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有声腔推力室的声学振型及其阻尼特性研究
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作者 覃建秀 张会强 《推进技术》 EI CAS CSCD 北大核心 2021年第7期1483-1492,共10页
为确定多声学模态压力振荡条件下带有1/4波长管声腔推力室的声学振型及其阻尼特性,揭示1/4波长管声腔对推力室压力振荡的抑制作用机理,对有声腔推力室和无声腔推力室进行近圆周壁面的定容弹激励仿真,激发了多模态的声学振型,给出了推力... 为确定多声学模态压力振荡条件下带有1/4波长管声腔推力室的声学振型及其阻尼特性,揭示1/4波长管声腔对推力室压力振荡的抑制作用机理,对有声腔推力室和无声腔推力室进行近圆周壁面的定容弹激励仿真,激发了多模态的声学振型,给出了推力室压力分布的时空演化,并采用半带宽法定量评价每个激发声学振型的阻尼特性。结果表明:1/4波长管声腔成功抑制了目标振型(一阶切向振型)压力振荡,大幅度减小其幅值,而不是大幅度增加其半带宽,但可能增强其它非目标振型的压力振荡。声腔通过削弱目标振型波峰波谷压力差、声腔入口漩涡和增加壁面面积等三种方式来抑制目标振型压力振荡,主要以前者为主,前者旨在降低目标振型幅值,后两者是增加其半带宽。 展开更多
关键词 1/4波长管声腔 推力室 声学振型 阻尼特性 抑制作用 数值定容弹
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推力室状态对其声学振型及其阻尼特性的影响
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作者 覃建秀 张会强 《航空动力学报》 EI CAS CSCD 北大核心 2020年第11期2449-2455,共7页
为确定工程中冷态条件下获得的推力室声学特性能否表征真实条件下的声学特性,研究了冷态无流动、热态气相流动和湍流两相燃烧三种状态下推力室声学振型及其阻尼特性。在推力室稳态流场中的有限区域施加数值定容弹,激发其具有多模态声学... 为确定工程中冷态条件下获得的推力室声学特性能否表征真实条件下的声学特性,研究了冷态无流动、热态气相流动和湍流两相燃烧三种状态下推力室声学振型及其阻尼特性。在推力室稳态流场中的有限区域施加数值定容弹,激发其具有多模态声学振型的大幅值压力振荡,采用衰减时间和半带宽来定量评价所激发的不同声学振型压力振荡衰减快慢,进而获得其阻尼特性。在相同过载比的数值定容弹激励下,在冷态条件下能激发包含更多声学振型压力振荡,且该振荡衰减时间更长,相同振型压力振荡衰减比热态条件下慢。在冷态条件下,一阶切向振型振幅最大,为最容易被激发声学振型;一阶纵向振型半带宽最小,为最难衰减的振型。在热态条件下,一阶纵向振型为最容易激发声学振型,也为最难衰减声学振型。从所激发的主要振型及其相对衰减的快慢来看,冷态条件下获得的声学特性能够表征真实条件下的推力室的声学特征。 展开更多
关键词 推力室 数值定容弹 压力振荡 声学振型 阻尼特性
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基于数值定容弹方法的燃烧室声学特性研究 被引量:5
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作者 覃建秀 张会强 王兵 《推进技术》 EI CAS CSCD 北大核心 2018年第2期366-373,共8页
为确定给定构型燃烧室最容易激发的声学振型,提出了能够实现大幅值非特定频率的"数值定容弹"模型。圆柱体内声学振型频率的预测值与理论结果偏差在7%以内。对姿轨控发动机推力室进行了数值定容弹激励,给出了推力室压力分布的... 为确定给定构型燃烧室最容易激发的声学振型,提出了能够实现大幅值非特定频率的"数值定容弹"模型。圆柱体内声学振型频率的预测值与理论结果偏差在7%以内。对姿轨控发动机推力室进行了数值定容弹激励,给出了推力室压力分布的时空演化,获得了多声学模态压力振荡及其最容易激发的声学振型。进一步研究了收缩比对推力室声学特性的影响。结果表明:随着收缩比增大,一阶和二阶切向声学振型的幅值增加,但对应的频率基本保持不变;而一阶纵向和一切-一纵声学振型的幅值减小,但对应的频率增大,当收缩比较大时,一阶纵向和一切-一纵声学振型消失。可见,与短粗构型相比,细长推力室构型有利于抑制切向声学振型。 展开更多
关键词 压力振荡 数值定容弹方法 声学频率 声学振型 燃烧室
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基于数值定容弹方法的推力室阻尼特性研究 被引量:1
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作者 覃建秀 张会强 《推进技术》 EI CAS CSCD 北大核心 2019年第7期1577-1584,共8页
为确定推力室的声学振型频率及其阻尼特性,给出推力室最容易激发声学振型和最难衰减声学振型,建立了基于数值定容弹和半带宽法的推力室声学振型及其阻尼特性的数值模拟方法。对小推力姿轨控发动机推力室进行近圆周壁面的定容弹激励仿真... 为确定推力室的声学振型频率及其阻尼特性,给出推力室最容易激发声学振型和最难衰减声学振型,建立了基于数值定容弹和半带宽法的推力室声学振型及其阻尼特性的数值模拟方法。对小推力姿轨控发动机推力室进行近圆周壁面的定容弹激励仿真,激发出了多模态的声学振型,其中,一阶切向振型为最容易激发振型,而一阶纵向振型为最难衰减振型。进一步讨论了推力室构型参数对其阻尼特性的影响,结果表明:随推力室内径增大,纵向振型得到抑制,而切向振型变得不易衰减;随推力室收缩比增加,一阶切向振型半带宽先增大后保持不变;随推力室圆柱段长度增加,各振型半带宽没有明显的变化趋势。 展开更多
关键词 压力振荡 声学振型 定容弹 阻尼特性 半带宽
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Surface roughness prediction model in ultrasonic vibration assisted grinding of BK7 optical glass 被引量:9
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作者 ZHAO Pei-yi ZHOU Ming +1 位作者 ZHANG Yuan-jing QIAO Guo-chao 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第2期277-286,共10页
Pre-knowledge of machined surface roughness is the key to improve whole machining efficiency and meanwhile reduce the expenditure in machining optical glass components.In order to predict the surface roughness in ultr... Pre-knowledge of machined surface roughness is the key to improve whole machining efficiency and meanwhile reduce the expenditure in machining optical glass components.In order to predict the surface roughness in ultrasonic vibration assisted grinding of brittle materials,the surface morphologies of grinding wheel were obtained firstly in the present work,the grinding wheel model was developed and the abrasive