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Geometric optimization model for the solar cavity receiver with helical pipe at different solar radiation

Chongzhe ZOU, Huayi FENG, Yanping ZHANG, Quentin FALCOZ, Cheng ZHANG, Wei GAO

《能源前沿（英文）》 2019年 第13卷 第2期   页码 284-295 doi: 10.1007/s11708-019-0613-3

摘要： In consideration of geometric parameters, several researches have already optimized the thermal efficiency of the cylindrical cavity receiver. However, most of the optimal results have been achieved at a fixed solar radiation. At different direct normal irradiance (DNI), any single optimal result may not be suitable enough for different regions over the world. This study constructed a 3-D numerical model of cylindrical cavity receiver with DNI variation. In the model of a cylindrical cavity receiver containing a helical pipe, the heat losses of the cavity and heat transfer of working medium were also taken into account. The simulation results show that for a particular DNI in the range of 400 W/m to 800 W/m , there exists a best design for achieving a highest thermal efficiency of the cavity receiver. Besides, for a receiver in constant geometric parameters, the total heat losses increases dramatically with the DNI increasing in that range, as well as the temperature of the working medium. The thermal efficiency presented a different variation tendency with the heat losses, which is 2.45% as a minimum decline. In summary, this paper proposed an optimization method in the form of a bunch of fitting curves which could be applied to receiver design in different DNI regions, with comparatively appropriate thermal performances.

关键词： cylindrical cavity receiver     3-D numerical simulation     geometric optimization     direct normal irradiation    

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Effects of critical geometric parameters on the optical performance of a conical cavity receiver

Hu XIAO, Yanping ZHANG, Cong YOU, Chongzhe ZOU, Quentin FALCOZ

《能源前沿（英文）》 2019年 第13卷 第4期   页码 673-683 doi: 10.1007/s11708-019-0630-2

摘要： The optical performance of a receiver has a great influence on the efficiency and stability of a solar thermal power system. Most of the literature focuses on the optical performance of receivers with different geometric shapes, but less research is conducted on the effects of critical geometric parameters. In this paper, the commercial software TracePro was used to investigate the effects of some factors on a conical cavity receiver, such as the conical angle, the number of loops of the helical tube, and the distance between the focal point of the collector and the aperture. These factors affect the optical efficiency, the maximum heat flux density, and the light distribution in the conical cavity. The optical performance of the conical receiver was studied and analyzed using the Monte Carlo ray tracing method. To make a reliable simulation, the helical tube was attached to the inner wall of the cavity in the proposed model. The results showed that the amount of light rays reaching the helical tube increases with the increasing of the conical angle, while the optical efficiency decreases and the maximum heat flux density increases. The increase in the number of loops contributed to an increase in the optical efficiency and a uniform light distribution. The conical cavity receiver had an optimal optical performance when the focal point of the collector was near the aperture.

关键词： parabolic collector     conical cavity receiver     critical geometric parameters     optical performance    

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Numerical simulation of the heat flux distribution in a solar cavity receiver

Yueshe WANG, Xunwei DONG, Jinjia WEI, Hui JIN

《能源前沿（英文）》 2011年 第5卷 第1期   页码 98-103 doi: 10.1007/s11708-010-0019-8

摘要： In the solar tower power plant, the receiver is one of the main components of efficient concentrating solar collector systems. In the design of the receiver, the heat flux distribution in the cavity should be considered first. In this study, a numerical simulation using the Monte Carlo Method has been conducted on the heat flux distribution in the cavity receiver, which consists of six lateral faces and floor and roof planes, with an aperture of 2.0 m×2.0 m on the front face. The mathematics and physical models of a single solar ray’s launching, reflection, and absorption were proposed. By tracing every solar ray, the distribution of heat flux density in the cavity receiver was obtained. The numerical results show that the solar flux distribution on the absorbing panels is similar to that of CESA-I’s. When the reradiation from walls was considered, the detailed heat flux distributions were issued, in which 49.10% of the total incident energy was absorbed by the central panels, 47.02% by the side panels, and 3.88% was overflowed from the aperture. Regarding the peak heat flux, the value of up to 1196.406 kW/m was obtained in the center of absorbing panels. These results provide necessary data for the structure design of cavity receiver and the local thermal stress analysis for boiling and superheated panels.

