粘土空心砖的热物理性能分析

本文提出热物理性能应作为粘土空心砖的主要性能指标，并对粘土空心砖的传热过程和热导率进行了分析。     

高导热碳/碳复合材料的制备

以中间相沥青和中间相沥青基碳纤维为原料, 采用碳布热压法、液相浸渍法制备了二维和三维高导热碳/碳复合材料, 且所制得复合材料的热导率分别高达443和340 W/(m·K). 依据碳/碳复合材料的热导率模型, 分析了不同结构特征参数对材料热导率的影响. 结果表明, 基体碳热导率、孔隙率以及界面相厚度均会在一定程度上影响材料的导热性能.     

TiC含量对AlN-TiC复相材料导热性能的影响

采用热压烧结工艺制备了AlN-TiC复相材料。通过激光导热仪,研究了TiC含量对材料导热性能的影响。结果表明:随着TiC的质量分数的增加,复相材料的热导率逐渐下降,当TiC的质量分数增至50t%时,热导率由102.9 W/(m.K)下降到46.6 W/(m.K),并对A1N-TiC的相组成和显微结构进行了观察分析。     

Thermal conductivity of nanoscale thin nickel films

The inhomogeneous non-equilibrium molecular dynamics (NEMD) scheme is applied to model phonon heat conduction in thin nickel films. The electronic contribution to the thermal conductivity of the film is deduced from the electrical conductivity through the use of the Wiedemann-Franz law. At the average temperature of T=300 K, which is lower than the Debye temperature ΘD=450 K, the results show that in a film thickness range of about 1?11 nm, the calculated cross-plane thermal conductivity decreases almost linearly with the decreasing film thickness, exhibiting a remarkable reduction compared with the bulk value. The electrical and thermal conductivities are anisotropic in thin nickel films for the thickness under about 10 nm. The phonon mean free path is estimated and the size effect on the thermal conductivity is attributed to the reduction of the phonon mean free path according to the kinetic theory.     

液体混合物热导率的测量及其数据的关联

在恒温条件下，使用由程序控制的量热器测量液体混合物的热导率．这种方法不仅可测低热导率的有机溶液，而且可测高热导率的水溶液．实验中测了八个双元体系，五个三元体系．同时提出了一个计算液体混合物热导率的方法．     

炭砖炉缸侧壁异常侵蚀诊断研究

利用炭砖炉缸炉底侵蚀计算模型,结合炉缸侧壁填料及耐火材料导热系数的化验结果,对某钢厂高炉炉缸异常侵蚀进行了诊断和模拟研究。得出,由于炉缸填料导热系数过低,导致开炉后陶瓷杯侵蚀过快,陶瓷杯基体被侵蚀光后,碳砖热面温度达到其脆化温度,且冷热面温差较大时,导致环裂;风口漏水使锌碱金属及渣铁渗入继续加剧了环裂;炉缸侧壁窜气使靠近冷面的电偶异常升温;环缝分布在距碳砖冷面300~550 mm范围,炉缸形成较明显的"象脚状"侵蚀,碳砖最薄剩余厚度为644 mm。通过诊断和模拟试验,采取了灌浆、加强风口漏水巡检、改换长风口等有效护炉措施,使得电偶温度控制在低于历史最高值的情况下,保持高炉正常运行。     

轻型漂珠保温砖的研制

粉煤灰漂珠作为一种新兴多功能材料,由于它具有轻质、绝热、耐酸碱、无毒、不燃烧、无臭味等特点,将之用作生产轻质保温材料首选材料,并探索出一条合理的生产工艺路线,为粉煤灰的综合利用开辟了一条新途径,对窑炉工业的发展将产生积极的推动作用;生产的轻型漂珠保温砖的耐火度为1100~1300℃,最佳使用温度为400~1150℃,导热系数为0.105~0.127W(m.K)。     

耐火保温材料导热系数的测定

在中华人民共和国黑色冶金行业标准YB/T 059-91的基础上,设计并做出了测量耐火保温材料导热系数的实验仪器.阐述了此仪器的实验装置、测量原理及其测试方法、实验结果等.通过测量已知导热系数的碳化硅砖的导热系数,得其误差小于8%;通过对同一试样的两个小试样进行平行测量,得其相对偏差小于3%.     

空心玻璃微球热导率的测定

介绍了一种用探针法测定多功能材料空心玻璃微球热导率的方法。在自制的探针内设置加热电阻和测量热电偶，温度信号经８０３１单片机处理后送到４８６ＰＣ储存，通过曲线拟合计算求得热导率。     

用温—时积分法测定熔石英玻璃的导热系数

最近,我们用《温—时积分法》测定了纯度为99.95％的熔石英玻璃的常温导热系数,其准确度估计到5％,从而验证了《温—时积分法》是测定导热系数实用、可靠的新方法。     

相变蓄热材料导热系数对太阳能通风墙性能的影响

通过对相变蓄热型太阳能烟囱模型通风蓄放热变化过程的计算,分析比较不同相变蓄热墙导热系数对太阳能烟囱性能的影响.计算结果表明:吸热板最大表面温度随着相变蓄热墙导热系数的增大越接近相变蓄热墙的相变温度;蓄热阶段,入口平均风速随着相变蓄热墙导热系数的增大而减小;放热阶段,入口平均风速随着相变蓄热墙导热系数的增大反而越大;相变蓄热墙导热系数越大,蓄热型太阳能烟囱系统16 h的累计通风量越高,但在导热系数增大到0.66 W·(m·K)^-1后,再增大材料导热系数,累计通风量几乎不再增加.     

