检索结果-内蒙古大学图书馆

Numerical simulation on the forced oscillation of rigid riser with helical strakes in different section shapes

OCEAN engineering 2019年 190卷 106439-000页

作者： Liu, Qingsong Hao, Winxing Li, Chun Miao, Weipao Ding Qinwei Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai 200093 Peoples R China

In order to study the helical strakes' suppression effects on the vibration riser, triangle and circular sections helical strakes are proposed. With the technology of dynamic mesh, forced oscillation in steady flow of the riser with helical strakes in different cross-section shapes at low Reynolds number are numerically simulated. The analysis is focused on the lock-in range, as well as the force status and trailing vortex structure under different values of amplitude (A) and oscillation frequency (f(e)), and draw comparisons to the bare riser's results. Research shows the lock-in range will increase with the increase of amplitude ratio (A/D), the riser with all three different shaped helical strakes have larger lock-in range than bare riser. Before entering into the lock-in region, riser with different shaped helical strakes all have good effects on suppressing the vibrations of riser. Within and after lock-in region, riser with triangle and circular sections helical strakes have smaller lift force than that with rectangular section, which reduced lift coefficient by 65.83% and 83.53%. The trailing vortex structures of the riser with helical strakes are in strength three-dimensional character. Inside the lock-in region, riser with triangle and circular sections have better suppression effect than that with rectangular section. Outside the lock-in region, riser with triangle section helical strakes has the best vortex suppression effect, of which the influence on the flow field is greatest and the vortex-induced force is least.

关键词： Helical strakes Forced oscillation Lock-in Vortex-induced vibrations Suppression

来源：评论

学校读者我要写书评

暂无评论

Performance analysis of a novel household water purification system based on humidification-dehumidification principle

引用

DESALINATION 2019年 469卷 114099-000页

作者： Li, Kun Wu, Weidong Hu, Kun Wang, Li Hua, Ruoqiu Univ Shanghai Sci & Technol Sch Energy & Power Engnr Shanghai 200093 Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai 200093 Peoples R China

In order to avoid frequent cleaning and replacement of filters in the household membrane filtration water purifiers, a novel household water purification system based on the Humidification-Dehumidification (HDH) principle was proposed in this work. A heat pump (HP) unit was utilized in the system for both heating and cooling the closed circulating air. Experimental investigation was conducted by simulating annual working conditions of different water inlet temperatures (5 to 25 degrees C). The performance parameters including system operating conditions, power consumption, water production rate and pure water production per unit energy consumption were analyzed. The results showed that the system performance parameters had a close relationship with the water inlet temperature. The higher water inlet temperature would lead to larger power consumption but greater pure water production rate with a maximum of 692 g/h. The pure water production per unit energy consumption firstly rose and then declined with decreasing the water inlet temperature and reached a maximum of 1996.5 g/(kWh) at 15 degrees C. The pure water production rate of this system was not less than 580 g/h, which could meet the needs of general household drinking water, and the removal rate of the total dissolved solids (TDS) was up to 97%.

关键词： Humidification-Dehumidification (HDH) heat pump (HP) Pure water preparation Household Performance analysis

来源：评论

学校读者我要写书评

暂无评论

Influence of microcylinders with different vibration laws on the flow control effect of a horizontal axis wind turbine

引用

WIND ENERGY 2019年第12期22卷 1800-1824页

作者： Wang, Ying Li, Gaohui Luo, Dahai Huang, Diangui Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Univ Shanghai Sci & Technol Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai Peoples R China

Due to the flow separation on the blade of the NREL Phase VI wind turbine, a new flow control technique involving installation of an off-surface vibrating small structure is proposed. By considering the actual flow condition, fluid-solid coupling is applied in which two kinds of microcylinder vibration modes are set up, and the aerodynamic performance is numerically studied. The influence of the vibration modes, amplitude, and frequency of the off-surface vibrating small structure on the aerodynamic performance is explored. For various stall conditions, the flow separation can be well suppressed by utilizing a suitable vibrating microcylinder rather than a static microcylinder. In addition, the vibrating microcylinder shows a noticeable suppression effect on large flow separation. Both the vibration direction and vibration amplitude play leading roles in the improvement of the aerodynamic performance, and a microcylinder with a high vibration frequency can more quickly suppress surface flow separation to achieve an optimum aerodynamic performance than a microcylinder with a low vibration frequency. By setting microcylinders with suitable vibration rules close to the blade surface, the wind energy coefficient can be obviously increased compared with those obtained when adding a static microcylinder or without microcylinder addition.

