Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract: Fossil energy utilization faces new challenges under carbon peak and carbon neutrality (“dual carbon” for short) targets. In this study, the present status of fossil energy utilization in China is summarized. Based on the situation of energy resources in China, the idea of highly efficient and clean utilization of fossil energy under dual carbon constraint is proposed. The technical development suggestions are put forward from three aspects including high efficient combustion and conversion of coal, high efficient utilization of oil and gas, and waste treatment of the chemical processing of coal. It aims to provide scientific and technological support for the realization of dual carbon targets and the construction of a new energy system.
Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract: Energy storage is one of the important supporting technologies to achieve the “dual carbon” goals, and it is an important means to stabilize renewable energy fluctuations and reduce the impact of large-scale new energy access on the power grid. At present, the competition of global energy resources is becoming increasingly fierce, and China is also facing significant changes in the adjustment of energy structure. To implement the energy strategy of “four revolutions and one cooperation” in the new era, and to realize the “14th Five-Year Plan” as well as the “Long-range Objectives Through the Year 2035”, China needs to build a new system of energy structure with Chinese characteristics, driven by “clean, low-carbon, safe and efficient” energy resources. Achieving the complementary integration of clean energy and fossil energy is the key to building a new “clean, low-carbon, safe and efficient” energy system. The development of large-scale energy storage technology is not only a necessary measure for the low-carbon and clean power system, but also a powerful means to seize the strategic commanding heights of the international energy technology and ensure national energy security.
Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract: Promoting the healthy development of energy storage technology and industry has great strategic significance on increasing the proportion of renewable energy, ensuring energy security, improving energy efficiency, and promoting the energy revolution. As one of the most important technologies, physical energy storage technology has received extensive attention. In this study, the major needs of physical energy storage technology are analyzed, and the development status and trends of five types of physical energy storage technologies and industry are summarized. Then the development problems and challenges of these physical energy storage technologies are confirmed, and corresponding recommendations are put forward. The study aims at providing a detailed reference for the research and development of physical energy storage technology and industry in China.
Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract: In China, coal is the main energy resource, which makes it to be the basic energy. It has always been the focus for the scientists, industry, and society that how to realize the coal clean and efficient combustion. The coal-fired power generation accounts for 65% of total amount of electricity, and coal combustion can also provide heat for the fields of iron and steel, building materials and chemical industry. Meanwhile, the harmful pollutants of released nitrogen, sulfur, dust, and