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Experimental research on cyclone performance at high temperature

LI Wenqi, CHEN Jianyi

《机械工程前沿(英文)》 2007年 第2卷 第3期   页码 310-317 doi: 10.1007/s11465-007-0055-1

摘要: To predict the influence of operating temperatures on cyclone performance, an experimental investigation was conducted on particle separation in a reverse flow, tangential volute-inlet cyclone separator with a diameter of 300 mm and with air heated up to 973 K. The test powder silica has a mass median diameter of 10 um, while inlet velocity range was 12-36 m/s. Both the separation efficiency and pressure drop of the cyclone were measured as a function of the inlet velocity and operating temperature. At the same inlet velocity, both the separation efficiency and pressure drop decrease with increasing temperature. In addition, optimum inlet velocity, at which the cyclone has its highest separation efficiency, tends to increase with a rise in temperature. An analysis on our own data and published results has shown that the fractional efficiency of a cyclone is a definite function of dimensionless numbers such as the Stokes number, the Reynolds number, the Froude number, dimensionless cyclone inlet area, and dimensionless outlet diameter. A nondimensional experimental correlation of the cyclone performance, including the influence of temperature, was obtained on the basis of our own previous work. The prediction of the influence of temperature on separation efficiencies and pressure drops is in fairly good agreement with experimental results.

关键词: diameter     definite function     nondimensional experimental     cyclone performance     influence    

Modeling the gas flow in a cyclone separator at different temperature and pressure

Gujun WAN, Guogang SUN, Cuizhi GAO, Ruiqian DONG, Ying ZHENG, Mingxian SHI

《化学科学与工程前沿(英文)》 2010年 第4卷 第4期   页码 498-505 doi: 10.1007/s11705-010-0502-0

摘要: The gas flow field in a cyclone separator, operated within a temperature range of 293 K – 1373 K and a pressure range of 0.1 – 6.5 MPa, has been simulated using a modified Reynolds-stress model (RSM) on commercial software platform FLUENT 6.1. The computational results show that the temperature and pressure significantly influence the gas velocity vectors, especially on their tangential component, in the cyclone. The tangential velocity decreases with an increase in temperature and increases with an increase in pressure. This tendency of the decrease or increase, however, reduces gradually when the temperature is above 1000 K or the pressure goes beyond 1.0 MPa. The temperature and pressure have a relatively weak influence on the axial velocity profiles. The outer downward flow rate increases with a temperature increase, whereas it decreases with a pressure increase. The centripetal radial velocity is strong in the region of 0 – 0.25 below the vortex finder entrance, which is named as a short-cut flow zone in this study. Based on the simulation results, a set of correlations was developed to calculate the combined effects of temperature and pressure on the tangential velocity, the downward flow rate in the cyclone and the centripetal radial velocity in the short-cut flow region underneath the vortex finder.

关键词: cyclone separator     high temperature     high pressure     flow field     numerical simulation    

海洋气象观测系统在热带气旋资料同化中的应用

万齐林,何金海

《中国工程科学》 2012年 第14卷 第10期   页码 33-42

摘要:

在分析南海海洋气象观测现状和发展规划的基础上,发现有必要发展合适的资料同化技术,提高资料利用效率,才能克服海洋气象资料相对缺乏来提升数值预报水平。利用多尺度/分块逐批资料同化技术,进行热带气旋资料同化试验。结果表明:多尺度/分块逐批资料同化技术能够适应具有多尺度特征的热带气旋资料同化,较好地满足热带气旋资料同化对流依赖背景误差协方差同化技术的要求,能够较合理高效地利用海洋气象观测资料。基于多尺度/分块逐批资料同化技术,加强海洋气象观测系统的应用,是形成高质量热带气旋初值环流的一种有效途径。

关键词: 海洋气象观测     资料利用效率     多尺度/分块逐批资料同化     热带气旋初值环流    

不同侧向入口旋风分离器流场数值分析

陈启东,左志全

《中国工程科学》 2014年 第16卷 第2期   页码 58-67

摘要:

利用雷诺应力模型(RSM)对直切单入口、直切双入口、斜切单入口、斜切双入口、斜切螺旋面单入口、斜切螺旋面双入口6 种不同侧向入口旋风分离器内部气相流场进行了计算分析。结果表明:双入口结构旋风分离器内部压力场和速度场具有更好的对称性与稳定性;仅改变入口斜切角度对旋风分离器内部速度场和压力场的分布影响不大;当本文中6 种分离器内部具有相近的切向速度径向分布时,斜切螺旋面入口结构分离器压力损失减少约25 %,入口所需总压降低17 %,处理相同气体量的能耗约下降17 %;斜切螺旋面双入口(XS-L型)分离器是一种综合性能比较优的旋风分离器。

