The optimal configuration of reciprocating engine based on maximum entransy loss

A class of two-heat-reservoir heat engine model with heat leakage,finite heat capacity high-temperature source and infinite heat capacity low-temperature heat sink,is researched with the finite-time thermodynamic theory and the entransy theory.The optimal configuration based on the minimum entropy generation and the maximum entransy loss under the given cycle is searched,which are compared with the optimal configuration based on the maximum output work,and all the heat transfer in the model is assumed to obey the Newton’s law.The results show that,for the infinite heat capacity high-temperature source,the optimal configuration does not change whether heat leakage exists or not;however,for the finite hightemperature reservoir,the optimal configuration is different among which based on the minimum entropy generation,the maximum entransy loss,and the maximum output work when the heat leakage exists.     

Acid condensation and heat transfer characteristics on H-type fin surface with bleeding dimples and longitudinal vortex generators

Acid condensation rate is an important factor denoting the acid corrosion, and the reduction of the acid condensation can significantly relieve the acid corrosive effect on the wall surface and improve the security of the equipments. In this study, the characteristics of both heat transfer and acid condensation of the finned tube in heat exchanger were numerically studied. In the numerical model, we simulated the acid condensation by considering the vapor-liquid equilibrium effect and multi-component diffusion effect. Based on the H-type finned oval tube, we proposed three novel types of fins to both enhance the heat transfer and reduce the acid condensation. The parametric effects of gas temperature, acid vapor concentration, water vapor concentration, and Reynolds number were investi- gated on different fin structures. The results show that the tube bank with the new structured fins can improve the performance on both heat transfer and acid anticondensation.     

Crystal structures,antibacterial activity and thermal decomposition kinetics of lanthanide complexes with 4-chloro-2-methoxybenzoic acid and 1,10-phenanthroline

A series of lanthanide complexes [Ln(4-Cl-2-MOBA)3phen]2(Ln=Sm(1), Nd(2), Ho(3), Eu(4), Dy(5), and Tb(6); 4-Cl-2-MOBA=4-chloro-2-methoxybenzoate, phen=1,10-phenanthroline) were synthesized and characterized. The single-crystal X-ray diffraction demonstrates that 1–3 are isomorphous, which present dimeric structures with four 4-Cl-2-MOBA anions function as bridging ligands. Complexes 1 and 4–6 display their characteristic luminescence emission bands of central Ln3?ions. The heat capacities, the thermodynamic functions and the thermogravimetry–Fourier transform infrared spectra of gaseous products of complexes 1–6 were investigated.Their non-isothermal kinetics of the second decomposition stage was studied by the integral isoconversional non-linear method and Stark method. Furthermore, 1–6 exhibited excellent antibacterial activity against Candida albicans,Escherichia coli and Staphylococcus aureu.     

最大熵谱的振幅谱和相位谱计算

最大熵谱估计是高分辩率的现代谱估计方法,它有着传统谱估计方法不可比拟的优越性。但最大熵谱估计中振幅失真,使它的应用受到很大限制。本文着重介绍了运用准确最小二乘法计算最大熵谱信号的最佳频率成分,再利用三角函数回归法求取原始信号的真实振幅谱和相位谱。对最佳频率成分位置的确定,采用-种既简便又准确的方法,比前人的方法更为优越。     

论煤系地层烃产物初次运移的相态界线

确定源岩油相、气相、水溶相各种相态的初次运移界线是定量计算油气资源及油气评价的核心问题之一。本文以川西北T3X煤系地层为对象,首先通过对热模拟资料的重新整理,得到一个“理论揭煤”的各热模拟阶段中产物的全组分数据,并用PR状态方程计算出相图;第二,考虑到孔隙水的溶解作用,在静态上分别对煤层、泥岩成烃产物的相态进行了计算。计算表明,腐植型母质,其生成时的初始产物全为气相、煤系泥岩中,由于孔隙水大量存在,R。小于1.14%以前烃体系是油相,之后才会出现气相;煤层始终难有油相存在;第三,在含煤层5%的剖面中,R。小于0.95%以前只出现油相,大于此值之后具有气相。此外,通过I型母质热模拟资料,据油气比大小,对某生烃初始产物相态界线进行了初步划分。     

热歧化反应法在Al_2O_3陶瓷表面沉积钛的动力学研究

利用融盐热歧化反应进行了氧化铝陶瓷材料表面沉积钛金属的动力学研究．结果表明,氧化铝陶瓷表面钛膜的厚度随着反应温度和反应时间的增加而增加,膜的厚度与反应时间成很好的线性关系,沉积速率与融盐中Ｋ２ＴｉＦ６的起始浓度成线性关系,沉积过程是受融盐与氧化铝陶瓷基体之间的界面反应控制．其沉积过程的活化能为１３７．６ＫＪ／ｍｏｌ．     

矩形微通道中压力驱动流体的热传导数值模拟

本文利用基于控制体积法的SIMPLEC算法对微通道中的压力驱动流体的热传导问题进行了数值模拟．首先通过Poisson-Boltzmann方程求解微通道中的电荷密度,然后通过包含了外加电场力的Navier-Stokes方程对电粘现象进行深入的研究．上述的方程通过与温度相关的介电常数,粘性系数以及热导率和能量方进行程耦合求解,进而研究了微管道的特征尺度和宽高比对Nusselt数（Nu）以及Poiseuille数（Po）的影响,研究发现,电粘效应和流体的热物理属性对于微管道中的Po数和Nu数有着非常显著的影响,尤其是热物理属性更为重要。     

西南郊污水处理厂DE型氧化沟工艺设计探讨

本文以西安市西南郊污水处理厂二级生化处理的DE型氧化沟工艺设计为例,参照德国和国内现有的设计规范,对氧化沟系统的容积、需氧量、构筑物的水力计算及主要设备选型进行了详细分析与探讨,其结论可作为工程技术人员在设计污水厂时参考。     

大型速冻设备高效蒸发器传热技术研究

对于大型架构下的速冻设备,采纳不同型式,蒸发器特有的传热系数都会凸显差异。本文探析了高效情形下的这类蒸发器,辨识管路排列、管径尺寸数值、翅片各类形态。不结霜情形下,传热特性最为优良的蒸发器应当配有整体框架内的波纹翅片。对于这类器材,设定传热测验以便获得吻合的系数数值。     

热力管道跨路桥架加固有限元受力分析

热力管道跨路桥架一般采用钢结构桁架,其特点是跨度大,两个方向刚度差别大,目前桥架所属公司经常不把桥架作为热力管道桥架单独使用。如果在已有非热力管道的跨路桥架上面再添加热力管道,合理的计算热力管道荷载,对比加载前后桁架各杆件的受力情况,成为跨路桥架加固方案的关键。本文详细介绍了热力管道的荷载特点及计算,通过对实际工程进行热力管道加载前后有限元模拟受力分析对比,为以后的类似工程提供参考。