others will greatly affect air environment. Therefore, realizing coal clean and efficient combustion in industry field taking 90% amount of total coal combustion plays a critical role in winning the battles of pollution control and blue sky protection, and it is urgent to update the coal clean and efficient combustion technology in industry field fundamentally. In this paper, the current situation of coal clean and efficient combustion technology is reviewed, and it is proposed that the transformational technology greatly inhibiting nitrogen oxides (the main component of haze) in combustion process and combining flue gas cleaning technology can realize ultra-low emission or even near zero emission of pollutants in normal coal combustion economically, which can provide technological support for coal clean and efficient combustion in industry field.
Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract: As an important means to achieve the goal of carbon neutralization, hydrogen energy has attracted global attention. As the United States has more than 30 years of practical experience in hydrogen energy R&D and application, this study conducts a detailed investigation on the hydrogen energy development plan and strategy formulated by the U.S. government, analyzes the U.S. hydrogen energy strategy and development objectives, direction and achievements since 1990, and focuses on the latest U.S. hydrogen energy development strategy in 2020 and the hydrogen energy breakthrough plan in 2021. It is concluded that the current US government has moved from initially establishing hydrogen energy technology reserves and promoting the application of hydrogen fuel cells in the transportation industry to accelerating the R&D and commercialization of the low-cost whole chain of hydrogen energy, especially green hydrogen technology under the goal of carbon neutralization, with diversified goals such as realizing the goal of carbon neutralization, establishing and developing hydrogen economy, and occupying a leading position in the global hydrogen energy technology and market. At the same time, the United States has relatively mature R&D and demonstration experience in electrolytic water technology. In the future, it will develop in the direction of megawatt scale and clean hydrogen production from renewable energy such as solar energy and nuclear energy. Based on such analysis, it is suggested that China should strengthen top-level design of hydrogen energy development, tackle key problems and breaking through core technologies of hydrogen energy, establish the development model of the
Subjects: Dynamic and Electric Engineering >> Engineering Thermophysics submitted time 2017-10-17 Cooperative journals: 《工程热物理学报》
Abstract:为满足高超声速飞行器对高比冲和大推力发动机的需要,提出了一种可重复使用的进气预冷富燃预燃混合排气涡扇发动机(Pre-cooled and Fuel-rich Pre-burned Mixed-flow Turbofan,PFPMT)热力循环。PFPMT发动机的特点是增大内涵空气进气预冷程度,内涵压气机为富燃燃气发生器提供空气作为氧化剂,内涵空气与预冷器出口燃料混合燃烧产生富燃燃气,驱动涡轮、带动内涵压气机与风扇增压,风扇外涵空气与涡轮出口排气在主燃烧室中掺混燃烧,产生高温燃气由喷管产生推力。对发动机热力循环进行了参数化分析,发动机比冲随着压气机压比的增大而增加,尤其是随着风扇压比增加的更为明显;单位推力主要随风扇压比增加而增加,受内涵压比影响较小。发动机地面的比冲与单位推力分别可以达到4500 s与900 N·s/kg以上;在Ma=5.0飞行条件下,发动机比冲与单位推力在3500 s与1100 N·s/kg以上。
Subjects: Dynamic and Electric Engineering >> Engineering Thermophysics submitted time 2017-10-17 Cooperative journals: 《工程热物理学报》
Abstract:本文深入探讨了定常来流条件下过渡段内部流动机理和损失机制。通过保持过渡段长高比、雷诺数和进口旋流不变,借助实验和数值模拟方法,系统地研究了过渡段中位角和出口面积对其内部流动及气动性能影响。研究发现,过渡段内部流场结构主要以对涡及轮毂和机匣区域附面层分离为主。过渡段来流尾迹、中位角及进出口面积比是影响过渡段内部流动损失的三个主要因素。其中,中位角决定了机匣第一弯逆压梯度强度,面积比主要控制第二弯静压升,上游尾迹是诱发机匣侧流动分离的主要诱因。在大中位角情况下,机匣第一弯的流动分离更严重,分离明显提前。在大面积比情况下,机匣侧不仅出现由上游尾迹堆积产生的流动分离,还会出现机匣附面层自身二维分离。随着过渡段的中位角和面积比增大,损失急剧增加。