关键词： solar cavity receiver     Monte Carlo method     heat flux distribution    

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Numerical simulation and experiment research of radiation performance in a dish solar collector system

Yong SHUAI, Xinlin XIA, Heping TAN

《能源前沿（英文）》 2010年 第4卷 第4期   页码 488-495 doi: 10.1007/s11708-010-0007-z

摘要： The Monte Carlo ray-tracing method is applied and coupled with optical properties to predict the radiation performance of solar concentrator/cavity receiver systems. Several different cavity geometries are compared on the radiation performance. A flux density distribution measurement system for dish parabolic concentrators is developed. The contours of the flux distribution for target placements at different distances from the dish vertex of a solar concentrator are taken by using an indirect method with a Lambert and a charge coupled device (CCD) camera. Further, the measured flux distributions are compared with a Monte Carlo-predicted distribution. The results can be a valuable reference for the design and assemblage of the solar collector system.

关键词： Monte Carlo method     solar energy     radiation performance     cavity receiver    

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Finite element modeling of counter-roller spinning for large-sized aluminum alloy cylindrical parts

Dawei ZHANG, Fan LI, Shuaipeng LI, Shengdun ZHAO

《机械工程前沿（英文）》 2019年 第14卷 第3期   页码 351-357 doi: 10.1007/s11465-019-0528-z

摘要： Counter-roller spinning (CRS), where the mandrel is replaced by rollers, is an effective means of manufacturing large-sized, thin-walled, cylindrical parts with more than 2500 mm diameter. CRS is very complex because of multi-axis rotation, multi-local loading along the circumference, and radial-axial compound deformation. Analytical or experimental methods cannot fully understand CRS. Meanwhile, numerical simulation is an adequate approach to investigate CRS with comprehensive understanding and a low cost. Thus, a finite element (FE) model of CRS was developed with the FORGE code via meshing technology, material modeling, determining the friction condition, and so on. The local fine mesh moving with the roller is one of highlights of the model. The developed 3D-FE model was validated through a CRS experiment by using a tubular blank with a 720 mm outer diameter. The developed 3D-FE model of CRS can provide a basis for parameter optimization, process control, die design, and so on. The data on force and energy predicted by the 3D-FE model can offer reasonable suggestions for determining the main mechanical parameters of CRS machines and selecting the motors. With the predicted data, an all-electric servo-drive system/machine with distributed power was designed in this work for CRS with four pairs of rollers to manufacture a large-sized, thin-walled, cylindrical part with 6000 mm diameter.

关键词： large-sized cylindrical part     counter-roller spinning     aluminum alloy     finite element method     distributed power    

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Design of a piezoelectric transducer cylindrical phase modulator for simulating acoustic emission signals

HE Cunfu, HANG Lijun, WU Bin

《机械工程前沿（英文）》 2007年 第2卷 第3期   页码 370-373 doi: 10.1007/s11465-007-0065-z

摘要： To conveniently carry out the pipeline leak experiment in a laboratory, leak acoustic signals are simulated by using the converse piezoelectric effect of a piezoelectric transducer (PZT) cylindrical phase modulator. On the basis of the piezoelectric equations and electromechanical equivalence principle, the transfer function of a PZT cylindrical phase modulator is delivered. A PZT cylindrical phase modulator is designed, and the numerical simulation is conducted. Results prove that the PZT cylindrical phase modulator can effectively simulate leak acoustic emission signals when the frequency is lower than 25 KHz.

关键词： KHz     numerical simulation     modulator     cylindrical     PZT    

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A frequency error estimation for isogeometric analysis of Kirchhoff–Love cylindrical shells

《结构与土木工程前沿（英文）》 doi: 10.1007/s11709-023-0006-x

摘要： A frequency error estimation is presented for the isogeometric free vibration analysis of Kirchhoff–Love cylindrical shells using both quadratic and cubic basis functions. By analyzing the discrete isogeometric equations with the aid of harmonic wave assumption, the frequency error measures are rationally derived for the quadratic and cubic formulations for Kirchhoff–Love cylindrical shells. In particular, the governing relationship of the continuum frequency for Kirchhoff–Love cylindrical shells is naturally embedded into the frequency error measures without the need of explicit frequency expressions, which usually are not trivial for the shell problems. In accordance with these theoretical findings, the 2nd and 4th orders of frequency accuracy are attained for the isogeometric schemes using quadratic and cubic basis functions, respectively. Numerical results not only thoroughly verify the theoretical convergence rates of frequency solutions, but also manifest an excellent magnitude match between numerical and theoretical frequency errors for the isogeometric free vibration analysis of Kirchhoff–Love cylindrical shells.