关键词: 旋风分离器     侧向入口     压降     入口总压     能耗    

我国台风监测预报预警体系的现状及建议

端义宏,陈联寿,许映龙,钱传海

《中国工程科学》 2012年 第14卷 第9期   页码 4-9

摘要:

近年来,在全球气候变暖背景下,全球高影响台风事件频发,灾害影响日趋严重。在我国,以登陆台风为代表的极端天气事件呈明显增多的趋势,登陆台风的平均强度明显增强、强台风数量明显增多,台风登陆时间更加集中、登陆季节明显缩短。分析了我国台风灾害的特征及台风监测、预报预警体系的现状和存在的问题,提出了在我国经济社会快速发展时期加强我国台风监测预报预警体系的对策建议和措施。

关键词: 台风监测     预报预警     业务现状    

Performance-based and performance-driven architectural design and optimization

Xing SHI

《结构与土木工程前沿(英文)》 2010年 第4卷 第4期   页码 512-518 doi: 10.1007/s11709-010-0090-6

摘要: As the architecture, engineering, and construction (AEC) industry is marching into the sustainable and low-carbon era, the performance of architecture has drawn more attention than ever. Simulation technology has made quantified analysis of architectural performance possible and, therefore, directly enables architects and engineers to incorporate performance analysis into the design work flow. It is argued that performance-based and performance-driven architectural designs differ in that the latter involves computer-aided optimization technique so that the performance can be used as the criteria to truly “drive” the design. The paper starts with a brief introduction of performance issues in architectural design, followed by a review of the evolution of performance-based architectural design. The concept of performance-driven architectural design is presented, and some design projects and research work are reviewed. The driving engine, i.e., optimization technique, and its application in architectural design is discussed. Challenges to making performance-driven design a common practice are explained, and a schematic of integrated performance-based/driven architectural design software is proposed.

关键词: performance     optimization     architectural design     simulation     sustainability    

Flexural and longitudinal shear performance of precast lightweight steel–ultra-high performance concrete

《结构与土木工程前沿(英文)》 2023年 第17卷 第5期   页码 704-721 doi: 10.1007/s11709-023-0941-6

摘要: In this study, the flexural and longitudinal shear performances of two types of precast lightweight steel–ultra-high performance concrete (UHPC) composite beams are investigated, where a cluster UHPC slab (CUS) and a normal UHPC slab (NUS) are connected to a steel beam using headed studs through discontinuous shear pockets and full-length shear pockets, respectively. Results show that the longitudinal shear force of the CUS is greater than that of the NUS, whereas the interfacial slip of the former is smaller. Owing to its better integrity, the CUS exhibits greater flexural stiffness and a higher ultimate bearing capacity than the NUS. To further optimize the design parameters of the CUS, a parametric study is conducted to investigate their effects on the flexural and longitudinal shear performances. The square shear pocket is shown to be more applicable for the CUS, as the optimal spacing between two shear pockets is 650 mm. Moreover, a design method for transverse reinforcement is proposed; the transverse reinforcement is used to withstand the splitting force caused by studs in the shear pocket and prevent the UHPC slab from cracking. According to calculation results, the transverse reinforcement can be canceled when the compressive strength of UHPC is 150 MPa and the volume fraction of steel fiber exceeds 2.0%.

关键词: precast steel–UHPC composite beam     flexural performance     longitudinal shear performance     parametric study     transverse reinforcement ratio    

Comparison of indices for stiffness performance evaluation

Giuseppe CARBONE, Marco CECCARELLI,

《机械工程前沿(英文)》 2010年 第5卷 第3期   页码 270-278 doi: 10.1007/s11465-010-0023-z

摘要: This paper addresses the problem of a numerical evaluation of the stiffness performance for multibody robotic systems. An overview is presented with basic formulation concerning indices that are proposed in literature. New indices are also outlined. Stiffness indices are computed and compared for a case study. Results are used for comparing the effectiveness of the stiffness indices. The main goal is to propose a performance index describing synthetically the elastostatic response of a multibody robotic system and also for design purposes.

关键词: robotics     stiffness     performance indices    

Performance of steel bridge deck pavement structure with ultra high performance concrete based on resin

《结构与土木工程前沿(英文)》 2021年 第15卷 第4期   页码 895-904 doi: 10.1007/s11709-021-0759-z

摘要: This research investigated a pavement system on steel bridge decks that use epoxy resin (EP) bonded ultra-high performance concrete (UHPC). Through FEM analysis and static and dynamic bending fatigue tests of the composite structure, the influences of the interface of the pavement layer, reinforcement, and different paving materials on the structural performance were compared and analyzed. The results show that the resin bonded UHPC pavement structure can reduce the weld strain in the steel plate by about 32% and the relative deflection between ribs by about 52% under standard axial load conditions compared to traditional pavements. The EP bonding layer can nearly double the drawing strength of the pavement interface from 1.3 MPa, and improve the bending resistance of the UHPC structure on steel bridge decks by about 50%; the bending resistance of reinforced UHPC structures is twice that of unreinforced UHPC structure, and the dynamic deflection of the UHPC pavement structure increases exponentially with increasing fatigue load. The fatigue life is about 1.2 × 107 cycles under a fixed force of 9 kN and a dynamic deflection of 0.35 mm, which meets the requirements for fatigue performance of pavements on steel bridge decks under traffic conditions of large flow and heavy load.

