the support ratio decreases. Disregarding the supporting effect of the cutterhead will result in a tunnel face with underestimated stability. To satisfy the requirement of chamber openings at atmospheric pressure, the stratum reinforcement strength and range at the shield end are provided based on different cutterhead aperture ratios.

关键词： tunnel face stability cutterhead configuration aperture ratio pressure gradient support ratio

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Wind tunnel test study on the wind pressure coefficient of claddings of high-rise buildings

Yong QUAN, Yi LIANG, Fei WANG, Ming GU

《结构与土木工程前沿（英文）》 2011年第5卷第4期页码 518-524 doi: 10.1007/s11709-011-0128-4

摘要： The area-averaged most unfavorable wind pressure coefficients (MUWPCs) on various regions of building surfaces and the influence of the side ratio and the terrain category were studied based on wind tunnel test data of scale models of typical high-rise buildings with rectangular cross-sections. The negative area-averaged MUWPCs in the middle-height edge areas generally increased with an increasing / side ratio. The area-averaged MUWPCs can be well fitted with a function of the average area reduced by the square of the building depth, . In addition, no unique pattern was found for the effect of the terrain category on the MUWPCs.

关键词： side ratio area-averaged pressure coefficients cladding terrain category

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Optimal ratio of bend channel in centrifugal compressor

WEN Suping, HU Xiaowen, LI Tingbin, ZHANG Yong, WANG Jun

《能源前沿（英文）》 2008年第2卷第4期页码 381-385 doi: 10.1007/s11708-008-0084-4

摘要： A numerical investigation on the flow in a bend channel by coupling the impeller with the vaneless diffuser in a centrifugal compressor with different ratios (bend radius to bend channel width ) is presented. The jet-wake effect of the impeller outlet is considered and flow pattern in the bend channel and the performance of the centrifugal compressor stage are investigated. The results indicate that there is an optimal ratio for increasing the stage efficiency to the highest for a specific compressor stage. The change in ratio significantly affects the flow angle of the bend channel outlet. The prime reason for the total pressure loss in the bend channel is the wall friction in the bend channel.

关键词： specific compressor different centrifugal compressor pressure impeller

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我国能源绿色开发利用路径研究

李全生,张凯

《中国工程科学》 2021年第23卷第1期页码 101-111 doi: 10.15302/J-SSCAE-2021.01.012

摘要：

能源绿色开发利用是贯彻落实能源安全新战略和加快新时代生态文明建设的重要任务。为推进能源生产和消费革命，本文从我国能源发展现状与存在的问题出发，在阐述能源绿色开发利用的内涵和发展原则的基础上，构建了能源绿色开发评价模型和能源利用系统评价指标模型，对能源绿色开发利用的经济效益和环境效益进行评价，预测了我国面向2030 年、2050 年的能源绿色开发利用发展目标。研究指出，我国能源绿色开发利用的实施路径可着重从两方面展开：在能源布局方面，开展化石能源的清洁高效开发利用，清洁能源的规模化开发利用和能源系统的智能化，重点实施绿色煤炭工程、稳油增气工程和加强能源集约化、节约化利用；在科技创新方面，从加强对煤炭安全高效、清洁低碳利用的科技攻关，加快攻克深层深水和非常规油气勘探开发关键技术，推进清洁能源规模化开发利用的科技创新等5 方面推进。为构建清洁低碳、安全高效的能源体系，本文从能源管理体制创新、能源价格市场化机制形成、能源绿色开发利用考核、能源绿色开发利用科技创新体系等方面提出了对策建议。

关键词：能源，绿色开发利用，能源绿色开发评价模型，绿色煤炭工程，能源智能化

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Energy field-assisted high-speed dry milling green machining technology for difficult-to-machine metal