关键词： isogeometric analysis     Kirchhoff–Love cylindrical shell     free vibration     frequency error     convergence    

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Effect of cavity defect on the triaxial mechanical properties of high-performance concrete

Yanbin ZHANG; Zhe WANG; Mingyu FENG

《结构与土木工程前沿（英文）》 2022年 第16卷 第5期   页码 600-614 doi: 10.1007/s11709-022-0821-5

摘要： The stress concentration of pipe structure or cavity defect has a great effect on the mechanical properties of the high-performance concrete (HPC) members in deep underground locations. However, the behaviour of HPC with cavities under triaxial compression is not understood, especially when pressurized liquid flows into the fractures from the cavity. This study aims to investigate the effect of the cavity and the confining pressure on the failure mechanisms, strengths, and deformation properties of HPC with a new experimental scheme. In this experiment, the pressurized liquid can only contact the surface of the sample in the cavity, while the other surfaces are isolated from the pressurized liquid. To further explore the effect of the cavity, the same experiments are also conducted on sealed and unsealed intact samples without a cavity. The failure modes and stress-strain curves of all types of the samples are presented. Under various confining pressures, all the samples with a cavity suffer shear failure, and there are always secondary tensile fractures initiating from the cavity sidewall. Additionally, it can be determined from the failure modes and the stress-strain curves that the shear fractures result from the sidewall failure. Based on the different effects of the cavity on the lateral deformations in different directions, the initiation of the sidewall fracture is well predicted. The experimental results show that both the increase of the confining pressure and the decrease of the cavity size are conducive to the initiation of sidewall fracture. Moreover, the cavity weakens the strength of the sample, and this study gives a modified Power-law criterion in which the cavity size is added as an impact factor to predict the strength of the sample.

关键词： high-performance concrete     cavity     conventional triaxial compression     pressurized liquid     modified power-law criterion    

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Investigation on a cylindrical ultrasonic micromotor

ZHU Hua, CHEN Chao, ZHAO Chunsheng

《机械工程前沿（英文）》 2007年 第2卷 第4期   页码 394-398 doi: 10.1007/s11465-007-0068-9

摘要： The relationship between the arrangement of ceramics and the force coefficient shows that the maximum excitation efficiency will be obtained when the ceramics are placed at the trough of the first bending mode of the stator. Therefore, a cylindrical ultrasonic micromotor with a novel stator is proposed. The prototype motor is 5 mm in diameter, 30 mm in length and 4.2 g in weight. The micromotor operates with the first bending mode at 53 kHz. Its maximum speed is 350 r/min when the drive voltage is 200 V and the stall torque reaches 2.5 mN · m. As this motor is suitable for miniaturization because of its simple structure, another cylindrical ultrasonic micromotor is developed. Piezoelectric ceramic tube is used as its stator. This micromtor is 2 mm in diameter, 7 mm in length and 0.258 g in weight. Its speed reaches 813 r/min when the drive voltage is 60 V at 75 kHz. The operation mechanism, structure and design method of these two motors are introduced.

关键词： coefficient     bending     kHz     suitable     weight    

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Multifractal characteristics of cylindrical sludge drying

Weiyun WANG, Aimin LI,

《环境科学与工程前沿（英文）》 2009年 第3卷 第4期   页码 464-469 doi: 10.1007/s11783-009-0040-5

摘要： This paper analyzes dewatered sludge drying using the multifractal theory. The drying rates of cylindrical sludge with equal masses but different cross-sectional diameters was studied, from which multifractal parameters such as partition function and quality exponent were obtained. The parameters acquired were used to calculate the multifractal singularity spectrum and indicate the presence of multifractal characteristics. The smaller cross-sectional diameters of the sludge were found to be non-homogeneous, and required quantitative methods to analyze.

