科创中国

南水北调中线天津干线采用全箱涵无压接有压自流输水方案,调节池是实现无压流和有压流平稳过渡的重要控制性建筑物.经多方案比选,斜坡式调节池结构安全稳定,水力条件好,实现了上下游流态的平稳衔接.

Traditional model for calculating performance parameters of a fix-pad journal bearing leads to heavy workload,complicated and changeable formulae as it requires deriving various geometric formulae with different bearing types such as circular journal bearing,dislocated bearing and elliptic bearing.Considering different pad preload ratios for non-standard bearing,traditional model not only becomes more complicated but also reduces scalability and promotion of the calculation programs.For the complexly case of traditional model while dealing with various fix-pad journal bearings,unified coordinate system model for performance calculation of fix-pad journal bearing is presented in the paper.A unified coordinate system with the bearing center at the origin is established,and the eccentricity ratio and attitude angle of axis relative to each pad are calculated through the coordinates of journal center and each pad center.Geometric description of fix-pad journal bearing is unified in this model,which can be used for both various standard bearing and non-standard bearing with different pad preload ratios.Validity of this model is verified with an elliptical bearing.Performance of a non-standard four-leaf bearing with different pad preload ratios is calculated based on this model.The calculation result shows that increasing preload ratio of the pad 1 and keeping that of the left three pads constant improves bearing capacity,stiffness and damping coefficients.This research presents a unified coordinate system model unifies performance calculation of fix-pad journal bearings and studied a non-standard four-leaf bearing with different pad preload ratios,the research conclusions provides new methods for performance calculation of fix-pad journal bearings.

以阿克苏地区水文地质普查报告和温宿县地下水资源开发利用规划等相关资料及实地调查、测量等工作取得的原始资料为基础,说明了研究区的水文地质条件,确定计算研究区的地下水水量均衡方程和计算参数,利用搜集到相关数据进行地下水水量均衡计算,计算结果表明:该区地下水补给量略大于排泄量,主要的补给源为河流渠系的入渗和山前侧向人渗;主要排泄量为向下游的排泄量和潜入蒸发量.

考虑非线性吸附平衡关系、吸附剂内外传质阻力以及表面扩散系数为固相浓度的函数的基础上,建立间歇搅拌吸附槽中大孔吸附树脂吸附DMF的表面扩散模型,由于该模型为高度非线性的偏微分方程,只能采用数值方法求解.因此,对MATLAB中pdepe函数进行适当修改,并针对吸附表面扩散模型边界条件的特点建立边界条件函数,使其可应用于具有Robin边界条件的吸附数学模型的求解.当间歇搅拌吸附槽的搅拌速度为100rpm,温度为298K条件下,应用修改后的pdepe函数结合优化工具箱求解吸附表面扩散模型,获得有效表面扩散系数Dn=1.04*10^-10m^2/s和液相传质系数Kp=9.60*10^-6m/s;模型计算得到的吸附速率与实验测定结果的均方根误差为ε=0.008.结果表明:DMF在NKA-Ⅱ树脂上吸附动力学过程与吸附表面扩散模型吻合良好,应用修改后的pdepe函数可方便地求解具有Robin边界条件的表面吸附模型,结果准确可靠.

在洪水计算中,河道糙率是一个重要参数.通过对河道糙率影响因素分析,利用李营水文试验站的实测资料,阐述了河道糙率的计算方法.糙率确定时影响因素较多,不同的水深、植被、河床等因素,都会对糙率值产生影响.在实际计算中,大部分设计河段没有实测糙率资料,在实际应用中要借助相似河道的参数代替,对计算精度影响较大.收集了国内外不同情况下的河道糙率实验资料,可供河道糙率计算参考.