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分子热运动揭示的传递现象
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作者 孙志仁 《化工高等教育》 2020年第2期141-146,共6页
作者利用三维分子热运动模型统计得到分子热运动平均速度和分子平均自由程,以及分量和总量之间的关系;运用传递通量概念,推导动量通量、热量通量和质量通量表达式,并与牛顿黏性定律、傅立叶导热定律和费克分子扩散定律进行对比,获得了... 作者利用三维分子热运动模型统计得到分子热运动平均速度和分子平均自由程,以及分量和总量之间的关系;运用传递通量概念,推导动量通量、热量通量和质量通量表达式,并与牛顿黏性定律、傅立叶导热定律和费克分子扩散定律进行对比,获得了气体动力学理论结论。 展开更多
关键词 分子热运动 统计模型 分子热运动平均速度 分子平均自由程 传递通量
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特定辐照度下均匀辐射的红外星模拟器光学系统设计 被引量:1
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作者 郑茹 李长余 +3 位作者 高越 李光茜 刘博 孙阔 《光子学报》 EI CAS CSCD 北大核心 2022年第4期16-24,共9页
为实现星光定向仪地面标定工作,同时满足辐射均匀性、特定辐照度和光谱三项模拟要求,提出了特定辐照度下均匀辐射的红外星模拟器光学系统设计方案。根据辐照度模拟要求和均匀辐照要求,建立光源系统辐通量传递模型,设计了满足辐射光谱要... 为实现星光定向仪地面标定工作,同时满足辐射均匀性、特定辐照度和光谱三项模拟要求,提出了特定辐照度下均匀辐射的红外星模拟器光学系统设计方案。根据辐照度模拟要求和均匀辐照要求,建立光源系统辐通量传递模型,设计了满足辐射光谱要求的均匀辐射光源系统。结合星光定向仪和红外星模拟器的对接要求,设计了具有高成像质量的透射式准直光学系统。结合设计结果,利用Tracepro软件对光学系统进行建模,仿真分析光源系统辐射面和光学系统出口处的辐照度和辐照均匀性,并利用辐照计对光源辐射面辐照度和均匀性进行实验测试,验证理论分析的准确性。实测结果表明,光源辐射面的辐照度达到指标要求,辐照不均匀度为2.75%,满足红外星模拟器研制要求。 展开更多
关键词 红外星模拟器 通量传递模型 Tracepro软件 准直光学系统 辐照均匀性
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不同磷水平下雷竹幼苗叶绿素荧光特性 被引量:7
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作者 郭安娜 桂仁意 +2 位作者 宋瑞生 潘月 戎洁庆 《浙江农林大学学报》 CAS CSCD 北大核心 2013年第1期9-14,共6页
为了解不同磷水平下雷竹Phyllostachys violascens幼苗叶片叶绿素荧光特性的变化,试验以无性繁殖的雷竹幼苗作为试验材料,采用砂培试验方法,研究了不同磷水平(0,0.5,5.0,50.0,500.0 mg.L-1)对雷竹幼苗叶绿素荧光参数和光通量密度-光... 为了解不同磷水平下雷竹Phyllostachys violascens幼苗叶片叶绿素荧光特性的变化,试验以无性繁殖的雷竹幼苗作为试验材料,采用砂培试验方法,研究了不同磷水平(0,0.5,5.0,50.0,500.0 mg.L-1)对雷竹幼苗叶绿素荧光参数和光通量密度-光合电子传递速率(PAR-ETR)响应曲线的影响。结果表明,随着磷质量浓度的升高,幼苗叶片潜在光化学活性(Fo/Fm)呈逐渐降低趋势,最大光化学效率(Fv/Fm)在0~50.0 mg.L-1磷质量浓度范围内逐渐下降。磷质量浓度为5.0 mg.L-1时,初始荧光(Fo),最大荧光(Fm),适时最小荧光(Ft)和可变荧光(Fv)均达到最大值,电子传递速率(ETR)和光系统Ⅱ(PSⅡ)实际光化学效率(Y)较大,光化学猝灭系数(qP)和非光化学猝灭系数(qN和NPQ)相对较低,说明在5.0 mg.L-1磷质量浓度下,雷竹幼苗叶片的光合能力较强,接近适宜雷竹幼苗生长的磷质量浓度。磷质量浓度过高(50.0和500.0 mg.L-1)均导致雷竹幼苗叶片ETR下降,热耗散增加,光化学效率和光量子产额降低。 展开更多
关键词 植物生理学 雷竹 叶绿素荧光 通量密度-光合电子传递速率(PAR-ETR)响应曲线
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模糊数学在建筑物理中的应用
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作者 陈仲林 《重庆建筑工程学院学报》 CSCD 1989年第1期119-123,共5页
本文从光通量定义出发,用模糊数学中的模糊随机事件的概率,研究了室内表面相互反射后获得的光通量增量这个模糊观象,建议了一种计算光通量传递的新途径。
关键词 模糊数学 建筑物理 通量传递
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Mixed convective heat and mass transfer analysis for peristaltic transport in an asymmetric channel with Soret and Dufour effects 被引量:5
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作者 F.M.Abbasi A.Alsaedi T.Hayat 《Journal of Central South University》 SCIE EI CAS 2014年第12期4585-4591,共7页
The present investigation addresses the simultaneous effects of heat and mass transfer in the mixed convection peristaltic flow of viscous fluid in an asymmetric channel. The channel walls exhibit the convective bound... The present investigation addresses the simultaneous effects of heat and mass transfer in the mixed convection peristaltic flow of viscous fluid in an asymmetric channel. The channel walls exhibit the convective boundary conditions. In addition, the effects due to Soret and Dufour are taken into consideration. Resulting problems are solved for the series solutions. Numerical values of heat and mass transfer rates are displayed and studied. Results indicate that the concentration and temperature of the fluid increase whereas the mass transfer rate at the wall decreases with increase of the mass transfer Biot number. Furthermore, it is observed that the temperature decreases with the increase of the heat transfer Biot number. 展开更多