关键词： multifractal characteristic     multifractal singularity spectrum     sewage sludge drying    

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Liquid-based high-temperature receiver technologies for next-generation concentrating solar power: A

《能源前沿（英文）》 2023年 第17卷 第1期   页码 16-42 doi: 10.1007/s11708-023-0866-8

摘要： To reduce the levelized cost of energy for concentrating solar power (CSP), the outlet temperature of the solar receiver needs to be higher than 700 °C in the next-generation CSP. Because of extensive engineering application experience, the liquid-based receiver is an attractive receiver technology for the next-generation CSP. This review is focused on four of the most promising liquid-based receivers, including chloride salts, sodium, lead-bismuth, and tin receivers. The challenges of these receivers and corresponding solutions are comprehensively reviewed and classified. It is concluded that combining salt purification and anti-corrosion receiver materials is promising to tackle the corrosion problems of chloride salts at high temperatures. In addition, reducing energy losses of the receiver from sources and during propagation is the most effective way to improve the receiver efficiency. Moreover, resolving the sodium fire risk and material compatibility issues could promote the potential application of liquid-metal receivers. Furthermore, using multiple heat transfer fluids in one system is also a promising way for the next-generation CSP. For example, the liquid sodium is used as the heat transfer fluid while the molten chloride salt is used as the storage medium. In the end, suggestions for future studies are proposed to bridge the research gaps for > 700 °C liquid-based receivers.

关键词： next-generation concentrating solar power     liquid-based solar receiver     molten salt     liquid metals    

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Cylindrical particulate internal flows: A review

Lizhong HUANG, Xiang GAO, Jianzhong LIN

《机械工程前沿（英文）》 2012年 第7卷 第4期   页码 385-393 doi: 10.1007/s11465-012-0354-z

摘要：

The study of cylindrical particulate internal flows has wide industrial applicability hence received much attention. This article reviews the cylindrical particulate internal flows over the past twenty years. The research is related to the cylindrical particulate flows in the straight channel, curved channel and rotational channel. Finally, several open research issues have been identified.

关键词： cylindrical particulate flow     internal flow    

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―Summary of investigations on rotating cavity at IDG, RWTH Aachen University

Dieter BOHN, Jing REN,

《能源前沿（英文）》 2009年 第3卷 第4期   页码 489-497 doi: 10.1007/s11708-009-0040-y

摘要： Annular cavities are found inside rotor shafts of turbomachines with an axial or radial throughflow of cooling air, which influences the thermal efficiency and system reliability of the gas turbines. The flow and heat transfer phenomena in those cavities should be investigated in order to minimize the thermal load and guarantee the system reliability. An experimental rig is set up in the Institute of Steam and Gas Turbines, RWTH Aachen University, to analyze the flow structure inside the rotating cavity with an axial throughflow of cooling air. The corresponding 3D numerical investigation is conducted with the in-house flow solver CHTflow, in which the Coriolis force and the buoyancy force are implemented in the time-dependent Navier-Stokes equations. Both the experimental and numerical results show that the whole flow structure rotating slower than the cavity rotating speed. The flow passing the observation windows in the experimental and numerical results indicates the quite similar trajectories. The computed sequences and periods of the vortex flow structure correspond closely with those observed in the experiment. Furthermore, the numerical analysis reveals a flow pattern changing between single pair, double pair, and triple pair vortices. It is suggested that the vortices inside the cavity are created by the gravitational buoyancy force in the investigated case, while the number and strength of the vortices are controlled mainly by the Coriolis force.

关键词： rotating cavity     buoyancy     unsteady flow    

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A new approach for fuel injection into a solar receiver/reactor: Numerical and experimental investigation

M Helal Uddin, Nesrin Ozalp, Jens Heylen, Cedric Ophoff

《化学科学与工程前沿（英文）》 2018年 第12卷 第4期   页码 683-696 doi: 10.1007/s11705-018-1782-z

摘要：

An innovative and efficient design of solar receivers/reactors can enhance the production of clean fuels via concentrated solar energy. This study presents a new jet-type burner nozzle for gaseous feedstock injection into a cavity solar receiver inspired from the combustion technology. The nozzle design was adapted from a combustion burner and successfully implemented into a solar receiver and studied the influence of the nozzle design on the fluid mixing and temperature distribution inside the solar receiver using a 7 kW solar simulator and nitrogen as working fluid. Finally, a thorough computational fluid dynamics (CFD) analysis was performed and validated against the experimental results. The CFD results showed a variation of the gas flow pattern and gas mixing after the burner nozzle adaptation, which resulted an intense effect on the heat transfer inside the solar receiver.

