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Development of a fan-stirred constant volume combustion chamber and turbulence measurement with PIV

《能源前沿（英文）》 2022年第16卷第6期页码 973-987 doi: 10.1007/s11708-021-0762-z

摘要： A fan-stirred combustion chamber is deve-loped for spherically expanding flames, with P and T up to 10 bar and 473 K, respectively. Turbulence characteristics are estimated using particle image velocimetry (PIV) at different initial pressures (P = 0.5–5 bar), fan frequencies (ω = 0–2000 r/min), and impeller diameters (D = 100 and 114 mm). The flame propagation of methanol/air is investigated at different turbulence intensities (u′=0–1.77 m/s) and equivalence ratios (φ = 0.7–1.5). The results show that u′ is independent of P and proportional to ω, which can be up to 3.5 m/s at 2000 r/min. L_T is independent of P and performs a power regression with ω approximately. The turbulent field is homogeneous and isotropic in the central region of the chamber while the inertial subrange of spatial energy spectrum is more collapsed to –5/3 law at a high Re_T. Compared to laminar expanding flames, the morpho-logy of turbulent expanding flames is wrinkled and the wrinkles will be finer with the growth of turbulence intensity, consistent with the decline of the Taylor scale and the Kolmogorov scale. The determined S_L in the present study is in good agreement with that of previous literature. The S_L and S_T of methanol/air have a non-monotonic trend with φ while peak S_T is shifted to the richer side compared to S_L. This indicates that the newly built turbulent combustion chamber is reliable for further experimental study.

关键词： fan-stirred combustion chamber turbulence characteristics particle image velocimetry (PIV) methanol turbulent expanding flames

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湍流效应对桁架式桥梁断面气动弹性性能影响的研究

Hoang Trong Lam, Hiroshi Katsuchi, Hitoshi Yamada

《工程（英文）》 2017年第3卷第6期页码 845-853 doi: 10.1016/j.eng.2017.10.001

摘要：

本文介绍了在不同湍流条件下通过随机系统识别（SSI）方法提取颤振导数（FD）的过程。研究旨在通过对节段模型风洞试验来研究湍流对悬索式大跨度桥梁的影响。针对不同的湍流特性，对桁架式桥梁断面进行了几项风洞试验，包括降低湍流强度和湍流尺度。研究包括湍流对模型动态响应的影响。利用系统识别技术提取FD，对风洞试验中的瞬态响应和抖振响应进行了分析，同时讨论了该方法存在的困难。利用时域SSI 同时从一自由度（1DOF）和二自由度（2DOF）系统提取所有的FD。最后，讨论了不同情况下的结果并得出结论。

关键词：颤振导数系统识别湍流效应抖振响应

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Numerical simulation of sudden-expansion two-phase flows with two-scale second-order moment particle turbulence

ZENG Zhuoxiong, HAN Shoulei, ZHOU Lixing

《能源前沿（英文）》 2007年第1卷第2期页码 202-206 doi: 10.1007/s11708-007-0026-6

摘要： A two-scale second-order moment particle turbulence model is developed, based on the concept of particle large-scale fluctuation due to turbulence and particle small-scale fluctuation due to collision. The model is employed to simulate gas-particle flows in a sudden-expansion chamber. Simulation results are compared with the experimental results and with those obtained by the single-scale second-order moment two-phase turbulence model. It is shown that the two-scale model is with higher calculating accuracy than the single-scale model.