trajectories in ultrasonic vibration assisted grinding were also investigated,the theoretical model for surface roughness was developed based on the above analysis.The prediction model was developed by using Gaussian processing regression(GPR)due to the influence of brittle fracture on machined surface roughness.In order to validate both the proposed theoretical and GPR models,32sets of experiments of ultrasonic vibration assisted grinding of BK7optical glass were carried out.Experimental results show that the average relative errors of the theoretical model and GPR prediction model are13.11%and8.12%,respectively.The GPR prediction results can match well with the experimental results. 展开更多
关键词 surface roughness prediction model ultrasonic vibration optical glass GPR regression
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Entanglement Dynamics of Two-Qubit System in Different Types of Noisy Channels 被引量:1
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作者 SHAN Chuan-Jia LIU Ji-Bing CHENG Wei-Wen LIU Tang-Kun HUANG Yan-Xia LI Hong 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第6期1013-1016,共4页
In this paper, we study entanglement dynamics of a two-qubit extended Werner-like state locally, interacting with independent noisy channels, i.e., amplitude damping, phase damping, and depolarizing channels. We show ... In this paper, we study entanglement dynamics of a two-qubit extended Werner-like state locally, interacting with independent noisy channels, i.e., amplitude damping, phase damping, and depolarizing channels. We show that the purity of initial entangled state has direct impacts on the entanglement robustness in each noisy channel. That is, if the initial entangled state is prepared in mixed instead of pure form, the state may exhibit entanglement sudden death (ESD) and/or be decreased for the critical probability at which the entanglement disappear. 展开更多
关键词 entanglement dynamics entanglement sudden death PURITY
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Optimization of uncertain acoustic metamaterial with Helmholtz resonators based on interval model 被引量:1
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作者 XIA BaiZhan QIN Yuan +2 位作者 CHEN Ning Yu DeJie JIANG Chao 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2017年第3期385-398,共14页
In summary,the interval uncertainty is introduced to the acoustic metamaterial with Helmholtz resonators.And then,new descriptions(the conservative approximation,the unsafe approximation and the approximation precisio... In summary,the interval uncertainty is introduced to the acoustic metamaterial with Helmholtz resonators.And then,new descriptions(the conservative approximation,the unsafe approximation and the approximation precision)on uncertainties of physical properties of this interval acoustic metamaterial are defined.Lastly,an optimization model for this interval acoustic metamaterial is proposed.The organization of this paper is listed as follows.The acoustic transmission line method(ATLM)for an acoustic metamaterial with Helmholtz resonators is described in Section 2.In Section3,uncertain analysis of the interval acoustic metamaterial is presented.In Section 4,optimization model of the interval acoustic metamaterial is proposed.The discussion on optimization results is shown in Section 5.In section 6,some conclusions are given. 展开更多
关键词 acoustic metamaterial sound intensity transmission coefficient negative effective bulk modulus interval model optimization
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