Subjects: Dynamic and Electric Engineering >> Engineering Thermophysics submitted time 2017-10-17 Cooperative journals: 《工程热物理学报》
Abstract:异丙醇-丙酮-氢气化学热泵(IAH-CHP)是一种可同时提升能量品位与实现能量存储的系统。丙酮加氢反应器是异丙醇-丙酮-氢气化学热泵系统的重要组成部分。它对异丙醇-丙酮-氢气化学热泵系统的性能具有重要的影响。本文将泡沫金属反应器用于实现丙酮加氢反应,以提升丙酮加氢的反应效率与能量利用效率。首先建立丙酮加氢泡沫金属反应器的模型,然后通过模拟计算对泡沫金属反应器与颗粒填充反应器的性能进行了研究。研究结果表明:对于丙酮加氢等慢速反应,考虑壁面传热时,泡沫金属反应器的性能优于颗粒填充反应器。主要原因为泡沫金属反应器具有好的壁面传热特性与低的压降。
Subjects: Dynamic and Electric Engineering >> Engineering Thermophysics submitted time 2017-10-17 Cooperative journals: 《工程热物理学报》
Abstract:本文提出并研究了一种回收透平排气有效成分的新型功冷联产系统。该系统通过对高温高压过热氨水蒸气进行热能梯级利用和有效成分回收,实现了动力循环与制冷循环间能量和物质的双重耦合。经过部分冷凝后的透平排气中有效成分浓度明显提高,对这部分有效成分的回收可以有效增加系统制冷量。新系统等效作功效率为20.19%,比常规分产系统提高了44.32%,相对节能率为31.61%。与常规开式和常规闭式功冷联产系统相比,新系统等效作功效率提升幅度分别为7.28%和17.04%。通过研究能量传递与转换过程,阐明了系统的节能机理。新提出了平均能量品位差△A的概念,分析了系统对输入的利用情况和热力性能进一步提升的潜力。另外,还初步探索了系统中动力循环与制冷循环的耦合特性。
Subjects: Dynamic and Electric Engineering >> Engineering Thermophysics submitted time 2017-10-17 Cooperative journals: 《工程热物理学报》
Abstract:针对传统煤制天然气过程存在的能量利用不合理、碳捕集能耗过高等技术瓶颈,本文探索了一种能实现CO_2零排放的基于化学链燃烧的生物质煤互补天然气动力联产系统。生物质与煤互补从气化源头调节了合成气中H2/CO比例,有利于甲烷化反应过程,化学链燃烧实现了零能耗的CO_2捕集。研究结果表明:系统总能效率(η_(en))为57.03%,效率(η_(ex))为54.65%,系统能源节约率高达18.6%,实现了系统CO_2零排放。分析了关键参数如氧气碳比(O/C)、蒸气碳比(S/C)、生物质煤互补比例和未反应气循环倍率对系统热力学性能的影响。),异辛烷与醇类(包括丙醇、戊醇、己醇、庚醇)的黏度进行了计算,计算结果表明,计算值与实验值之间的总体平均绝对偏差为1.00%,最大偏差为9.75%。
Subjects: Dynamic and Electric Engineering >> Engineering Thermophysics submitted time 2017-10-17 Cooperative journals: 《工程热物理学报》
Abstract:本文提出了太阳能光伏电池与甲醇中低温重整反应相结合的发电系统;通过太阳能的梯级利用以及物理能与化学能之间的品位耦合,太阳能净发电效率较单一光伏或甲醇热化学发电方式获得显著提升。热力学分析表明,在100~250℃C的系统运行温度范围内,系统的理论太阳能净发电效率达43.6%~44.3%(已考虑光学损失),显著高于光伏系统(22.5%)及热化学系统(32.7%)。系统约50%的太阳净发电量来自甲醇重整产物氢气,以化学能形式实现了太阳能的高效储能,且光伏、热化学发电随温度变化的相反趋势间互补达到了稳定输出的效果。此外,系统产生的电能中约25%来自太阳能,高于单一太阳能甲醇热化学发电系统的14%,对化石能源的依赖度降低。光伏与热化学互补发电为太阳能高效综合利用提供了新的思路。
Subjects: Dynamic and Electric Engineering >> Engineering Thermophysics submitted time 2017-10-13 Cooperative journals: 《工程热物理学报》
Abstract:低温条件下碳化硅等半导体材料热导率的实验研究极少,数据匮乏,无法满足理论模型的优化需求。现有实验测量以接触式的稳态法导热系数测量为主,实验误差大,且低温测量成本过高。本文通过常规飞秒激光抽运探测热反射法与低温系统的有机结合,完成了4~300 K低温条件下单晶碳化硅热导率的测试及其随温度的变化规律,研究表明单晶碳化硅热导率在100 K左右存在极大值,温度低于100 K时其热导率与温度呈正相关,温度高于100 K时其热导率与温度呈负相关。极值点的位置与理论值的偏差可能是由于样品电子浓度、缺陷分布等因素影响。
Subjects: Dynamic and Electric Engineering >> Engineering Thermophysics submitted time 2017-03-22 Cooperative journals: 《工程热物理学报》
Abstract:在射流搅拌反应器中开展了常压下航空煤油替代燃料的低温(500-1100 K)氧化实验研究。利用气相色谱和气质联用仪测得了34个物种的摩尔分数曲线。通过研究芳烃和正癸烷间的耦合作用阐述了替代燃料低温区负温度系数效应对燃料燃烧特性的影响,揭示了实际航空燃料的低温自动点火机理。建立包括975物种和5920反应的亚琛替代燃料的动力学模型,并利用该模型准确地预测实际燃料燃烧的点火延迟等。结果将有助于理解燃气轮机低温点火过程。
Subjects: Dynamic and Electric Engineering >> Engineering Thermophysics submitted time 2017-03-22 Cooperative journals: 《工程热物理学报》
Abstract:为研究Wurster流化床内颗粒流动规律并优化反应过程,本文利用12-4-8组合电极电容层析成像(Electrical Capacitance Tomography,ECT)传感器对Wurster流化床冷态实验和加湿实验过程进行监测,得到了ECT重构图像以及颗粒浓度时变曲线。首先,根据冷态实验数据比较了不同操作条件下流化床内颗粒流态和浓度波动特性;其次,通过加湿实验数据分析了包衣液流率对于颗粒流动的影响。最后,结合以上分析结果,总结了颗粒包衣过程的优化方案。
Subjects: Dynamic and Electric Engineering >> Engineering Thermophysics Subjects: Energy Science >> Survey of Energy Sources submitted time 2017-03-22 Cooperative journals: 《工程热物理学报》
Abstract: 致动面模型利用无厚度的平面代替风力机叶片,在平面上施加不连续压力来模拟叶片对气流的作用,结合N-S方程,在FLUENT中进行数值模拟计算,是对致动线方法的延伸与改进。运用该方法能够简化风力机的模型,从而减少网格数量和计算时间。采用线性分布下的致动面模型,提出一种致动面网格的辨识方法,对单台Nibe A型风力机的远近尾流区域进行模拟计算,包括尾流风速变化,湍流强度,涡结构,并将数值模拟的结果与致动线模型计算结果以及实验数据进行对比分析,主要是风轮后特定距离截面的风速变化,验证了致动面方法的优越性以及用于风力机尾流场计算的可行性。