关键词： solar reactor     nozzle     CFD     heat transfer     mixing and recirculation    

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Predication of discharge coefficient of cylindrical weir-gate using adaptive neuro fuzzy inference systems

Abbas PARSAIE,Amir Hamzeh HAGHIABI,Mojtaba SANEIE,Hasan TORABI

《结构与土木工程前沿（英文）》 2017年 第11卷 第1期   页码 111-122 doi: 10.1007/s11709-016-0354-x

摘要： Settlement of sediments behind weirs and accumulation of materials floating on water behind gates decreases the performance of these structures. Weir-gate is a combination of weir and gate structures which solves them Infirmities. Proposing a circular shape for crest of weirs to improve their performance, investigators have proposed cylindrical shape to improve the performance of weir-gate structure and call it cylindrical weir-gate. In this research, discharge coefficient of weir-gate was predicated using adaptive neuro fuzzy inference systems (ANFIS). To compare the performance of ANFIS with other types of soft computing techniques, multilayer perceptron neural network (MLP) was prepared as well. Results of MLP and ANFIS showed that both models have high ability for modeling and predicting discharge coefficient; however, ANFIS is a bit more accurate. The sensitivity analysis of MLP and ANFIS showed that Froude number of flow at upstream of weir and ratio of gate opening height to the diameter of weir are the most effective parameters on discharge coefficient.

关键词： weir-gate     soft computing     crest geometry     circular crest weir     cylindrical shape    

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标题 作者 时间 类型 操作

Geometric optimization model for the solar cavity receiver with helical pipe at different solar radiation

Chongzhe ZOU, Huayi FENG, Yanping ZHANG, Quentin FALCOZ, Cheng ZHANG, Wei GAO

期刊论文

Effects of critical geometric parameters on the optical performance of a conical cavity receiver

Hu XIAO, Yanping ZHANG, Cong YOU, Chongzhe ZOU, Quentin FALCOZ

期刊论文

Numerical simulation of the heat flux distribution in a solar cavity receiver

Yueshe WANG, Xunwei DONG, Jinjia WEI, Hui JIN

期刊论文

Numerical simulation and experiment research of radiation performance in a dish solar collector system

Yong SHUAI, Xinlin XIA, Heping TAN

期刊论文

Finite element modeling of counter-roller spinning for large-sized aluminum alloy cylindrical parts

Dawei ZHANG, Fan LI, Shuaipeng LI, Shengdun ZHAO

期刊论文

Design of a piezoelectric transducer cylindrical phase modulator for simulating acoustic emission signals

HE Cunfu, HANG Lijun, WU Bin

期刊论文

A frequency error estimation for isogeometric analysis of Kirchhoff–Love cylindrical shells

期刊论文

Effect of cavity defect on the triaxial mechanical properties of high-performance concrete

Yanbin ZHANG; Zhe WANG; Mingyu FENG

期刊论文

Investigation on a cylindrical ultrasonic micromotor

ZHU Hua, CHEN Chao, ZHAO Chunsheng

期刊论文

Multifractal characteristics of cylindrical sludge drying

Weiyun WANG, Aimin LI,

期刊论文

Liquid-based high-temperature receiver technologies for next-generation concentrating solar power: A

期刊论文

Cylindrical particulate internal flows: A review

Lizhong HUANG, Xiang GAO, Jianzhong LIN

期刊论文

―Summary of investigations on rotating cavity at IDG, RWTH Aachen University

Dieter BOHN, Jing REN,

期刊论文

A new approach for fuel injection into a solar receiver/reactor: Numerical and experimental investigation

M Helal Uddin, Nesrin Ozalp, Jens Heylen, Cedric Ophoff

期刊论文

Predication of discharge coefficient of cylindrical weir-gate using adaptive neuro fuzzy inference systems

Abbas PARSAIE,Amir Hamzeh HAGHIABI,Mojtaba SANEIE,Hasan TORABI

期刊论文