关键词： gas-particle single-scale second-order large-scale fluctuation second-order sudden-expansion

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Evaluation of the wind energy potential of two south west sites in Nigeria

Olaleye M. AMOO

《能源前沿（英文）》 2012年第6卷第3期页码 237-246 doi: 10.1007/s11708-012-0201-2

摘要： Wind resource assessment is a crucial first step in gauging the potential of a site to produce energy from wind turbines. In this paper, the wind energy potential of Abeokuta (07°03'N, 03°19'E) and Ijebu-Ode (06°47'N, 03°58'E), two south west sites in Nigeria were examined. Twenty years (1990–2010) of monthly mean wind data from a 10 m height were subjected to two-parameter Weibull analysis and other statistical analyses. The results show that the average annual mean wind speed variation for Abeokuta ranges from 2.2 to 5.0 m/s. For Ijebu-Ode, it ranges from 2.0 to 5.0 m/s. The wind power density variation based on the Weibull analysis ranges from 4.26 to 24.51 W/m for Abeokuta and from 8.54 to 76.46 W/m for Ijebu-Ode. Ijebu-Ode was found to be the better of the two sites in terms of annual variation of mean wind speed.

关键词： wind potential wind speed wind power density wind gust turbulence intensity Nigeria

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零方程湍流模型在列车车厢内气流数值模拟中的应用

杨培志,顾小松

《中国工程科学》 2006年第8卷第1期页码 26-29

摘要：

采用k-ε湍流模型对列车车厢内气流进行数值模拟需要消耗大量的计算时间，为此，提出了采用零方程湍流模型对列车车厢内的气流组织进行数值模拟；分别采用零方程湍流模型与k-ε湍流模型对列车车厢内的空气流动及传热进行了数值计算，经分析比较可知，该两种湍流模型的数值计算结果吻合程度较好，采用零方程湍流模型可大大缩短计算时间，利用其简单、快捷的特点，可以为列车空调系统的工程设计提供简便的数值模拟方法。

关键词：空调零方程湍流模型数值模拟列车

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Simulating the air flow in the conveying pipe of the foreign fiber detection device

Ting CHEN, Lili WU, Ke WANG,

《化学科学与工程前沿（英文）》 2010年第4卷第3期页码 275-279 doi: 10.1007/s11705-009-0274-6

摘要： Cotton bales are frequently intermingled with foreign fibers which will interfere in the process of spinning, weaving and dyeing and will worsen the product quality. Nowadays, cotton fibers are sorted manually in most of the cotton textile mills with very low efficiency. There is a great demand for foreign fiber detection devices in Chinese cotton textile mills. The air flow in the conveying pipe of the device has an important effect on the image acquisition, image analysis and removal of foreign fibers. As a primary effort, the air flow in the conveying pipe of the foreign fiber detection device was simulated numerically. The effects of the inlet air velocity on the air turbulence intensity and air velocity along the detecting section were studied.

关键词： product quality Chinese process turbulence intensity primary

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Recent progress in hydrodynamic characteristics research and application of annular centrifugal extractors

《化学科学与工程前沿（英文）》 2022年第16卷第6期页码 854-873 doi: 10.1007/s11705-022-2156-0

摘要： The annular centrifugal extractor (ACE) integrates mixing and separation. It has been widely used in many industrial fields because of its low residence time, compact structure, and high mass transfer efficiency. Most of the literature has focused on flow instabilities, flow visualization, and computational fluid dynamics simulations. More recently, research on hydrodynamic behavior and structural optimization has received widespread attention. With the development of ACE technology, applications have been broadened into several new areas. Hence, this paper reviews research progress regarding ACE in terms of hydrodynamic characteristics and the structural improvements. The latest applications covering hydrometallurgy, nuclear fuel reprocessing, bio-extraction, catalytic reaction, and wastewater treatment are presented. We also evaluate future work in droplet breakup and coalescence mechanisms, structural improvements specific to different process requirements, scaling-up methods, and stability and reliability after scaling-up.