关键词: steel bridge deck pavement     ultra-high-performance concrete     epoxy resin     composite structure     bending fatigue performance    

Cutting performance of surgical electrodes by constructing bionic microstriped structures

《机械工程前沿(英文)》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0728-9

摘要: Surgical electrodes rely on thermal effect of high-frequency current and are a widely used medical tool for cutting and coagulating biological tissue. However, tissue adhesion on the electrode surface and thermal injury to adjacent tissue are serious problems in surgery that can affect cutting performance. A bionic microstriped structure mimicking a banana leaf was constructed on the electrode via nanosecond laser surface texturing, followed by silanization treatment, to enhance lyophobicity. The effect of initial, simple grid-textured, and bionic electrodes with different wettabilities on tissue adhesion and thermal injury were investigated using horizontal and vertical cutting modes. Results showed that the bionic electrode with high lyophobicity can effectively reduce tissue adhesion mass and thermal injury depth/area compared with the initial electrode. The formation mechanism of adhered tissue was discussed in terms of morphological features, and the potential mechanism for antiadhesion and heat dissipation of the bionic electrode was revealed. Furthermore, we evaluated the influence of groove depth on tissue adhesion and thermal injury and then verified the antiadhesion stability of the bionic electrode. This study demonstrates a promising approach for improving the cutting performance of surgical electrodes.

关键词: surgical electrodes     tissue adhesion     thermal injury     bionic structures     cutting performance     medical tools    

Recovery and reuse of floc sludge for high-performance capacitors

《环境科学与工程前沿(英文)》 2022年 第16卷 第6期 doi: 10.1007/s11783-021-1512-5

摘要:

• The feasibility of facile fabrication of capacitor from floc sludge is discussed.

关键词: Floc sludge     Porous carbon electrode     Energy storage performance     Supercapacitors    

Discrete-event stochastic systems with correlated inputs: Modeling and performance evaluation

《工程管理前沿(英文)》 2022年 第9卷 第2期   页码 214-220 doi: 10.1007/s42524-022-0192-6

摘要: In the majority of the previous works on discrete-event stochastic systems, they have been assumed to have independent input processes. However, in many applications, these input processes can be highly correlated. Furthermore, the performance measures of the systems with correlated inputs can be significantly different from those with independent inputs. In this paper, we provide an overview on some commonly used methods for modeling correlated input processes, and we discuss the difficulties and possible future research topics in the study of discrete-event stochastic systems with correlated inputs.

关键词: discrete-event stochastic system     correlated input     performance evaluation    

Weakening behavior of waterproof performance in joints of shield tunnels under adjacent constructions

《结构与土木工程前沿(英文)》   页码 884-900 doi: 10.1007/s11709-022-0912-3

摘要: Groundwater leakage in shield tunnels poses a threat to the safety and durability of tunnel structures. Disturbance of adjacent constructions during the operation of shield tunnels frequently occurs in China, leading to deformation of tunnel lining and leakage in joints. Understanding the impact of adjacent constructions on the waterproofing performance of the lining is critical for the protection of shield tunnels. In this study, the weakening behavior of waterproof performance was investigated in the joints of shield tunnels under transverse deformation induced by adjacent construction. First, the relationship between the joint opening and transverse deformation under three typical adjacent constructions (upper loading, upper excavation, and side excavation) was investigated via elaborate numerical simulations. Subsequently, the evolution of the waterproof performance of a common gasket with a joint opening was examined by establishing a coupled Eulerian–Lagrangian model of joint seepage, and a formula describing the relationship between waterproof performance and joint opening was proposed. Finally, the weakening law of waterproofing performance was investigated based on the results of the aforementioned studies. It was determined that the joints with the greatest decline in waterproof performance were located at the tunnel shoulder in the upper loading case, tunnel crown in the upper excavation case, and tunnel shoulder in the side excavation case. When the waterproof performance of these joints decreased to 50% and 30%, the transverse deformations were 60 and 90 mm under upper loading, 90 and 140 mm under upper excavation, and 45 and 70 mm under side excavation, respectively. The results provide a straightforward reference for setting a controlled deformation standard considering the waterproof performance.