关键词 peristaltic transport heat and mass transfer Soret and Dufour effects convective boundary conditions
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Relative Flow Analysis around Passing-Train in the Single-Bore Subway Tunnel with Vertical Ventilation Using Moving IBM 被引量:1
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作者 Yong-Jun Jang 《Journal of Energy and Power Engineering》 2014年第8期1482-1486,共5页
Moving IBM (immersed boundary method) is applied to analyze the relative motion of railway car flow in the single-bore subway tunnel with vertical ventilation. The tested car body is modeled by cylinder type body. T... Moving IBM (immersed boundary method) is applied to analyze the relative motion of railway car flow in the single-bore subway tunnel with vertical ventilation. The tested car body is modeled by cylinder type body. The subway tunnel is assumed to be the single-car-passing straight type (single-bore tunnel). The modeled car is relatively moved forward. On the other hand, the tunnel and vertical ventilation are fixed. The momentum equations are solved by LES (large eddy simulation) method. The initial condition of fluid in the subway tunnel is stationary. The Reynolds number is 1,500 based on the cylinder radius. The turbulent flow field in the subway tunnel and vertical ventilation shaft are to be qualitatively investigated. 展开更多
关键词 Moving IBM LES subway tunnel vertical ventilation FDS (fire dynamics simulator)
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Deterioration in Heat Transfer of Endothermal Hydrocarbon Fuel 被引量:10
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作者 Weixing Zhou Wen Bao Jiang Qin Yunfeng Qu 《Journal of Thermal Science》 SCIE EI CAS CSCD 2011年第2期173-180,共8页
Numerical studies under supercritical pressure are carried out to study the heat transfer characteristics in a single-root coolant channel of the active regenerative cooling system of the scramjet engine, using actual... Numerical studies under supercritical pressure are carried out to study the heat transfer characteristics in a single-root coolant channel of the active regenerative cooling system of the scramjet engine, using actual physical properties of pentane. The relationships between wall temperature and inlet temperature, mass flow rate, wall heat flux, inlet pressure, as well as center stream temperature are obtained. The results suggest that the heat transfer deterioration occurs when the fuel temperature approaches the pseudo-critical temperature, and the wall temperature increases rapidly and heat transfer coefficient decreases sharply. The decrease of wall heat flux, as well as the increase of mass flow rate and inlet pressure makes the starting point of the heat transfer deterioration and the peak point of the wall temperature move backward. The wall temperature increment induced by heat transfer deterioration decreases, which could reduce the severity of the heat transfer deterioration. The relational expression of the heat transfer deterioration critical heat flux derives from the relationship of the mass flow rate and the inlet pressure. 展开更多
关键词 supercritical pressure PENTANE heat transfer deterioration numerical study
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