关键词： annular centrifugal extractor hydrodynamic characteristics structure optimization the latest application

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Clinical characteristics and outcomes of biopsy-proven diabetic nephropathy

null

《医学前沿（英文）》 2017年第11卷第3期页码 386-392 doi: 10.1007/s11684-017-0574-z

摘要：

Kidney damage is common in patients with diabetes mellitus (DM). However, whether the type of kidney damage can be reliably diagnosed using clinical data alone remains unclear. Predictive factors for diabetic nephropathy (DN) outcomes are also poorly understood. In this study, the clinical manifestations of 111 cases of biopsy-proven DN were described, and the clinical and pathological parameters of patients with different DN outcomes were compared. Results showed that long DM duration (>10 years in 32.4% of patients), severe proteinuria (62.2%), and renal dysfunction (estimated glomerular filtration rate [eGFR]<60 mL/(min·1.73 m²)) (52.3%) did not accurately indicate whether the condition of these patients progressed to DN. Hematuria (48.6%) failed to specify either DN or nondiabetic renal disease. Diabetic retinopathy (78.4%) was a crucial complication in patients with DN. Kaplan–Meier analysis revealed that the renal survival of 53 patients who were diagnosed with DN and were followed up was not significantly associated with glomerular classification (P>0.05). Cox’s regression analysis demonstrated that renal survival time was significantly influenced by sex (b= 1.394, P= 0.038), hematuria (b= 0.036, P= 0.029), and eGFR (b= −0.039, P= 0.002) but was not significantly affected by age, 24 h urinary protein excretion, or glomerular classification (P>0.05). In conclusion, the clinical characteristics of DN vary, and renal biopsy is necessary to determine renal damage patterns. Sex, hematuria, and the eGFR may affect DN outcomes, whereas the glomerular classification may not.

关键词： diabetic nephropathy clinical characteristics renal biopsy outcomes

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Obesity in China: its characteristics, diagnostic criteria, and implications

null

《医学前沿（英文）》 2015年第9卷第2期页码 129-133 doi: 10.1007/s11684-015-0387-x

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空调硬卧车内气流组织的数值模拟研究

张登春

《中国工程科学》 2004年第6卷第9期页码 66-72

摘要：

空调车内气流组织研究是车厢内热环境控制的基础，合理的车内气流组织可有效地改善乘客的冷热舒适性。采用k-ε湍流模型对25K型空调硬卧车内气流组织进行了数值模拟，研究了不同送风方式和送风参数下车内空气流场和温度场分布规律，并与实验结果进行了对照，两者基本一致。研究结果对于改善硬卧车内人体冷热舒适性提供了理论依据，对车内气流组织优化设计有指导意义。

关键词：硬卧车湍流模型气流组织数值模拟

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null

《医学前沿（英文）》 2017年第11卷第3期页码 340-348 doi: 10.1007/s11684-017-0570-3

摘要：

In light of the rapid increase in the number of obesity incidences worldwide, obesity has become an independent risk factor for chronic kidney disease. Obesity-related glomerulopathy (ORG) is characterized by glomerulomegaly in the presence or absence of focal and segmental glomerulosclerosis lesions. IgM and complement 3 (C3) nonspecifically deposit in lesions without immune-complex-type deposits during ORG immunofluorescence. ORG-associated glomerulomegaly and focal and segmental glomerulosclerosis can superimpose on other renal pathologies. The mechanisms under ORG are complex, especially hemodynamic changes, inflammation, oxidative stress, apoptosis, and reduced functioning nephrons. These mechanisms synergize with obesity to induce end-stage renal disease. A slow increase of subnephrotic proteinuria (<3.5 g/d) is the most common clinical manifestation of ORG. Several treatment methods for ORG have been developed. Of these methods, renin–angiotensin–aldosterone system blockade and weight loss are proven effective. Targeting mitochondria may offer a novel strategy for ORG therapy. Nevertheless, more research is needed to further understand ORG.