《机械工程前沿（英文）》 2023年第18卷第2期 doi: 10.1007/s11465-022-0744-9

摘要： Energy field-assisted machining technology has the potential to overcome the limitations of machining difficult-to-machine metal materials, such as poor machinability, low cutting efficiency, and high energy consumption. High-speed dry milling has emerged as a typical green processing technology due to its high processing efficiency and avoidance of cutting fluids. However, the lack of necessary cooling and lubrication in high-speed dry milling makes it difficult to meet the continuous milling requirements for difficult-to-machine metal materials. The introduction of advanced energy-field-assisted green processing technology can improve the machinability of such metallic materials and achieve efficient precision manufacturing, making it a focus of academic and industrial research. In this review, the characteristics and limitations of high-speed dry milling of difficult-to-machine metal materials, including titanium alloys, nickel-based alloys, and high-strength steel, are systematically explored. The laser energy field, ultrasonic energy field, and cryogenic minimum quantity lubrication energy fields are introduced. By analyzing the effects of changing the energy field and cutting parameters on tool wear, chip morphology, cutting force, temperature, and surface quality of the workpiece during milling, the superiority of energy-field-assisted milling of difficult-to-machine metal materials is demonstrated. Finally, the shortcomings and technical challenges of energy-field-assisted milling are summarized in detail, providing feasible ideas for realizing multi-energy field collaborative green machining of difficult-to-machine metal materials in the future.

关键词： difficult-to-machine metal material green machining high-speed dry milling laser energy field-assisted milling ultrasonic energy field-assisted milling cryogenic minimum quantity lubrication energy field-assisted milling

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滇池北部重点水域蓝绿藻季节性变动下水体N∶P比值变化研究

何锋,段昌群,杜劲松,韩亚平,郭艳英,潘珉,宋任彬

《中国工程科学》 2010年第12卷第6期页码 94-98

摘要：

受多种因素影响，滇池外海北部水域为蓝藻富集区。调查研究了蓝藻生物量季节性变动规律，对区域原水（不过滤）和净水（过滤了藻类）中N和P含量的变化也进行了监测。目的是研究蓝藻季节性消长对水体N和P含量的影响。结合生态化学计量学理论和方法，分析两者之间的关系。研究表明， 4—11月，为蓝藻水华爆发的时段，其中以5—9月最为严重。通过分析，水体N和P随蓝藻生物量呈现相应变动规律，水体叶绿素和TN，TP之间都呈现正相关关系，相关系数分别为0.955 和0.952 。利用生态化学计量学分析，蓝藻和水体中N∶P比值没有固定性，表明蓝藻没有表现出强烈的化学计量特征，而蓝藻的季节性变动也没有导致本区域水体具化学计量特性。通过分析滇池水体N∶P比值与蓝藻生物量变化之间相关关系,相关系数为-0.308，表明富营养化水体中N∶P比率对蓝藻生物量直接影响不大。因此,只有通过降低水体中N和P的浓度，才能控制蓝藻的爆发。

关键词：滇池蓝绿藻 N∶P比值变化生态化学计量学

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Heating energy performance and part load ratio characteristics of boiler staging in an office building

Da Young LEE, Byeong Mo SEO, Yeo Beom YOON, Sung Hyup HONG, Jong Min CHOI, Kwang Ho LEE

《能源前沿（英文）》 2019年第13卷第2期页码 339-353 doi: 10.1007/s11708-018-0596-5

摘要： Commercial buildings account for significant portions of the total building energy in South Korea and thus a variety of research on the boiler operation related to heating energy in office buildings has been carried out thus far. However, most of the researches have been conducted on the boiler itself, i.e., the part load ratio characteristics and the corresponding gas energy consumption patterns are not analyzed in the existing studies. In this study, the part load ratio and the operating characteristics of gas boiler have been analyzed within an office building equipped with the conventional variable air volume system. In addition, the gas consumption among different boiler staging schemes has been comparatively analyzed. As a result, significant portions of total operating hours, heating load and energy consumption has been found to be in a part load ratio range of 0 through 40% and thus energy consumption is significantly affected by boiler efficiency at low part load conditions. This suggests that boiler operation at the part load is an important factor in commercial buildings. In addition, utilizing sequential boiler staging scheme can save a gas usage of about 7%. For annual heating energy saving, applying the sequential control boiler with a 3:7 proportion staging is considered to be the optimal control algorithm for maximum efficiency of boilers.

