关键词： 数字游戏心流体验   学业能力   社会互动倾向  

摘要： 数字化游戏学习是兼顾教育严肃性与游戏趣味性的创新教学方式。为了让学生在学习中保持如同玩游戏般的投入,学生的心流体验极为重要。本研究探讨数字化游戏学习环境下影响学生心流体验的因素,依序检验学业能力与社会互动倾向带来的个别影响效果以及交互作用效果。研究者发展公民数字化游戏学习教学,并实施于中国台湾省的一所高中;共有126名高二学生纳入资料分析。研究结果显示学业能力与社会互动倾向对于学生数字化游戏学习过程中的心流体验具有交互作用影响,只有高学业能力的学生,社会互动才有助于游戏学习过程中心流体验的产生。本研究的结果修正过去的研究认为社会互动必然是心流体验来源的论述,且对于教师的教学活动安排,提出具有实证证据的指引。

关键词： 工程力学  

ISBN: (纸本)9787502472511

摘要： 本书共分为11章，详细阐述了流体力学的基本理论及其在环境领域的应用，主要内容包括：流体力学的基本概念，流体静力学，流体动力学基础，流体的流动阻力计算，有压管流与孔口、管嘴出流，渗流力学基础，流体机械：泵和风机，相似原理与量纲分析，大气污染扩散基础及应用，海洋石油污染运移分析及控制，二氧化碳封存流动理论基础及应用。本书每章末都附有相关习题，书末附有习题参考答案。

关键词： MAE   MSE   Optimum grid size determination   Salinity distribution   The Ara Canal   The CFL condition   3-D model EFDC  

摘要： This study analyzes guidelines to select optimum number of grids to represent behavior of a given water system appropriately. The EFDC model was chosen as a 3-D hydrodynamic and water quality model and salt was chosen as a surrogate variable of pollutant. The model is applied to an artificial canal that receives salt water from coastal area and fresh water from a river from respective gate according to previously developed gate operation rule. Grids are subdivided in vertical and horizontal (longitudinal) directions, respectively until no significant changes are found in salinity concentrations. The optimum grid size was determined by comparing errors in average salt concentrations between a test grid systems against the most complicated grid system. MSE (mean squared error) and MAE (mean absolute error) are used to compare errors. The CFL (Courant-Friedrichs-Lewy) number was used to determine the optimum number of grid systems for the study site though it can be used when explicit numerical method is applied only. This study suggests errors seem acceptable when both MSE and MAE are less than unity approximately.

关键词： Hydrokinetic energy conversion   Hydrokinetic turbine   Performance parameter   Reliability   Techno-economic   Environmental impact  

摘要： The hydrokinetic energy conversion system has capabilities to supply inevitable and secured power which is obtained from free stream like ocean, river, and man-made channel etc. So far, researchers have done different work on resource availability, design parameter, electricity generation cost, reactivity of plant, its impact on environmental separately. In this paper an attempt is made to review the technology, performance, design optimization, reliability, techno-economic analysis and environmental impact of the hydrokinetic energy conversion systems altogether to establish the relationship between the above said aspects towards the viability of power project. After conducting these reviews it has become clear that in order to avoid cavitation, coefficient of pressure should be less than cavitation coefficient especially at leading edge of hydrokinetic turbine blade. Moreover, to avoid stall and separation, angle of attack should be kept as less as possible. By implementing hydrofoil blade profile, performance of the hydrokinetic turbine can be improved. Sometimes, implementation of double blade hydrofoil may be beneficial and increase the coefficient of lift more than that of the single blade hydrofoil. Apart from the above considerations it is to be noted that deployment of turbine near bed level should be avoided as it brings down available power, increase hydrodynamic loading, turbulence level, and fouling by sediments. Moreover to increase the performance arm and end plate can be incorporated in hydrokinetic turbine design. It is also observed that hybrid conversion system is also viable in order to reduce power generation cost. This paper will help researchers to identify areas of design parameter of hydrokinetic turbine that need to improve and encourage the project developer, funding and financial institution, policy maker or government officials, and local community, to provide knowledge about hydrokinetic energy conversion system for executing the projec