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Dynamic characteristics of molten droplets and hot particles falling in liquid pool

Liangxing LI, Weimin MA, Huixiong LI, Tingkuan CHEN,

《能源前沿（英文）》 2010年第4卷第2期页码 246-251 doi: 10.1007/s11708-009-0077-y

摘要： The dynamic characteristics of molten droplets and hot particles at the very beginning of their fall into coolant pools are presented. The falling course of a single droplet or a single hot particle was recorded by a high-speed camera and a curve of velocity . time was obtained. Emphasis was placed on the effects of the droplet’s size and temperature, the coolant’s temperature and properties, and the droplet’s physical properties on the moving behavior. The results for the all cases showed that the velocity of a falling droplet/particle decreased rapidly but rebounded shortly, at the beginning of droplet/particle falling in the coolant. Following such a V-shaped evolution in velocity, the droplet/particle slows down gradually to a comparatively steady velocity. An increase in either coolant temperature or droplet temperature results in a larger velocity variation in the “J-region”, but a smaller deceleration when it moves out of the “J-region”. The elevated volatility of a coolant leads to a steeper deceleration in the “J-region” and beyond. The bigger size of a particle leads to a greater velocity variation in the “J-region” and terminal velocity. A high melting point and thermal conductivity as well as lower heat capacity contribute to dramatic variation in the “J-region” and low terminal velocity.

关键词： dynamic characteristics molten droplets high-temperature particles fuel and coolant interactions

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旅客列车硬座车厢内气流模拟与浓度场分析

张登春,翁培奋

《中国工程科学》 2007年第9卷第11期页码 80-86

摘要：

采用稳态不可压缩雷诺时均N-S方程、k-ε湍流模型，对旅客列车空调硬座车厢内气流场和浓度场进行了数值计算。采用立方体代表旅客，以人体呼出的CO₂作为代表性污染物，研究了非空载下车厢内气流和浓度分布。计算结果表明：现有的送风方式除车厢两端外，车厢内沿长度方向气流分布比较均匀；人体散热和太阳辐射对车厢内流场温度场影响较大，非空载时车厢内流场分布与空载时有较大差别，太阳照射和人体产生的热气流使车厢内存在较大的温度梯度；车厢内过道区浓度较低，但座位区由于人员集中，人体呼吸区污染物积聚，浓度偏高，且车厢中部断面污染

关键词：车厢湍流模型流场浓度场计算流体动力学

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Combustion characteristics and kinetics of bio-oil

Ruixia ZHANG, Zhaoping ZHONG, Yaji HUANG

《化学科学与工程前沿（英文）》 2009年第3卷第2期页码 119-124 doi: 10.1007/s11705-009-0068-x

摘要： The combustion characteristics of bio-oils derived from rice husk and corn were studied by thermogravimetry analysis. According to the thermogravimetry (TG), differential thermogravimetry (DTG) and differential thermal analysis (DTA) curves of bio-oils in air and nitrogen atmosphere, we analyzed the combustion characteristics of different kinds of bio-oils in different atmospheres and worked out the combustion kinetics parameters of the bio-oil, providing reliable base data for the burning of bio-oil. The thermogravimetry indicated that the combustion process of bio-oil was divided into three stages. At the same time, the combustion process can be described by different order reaction models, and with the method of Coats-Redfern, the activation energy and frequency factor of different kinds of bio-oils were obtained.

关键词： bio-oil combustion characteristics combustion kinetics

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Study on combustion characteristics of blended coals

LI Yonghua, WANG Chunbo, CHEN Hongwei

《能源前沿（英文）》 2007年第1卷第1期页码 96-100 doi: 10.1007/s11708-007-0010-1

摘要： Power plants in China have to burn blended coal instead of one specific coal for a variety of reasons. So it is of great necessity to investigate the combustion of blended coals. Using a test rig with a capacity of 640 MJ/h with an absolute milling system and flue gas online analysis system, characteristics such as burnout, slag, and pollution of some blended coals were investigated. The ratio of coke and slag as a method of distinguishing coal slagging characteristic was introduced. The results show that the blending of coal has some effect on NO but there is no obvious rule. SO emission can be reduced by blending low sulfur coal.

关键词： combustion capacity variety blended burnout