基于虚拟仪器的导热系数测量平台设计

材料的热传导行为在热能动力、冶金、化工、电子、建筑等方面受到广泛的关注,常需要能准确地测量出材料的导热系数。该文基于一维导热之上的双热流计稳态法来测量材料导热系数,通过对达到稳态之后的各通道温度的分析获得与材料导热系数相关的数据。通过LabVIEW程序设计分析仪器平台系统,计算出材料的导热系数。软硬件结合使得实际测得的材料导热系数更加准确可信,大大降低了传统方法所带来的误差。     

新型HY-MAC快速导热火道墙砖研发和应用

传统高铝制火道墙砖引起的高能耗,导致目前我国铝电解行业的发展受到严重的制约.文章以提高产能、制品质量、炉子使用寿命和降低能耗为目的,研究开发了一种新型HY-MAC快速导热火道墙砖.通过对比试验,发现这种新型墙砖在导热系数、耐压强度、抗弯曲和抗腐蚀能力等方面,比传统高铝质火道墙砖有较为显著的优势.应用此新型火道墙砖,可以减少维护成本及劳动强度,用低温、低能耗可达到高制品质量.为下游铝电解降低成本奠定了基础,取得了明显的经济效益.     

Thermal conductivity measurement of InGaAs/InGaAsP superlattice thin films

The thermal conductivities of InGaAs/ InGaAsP superlattices with different period lengths were measured from 100 to 320 K using 3ω method. In this temperature range, the thermal conductivities were found to decrease with an increase in temperature. For the period length-dependant thermal conductivity, the minimum value does exist at a certain period length, which demonstrates that at a short period length, superlattice thermal conductivity increases with a decrease in the period length. When the period is longer than a certain period length, the interface thermal resistance dominates in phonon transport. The experimental and theoretical results confirmed the previous predictions from the lattice dynamics analysis, i.e. with the increase in period length, the dominant mechanisms of phonon transport in superlattices will shift from wave mode to particle mode. This is crucial for the cutoff of the phonons and lays a sound foundation for the design of superlattice structures.     

TiB_2含量对AlN-TiB_2复合材料导热性能的影响

采用热压烧结工艺制备了AlN-TiB2复合材料。通过激光导热仪,研究了TiB2含量对材料导热性能的影响。结果表明：随着TiB2含量的增加,复合材料的热导率逐渐下降,当TiB2含量增至50wt%时,热导率由102.9W.m-1.K-1下降到36.6W.m-1.K-1,并对A1N-TiB2的相组成和显微结构进行了观察分析。     

W9M03Cr4V材料的低温热导率测量

通过试验测定了W9M03Cr4V材料在80K-300K的低温热导率，冷却介质采用液氮，试验采用稳态法。并使用中国科学院理化技术研究所的“金属材料低温热导测试装置”。该试验数据精确度高。为高速钢刀具深冷处理的计算机模拟提供了必要的数据，同时填补了该材料低温参数的国内空白。     

用熔冰法测量不良导热体的热导率

透过不良导热体的热量可通过其熔解冰块的质量测出,由此设计出一种新方法来测定不良导热体的热导率。     

Finite Difference Approach for Estimating the Thermal Conductivity by 6-point Crank-Nicolson Scheme

Introduction Inengineeringthermo physicsandpowerengineering fields,thethermalphysicalparametersareverycriticalfor calculationanddesign.Thephysicalparametersofmaterial areusuallydeterminedbyexperiments.Alongwiththe academicachievementsofrelatedfields,thestudyon materialthermalparametershasfocusedontheoretical methodsinadditiontotheexperimentalmeasurement.Fromthepointofviewofheattransfer,it srelatedtothe InverseHeatConductionProblem(IHCP)andhasbeena topicwhichattractedwideresearchinterests.M…     

Effects of Carbon Content and Solidification Rate on the Thermal Conductivity of Grey Cast Iron

The thermal conductivity/diffusivity of pearlitic grey irons with various carbon contents was investigated by the laser flash method. The materials were cast in controlled thermal environments producing three dissimilar cooling rates. The cooling rates together with the carbon content largely influence the thermal conductivity of grey iron. Linear relationships exist between the thermal conductivity and the carbon content, the carbon equivalent, and the fraction of the former primary solidified austenite transformed into pearlite. The results show that the optimal thermal transport properties are obtained at medium cooling rates. Equations are given for the thermal conductivity of pearlite, solidified as pre-eutectic austenite, and the eutectic of grey iron. The thermal conductivity of pearlitic grey iron is modelled at both room temperature and elevated temperatures with good accuracy.     

脱硫建筑石膏空心砌块及其热工性能的研究

利用脱硫建筑石膏代替天然建筑石膏生产石膏空心砌块,并对其砌筑墙体的保温性能进行了测试.研究表明,生产的脱硫建筑石膏空心砌块断裂荷载达到4.50 kN,其墙体的实测传热系数为1.06 W/(m2·K),保温性能明显优于烧结多孔砖和普通混凝土空心砌块.