中英双语教学背景下学期大作业对本科生学习的提升作用

中英双语学期大作业是双语课程传热与流体流动的数值计算的核心教学任务。此研究以2013、2014和2015三届学生作为研究对象,通过统计连续三年的教学数据,详细分析了英语课程大作业对促进理工科学生学习效果的提升作用。研究表明,布置英语学期大作业后,学生的英语科技学术论文写作和口语表达水平明显提高,课堂互动提问水平有了明显提升,课堂参与度不断提高,参与英语大作业的学生比不参与的学生有更明显的进步。学生反馈及教学实践效果表明,设计优良的英语学期大作业促进了双语教学水平的提升,对本科生的双语学习效果产生了明显的催化作用

Predictive Study of Bubble Mean Diameter in Subcooled Flow Boiling

通道内截面汽泡平均直径是计算两相流相间界面传递方程以及计算汽液相界面浓度的重要参数。综合考虑过冷沸腾工况下汽泡动力学、两相热力学以及汽泡聚合效应; 对通道内汽泡尺寸的影响,提出过冷沸腾通道内截面汽泡平均直径预测模型。将该模型与实验数据进行比较,预测值与实验值偏差12.5%。Bubble mean diameter is a key parameter to calculate the interfacial; transfer equation of two phase flow and interfacial concentration.; Taking into account the effects of both the thermal, hydrodynamic; conditions and bubble coalescence rate on the mean bubble size in the; channel, a model has been developed. The proposed model agreed well with; the experimental data within the averaged relative deviation of 12.5%.福建省自然科学基

涡轮机械转子在二氧化碳工质中风摩损耗的数值分析

在超临界二氧化碳布雷顿循环系统设计中，为提高系统能量转换效率，需要准确预测风摩损耗。风摩损耗大小与转子转速，转子几何结构，工质状态密切相关。本文针对2 MPa二氧化碳工质中，高转速（23 000 r/min）转子的风摩损耗特性进行数值计算分析。研究结果表明：转子粗糙高度对超临界二氧化碳布雷顿循环系统中高转速以及可能出现的较高压力工况下的风摩损耗具有显著影响。已有风摩损耗经验关系式未考虑粗糙度的影响，直接使用可能带来较大误差。风摩损耗随着转子粗糙高度的增加而增加，随转子转速的增加而增加，气腔间距的变化对风摩损耗不会造成明显影响。厦门大学能源学院发展基金(2018NYFZ01

超临界二氧化碳再压缩布雷顿循环变工况特性分析

超临界二氧化碳再压缩布雷顿循环是高效紧凑的能量转换方式。目前许多研究在分析循环的特性时,常假设压缩机和透平的效率为恒定,该假设与实际情况差别很大。本文使用MODELICA作为工具,建立了超临界二氧化碳再压缩布雷顿循环模型。对于压缩机和透平,加入了真实压缩机和透平的特性曲线模型。通过模拟计算发现,循环输入功率和循环流量的改变将对循环火用效率和各组件的火用损产生影响。循环偏离设计工况时,适当控制输入功率和循环流量可调节循环输出功率和火用效率。福建省自然科学基金资助项目(2016J05020,2016J05137

Analysis of Levelized Cost of Electricity for Travelling Wave Reactor

本文通过平准化发电成本的方法,以燃料循环作为研究对象,对行波堆一次通过式燃料循环和二次通过式燃料循环的经济性进行了研究,并选取10个重要的经济和技术参数进行成本敏感性分析。研究结果表明,行波堆的平准化发电成本低于现有压水堆和快堆,其中,行波堆一次通过式燃料循环方式的平准化发电成本最低。敏感性分析表明,贴现率、燃耗深度、隔夜价和反应堆热效率是影响行波堆经济性最重要的参数,而燃料价格和废物处置的价格由于占成本的比例较小,对行波堆经济性的影响不大。Based on levelized cost of electricity(LCOE)method,the fuel cycle was selected as the object of the study,the economics of once-through fuel cycle and twicethrough fuel cycle for travelling wave reactor(TWR)was studied.Ten important economic and technical parameters were proposed for the sensitivity analysis.The results show that the LCOE of TWR is lower than that of conditional light water reactor and fast reactor.Furthermore,the LCOE of once-through fuel cycle of TWR is lower than that of twice-through cycle.The sensitivity analysis indicates that the discount rate,burn-up,overnight cost and thermal efficiency impact the LCOE severely,while the price of uranium and the cost of waste disposal barely impact the LCOE.厦门大学校长基金资助项目(20720150095

一种磺化聚醚醚酮基复合离子交换膜及其制备方法

本发明公开了一种聚醚醚酮基复合离子交换膜，该复合离子交换膜以聚醚醚酮为基体，在其中掺杂占磺化聚醚醚酮基体质量0.5%～20%的SO42-/MxOy型固体超强酸，通过SO42-/MxOy型固体超强酸的协同作用，在保证复合离子交换膜具有良好的机械性能和较低的甲醇渗透率的同时，有效提高了该复合离子交换膜的质子导电率，因此能够作为一种性能优良的新能源材料，在诸如电解制备装置、氯碱工业、电渗析、化学催化、气体分离等技术领域具有良好的应用前景

Flow Inversion Mechanism in the Primary Side of an Inverted U-tube Steam Generator Under Natural Circulation

