共查询到19条相似文献,搜索用时 156 毫秒
1.
从P-R状态方程出发,用Newton迭代法求出真实气体的摩尔体积,然后用数值方法求P-R方程的过剩焓对温度的偏导数,从而得到真实气体的剩余等压热容,由此计算出真实气体的等压热容。给出了Newton迭代方法和偏导数数值解法。编写求解程序,实际计算了一些烃类物质的等压热容。结果表明计算的误差可满足工程应用。 相似文献
2.
本文对有固相碳的碳-氢-氧-硫-惰气(CHOSI)非均相系统,提出了一种计算气相平衡组成的迭代算法。将化学平衡方程和物料衡算方程进行数学变换,用牛顿迭代法求解二元三次方程,从而达到快速、准确地计算CHOSI非均相系统的平衡组成。该算法能计算200~1800℃,0.1~10.0MPa和不同原子比下,有固相碳的化学平衡组成。 相似文献
3.
注射充模过程的压力求解方法及其比较 总被引:1,自引:3,他引:1
提出了一个LU局部分解方法来求解注射充模过程的压力方程,并与其他迭代方法进行了比较。LU局部分解法是当矩阵在逐渐变大时,保留已经分解的部分,只对新增加的部分进行分解,因此相当于只对最后的稀疏矩阵进行了分解。计算表明,LU局部分解法比预条件共轭梯度法快大约1个量级,而预条件共轭梯度方法又比超松弛迭代法快大约1个量级。 相似文献
4.
5.
6.
7.
8.
给出了4种热力学状态方程求摩尔体积的求解算法,讨论了这些算法的数学原理、收敛特性和具体迭代格式,并以Peng-Robinson方程为例进行了具体计算和比较。主要结论:简单迭代法收敛稳定但收敛速度慢;Aitken-Steffensen方法简单、稳定且和Newton方法具有相同的二阶收敛;Newton方法速度较快但算法比较复杂,需要计算导数;加速Newton方法速度最快但最复杂。推荐优先使用Aitken-Steffensen方法,其次是加速Newton方法。 相似文献
9.
马丁-侯(M-H)方程在计算液相体积、高压气体的焓熵、以及极性液体的焓熵方面有很好的精度优势,但对其中B4参数的求取需要迭代计算而影响了M-H方程在工程计算中的应用.今首先将M-H方程的m参数和物质的偏心因子ω关联起来,在保持M-H方程计算气相体积精度的条件下得到计算m的普适方法.然后提出参数B4与物质的对比温度Tr以... 相似文献
10.
11.
Peter Kühl Moritz DiehlTom Kraus Johannes P. SchlöderHans Georg Bock 《Computers & Chemical Engineering》2011,35(1):71-83
A moving horizon estimation (MHE) approach to simultaneously estimate states and parameters is revisited. Two different noise models are considered, one with measurement noise and one with additional state noise. The contribution of this article is twofold. First, we transfer the real-time iteration approach, developed in Diehl et al. (2002) for nonlinear model predictive control, to the MHE approach to render it real-time feasible. The scheme reduces the computational burden to one iteration per measurement sample and separates each iteration into a preparation and an estimation phase. This drastically reduces the time between measurements and computed estimates. Secondly, we derive a numerically efficient arrival cost update scheme based on one single QR-factorization. The MHE algorithm is demonstrated on two chemical engineering problems, a thermally coupled distillation column and the Tennessee Eastman benchmark problem, and compared against an Extended Kalman Filter. The CPU times demonstrate the real-time applicability of the suggested approach. 相似文献
12.
Eric Favre Vronique Falk Christine Roizard Eric Schaer 《Education for Chemical Engineers》2008,3(1):e22-e27
Teaching chemical engineering has always been faced with a dilemma: either keep in touch with industry needs or incorporate new scientific concepts into the curriculum. In this paper, a short historical analysis of the evolution of chemical engineering teaching is presented and the recent trends of the two previous facets (industry and science) are briefly reviewed. The process vs product engineering concept is proposed as one of the means to achieve a better alignment between the curriculum and industry needs. A chemical engineering teaching framework, based in part on a product and a process oriented component, which has been in place in our department 5 years ago, is described and discussed. The concept of sustainable chemistry, including process and product considerations, which can be seen as the next frontier in chemical engineering education, is finally analysed from the education point of view. 相似文献
13.
Phase equilibria of binary mixtures of hydrocarbons . Seven methods for the calculation of phase equilibria of binary mixtures from vapour pressure data have been programmed. Results of computations for hydrocarbon mixtures are discussed, using just one regression method and six iteration procedures based on the Gibbs-Duhem equation. The iteration methods use the approximation of experimental vapour pressure data, e. g. by means of cubic splines or orthogonal polynomials. The practical application of the results, e.g. for the simulation of separation columns, requires the regression of the vapour mole fractions following the iterative solution of the Gibbs-Duhem equation. 相似文献
14.
Many models derived from first principles contain more parameters than can be reliably estimated from data. Selecting a subset of the parameters for estimation is one common approach to deal with this problem. One popular method sequentially selects parameters based on orthogonalization of the sensitivity vectors; however, it has the drawback that only one parameter is added at each step of the iteration and that no correlations of not yet chosen parameters can be taken into account. To address this drawback, a generalization of the parameter set selection procedure based on orthogonalization is presented in this work. The procedure can add any number of parameters at each iteration such that correlations among the parameters that will be added to the set of estimated parameters can be taken into account. It is shown that two existing parameter set selection techniques form special cases of the presented method. © 2011 American Institute of Chemical Engineers AIChE J, 2012 相似文献
15.
16.
17.
18.
分子科学与工程专业以化学、工程学为基础,探索化学分子机制及其在化学工程方面的应用,其中包括生物体系中化学分子机制及其工程应用。生物化学作为分子科学与工程专业的必修课之一,对于提高学生在生物化学方面的基础知识非常重要,同时有助于学生深入了解生物化学反应机制和应用。我们针对分子科学与工程专业的特点和培养目标,结合生物化学的课程特点,阐述了针对该专业的生物化学课堂教学体会,从提高学生兴趣、加强重点内容讲解、联系课堂教学和科研实际、紧随生物化学最新研究进展等几个方面做了较为详细的探索和总结。 相似文献