关键词： aerodynamic performance flow control horizontal axis wind turbine simulation vibrating microcylinder

来源：评论

学校读者我要写书评

暂无评论

Macro assessment of microalgae-based CO2 sequestration: Environmental and energy effects

引用

ALGAL RESEARCH-BIOMASS BIOFUELS AND BIOPRODUCTS 2020年 51卷

作者： Zhao, Bingtao Su, Yaxin Univ Shanghai Sci & Technol Sch Energy & Power Engn 516 Jungong Rd Shanghai 200093 Peoples R China Univ Shanghai Sci & Technol Shanghai Key Lab Multiphase Flow & Heat Transfer 516 Jungong Rd Shanghai 200093 Peoples R China Donghua Univ Sch Environm Sci & Engn 2999 North Renmin Rd Shanghai 201620 Peoples R China

Microalgae are the most important types of bioenergy-producing and environmentally friendly media used in carbon sequestration, but the macro performance in carbon emission reduction has not yet been understood accurately. To assess the performance and the enviro-energy effect of microalgae-based CO2 sequestration, a comprehensive quadric surface-based logistic model was proposed to characterize the specific production rate of microalgae cultivated under varying key physicochemical factors, including input CO(2 )concentration, N-source concentration, P-source concentration, light intensity, and culture temperature. The effects of these factors were addressed based on the proposed model. The results indicate that the quadric surface-based logistic model predicts the specific production rate more accurately and effectively (R-2 = 0.9509) than the conventional multifactors Monod-Droop model. It enhances the generalization performance by including more influencing factors, considering the independent and interactive effects, and avoiding the possibility of negative values that occur in regular response surface methodology. Furthermore, the performances of microalgal-biomass yields and CO2 sequestration were determined. It is suggested that, theoretically, a maximum of 2.35 GtCO(2) can be sequestrated in 100,000 km(2) culture area, accounting for 8.01-5.31% of global CO2 emission reductions in 2020. On average, annual 0.5393 GtCO(2) sequestration and 324.33 million tons of microalgal-biomass yields would be benefited when using 53,000 km(2) culture area, even though the high economic performance for the microalgal-diesel conversion is challenging to achieve. Microalgae show a great potential in environmentally friendly CO2 mitigation by converting both atmospheric and industrial CO2 into biomass and bioenergy.

关键词： Microalgae Carbon dioxide sequestration Specific production rate Quadric surface-based logistic modeling Environmental and energy effects

来源：评论

学校读者我要写书评

暂无评论

Numerical and experimental investigation into the dynamic response of a floating wind turbine spar array platform

引用

JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY 2018年第3期32卷 1105-1116页

作者： Ding, Qinwei Li, Chun Yu, Nanting Hao, Wenxing Ji, Jie Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai Peoples R China Univ Plymouth Sch Engn Plymouth Devon England

The station keeping ability of a platform is the most fundamental guarantee to securing the dynamic stability of a Floating offshore wind turbine (FOWT) when being subjected to complex marine environment. These are usually evaluated in terms of rigid body dynamic response of a floating platform which supports whole FOWT. To investigate the dynamic response of array of FOWT, we put forward the concept of a large FOWT farm which consists of nine spar-type wind turbine array and meanwhile shares mooring line system by connecting those FOWT to one another. The whole FOWT is established based on OC3-Hywind spar buoy platform with NREL 5MW wind turbine. Considering effects of wind, wave and current loads, the dynamic response of the proposed FOWT was conducted based on FEM software ANSYS AQWA under both operational condition and survival condition. Besides, comparisons of dynamic response between the original single FOWT and the proposed FOWT farm were also made. Several interesting conclusions were gained through the investigation. For the original single FOWT, RAO in surge, heave and pitch are concentrated in low frequency, while the peak value of frequency is about 0.2 rad/s. In addition, FOWT (P1, P3, P7 and P9) located on the four vertices of 3x3 have higher sway motion which range from about -0.15 m similar to 0.15 m, while sway motion of the rest can be neglected. With the worsening of environmental condition, surge motion of the original single FOWT increases significantly, while it's not significant for the proposed FOWT farm. At the same time, statistic values of pitch motion of the proposed FOWT farm are quite close to those of the original single FOWT. While, under the survival condition, range of pitch motion of the proposed FOWT farm is significantly smaller than that of the original single FOWT. In all, the results verify the effectiveness of the proposed FOWT farm.