在自然循环工况下,倒U型管蒸汽发生器(UTSG)的进出口存在负压降,使得UTSG内的部分倒U型管易发生倒流现象.针对特定的UTSG,定量地建立倒; U型管进出口压差随一次侧质量流量变化的水动力曲线,并采用最佳估算程序Relap5对UTSG进行建模分析.针对同一给定的自然循环工况,分别采用UT; SG入口总质量流量从高到低和从低到高两种质量流量加载方式趋近.研究发现,自然循环工况的质量流量加载方式对UTSG倒流的发生有显著影响;从低到高的; 质量流量加载方式会导致更多倒U型管发生倒流,产生更大的流动阻力;在其他运行参数相同的情况下,UTSG倒流反转为正流的临界质量流量远高于正流反转为; 倒流的临界质量流量;采用从高到低的质量流量加载方式到达自然循环工况更有利于避免UTSG倒流的发生.For natural circulation,it is shown that the negative drop of pressure; in the primary side of a inverted U-tube steam generator(UTSG)caused by; the density difference of the fluid inside may result in reverse flows; within some inverted U-tubes.A model of a given UTSG with nine parallel; U-tubes is established using the best estimate code Relap5.Two; conditions with different UTSG inlet mass flow rate loading methods are; compared.Results show that mass flow rate loading methods significantly; affect UTSG reverse flow phenomenon.Approaching the natural circulation; by decreasing the inlet mass flow rate leads to less reverse flow; U-tubes and flow resistance than increasing the inlet mass flow rate; from zero.And the critical mass flow rate of flow inversion for the; former condition is smaller than that for the later.In; conclusion,reaching natural circulation by decreasing inlet mass flow; rate of UTSG may avoid reverse flow.福建省自然科学基

Numerical Analysis of Reverse Flow in Inverted U-tube of Steam Generator Under Natural Circulation

在自然循环工况下,倒U型管蒸汽发生器(inverted U-tube steam; generator,UTSG)内有部分倒U型管会发生倒流现象,严重影响一回路系统的自然循环能力.采用计算流体力学(computational; fluid; dynamics,CFD)方法对自然循环工况下UTSG一次侧流体的流动特性进行三维数值模拟研究.结果表明:在低质量流量下,倒流集中发生在短管侧,; 而等长倒U型管中同时出现了倒流和正流的现象,这与入口腔室分配给各个倒U型管的初始质量流量有关.随着UTSG入口质量流量的增加,UTSG倒流管数减; 少;随着一次侧入口温度的升高,UTSG进出口压降为负值,压降绝对值逐渐增大,倒流管数增多.Under natural circulation condition,reverse flow occurs within some; tubes in inverted U-tube steam generator (UTSG), which can seriously; influence the capacity of natural circulation of primary loop system.In; this study,the computational fluid dynamics (CFD) method is used to; simulate the primary side, flow characteristics of UTSG under natural; circulation condition.The results show that at a low mass flow; rate,reverse flow mostly occurs at the short pipe side, while reverse; flow as well as normal flow simultaneously occur in equal length; U-tubes.This phenomenon is related to the initial mass flow rate; assigned to each inlet tube by the inlet chamber.The less the initial; mass flow rate is,the more likely the reverse flow occurs.With the; increase of the inlet mass flow rate of UTSG,the number of the reverse; flow pipes of UTSG is reduced.With the increase of the primary inlet; temperature,the pressure drop of UTSG is negative,the absolute value of; the difference of pressure increases gradually,and the number of the; reverse flow tubes increases.福建省自然科学基

基于Matlab遗传算法工具箱的同心式磁力齿轮优化设计

运用全局解析法对同心式磁力齿轮电磁场、电磁转矩进行分析和计算,在此基础上,利用Matlab优化工具箱中的遗传算法对其优化设计。实验结果表明,基于Matlab遗传算法工具箱的同心式磁力齿轮优化设计方法得到了令人满意的结果,并为同心式磁力齿轮的分析和设计提供了一个新的途径。这对同心式磁力齿轮的研究及应用具有重要意义

Modeling and Analysis of Nuclear Reactor System Using Supercritical-CO_2 Brayton Cycle

超临界二氧化碳(S-CO2)有可能作为循环工质应用于第四代核能系统中的3种快中子反应堆系统和当前常见商用反应堆系统内.使用工程等式求解器(EngInEErIng EQuATIOn SOlVEr,EES)工具,对S-CO2布雷顿循环进行了理论建模和分析.其中,针对系统中的重要部件换热器,进行了较为详细的建模.分析了S-CO2布雷顿循环系统的循环热效率,并与核工业中常用的循环工质进行对比.结果表明,S-CO2作为循环工质在特定的温度下具有较高的热转化效率.同时,针对不同的反应堆类型,对比分析S-CO2布雷顿循环与各种类型反应堆系统耦合时的热力循环效率与特性.结果表明,SCO2作为循环工质材料最适合在气冷快堆与液态金属快堆(钠冷快堆和铅冷快堆)中使用,具有热效率和铀资源利用率高等优势.The supercritical carbon dioxide(S-CO2)is considered as a potential working medium for the commercial nuclear reactor system and three types of Gen IV fast reactors.Engineering equation solver(EES)was introduced to set up a model for SCO2 Brayton cycle,and a detailed modeling for the significant components,such as heat exchanger,turbine and compressor,was carried out.After the analysis of thermal efficiency of the S-CO2 Brayton cycle system,results were compared with common mediums used in current nuclear industry,which shows the S-CO2 using as working medium has the highest thermal efficiency under the specific temperature.Meanwhile,thermal efficiencies and characteristics of the S-CO2 Brayton cycle system,coupling with various types of reactor systems,were analyzed.Preliminary analysis showed that S-CO2,using as cycle working fluid material,was most suitable for the gas-cooled fast reactor and the liquid metal-cooled fast reactor(the sodium-cooled fast reactor and the lead-cooled fast reactor),with the advantage of high thermal efficiency and high utilization of uranium resources.教育部重点实验室开发基金(ARES201402