关键词： 浮力系数   管柱单元   力学分析   管柱力学  

摘要： 通过对液压环境(即静流体作用)下的管柱进行离散分析,说明了现有模型在分析静流体对管柱单元作用力时的不足。采用微元法结合高斯公式对静流体下管柱单元的受力进行了分析,运用先补全,再减去所补面积的等效方法,得到了静流体对管柱单元侧面产生的作用力的理论计算方法。建立了液压环境下,静流体对任意管柱单元(直线单元或曲线单元)X、Y、Z方向作用力和浮力系数的理论计算模型。基于相关理论计算模型,结合ANSYS有限元进行模拟计算,得出了在水深300m^3000m处,30°和90°等曲率圆弧管柱的X、Y、Z方向作用力的理论计算结果与ANSYS模拟分析结果。相关结果对比表明:ANSYS有限元计算结果与理论计算结果间最大的绝对误差不足0.4%,验证了本文建立的理论计算模型的正确性。

关键词： 微重力   液氢   重力加速度   接触角   充液量  

摘要： 在重力场下,贮箱中流体的状态是已知的,流体状态是按规律分层分布的,而在微重力环境下,贮箱中流体状态是未知的,气相和液相的分布是不规则的,其界面的几何形状也是不确定的。通过采用VOF方法,对贮箱中的液氢在微重力条件下进行了数值模拟研究,主要考虑了不同重力加速度,接触角和不同充液量等因素的影响,从而得到在微重力条件下影响气液分布的主要因素。

关键词： 《流体力学》课程   实验教学   教学改革   建筑环境与能源应用工程  

摘要： 针对建筑环境与能源应用工程专业的发展形式和特点,结合我校的定位和学生培养目标,指出建筑环境与能源应用工程专业《流体力学》课程实验教学存在的问题,并提出了实验教学改革的建议。

关键词： Solid fuels combustion   Clean operation   Fluidized bed   Local scale   Model classification  

摘要： Purpose Fluidized bed combustion is currently intensively developed throughout the world to produce energy from several types of solid fuels, while significantly reducing pollutant emissions with respect to conventional combustion units. Accurate models must be formulated at both bed and particle levels to operate efficiently such units, since local phenomena such as particle temperature and combustion rate are crucial aspects for process improvement and control. In this sense, this article proposes a classification of local scale models to represent the evolution of char heterogeneous combustion of any carbonaceous particles. Methods Existing models are described and classified based on the characteristics of the governing equations, the thermal behavior of the gas and solid phases and the description of both the burning particle and the surrounding gas, under a heterogeneous or pseudo-continuous assumption. Criteria for choosing one model instead of others are also considered, depending on the case. The so-called Intrinsic Reactivity Models are described in detail for evaluating the pertinence of their simulated results. The use of CFD to build a simulation scheme of the solid combustion process at local scale is also presented and discussed. Results A complete description of the solid fuel burning process is given, along with useful information concerning the evolution of different variables, such as particle internal temperature that governs the reaction rate and gas composition. Conclusions This comparative analysis gives a strong basis to select the appropriate modeling approach. Finally, recommendations are proposed for model application and future development.

关键词： 东丽湖地区地热流体   地球化学特征   赋存环境   沧东断裂   天津市  

摘要： 东丽湖地区位于山岭子地热异常区中心地带,沧东断裂带之上,有3个热储层。其中,奥陶系与雾迷山组水质相似,水化学类型以Cl·HCO_3·SO_4-Na和Cl·SO_4·HCO_3-Na为主,矿化度1 400~1 750mg/L,为部分平衡水;而明化镇组以HCO3·Cl-Na为主,矿化度1 500mg/L,为完全平衡水。地热流体γ(Na)/γ(Cl)均较高,二氧化碳分压(pco2)为10^(-1.98)~10^(-2.7) Mpa,地下水碳酸平衡具有开系统的特征。流体中方解石、白云石、文石处于微饱和状态。深部奥陶系水质与雾迷山组热储温度适合用玉髓温标计算,而浅部明化镇组热储温度则用Na-K温标计算。东丽湖奥陶系与雾迷山组连通性较好,垂向上对流强烈。明化镇储层局部地区受到了基岩裂隙型地热流体的垂向补给。

关键词： 微流体   流容   等效电路理论   动态响应   带通滤波器  

摘要： 要充分理解并利用微流体系统中流体的流动,需要对流体的动态特性有全面的了解。目前,流感与流阻的计算已经被大家熟知,可流容的计算仍是一个难点。本文设计了一个微流体流容器件,提出了测量微流体系统流容特性的方法。流容器件由圆形截面的一段玻璃管和一段弹性管组成。基于微流体等效电路理论我们对器件模型进行分析,仿真实验了系统在恒压和动态压强下不同的响应情况。利用恒压驱动的衰减振荡结果拟合出弹性流道的流容值,并与动态压强输入模型的共振响应结果进行了对比验证。结果证明,仿真结果与理论分析一致,拟合的流容值正确,提出的分析方法正确。整个模型的动态响应特性与电路中的带通滤波器类似。