关键词： Floating offshore wind turbine (FOWT) Spar Motion Stability AQWA

来源：评论

学校读者我要写书评

暂无评论

Research on a high-accuracy dynamic test method of the rotor temperature field of an explosion-proof motor

引用

HIGH TEMPERATURES-HIGH PRESSURES 2020年第5-6期49卷 397-409页

作者： Zhao, Qiang Yuan, Yichao Guo, Junjie Tang, Chuansheng Wu, Xuandong Univ Shanghai Sci & Technol Sch Energy & Power Engn Jungong Rd 516 Shanghai 200093 Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer Jungong Rd 516 Shanghai 200093 Peoples R China Wolong Elect Nanyang Explos Protect Grp Co LTD Zhongjing Rd 22 Nanyang 473000 Peoples R China Nanyang Inst Technol Sch Mech & Automot Engn Changjiang Rd 80 Nanyang 473004 Peoples R China

To achieve high-accuracy dynamic rotor temperature measurement of an explosion-proof motor during operation, a novel measurement method with a new-type FBG (Fiber Bragg Grating) sensor, is proposed in this paper. First, a new kind of FBG temperature sensors which could be employed in the narrow and small spaces of a motor's air-gap with microsize sealing was developed. Experiments have shown that the designed sensor has a linearity of 0.999, and a repeatability of greater than 274.5 K within the range of 323 K-443 K. Second, a rotor temperature test system with designed sensor was built;the test results showed that the error between the test results and simulation results was less than 8%, which verified the feasibility and validity of the presented method. Furthermore, introducing an all-optical signal into the motor's measurement field, this method was characterized by good fitness, immunity to electromagnetic interference, good explosion-proof performance, high accuracy, dynamic measurement, etc. Therefore, this method could be widely applied to the motor measurement field.

关键词： Explosion-proof motor Temperature field Dynamic test Rotor temperature

来源：评论

学校读者我要写书评

暂无评论

New insights into aerodynamic characteristics of oscillating wings and performance as wind power generator

引用

INTERNATIONAL JOURNAL OF ENERGY RESEARCH 2018年第2期42卷 776-789页

作者： Sun, Xiaojing Zhang, Laichao Huang, Diangui Zheng, Zhongquan Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai 200093 Peoples R China Univ Kansas Dept Aerosp Engn Lawrence KS 66045 USA

In this paper, the effects of nondimensional frequency f*, pitch amplitude (0), and airfoil thickness on the energy extraction performance of an oscillating wing wind power generator were numerically investigated. It is found that the optimum value of f* or theta(0) exists to achieve the maximum energy efficiency. Additionally, the thickness of airfoil also significantly affects the efficiency and the flow patterns around the oscillating foil. For thin airfoils, a relatively large-scale vortex was normally generated at its leading edge. This vortex detached from leading edge might be able to be caught by the airfoil again and then reutilized to increase its work capacity. By contrast, no induced leading edge vortex is formed on the upper surface of a thick airfoil. Nevertheless, the pressure difference between the upper and lower surface of the oscillating thick airfoil is greater than that of thin airfoil. Thus, the portion of the output power contributed by the oscillatory heaving motion is greatly increased and high energy extraction efficiency can still be achieved. For airfoils with moderate thickness, both flow phenomena observed on thin and thick oscillating airfoils that have high wind energy utilization efficiency are all likely to occur, depending on the adopted motion parameters.

