检索结果-南通市图书馆

Dynamic performance and temperature rising characteristic of a high-speed on/off valve based on pre-excitation control algorithm

引用

Chinese Journal of Aeronautics 2023年第10期36卷 445-458页

作者： Qi ZHONG Enguang XU Geng XIE Xiele WANG Yanbiao LI College of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310023China Key Laboratory of Special Purpose Equipment and Advanced Processing Technology Ministry of Education and Zhejiang ProvinceZhejiang University of TechnologyHangzhou 310023China

High speed on/off valve(HSV)is an essential component in aerospace digital hydraulic systems(ADHS).Dynamic performance and temperature rising characteristic are two important features,which determine the performance of HSV,and affect the response speed and reliability of *** the driving voltage is an effective method for improving the dynamic performance of ***,continuous high voltage excitation will lead to more wasted energy,higher temperature rising and lower *** solve this problem,a pre-excitation control algorithm(PECA)is proposed in this paper based on the theoretical model of the influence of electrical parameters on dynamic performance and temperature rising *** PECA,an appropriate initial coil current is generated by pre-excitation instead of increasing driving voltage,which significantly shortens the switching delay ***,based on real-time current online calculation and feedback mechanism,the adaptive switching of five equivalent voltages is ***,the coil current can be rapidly kept at the expected state without consuming more energy and generating more *** indicate that compared with conventional PWM control algorithm,the PECA can improve dynamic performance of HSV,shorten the total switching time by 71.5%,and increase the maximum operation ***,the linear area of flow characteristic is expended by 80.0%,the adjusting time of HSV-controlled system is reduced by 23%,while shortening steady error by 46.7%.Moreover,the temperature rising characteristics of HSV are better,the maximum operation temperature is reduced by 68.6%,and the time to reach the steady state temperature is shortened by 20%.From the results,it can be concluded that the PECA is not only an effective and practical control algorithm for improving the performance of HSVs and HSV-controlled systems while reducing the heat generation and decreasing the temperature rising of HSV,but also can be a potentia

关键词： High speed on/off valve Dynamic performance Pre-excitation temperature rising Flow characteristic

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Response of N_2O Emissions of Farmland Ecosystem on temperature rising

引用

Agricultural Science & Technology 2012年第9期13卷 1962-1966页

作者：刘柳松施建成中国科学院遥感应用研究所北京100101

[Objective] The aim was to study on response of N2O emissions of farm- land ecosystem on temperature rising. [Methed] In farmland ecosystem in Huaibei City in Anhui Province, N2O emission by twelve varieties of crop on temperature was researched with DeNitrification-DeComposition （NDC）. [Result] Response of dry- land crop on temperature rising can be divided into three categories, as follows： The first category, N2O emission of crop changed little during the temperature increasing, for example, from 0 to 3 %;, the emissions by potatoes, cotton, maize and rapeseed increased little and decreased little when temperature changed from 1.5 to 3 ℃. Crops of the second category declined with temperature increasing in N2O emission, for example, N2O emission decreased by 8.1% with temperature increasing from 0 to 3 ℃, including sugar cane, tobacco, wheat, soybean and pea. In third category, N2O emission of crop grew with temperature increasing, for example, the emission of rice, vegetables and fruit trees increased by 22.8% when the temperature grew from 0 to 3 ℃. [Conclusion] The research indicated that N2O emission in ecosystem of drv farmland increased little with temoerature risina.

关键词： Arid land Farmland ecosystem N20 emission temperature rising

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Sensitivity analysis of reservoir risk in marine gas hydrate drilling

引用

Petroleum 2021年第4期7卷 427-438页

作者： Wantong Sun Jun Pei Na Wei Jinzhou Zhao Jin Xue Shouwei Zhou Liehui Zhang Bjørn Kvamme Qingping Li Haitao Li Lin Jiang Chao Zhang Cong Li State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500China State Key Laboratory of Natural Gas Hydrate Beijing100027China CNOOC Research Institutes Limited Liability Company Beijing100027China Southern Marine Science and Engineering Guangdong Laboratory(Zhanjiang) Zhanjiang524013China

It is easy to change the original temperature state of marine gas hydrate reservoir by drilling,which leads to uncontrollable decomposition of gas hydrate and release of large amount of *** decomposition gas will further escape and expand,and the reservoir will break and collapse due to its weak cementation characteristic,which will easily lead to a series of other potential ***,in this study,based on the drilling process of marine gas hydrate,we establish the theoretical model and numerical calculation method of wellbore temperature field,analyze the influence on wellbore temperature of drilling fluid displacement,density,viscosity and injection temperature,and seawater *** the sensitivity laws of reservoir risk in marine gas hydrate drilling are *** results show that with the increase of drilling fluid displacement,density,viscosity and injection temperature,the temperature in lower well section and bottom hole will increase,making the increasing amplitude of temperature in hydrate reservoir larger and the scope of influence on hydrate reservoir stability ***,drilling is more likely to raise the temperature of reservoirs in shallow seawater depth,posing greater ***,engineering measures to avoid risks caused by rising reservoir temperature in marine gas hydrate reservoir drilling are *** study is of great significance to ensure the safety of marine gas hydrate reservoir drilling.

关键词： Marine gas hydrate Drilling temperature rising Reservoir risk Sensitivity analysis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

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

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

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

在线全文

在线全文

在线全文

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：