关键词: shield tunnel     waterproof performance     horizontal transverse deformation     joint opening     weakening behavior    

Facility managers’ perceptions on building performance assessment

Rafaela BORTOLINI, Núria FORCADA

《工程管理前沿(英文)》 2018年 第5卷 第3期   页码 324-333 doi: 10.15302/J-FEM-2018010

摘要:

During the operational phase, building performance may decrease in various areas, so that the end users’ requirements are no longer met. Consequently, indicators are useful to assess and improve the performance of existing buildings. In this study, we carried out a literature review and organized a focus group with facility management experts to gather and analyze facility managers’ perceptions on operational indicators that could be used to assess the performance of buildings. The results revealed that the core indicators used to measure a building’s operational performance are related to safety and assets working properly, health and comfort, space functionality, and energy performance. The findings also revealed that these indicators can be obtained from three sources: a) facility managers/operators, who carry out corrective maintenance and perform technical inspections, b) regular users, who report complaints and fill-in satisfaction questionnaires, and c) sporadic users, who also fill-in satisfaction questionnaires. These indicators and their sources can contribute to a better analysis of building performance and the definition of measures to improve performance during the operational phase of a building.

关键词: building performance     facility management     non-residential buildings    

Nonlinear design-point performance adaptation approaches and their comparisons for gas turbine applications

Y. G. LI, P. PILIDIS,

《能源前沿(英文)》 2009年 第3卷 第4期   页码 446-455 doi: 10.1007/s11708-009-0042-9

摘要: Accurate performance simulation and understanding of gas turbine engines is very useful for gas turbine manufacturers and users alike and such a simulation normally starts from its design point. When some of the engine component parameters for an existing engine are not available, they must be estimated in order that the performance analysis can be started. Therefore, the simulated design point performance of an engine may be slightly different from its actual performance. In this paper, two nonlinear gas turbine design-point performance adaptation approaches have been presented to best estimate the unknown component parameters and match available design point engine performance, one using a nonlinear matrix inverse adaptation method and the other using a Genetic Algorithm-based adaptation approach. The advantages and disadvantages of the two adaptation methods have been compared with each other. In the approaches, the component parameters may be compressor pressure ratios and efficiencies, turbine entry temperature, turbine efficiencies, engine mass flow rate, cooling flows, and by-pass ratio, etc. The engine performance parameters may be thrust and SFC for aero engines, shaft power, and thermal efficiency for industrial engines, gas path pressures, temperatures, etc. To select the most appropriate to-be-adapted component parameters, a sensitivity bar chart is used to analyze the sensitivity of all potential component parameters against the engine performance parameters. The two adaptation approaches have been applied to a model gas turbine engine. The application shows that the sensitivity bar chart is very useful in the selection of the to-be-adapted component parameters, and both adaptation approaches are able to produce good quality engine models at design point. The comparison of the two adaptation methods shows that the nonlinear matrix inverse method is faster and more accurate, while the genetic algorithm-based adaptation method is more robust but slower. Theoretically, both adaptation methods can be extended to other gas turbine engine performance modelling applications.

关键词: gas turbine     engine     performance adaptation     performance matching     design-point performance simulation     influence coefficient matrix     genetic algorithm    

标题 作者 时间 类型 操作

Experimental research on cyclone performance at high temperature

LI Wenqi, CHEN Jianyi

期刊论文

Modeling the gas flow in a cyclone separator at different temperature and pressure

Gujun WAN, Guogang SUN, Cuizhi GAO, Ruiqian DONG, Ying ZHENG, Mingxian SHI

期刊论文

海洋气象观测系统在热带气旋资料同化中的应用

万齐林,何金海

期刊论文

不同侧向入口旋风分离器流场数值分析

陈启东,左志全

期刊论文

我国台风监测预报预警体系的现状及建议

端义宏,陈联寿,许映龙,钱传海

期刊论文

Performance-based and performance-driven architectural design and optimization

Xing SHI

期刊论文

Flexural and longitudinal shear performance of precast lightweight steel–ultra-high performance concrete

期刊论文

Comparison of indices for stiffness performance evaluation

Giuseppe CARBONE, Marco CECCARELLI,

期刊论文

Performance of steel bridge deck pavement structure with ultra high performance concrete based on resin

期刊论文

Cutting performance of surgical electrodes by constructing bionic microstriped structures

期刊论文

Recovery and reuse of floc sludge for high-performance capacitors

期刊论文

Discrete-event stochastic systems with correlated inputs: Modeling and performance evaluation

期刊论文

Weakening behavior of waterproof performance in joints of shield tunnels under adjacent constructions

期刊论文

Facility managers’ perceptions on building performance assessment

Rafaela BORTOLINI, Núria FORCADA

期刊论文

Nonlinear design-point performance adaptation approaches and their comparisons for gas turbine applications

Y. G. LI, P. PILIDIS,

期刊论文