关键词： energy extraction efficiency numerical study oscillating-wing wind power generators performance affecting factors

来源：评论

学校读者我要写书评

暂无评论

Investigation on aerodynamic performance of horizontal axis wind turbine by setting micro-cylinder in front of the blade leading edge

引用

ENERGY 2018年 143卷 1107-1124页

作者： Wang, Ying Li, Gaohui Shen, Sheng Huang, Diangui Zheng, Zhongquan Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai 200093 Peoples R China Univ Kansas Aerosp Engn Dept Lawrence KS 66045 USA

For NREL Phase VI horizontal axis wind turbine, a flow control method to suppress the flow separation by setting micro-cylinder in front of the blade leading edge is proposed, and the corresponding numerical simulation analysis for the aerodynamic performance of wind turbine is conducted. Firstly, the results predicted by simulation are confirmed experimentally. Under the same operating condition, the simulation and experimental results of low-speed shaft torque are compared, along with results from other studies. It can be found that the simulation results can accurately reflect the basic physical characteristics of flow field for NREL Phase VI wind turbine. Secondly, the influence of different diameters and positions of micro-cylinders on aerodynamic performance of wind turbine is discussed. Numerical results suggest that under different stall conditions, setting appropriate micro-cylinders in front of the blade leading edge can effectively suppress flow separation on wind turbine blades without increasing the load of wind turbine. Moreover, under different wind speeds, micro-cylinders with different diameters and positions have various impacts on aerodynamic performance of wind turbine. Through numerical calculation, the blade torque can maximally have an increase of 273% by setting a micro-cylinder with proper diameter and position in front of the blade leading edge. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： Horizontal axis wind turbine flow separation Aerodynamic performance Micro-cylinder

来源：评论

学校读者我要写书评

暂无评论

Error Analysis of Liquid Holdup Measurement in Gas-Liquid Annular flow Through Circular Pipes Using High-Speed Camera Method

引用

Journal of shanghai Jiaotong university(Science) 2018年第S1期23卷 34-40页

作者： LIU Li BAI Bofeng School of Nuclear Science and Engineering Shanghai Jiao Tong University State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University

Accurate measurement of gas-liquid phase fraction is essential for the proper modelling of the pressure drop, heat transfer coefficient, mass transfer rate and interfacial area in two-phase flows. In this paper, taking the issue of optical distortion into account, an analytical model was proposed to estimate and correct the liquid holdup in gas-liquid annular flow through a circular pipe using high-speed camera method. The error in the liquid holdup measurement generated from different refractive indices among transparent circular pipe, liquid film and air core was firstly theoretically analyzed based on the geometric optics. Experimental tests were then carried out to identify the difference as well as to validate the proposed model. Results indicated that the prediction of the liquid holdup has a good performance with the experimental data(i.e., mean relative error is 4.1%) and the measured liquid holdup is larger than the real one. It was found that the measured liquid holdup is larger than the real one. Generally, when the real liquid holdup gets smaller, the discrepancy between the measured liquid holdup by image and the real liquid holdup becomes more significant. Thus, after measuring the liquid holdup from the images, the value of the measured liquid holdup must be corrected by the present model in order to obtain the real liquid holdup.

关键词： gas-liquid annular flow liquid holdup optical refraction analytical correction

来源：评论

学校读者我要写书评

暂无评论

Research on the Influence of Helical Strakes on Dynamic Response of Floating Wind Turbine Platform

引用

China Ocean engineering 2017年第2期31卷 131-140页

作者： DING Qin-wei LI Chun School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai 200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai 200093 China

The stability of platform structure is the paramount guarantee of the safe operation of the offshore floating wind turbine. The NREL 5MW floating wind turbine is established based on the OC3-Hywind Spar Buoy platform with the supplement of helical strakes for the purpose to analyze the impact of helical strakes on the dynamic response of the floating wind turbine Spar platform. The dynamic response of floating wind turbine Spar platform under wind, wave and current loading from the impact of number, height and pitch ratio of the helical strakes is analysed by the radiation and diffraction theory, the finite element method and orthogonal design method. The result reveals that the helical strakes can effectively inhibit the dynamic response of the platform but enlarge the wave exciting force; the best parameter combination is two pieces of helical strakes with the height of 15%D （D is the diameter of the platform） and the pitch ratio of 5; the height of the helical strake and its pitch ratio have significant influence on pitch response.

关键词： floating wind turbine platform helical strakes orthogonal design

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：