关键词： EnergyPlus boiler part load ratio gas consumption office building boiler staging

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Early-life famine exposure, adulthood obesity patterns, and risk of low-energy fracture

《医学前沿（英文）》 doi: 10.1007/s11684-023-1023-9

摘要： Malnutrition in early life increases the risk of osteoporosis, but the association of early-life undernutrition combined with adulthood obesity patterns with low-energy fracture remains unknown. This study included 5323 community-dwelling subjects aged ≥40 years from China. Early-life famine exposure was identified based on the participants’ birth dates. General obesity was assessed using the body mass index (BMI), and abdominal obesity was evaluated with the waist-to-hip ratio (WHR). Low-energy fracture was defined as fracture occurring after the age of 40 typically caused by falls from standing height or lower. Compared to the nonexposed group, the group with fetal, childhood, and adolescence famine exposure was associated with an increased risk of fracture in women with odds ratios (ORs) and 95% confidence intervals (CIs) of 3.55 (1.57–8.05), 3.90 (1.57–9.71), and 3.53 (1.05–11.88), respectively, but not in men. Significant interactions were observed between fetal famine exposure and general obesity with fracture among women (P for interaction = 0.0008). Furthermore, compared with the groups with normal BMI and WHR, the group of women who underwent fetal famine exposure and had both general and abdominal obesity had the highest risk of fracture (OR, 95% CI: 3.32, 1.17–9.40). These results indicate that early-life famine exposure interacts with adulthood general obesity and significantly increases the risk of low-energy fracture later in life in women.

关键词： famine obesity body mass index waist-to-hip ratio low-energy fracture

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Xinjiang energy-based desert management project

Jishan HE

《工程管理前沿（英文）》 2019年第6卷第4期页码 587-591 doi: 10.1007/s42524-019-0075-7

关键词： desert governance comprehensive utilization of new energy modern agriculture the Belt and Road Initiative green development

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农业生态工程中人工辅助能产投比的计算分析研究

卞有生,柳英昆,卞晶

《中国工程科学》 2006年第8卷第8期页码 28-32

摘要：

人工辅助能产投比的高低从总体上反映了农业生态系统的功能和生产效率，是系统结构功能的体现，是评价农业生态工程的重要指标。文章以河南新县10户农民为案例，具体介绍了人工辅助能产投比的计算研究方法，并报告了连续3年的研究结果。

关键词：农业生态工程能量产投比

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低高宽比矩形微通道中流动沸腾的压降特性

张炳雷,徐进良,肖泽军

《中国工程科学》 2007年第9卷第12期页码 86-93

摘要：以甲醇为工质，在不同进口温度、质量流率、热流密度和倾角下，对低高宽比矩形微通道中流动沸腾压降特性进行了研究，并分别采用均相模型和分相模型对通道压降进行了计算。通过对比实验结果与计算结果发现，均相模型中两相平均粘度的计算应当采用Dukler公式，用其他计算式时误差较大；利用LockhartMartinelli关系式进行的分相模型计算发现，现有C值计算公式，如Chisholm,Lee and Lee，Mishima及Qu and Mudawar等，都不能用于预测该实验中低高宽比微通道的两相压降。实验发现当通

关键词：压降特性；均相模型；分相模型；微通道；流动沸腾

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标题作者时间类型操作

ZnO nanorefrigerant in R152a refrigeration system for energy conservation and green environment

D. SENDIL KUMAR,R. ELANSEZHIAN

期刊论文

油压极值比与极值比效率

齐茂林

期刊论文

节能环保工程水压爆破研究与应用

何广沂,段昌炎,荆山,王太超

期刊论文